77 FR 64508 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-22

... Activities; Submission to OMB for Review and Approval; Comment Request; NESHAP for Mercury (Renewal) AGENCY... further information about the electronic docket, go to www.regulations.gov . Title: NESHAP for Mercury (40... process mercury ore to recover mercury Estimated Number of Respondents: 107. Frequency of Response...

40 CFR 63.11645 - What are my mercury emission standards?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 14 2011-07-01 2011-07-01 false What are my mercury emission standards... Area Source Category Standards and Compliance Requirements § 63.11645 What are my mercury emission standards? (a) For existing ore pretreatment processes, you must emit no more than 127 pounds of mercury per...

40 CFR 63.11645 - What are my mercury emission standards?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 15 2012-07-01 2012-07-01 false What are my mercury emission standards... Area Source Category Standards and Compliance Requirements § 63.11645 What are my mercury emission standards? (a) For existing ore pretreatment processes, you must emit no more than 127 pounds of mercury per...

40 CFR 63.11645 - What are my mercury emission standards?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 15 2014-07-01 2014-07-01 false What are my mercury emission standards... Area Source Category Standards and Compliance Requirements § 63.11645 What are my mercury emission standards? (a) For existing ore pretreatment processes, you must emit no more than 127 pounds of mercury per...

40 CFR 63.11645 - What are my mercury emission standards?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 15 2013-07-01 2013-07-01 false What are my mercury emission standards... Area Source Category Standards and Compliance Requirements § 63.11645 What are my mercury emission standards? (a) For existing ore pretreatment processes, you must emit no more than 127 pounds of mercury per...

The southwestern alaska mercury belt and its relationship to the circum-pacific metallogenic mercury province

USGS Publications Warehouse

Gray, J.E.; Gent, C.A.; Snee, L.W.

2000-01-01

A belt of small but numerous mercury deposits extends for about 500 km in the Kuskokwim River region of southwestern Alaska. The southwestern Alaska mercury belt is part of widespread mercury deposits of the circumPacific region that are similar to other mercury deposits throughout the world because they are epithermal with formation temperatures of about 200??C, the ore is dominantly cinnabar with Hg-Sb-As??Au geochemistry, and mineralized forms include vein, vein breccias, stockworks, replacements, and disseminations. The southwestern Alaska mercury belt has produced about 1,400 t of mercury, which is small on an international scale. However, additional mercury deposits are likely to be discovered because the terrain is topographically low with significant vegetation cover. Anomalous concentrations of gold in cinnabar ore suggest that gold deposits are possible in higher temperature environments below some of the Alaska mercury deposits. We correlate mineralization of the southwestern Alaska mercury deposits with Late Cretaceous and early Tertiary igneous activity. Our 40Ar/39Ar ages of 70??3 Ma from hydrothermal sericites in the mercury deposits indicate a temporal association of igneous activity and mineralization. Furthermore, we suggest that our geological and geochemical data from the mercury deposits indicate that ore fluids were generated primarily in surrounding sedimentary wall rocks when they were cut by Late Cretaceous and early Tertiary intrusions. In our ore genesis model, igneous activity provided the heat to initiate dehydration reactions and expel fluids from hydrous minerals and formational waters in the surrounding sedimentary wall rocks, causing thermal convection and hydrothermal fluid flow through permeable rocks and along fractures and faults. Our isotopic data from sulfide and alteration minerals of the mercury deposits indicate that ore fluids were derived from multiple sources, with most ore fluids originating from the sedimentary wall rocks.

Isotope geochemistry of mercury in source rocks, mineral deposits and spring deposits of the California Coast Ranges, USA

NASA Astrophysics Data System (ADS)

Smith, Christopher N.; Kesler, Stephen E.; Blum, Joel D.; Rytuba, James J.

2008-05-01

We present here the first study of the isotopic composition of mercury in rocks, ore deposits, and active spring deposits from the California Coast Ranges, a part of Earth's crust with unusually extensive evidence of mercury mobility and enrichment. The Franciscan Complex and Great Valley Sequence, which form the bedrock in the California Coast Ranges, are intruded and overlain by Tertiary volcanic rocks including the Clear Lake Volcanic Sequence. These rocks contain two types of mercury deposits, hot-spring deposits that form at shallow depths (< 300 m) and silica-carbonate deposits that extend to depths of 1000 m. Active springs and geothermal areas continue to precipitate Hg and Au and are modern analogues to the fossil hydrothermal systems preserved in the ore deposits. The Franciscan Complex and Great Valley Sequence contain clastic sedimentary rocks with higher concentrations of mercury than volcanic rocks of the Clear Lake Volcanic Field. Mean mercury isotopic compositions ( δ202Hg) for all three rock units are similar, although the range of values in Franciscan Complex rocks is greater than in either Great Valley or Clear Lake rocks. Hot spring and silica-carbonate mercury deposits have similar average mercury isotopic compositions that are indistinguishable from averages for the three rock units, although δ202Hg values for the mercury deposits have a greater variance than the country rocks. Precipitates from spring and geothermal waters in the area have similarly large variance and a mean δ202Hg value that is significantly lower than the ore deposits and rocks. These observations indicate that there is little or no isotopic fractionation (< ± 0.5‰) during release of mercury from its source rocks into hydrothermal solutions. Isotopic fractionation does appear to take place during transport and concentration of mercury in deposits, however, especially in their uppermost parts. Boiling of hydrothermal fluids, separation of a mercury-bearing CO 2 vapor or reduction and volatilization of Hg (0) in the near-surface environment are likely the most important processes causing the observed Hg isotope fractionation. This should result in the release of mercury with low δ202Hg values into the atmosphere from the top of these hydrothermal systems. Estimates of mass balance suggest that residual Hg reservoirs are not measurably enriched in heavy Hg isotopes as a result of this process because only a small amount of Hg (< 4%) leaves actively ore-forming systems.

Isotope geochemistry of mercury in source rocks, mineral deposits and spring deposits of the California Coast Ranges, USA

USGS Publications Warehouse

Smith, C.N.; Kesler, S.E.; Blum, J.D.; Rytuba, J.J.

2008-01-01

We present here the first study of the isotopic composition of mercury in rocks, ore deposits, and active spring deposits from the California Coast Ranges, a part of Earth's crust with unusually extensive evidence of mercury mobility and enrichment. The Franciscan Complex and Great Valley Sequence, which form the bedrock in the California Coast Ranges, are intruded and overlain by Tertiary volcanic rocks including the Clear Lake Volcanic Sequence. These rocks contain two types of mercury deposits, hot-spring deposits that form at shallow depths (< 300??m) and silica-carbonate deposits that extend to depths of 1000??m. Active springs and geothermal areas continue to precipitate Hg and Au and are modern analogues to the fossil hydrothermal systems preserved in the ore deposits. The Franciscan Complex and Great Valley Sequence contain clastic sedimentary rocks with higher concentrations of mercury than volcanic rocks of the Clear Lake Volcanic Field. Mean mercury isotopic compositions (??202Hg) for all three rock units are similar, although the range of values in Franciscan Complex rocks is greater than in either Great Valley or Clear Lake rocks. Hot spring and silica-carbonate mercury deposits have similar average mercury isotopic compositions that are indistinguishable from averages for the three rock units, although ??202Hg values for the mercury deposits have a greater variance than the country rocks. Precipitates from spring and geothermal waters in the area have similarly large variance and a mean ??202Hg value that is significantly lower than the ore deposits and rocks. These observations indicate that there is little or no isotopic fractionation (< ?? 0.5???) during release of mercury from its source rocks into hydrothermal solutions. Isotopic fractionation does appear to take place during transport and concentration of mercury in deposits, however, especially in their uppermost parts. Boiling of hydrothermal fluids, separation of a mercury-bearing CO2 vapor or reduction and volatilization of Hg(0) in the near-surface environment are likely the most important processes causing the observed Hg isotope fractionation. This should result in the release of mercury with low ??202Hg values into the atmosphere from the top of these hydrothermal systems. Estimates of mass balance suggest that residual Hg reservoirs are not measurably enriched in heavy Hg isotopes as a result of this process because only a small amount of Hg (< 4%) leaves actively ore-forming systems. ?? 2008 Elsevier B.V. All rights reserved.

Investigation of Mercury Reduction in Gold Stripping Process at Elevated Temperature

NASA Astrophysics Data System (ADS)

Pramudya, Irawan

Mercury is present in many gold ores. By processing these ores, there is a potential of emitting mercury to the environment. Carbon regeneration kiln stacks have been observed as one of the primary source of mercury emission into the atmosphere. Before it is recycled back into the carbon in leach (CIL) or carbon in columns (CIC), carbon used in the gold extraction process needs to be reactivated thermally. Emission of mercury can be minimized by keeping the mercury left in the carbon low before it goes to the carbon regeneration kiln stacks. The objective of this study is establishing the optimum elution conditions of mercury cyanide from loaded carbon (which includes the eluent, concentration, temperature and elution time) with respect to gold stripping. Several methods such as acid washing (UNR-100, HCl or ethanol/UNR-100) were investigated prior to the stripping process. Furthermore, conventional pressurized Zadra and modified Zadra were also studied with regards to mercury concentration in the solution and vapor state as well as maximizing the gold stripping from industrial loaded carbon. 7% UNR-100 acid washing of loaded carbon at 80°C was able to wash out approximately 90% of mercury while maintaining the gold adsorption on the carbon (selective washing). The addition of alcohol in the UNR-100 acid washing solution was able to enhance mercury washing from 90% to 97%. Furthermore, mercury stripping using conventional pressurized (cyanide-alkaline) Zadra was best performed at 80°C (minimal amount of mercury reduced and volatilized) whereas using the same process only 40% of gold was stripped, which makes this process not viable. When alcohol was added to the stripping solution, at 80°C, 95% of gold was detected in the solution while keeping the reduction and volatilization of mercury low. The outcome of this study provides a better understanding of mercury behavior during the acid washing and stripping processes so that the risk of mercury exposure and contamination can be minimized while maximizing the gold overall recovery.

[Characteristic of Mercury Emissions and Mass Balance of the Typical Iron and Steel Industry].

PubMed

Zhang, Ya-hui; Zhang, Cheng; Wang, Ding-yong; Luo, Cheng-zhong; Yang, Xi; Xu, Feng

2015-12-01

To preliminarily discuss the mercury emission characteristics and its mass balance in each process of the iron and steel production, a typical iron and steel enterprise was chosen to study the total mercury in all employed materials and estimate the input and output of mercury during the steel production process. The results showed that the mercury concentrations of input materials in each technology ranged 2.93-159.11 µg · kg⁻¹ with the highest level observed in ore used in blast furnace, followed by coal of sintering and blast furnace. The mercury concentrations of output materials ranged 3.09-18.13 µg · kg⁻¹ and the mercury concentration of dust was the highest, followed by converter slag. The mercury input and the output in the coking plant were 1346.74 g · d⁻¹ ± 36.95 g · d⁻¹ and 177.42 g · d⁻¹ ± 13.73 g · d⁻¹, respectively. In coking process, mercury mainly came from the burning of coking coal. The sintering process was the biggest contributor for mercury input during the iron and steel production with the mercury input of 1075. 27 g · d⁻¹ ± 60.89 g · d⁻¹ accounting for 68.06% of the total mercury input during this production process, and the ore powder was considered as the main mercury source. For the solid output material, the output in the sintering process was 14.15 g · d⁻¹ ± 0.38 g · d⁻¹, accounting for 22.61% of the total solid output. The mercury emission amount from this studied iron and steel enterprise was estimated to be 553.83 kg in 2013 with the emission factor of 0.092 g · t⁻¹ steel production. Thus, to control the mercury emissions, iron and steel enterprises should combine with production practice, further reduce energy consumption of coking and sintering, or improve the quality of raw materials and reduce the input of mercury.

Mineral resource of the month: mercury

USGS Publications Warehouse

Brooks, William E.

2006-01-01

The ore of mercury, cinnabar, is soft and dark red, and native mercury is one of a few metals that is liquid at room temperatures. Cinnabar from Almaden, Spain, the world’s oldest producing mercury mine, was used during Roman times, and the chemical symbol for mercury (Hg) is from "hydrargyrum," from the Greek word meaning liquid silver. Cinnabar and mercury are associated with some hydrothermal mineral deposits and occur in fine-grained or sedimentary and volcanic rocks near hot springs or volcanic centers. Mercury may be recovered as a byproduct of processing copper, gold, lead-zinc or silver.

MERCURY IN STAMP SAND DISCHARGES: IMPLICATIONS FOR LAKE SUPERIOR MERCURY CYCLING

EPA Science Inventory

Approximately a half billion tons of waste rock from the extraction of native copper and silver ores was discharged into the Lake Superior basin. Stamping was the method of choice to recover these metals from the surrounding poor rock. This process created large amounts of extre...

Genesis of Silica-Carbonate Type Mercury Ore Deposits in Coast Range California from Mantle Derived Fluids

NASA Astrophysics Data System (ADS)

Rytuba, J. J.; Kirby, S. H.; Kellner, C. R.

2016-12-01

In the Coast Range of California 51 major mercury (Hg) deposits and numerous smaller Hg occurrences began forming when subduction transitioned to the transpressive continental-transform kinematics of the San Andreas Fault System. The Hg deposits become progressively younger to the north reflecting the change in tectonic environment as the Mendocino Triple Junction moved 400 km northward since the Miocene to its present location in northern California. The silica-carbonate mercury deposits are vein and replacement ore bodies developed within and adjacent to serpentinite that was emplaced along regional faults and altered to an assemblage of silica and carbonate minerals. The initial alteration process consists of the addition of carbonate to the serpentinite followed by introduction of silica into the central core. The peripheral zone of calcite-dolomite veining may extend for several kilometers outward from a mercury deposit. The large Hg deposits formed in structural traps, such as antiformal structures, and the ores locally extend into adjacent clastic metasedimentary rocks. The mineralogy of the primary ores is simple consisting of cinnabar, metacinnabar and elemental Hg. The deposits formed from low-temperature, <120oC, CO2-CH4-H2S-rich fluids. The hydrothermal fluids are consistent with a mantle source water derived from the former forearc during subduction and after the transition to transpressive continental-transform boundary as proposed by Kirby et al. (EPS, 2014). Some of the silica-carbonate Hg deposits are overprinted by younger hot spring type Hg mineralization associated temporally with volcanic vents. These Hg deposits have distinctly different types of alteration and geochemistry and formed in the near surface from meteoric waters.

Liquid-Oxygen-Compatible Cement for Gaskets

NASA Technical Reports Server (NTRS)

Elmore, N. L.; Neale, B. C.

1984-01-01

Fluorelastomer and metal bonded reliably by new procedure. To cure fluoroelastomer cement, metal plate/gasket assembly placed in vacuum bag evacuated to minimum vacuum of 27 inches (69 cm) of mercury. Vacuum maintained throughout heating process and until assembly returns to ambient room temperature. Used to seal gaskets and O-rings or used to splice layers of elastomer to form non-standard sized O-rings. Another possible use is to apply protective, liquid-oxygen-compatible coating to metal parts.

Mercury in the national parks

USGS Publications Warehouse

Pritz, Colleen Flanagan; Eagles-Smith, Collin A.; Krabbenhoft, David

2014-01-01

One thing is certain: Even for trained researchers, predicting mercury’s behavior in the environment is challenging. Fundamentally it is one of 98 naturally occurring elements, with natural sources, such as volcanoes, and concentrated ore deposits, such as cinnabar. Yet there are also human-caused sources, such as emissions from both coal-burning power plants and mining operations for gold and silver. There are elemental forms, inorganic or organic forms, reactive and unreactive species. Mercury is emitted, then deposited, then re-emitted—thus earning its mercurial reputation. Most importantly, however, it is ultimately transferred into food chains through processes fueled by tiny microscopic creatures: bacteria.

First discovery of high-mercury silver in ores of the Rogovik gold-silver deposit (Northeastern Russia)

NASA Astrophysics Data System (ADS)

Makshakov, A. S.; Kravtsova, R. G.; Goryachev, N. A.; Pal'yanova, G. A.; Pavlova, L. A.

2017-09-01

New data on mercurial mineralization are presented, and a detailed characteristic is given for the first discovery of mercurous silver in ores of the Rogovik gold-silver deposit (the Omsukchan trough, Northeastern Russia). It was found that native silver in the examined ores occurs as finely-dispersed inclusions in quartz filling microcracks and interstitions. It also occurs in associations with kustelite, Ag sulfosalts and selenides, selenitic acanthite, and argyrodite. The mercury admixture varies from "not detected" in the central parts of grains to 0.22-1.70 wt % along the edges, or, in independent grains, to the appearance of Ag amalgams containing 10.20-24.61 wt % of Hg. The xenomorph form of grains of 50 μm or less in size prevails. It is assumed that the appearance of mercurial mineralization is caused by the superposition of products of the young Hg-bearing Dogda-Erikit belt upon the more ancient Ag-bearing Omsukchan trough.

Mercury contamination from artisanal gold mining in Antioquia, Colombia: The world's highest per capita mercury pollution.

PubMed

Cordy, Paul; Veiga, Marcello M; Salih, Ibrahim; Al-Saadi, Sari; Console, Stephanie; Garcia, Oseas; Mesa, Luis Alberto; Velásquez-López, Patricio C; Roeser, Monika

2011-12-01

The artisanal gold mining sector in Colombia has 200,000 miners officially producing 30tonnes Au/a. In the Northeast of the Department of Antioquia, there are 17 mining towns and between 15,000 and 30,000 artisanal gold miners. Guerrillas and paramilitary activities in the rural areas of Antioquia pushed miners to bring their gold ores to the towns to be processed in Processing Centers or entables. These Centers operate in the urban areas amalgamating the whole ore, i.e. without previous concentration, and later burn gold amalgam without any filtering/condensing system. Based on mercury mass balance in 15 entables, 50% of the mercury added to small ball mills (cocos) is lost: 46% with tailings and 4% when amalgam is burned. In just 5 cities of Antioquia, with a total of 150,000 inhabitants: Segovia, Remedios, Zaragoza, El Bagre, and Nechí, there are 323 entables producing 10-20tonnes Au/a. Considering the average levels of mercury consumption estimated by mass balance and interviews of entables owners, the mercury consumed (and lost) in these 5 municipalities must be around 93tonnes/a. Urban air mercury levels range from 300ng Hg/m(3) (background) to 1million ng Hg/m(3) (inside gold shops) with 10,000ng Hg/m(3) being common in residential areas. The WHO limit for public exposure is 1000ng/m(3). The total mercury release/emissions to the Colombian environment can be as high as 150tonnes/a giving this country the shameful first position as the world's largest mercury polluter per capita from artisanal gold mining. One necessary government intervention is to cut the supply of mercury to the entables. In 2009, eleven companies in Colombia legally imported 130tonnes of metallic mercury, much of it flowing to artisanal gold mines. Entables must be removed from urban centers and technical assistance is badly needed to improve their technology and reduce emissions. Copyright © 2011 Elsevier B.V. All rights reserved.

ELEMENTAL MERCURY IN COPPER, SILVER, AND GOLD ORES: AN UNEXPECTED CONTRIBUTION TO LAKE SUPERIOR SEDIMENTS WITH GLOBAL IMPLICATIONS

EPA Science Inventory

Mercury and copper inventories are low in central Lake Superior and increase markedly towards the Keweenaw Peninsula...where copper, mercury, and silver inventories are elevated and highly correlated. High copper, silver, and mercury inventories can be traced back to shoreline st...

40 CFR 61.53 - Stack sampling.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 8 2011-07-01 2011-07-01 false Stack sampling. 61.53 Section 61.53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Mercury ore processing facility. (1) Unless a waiver of emission testing is obtained under...

40 CFR 61.53 - Stack sampling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.53 Section 61.53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Mercury ore processing facility. (1) Unless a waiver of emission testing is obtained under...

The price of gold: mercury exposure in the Amazonian rain forest.

PubMed

Branches, F J; Erickson, T B; Aks, S E; Hryhorczuk, D O

1993-01-01

Concern has surfaced over the recent discovery of human mercury exposure throughout the tropical rain forest of South America's Amazon River Basin. The probable source of mercury has been traced to gold mines located within the interior. The mining process involves the extraction of gold from ore by burning off a mercury additive, resulting in vaporization of elemental mercury into the surrounding environment. The purpose of this case series is to document mercury levels in miners and local villagers presenting with a history of exposure, or signs and symptoms consistent with mercury toxicity. Over a five year period (1986-91), the whole blood and urine mercury levels of 55 Brazilian patients demonstrating signs and symptoms consistent with mercury exposure were collected. Thirty-three (60%) of the subjects had direct occupational exposure to mercury via gold mining and refining. Whole blood mercury levels ranged from 0.4-13.0 micrograms/dL (mean 3.05 micrograms/dL). Spot urine levels ranged 0-151 micrograms/L (mean = 32.7 micrograms/L). Occupational mercury exposure is occurring in the Amazon River Basin. Interventions aimed at altering the gold mining process while protecting the workers and surrounding villagers from the source of exposure are essential. The impact of the gold mining industry on general environmental contamination has not been investigated.

Isotopic Variability of Mercury in Ore, Mine-Waste Calcine, and Leachates of Mine-Waste Calcine from Areas Mined for Mercury

PubMed Central

2009-01-01

The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that δ202Hg values relative to NIST 3133 of calcine (up to 1.52‰) in the Terlingua district, Texas, are as much as 3.24‰ heavier than cinnabar (−1.72‰) prior to retorting. In addition, δ202Hg values obtained from leachates of Terlingua district calcines are isotopically similar to, or as much as 1.17‰ heavier than associated calcines, most likely due to leaching of soluble, byproduct Hg compounds formed during ore retorting that are a minor component in the calcines. As a result of the large fractionation found between cinnabar and calcine, and because calcine is the dominant source of Hg contamination from the mines studied, δ202Hg values of calcine may be more environmentally important in these mined areas than the primary cinnabar ore. Measurement of the Hg isotopic composition of calcine is necessary when using Hg isotopes for tracing Hg sources from areas mined for Hg, especially mine water runoff. PMID:19848142

Isotopic variability of mercury in ore, mine-waste calcine, and leachates of mine-waste calcine from areas mined for mercury

USGS Publications Warehouse

Stetson, S.J.; Gray, J.E.; Wanty, R.B.; Macalady, D.L.

2009-01-01

The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that ??202Hg values relative to NIST 3133 of calcine (up to 1.52???) in the Terlingua district, Texas, are as much as 3.24??? heavier than cinnabar (-1.72???) prior to retorting. In addition, ??202Hg values obtained from leachates of Terlingua district calcines are isotopically similar to, or as much as 1.17??? heavier than associated calcines, most likely due to leaching of soluble, byproduct Hg compounds formed during ore retorting that are a minor component in the calcines. As a result of the large fractionation found between cinnabar and calcine, and because calcine is the dominant source of Hg contamination from the mines studied, ??202Hg values of calcine may be more environmentally important in these mined areas than the primary cinnabar ore. Measurement of the Hg isotopic composition of calcine is necessary when using Hg isotopes for tracing Hg sources from areas mined for Hg, especially mine water runoff. ?? 2009 American Chemical Society.

Human mercury exposure associated with small-scale gold mining in Burkina Faso.

PubMed

Tomicic, Catherine; Vernez, David; Belem, Tounaba; Berode, Michèle

2011-06-01

In Burkina Faso, gold ore is one of the main sources of income for an important part of the active population. Artisan gold miners use mercury in the extraction, a toxic metal whose human health risks are well known. The aim of the present study was to assess mercury exposure as well as to understand the exposure determinants of gold miners in Burkinabe small-scale mines. The examined gold miners' population on the different selected gold mining sites was composed by persons who were directly and indirectly related to gold mining activities. But measurement of urinary mercury was performed on workers most susceptible to be exposed to mercury. Thus, occupational exposure to mercury was evaluated among ninety-three workers belonging to eight different gold mining sites spread in six regions of Burkina Faso. Among others, work-related exposure determinants were taken into account for each person during urine sampling as for example amalgamating or heating mercury. All participants were medically examined by a local medical team in order to identify possible symptoms related to the toxic effect of mercury. Mercury levels were high, showing that 69% of the measurements exceeded the ACGIH (American Conference of Industrial Hygienists) biological exposure indice (BEI) of 35 μg per g of creatinine (μg/g-Cr) (prior to shift) while 16% even exceeded 350 μg/g-Cr. Basically, unspecific but also specific symptoms related to mercury toxicity could be underlined among the persons who were directly related to gold mining activities. Only one-third among the studied subpopulation reported about less than three symptoms possibly associated to mercury exposure and nearly half of them suffered from at least five of these symptoms. Ore washers were more involved in the direct handling of mercury while gold dealers in the final gold recovery activities. These differences may explain the overexposure observed in gold dealers and indicate that the refining process is the major source of exposure. This study attests that mercury exposure still is an issue of concern. North-South collaborations should encourage knowledge exchange between developing and developed countries, for a cleaner artisanal gold mining process and thus for reducing human health and environmental hazards due to mercury use.

Limitations in small artisanal gold mining addressed by educational components paired with alternative mining methods.

PubMed

Zolnikov, Tara R

2012-03-01

Current solutions continue to be inadequate in addressing the longstanding, worldwide problem of mercury emissions from small artisanal gold mining. Mercury, an inexpensive and easily accessible heavy metal, is used in the process of extracting gold from ore. Mercury emissions disperse, affecting human populations by causing adverse health effects and environmental and social ramifications. Many developing nations have sizable gold ore deposits, making small artisanal gold mining a major source of employment in the world. Poverty drives vulnerable, rural populations into gold mining because of social and economic instabilities. Educational programs responding to this environmental hazard have been implemented in the past, but have had low positive results due to lack of governmental support and little economic incentive. Educational and enforced intervention programs must be developed in conjunction with governmental agencies in order to successfully eliminate this ongoing problem. Industry leaders offered hopeful suggestions, but revealed limitations when trying to develop encompassing solutions to halt mercury emissions. This research highlights potential options that have been attempted in the past and suggests alternative solutions to improve upon these methods. Some methods include buyer impact recognition, risk assessment proposals exposing a cost-benefit analysis and toxicokinetic modeling, public health awareness campaigns, and the education of miners, healthcare workers, and locals within hazardous areas of mercury exposure. These methods, paired with the implementation of alternative mining techniques, propose a substantial reduction of mercury emissions. Copyright © 2011 Elsevier B.V. All rights reserved.

Mercury dispersion in soils of an abandoned lead-zinc-silver mine, San Quintín (Spain)

NASA Astrophysics Data System (ADS)

Esbrí, José Maria; Martín-Crespo, T.; Gómez-Ortiz, D.; Monescillo, C. I.; Lorenzo, S.; Higueras, P.

2010-05-01

The mine considered on this work, namely San Quintín, is a filonian field with hydrothermal ores exploited during almost fifty years (1887-1934), producing 550.000Tm of galena, 550Tm of silver and 5.000 of sphalerite. Some rewashing works of tailings muds was achieved in recent times (1973-1985), including flotation tests of cinnabar ore from Almadén mines. The main problems remaining on the site are an active acid mine drainage (with pH ~ 2) and heavy metal dispersion on soils including gaseous mercury emissions. We present here results of a survey including soils sampling with mercury analysis and other pedological parameters, as well as determinations of mercury inmission in the atmosphere, using a common sampling grid. Analysis of soils samples has been carried out using an atomic absorption spectrometer AMA254, while air determinations were made by the same technique, using a Lumex RA-915+. The maps have been obtained by means of SURFER 8 software, as well as by ArcGIS software, and puts forward dispersion of mercury from cinnabar ore dump (108 ?g×g-1) to nearby soils (0.3 ?g×g-1 at 700 m of distance). The dispersion of mercury vapor exceed WHO level for chronic exposure (200 ng×m-3) in a small area (250 meters from cinnabar dump).

40 CFR 61.50 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ore to recover mercury, use mercury chlor-alkali cells to produce chlorine gas and alkali metal hydroxide, and incinerate or dry wastewater treatment plant sludge. [40 FR 48302, Oct. 14, 1975] ...

Determination of mercurous chloride and total mercury in mercury ores

USGS Publications Warehouse

Fahey, J.J.

1937-01-01

A method for the determination of mercurous chloride and total mercury on the same sample is described. The mercury minerals are volatilized in a glass tube and brought into intimate contact with granulated sodium carbonate. The chlorine is fixed as sodium chloride, determined with silver nitrate, and computed to mercurous chloride. The mercury is collected on a previously weighed gold coil and weighed.

DISTRIBUTION OF MERCURY IN USEPA REGION IX R-EMAP STUDY AREAS

EPA Science Inventory

Mercury distribution within U .S. EP A Region IX Regional Environmental Monitoring and Assessment Program (R-EMAP) study units is associated with geology and land-use practices. Stream water and sediment data indicate mercury is mobilized from weathering of ore bearing rock, and ...

40 CFR 440.45 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.45 Effluent limitations representing the degree of effluent reduction...

40 CFR 440.45 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.45 Effluent limitations representing the degree of effluent reduction...

40 CFR 440.45 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.45 Effluent limitations representing the degree of effluent reduction...

Mercury Contamination from Historic Gold Mining in California

USGS Publications Warehouse

Alpers, Charles N.; Hunerlach, Michael P.

2000-01-01

Mercury contamination from historic gold mines represents a potential risk to human health and the environment. This fact sheet provides background information on the use of mercury in historic gold mining and processing operations in California, and describes a new USGS project that addresses the potential risks associated with mercury from these sources, with emphasis on historic hydraulic mining areas. Miners used mercury (quicksilver) to recover gold throughout the western United States at both placer (alluvial) and hardrock (lode) mines. The vast majority of mercury lost to the environment in California was from placer-goldmines, which used hydraulic, drift, and dredging methods. At hydraulic mines, placer ores were broken down with monitors (or water cannons, fig. 1) and the resulting slurry was directed throughsluices and drainage tunnels, where goldparticles combined with liquid mercury to form gold?mercury amalgam. Loss ofmercury in this process was 10 to 30 percent per season (Bowie, 1905), resulting in highly contaminated sediments at mine sites (fig. 2). Elevated mercury concentrations in present-day mine waters and sediments indicate thathundreds to thousands of pounds of mercury remain at each of the many sites affected by hydraulic mining. High mercury levels in fish, amphibians, and invertebrates downstream of the hydraulic mines are a consequence of historic mercury use. On the basis of USGS studies and other recent work, a better understanding is emerging of mercury distribution, ongoing transport, transformation processes, and the extent of biological uptake in areas affected by historic gold mining. This information will be useful to agencies responsible for prudent land and resource management and for protecting public health.

Atmospheric mercury emissions from mine wastes and surrounding geologically enriched terrains

USGS Publications Warehouse

Gustin, M.S.; Coolbaugh, M.F.; Engle, M.A.; Fitzgerald, B.C.; Keislar, R.E.; Lindberg, S.E.; Nacht, D.M.; Quashnick, J.; Rytuba, J.J.; Sladek, C.; Zhang, H.; Zehner, R.E.

2003-01-01

Waste rock and ore associated with Hg, precious and base metal mining, and their surrounding host rocks are typically enriched in mercury relative to natural background concentrations (<0.1 ??g Hg g-1). Mercury fluxes to the atmosphere from mineralized areas can range from background rates (0-15 ng m-2 h-1) to tens of thousands of ng m-2 h-1. Mercury enriched substrate constitutes a long-term source of mercury to the global atmospheric mercury pool. Mercury emissions from substrate are influenced by light, temperature, precipitation, and substrate mercury concentration, and occur during the day and night. Light-enhanced emissions are driven by two processes: desorption of elemental mercury accumulated at the soil:air interface, and photo reduction of mercury containing phases. To determine the need for and effectiveness of regulatory controls on short-lived anthropogenic point sources the contribution of mercury from geologic non-point sources to the atmospheric mercury pool needs to be quantified. The atmospheric mercury contribution from small areas of mining disturbance with relatively high mercury concentrations are, in general, less than that from surrounding large areas of low levels of mercury enrichment. In the arid to semi-arid west-ern United States volatilization is the primary means by which mercury is released from enriched sites.

Assessment of environmental mercury discharge at a four-year-old artisanal gold mining area on Lombok Island, Indonesia.

PubMed

Krisnayanti, Baiq Dewi; Anderson, Christopher W N; Utomo, Wani Hadi; Feng, Xinbin; Handayanto, Eko; Mudarisna, Nurul; Ikram, Hadiman; Khususiah

2012-10-26

Indonesian artisanal and small-scale gold mining activities (ASGM) have been described for the islands of Borneo (Kalimantan) and Sulawesi. But the increased gold price over recent years has seen operations extend to the islands of Lombok and Sumbawa. For the current research, an environmental assessment was conducted across three new ASGM locations. Gold is recovered by miners through a two-stage process of whole-ore amalgamation and cyanidation. Waste (tailings) is discharged to land or sea with no concern for contaminants in the tailings. The gold grade of ore is up to 5000 mg kg(-1). The mean gold grade of the amalgamation tailings is 7 mg kg(-1), dropping to 1.2 mg kg(-1) for the cyanidation tailings. The mean mercury concentration of the amalgamation tailings is about 3000 mg kg(-1) and greater than 1600 mg kg(-1) for the cyanidation tailings. Samples of paddy rice grain collected adjacent to cyanidation tailings ponds showed methyl mercury concentrations greater than 100 ng g(-1). This is five times above the Chinese permissible level for total mercury in food crops. The mean total mercury concentration in hair of Lombok ASGM workers was greater than that in a non-exposed population; however there was no difference in methyl mercury concentration. This indicates the primary pathway of mercury exposure is inhalation of volatile mercury in the atmosphere. Future exposure may come from ingestion of methyl mercury contaminated rice where discharge of cyanide tailings to paddies continues. To protect the environment and to enhance the sustainability of ASGM, appropriate tailings management must be implemented. The gold grade of the tailings indicates that the residual value might be recoverable with appropriate technology. Ongoing research is investigating systems such as phytoextraction that might assist ASGM operators in Lombok and Sumbawa to improve their environmental performance.

Study on Sumbawa gold recovery using centrifuge

NASA Astrophysics Data System (ADS)

Ferdana, A. D.; Petrus, H. T. B. M.; Bendiyasa, I. M.; Prijambada, I. D.; Hamada, F.; Sachiko, T.

2018-01-01

The Artisanal Small Gold Mining in Sumbawa has been processing gold with mercury (Hg), which poses a serious threat to the mining and global environment. One method of gold processing that does not use mercury is by gravity method. Before processing the ore first performed an analysis of Mineragraphy and analysis of compound with XRD. Mineragraphy results show that gold is associated with chalcopyrite and covelite and is a single particle (native) on size 58.8 μm, 117 μm up to 294 μm. characterization with XRD shows that the Sumbawa Gold Ore is composed of quartz, pyrite, pyroxene, and sericite compounds. Sentrifugation is one of separation equipment of gravity method to increase concentrate based on difference of specific gravity. The optimum concentration result is influenced by several variables, such as water flow rate and particle size. In this present research, the range of flow rate is 5 lpm and 10 lpm, the particle size - 100 + 200 mesh and -200 +300 mesh. Gold concentration in concentrate is measured by EDX. The result shows that the optimum condition is obtained at a separation with flow rate 5 lpm and a particle size of -100 + 200 mesh.

40 CFR 440.41 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false [Reserved] 440.41 Section 440.41 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.41 [Reserved] ...

40 CFR 440.41 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false [Reserved] 440.41 Section 440.41 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.41 [Reserved] ...

40 CFR 440.41 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false [Reserved] 440.41 Section 440.41 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.41 [Reserved] ...

40 CFR 440.41 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false [Reserved] 440.41 Section 440.41 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.41 [Reserved] ...

40 CFR 440.41 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false [Reserved] 440.41 Section 440.41 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.41 [Reserved] ...

Mercury distribution characteristics in primary manganese smelting plants.

PubMed

Back, Seung-Ki; Sung, Jin-Ho; Moon, Young-Hoon; Kim, Young-Hee; Seok, Kwang-Seol; Song, Geum-Ju; Seo, Yong-Chil

2017-08-01

The mercury (Hg) distribution characteristics were investigated in three primary manganese smelting plants in Korea for the assessment of anthropogenic Hg released. Input and output materials were sampled from each process, and Hg concentrations in the samples were analyzed. Among the input materials, the most mercury was found in the manganese ore (83.1-99.7%) and mercury was mainly released through fly ash or off gas, depending on the condition of off gas cleaning system. As off gas temperature decreases, proportion and concentration of emitted gaseous elemental mercury (Hg 0 ) in off gas decreases. Based on mass balance study from these three plants and national manganese production data, the total amount of mercury released from those Korean plants was estimated to 644 kg/yr. About half of it was emitted into the air while the rest was released to waste as fly ash. With the results of this investigation, national inventory for Hg emission and release could be updated for the response to Minamata Convention on Mercury. Copyright © 2017. Published by Elsevier Ltd.

Assessment of mercury in the Savannah River Site environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kvartek, E.J.; Carlton, W.H.; Denham, M.

Mercury has been valued by humans for several millennia. Its principal ore, cinnabar, was mined for its distinctive reddish-gold color and high density. Mercury and its salts were used as medicines and aphrodisiacs. At SRS, mercury originated from one of the following: as a processing aid in aluminum dissolution and chloride precipitation; as part of the tritium facilities` gas handling system; from experimental, laboratory, or process support facilities; and as a waste from site operations. Mercury is also found in Par Pond and some SRS streams as the result of discharges from a mercury-cell-type chlor-alkali plant near the city ofmore » Augusta, GA. Reactor cooling water, drawn from the Savannah River, transported mercury onto the SRS. Approximately 80,000 kg of mercury is contained in the high level waste tanks and 10,000 kg is located in the SWDF. Additional quantities are located in the various seepage basins. In 1992, 617 wells were monitored for mercury contamination, with 47 indicating contamination in excess of the 0.002-ppm EPA Primary Drinking Water Standard. More than 20 Savannah River Ecology Laboratory (SREL) reports and publications pertinent to mercury (Hg) have been generated during the last two decades. They are divided into three groupings: SRS-specific studies, basic studies of bioaccumulation, and basic studies of effect. Many studies have taken place at Par Pond and Upper Three Runs Creek. Mercury has been detected in wells monitoring the groundwater beneath SRS, but not in water supply wells in excess of the Primary Drinking Water Limit of 0.002 ppm. There has been no significant release of mercury from SRS to the Savannah River. While releases to air are likely, based on process knowledge, modeling of the releases indicates concentrations that are well below the SCDHEC ambient standard.« less

Use and legacy of mercury in the Andes.

PubMed

Cooke, Colin A; Hintelmann, Holger; Ague, Jay J; Burger, Richard; Biester, Harald; Sachs, Julian P; Engstrom, Daniel R

2013-05-07

Both cinnabar (HgS) and metallic mercury (Hg(0)) were important resources throughout Andean prehistory. Cinnabar was used for millennia to make vermillion, a red pigment that was highly valued in pre-Hispanic Peru; metallic Hg(0) has been used since the mid-16th century to conduct mercury amalgamation, an efficient process of extracting precious metals from ores. However, little is known about which cinnabar deposits were exploited by pre-Hispanic cultures, and the environmental consequences of Hg mining and amalgamation remain enigmatic. Here we use Hg isotopes to source archeological cinnabar and to fingerprint Hg pollution preserved in lake sediment cores from Peru and the Galápagos Islands. Both pre-Inca (pre-1400 AD) and Colonial (1532-1821 AD) archeological artifacts contain cinnabar that matches isotopically with cinnabar ores from Huancavelica, Peru, the largest cinnabar-bearing district in Central and South America. In contrast, the Inca (1400-1532 AD) artifacts sampled are characterized by a unique Hg isotopic composition. In addition, preindustrial (i.e., pre-1900 AD) Hg pollution preserved in lake sediments matches closely the isotopic composition of cinnabar from the Peruvian Andes. Industrial-era Hg pollution, in contrast, is distinct isotopically from preindustrial emissions, suggesting that pre- and postindustrial Hg emissions may be distinguished isotopically in lake sediment cores.

Characterization, mapping, and mitigation of mercury vapour emissions from artisanal mining gold shops.

PubMed

Cordy, Paul; Veiga, Marcello; Crawford, Ben; Garcia, Oseas; Gonzalez, Victor; Moraga, Daniel; Roeser, Monika; Wip, Dennis

2013-08-01

Artisanal miners sell their gold to shops that are usually located in the urban core, where the mercury-gold amalgam is burned to evaporate the mercury that was added during ore processing. People living and working near these gold shops are exposed to intermittent and extreme concentrations of mercury vapour. In the urban centres of Segovia, Colombia, and Andacollo, Chile, the average concentrations measured by mobile mercury vapour analyzer transects taken repeatedly over several weeks were 1.26 and 0.338μgm(-3), respectively. By World Health Organization standards, these towns are exposed to significant health hazard, and globally, the millions of miners, as well as non-miners who live near gold shops, are at serious risk of neurological and renal deficits. Measurements taken in Suriname, Ecuador and Peru reveal this to be a widespread phenomenon with unique regional variations and myriad attempts at remediation. Maps of average mercury concentrations show the spatial distribution of the hazard in relation to residential buildings and schools. Measurements from towers show the temporal variability of mercury concentrations, and suggest that large quantities of mercury are available for long-range atmospheric transport. Mercury mapping in Segovia in 2011 suggest a 10% reduction in airborne mercury concentrations over 2010, despite a 30% increase in gold production. This is attributable to the adoption of retorts by miners and regulations banning new processing centres to the rural periphery. This is the first full description of artisanal mining gold shop practices and of the character, quantity, and remediation of mercury emissions within urban mining centres. Copyright © 2013 Elsevier Inc. All rights reserved.

MERCURY IN METAL ORE DEPOSITS: AN UNRECOGNIZED, WIDESPREAD SOURCE TO LAKE SUPERIOR SEDIMENTS, CONTRIBUTION #1072

EPA Science Inventory

Mining operations have worked the rich mineral resources of the Lake Superior Basin for over 150 years, leaving industrially impacted regions with tailing piles and smelters. In Lake Superior sediments, mercury and copper inventories increase towards shorelines and are highly cor...

Changing patterns in the use, recycling, and material substitution of mercury in the United States

USGS Publications Warehouse

Wilburn, David R.

2013-01-01

Environmental concerns have led to numerous regulations that have dramatically decreased the reported production and use of mercury in the United States since the 1980s. Government legislation and subsequent industry actions have led to increased collection of mercury-containing materials and the recovery of mercury through recycling. Mercury emissions have been reduced and effective alternatives to mercury products have been developed for many applications. This study updates and quantifies the changes in demand, supply, use, and material flow for mercury in various sectors in the United States that have taken place since 1996. Nearly all primary mercury produced in the United States is derived as a byproduct of processing of gold and silver ore in Nevada. Since 2001, annual production of mercury from gold and silver mining in Nevada has decreased by 22 percent overall because ore from greater depths containing low grade mercury is recovered, and mercury emissions from this source have decreased by 95 percent as a result of increased regulation and improved collection and suppression technology. The distribution of consumption of mercury in the United States has changed as a result of regulation (elimination of large-scale mercury use in the paint and battery sectors), reduction by consumers (decommissioning of mercury-cell chloralkali manufacturing capacity), and technological advances (improvements in dental, lighting, and wiring sectors). Mercury use in the chloralkali sector, the leading end-use sector in the United States in 1996, has declined by 98 percent from 136 metric tons (t) in 1996 to about 0.3 t in 2010 because of increased processing and recycling efficiencies and plant closures or conversion to other technologies. As plants were closed, mercury recovered from the infrastructure of decommissioned plants has been exported, making the United States a net exporter of mercury, even though no mercury has been produced as the primary product from mines in the United States since 1992. In 1996, the three leading end-use sectors for mercury in the United States were chloralkali manufacturing (accounting for 38 percent of consumption), electrical and electronic instrumentation (13 percent of consumption), and instruments and measuring devices (11 percent of consumption). In 2010, the three leading end-use sectors were dental amalgam (accounting for between 35 and 57 percent of consumption), electrical and electronic instrumentation (29 percent of consumption), and batteries (8 percent of consumption). Mercury use in lighting is increasing because incandescent lights are being phased out in favor of mercury-containing compact fluorescent bulbs, but the demand for mercury per unit produced is small. Dental amalgam constituted the largest amount of mercury in use in the United States. One study reported about 290 t of mercury in dental amalgam was estimated to be contained in human mouths, an estimated 30 t of mercury amalgam was treated as waste, 28.5 t of mercury amalgam was released to the environment, 6 t of amalgam was recycled, and 3.5 t was treated and stored in landfills in 2009. Mercury contained in products recovered by State, municipal, or industry collection activities is recycled, but the estimated overall recycling rate is less than 10 percent. Increasingly, the U.S. mercury recycling industry has been processing a significant amount of mercury-containing material derived from foreign gold mining operations or decommissioned mercury-cell chloralkali plants. Regulation of mercury export and storage is expected to result in surplus mercury inventories in the United States. The Mercury Export Ban Act of 2008 limits elemental mercury exports for unregulated uses such as artisanal gold mining after January 1, 2013, and requires development of adequate long-term storage facilities in the United States for elemental mercury. During the past 4 years, producers and recyclers of elemental mercury have been exporting large quantities of mercury in anticipation of this regulation, but the U.S. inventory of mercury in 2010 was estimated to have exceeded 7,000 t from Government stockpiles and industry stocks. Costs attributed to long-term storage may affect the competitiveness of mercury recycling.

Historical exposure to inorganic mercury at the smelter works of Abbadia San Salvatore, Italy.

PubMed

Bellander, T; Merler, E; Ceccarelli, F; Boffetta, P

1998-02-01

Metallic mercury production from cinnabar ore may result in high exposures to inorganic mercury, that are difficult to assess separately from the exposures originating from underground extraction, and previously have only been scantily described. We retrieved and analysed the air and biological mercury determinations on workers involved in the smelting process of the Abbadia San Salvatore mine (Monte Amiata, Italy). Native mercury was not present in the ore, and the exposure in the underground extraction was low. The smelter operated from 1897 to 1983. Blood and urine (24/h urine collections and concentration samples) had been sampled in 1968 to 1982, and analysed for mercury by atomic absorption spectrophotometry, and relate to all subjects. Exposure to mercury in air had been determined in a small set of personal samples in 1982. The data relate to all jobs in the smelter process, and all jobs entailed substantial exposure to mercury. The overall distribution of breathing zone air, blood and urinary levels is right-skewed and similar to the log-normal distribution (air, median 48 micrograms/m3, n = 49; blood, arithmetic mean AM 49 micrograms/L; geometric mean GM 26 micrograms/L, n = 192; urinary excretion, AM 140 micrograms/24 h, GM 78 micrograms/24 h, n = 839; and urinary concentration, AM 160 micrograms/L, GM 83 micrograms/L, n = 632). Air, blood and urinary values show a high ratio of the between- and within-job variance, indicating differences in exposure by job. Cinnabar pigment production, of which the exposure has not been characterised previously, was the job with the highest air (AM 160 micrograms/m3) and urinary levels (excretion AM 690 micrograms/24 h; concentration AM 1100 micrograms/L). Other jobs with high urinary levels were soot purification, laboratory work, and bottling. Cleaning of condensers showed the highest blood level (AM 280 micrograms/L). There is a downwards time trend in mercury concentration in blood and in urine. The corresponding trend is not seen for urinary excretion levels, the reason for this being unclear. Roasters, which is the most frequently monitored group, show however a decreasing trend in all sets of data (e.g. the mean of urinary excretion decreased from 300 micrograms/24 h in 1968/69 to 50 micrograms/24 h in 1980/81). The mercury exposure experienced by the smelters of Abbadia San Salvatore is in line with the few available data on workers from other mercury mines and smelters, and our data confirm the high exposure levels in this occupational group, in particular at cinnabar pigment production, soot purification, and condenser cleaning.

Mercury and trace element contents of Donbas coals and associated mine water in the vicinity of Donetsk, Ukraine

USGS Publications Warehouse

Kolker, A.; Panov, B.S.; Panov, Y.B.; Landa, E.R.; Conko, K.M.; Korchemagin, V.A.; Shendrik, T.; McCord, J.D.

2009-01-01

Mercury-rich coals in the Donets Basin (Donbas region) of Ukraine were sampled in active underground mines to assess the levels of potentially harmful elements and the potential for dispersion of metals through use of this coal. For 29 samples representing c11 to m3 Carboniferous coals, mercury contents range from 0.02 to 3.5 ppm (whole-coal dry basis). Mercury is well correlated with pyritic sulfur (0.01 to 3.2 wt.%), with an r2 of 0.614 (one outlier excluded). Sulfides in these samples show enrichment of minor constituents in late-stage pyrite formed as a result of interaction of coal with hydrothermal fluids. Mine water sampled at depth and at surface collection points does not show enrichment of trace metals at harmful levels, indicating pyrite stability at subsurface conditions. Four samples of coal exposed in the defunct open-cast Nikitovka mercury mines in Gorlovka have extreme mercury contents of 12.8 to 25.5 ppm. This coal was formerly produced as a byproduct of extracting sandstone-hosted cinnabar ore. Access to these workings is unrestricted and small amounts of extreme mercury-rich coal are collected for domestic use, posing a limited human health hazard. More widespread hazards are posed by the abandoned Nikitovka mercury processing plant, the extensive mercury mine tailings, and mercury enrichment of soils extending into residential areas of Gorlovka.

Exposure to mercury in the mine of Almadén

PubMed Central

Gómez, Montserrat García; Klink, José Diego Caballero; Boffetta, Paolo; Español, Santiago; Sällsten, Gerd; Quintana, Javier Gómez

2007-01-01

Objectives To describe the process for obtaining mercury and the historical exposure of Almadén miners to mercury. Methods Information on every workplace and historical data on production, technological changes in the productive process and biological and environmental values of mercury was collected. A job‐exposure matrix was built with these values and the exposure to inorganic mercury was estimated quantitatively as μg/l of urine mercury. A cumulative exposure index was calculated for every worker by adding the estimates for every year in the different workplaces. Results In the mine, the highest exposures occurred during drilling, with values up to 2.26 mg/m3 in air, 2194 μg/l in urine and 374 μg/l in blood. Furnace operation and cleaning were the tasks with the highest values in metallurgy, peaking up to 3.37 mg/m3. The filling of bottles with mercury by free fall gave values within a range of 1.13–2.43 mg/m3 in air; these values dropped to 0.32–0.83 mg/m3 after introducing a new ventilation system. The toxicity effects of high doses of inorganic mercury on the central nervous and urinary systems have been known for decades. Conclusions The exposure of the workers in Almadén mines to mercury has been very high. The extremely high content cinnabar ore of the mine explains the increased concentrations of mercury in air at the work places. This, together with inadequate working conditions, explains the high mercury levels found in blood and urine during the study period. PMID:17227836

Mercury contamination in agricultural soils from abandoned metal mines classified by geology and mineralization.

PubMed

Kim, Han Sik; Jung, Myung Chae

2012-01-01

This survey aimed to compare mercury concentrations in soils related to geology and mineralization types of mines. A total of 16,386 surface soils (0~15 cm in depth) were taken from agricultural lands near 343 abandoned mines (within 2 km from each mine) and analyzed for Hg by AAS with a hydride-generation device. To meaningfully compare mercury levels in soils with geology and mineralization types, three subclassification criteria were adapted: (1) five mineralization types, (2) four valuable ore mineral types, and (3) four parent rock types. The average concentration of Hg in all soils was 0.204 mg kg(-1) with a range of 0.002-24.07 mg kg(-1). Based on the mineralization types, average Hg concentrations (mg kg(-1)) in the soils decreased in the order of pegmatite (0.250) > hydrothermal vein (0.208) > hydrothermal replacement (0.166) > skarn (0.121) > sedimentary deposits (0.045). In terms of the valuable ore mineral types, the concentrations decreased in the order of Au-Ag-base metal mines ≈ base metal mines > Au-Ag mines > Sn-W-Mo-Fe-Mn mines. For parent rock types, similar concentrations were found in the soils derived from sedimentary rocks and metamorphic rocks followed by heterogeneous rocks with igneous and metamorphic processes. Furthermore, farmland soils contained relatively higher Hg levels than paddy soils. Therefore, it can be concluded that soils in Au, Ag, and base metal mines derived from a hydrothermal vein type of metamorphic rocks and pegmatite deposits contained relatively higher concentrations of mercury in the surface environment.

Mercury isotope fractionation during ore retorting in the Almadén mining district, Spain

USGS Publications Warehouse

Gray, John E.; Pribil, Michael J.; Higueras, Pablo L.

2013-01-01

Almadén, Spain, is the world's largest mercury (Hg) mining district, which has produced over 250,000 metric tons of Hg representing about 30% of the historical Hg produced worldwide. The objective of this study was to measure Hg isotopic compositions of cinnabar ore, mine waste calcine (retorted ore), elemental Hg (Hg0(L)), and elemental Hg gas (Hg0(g)), to evaluate potential Hg isotopic fractionation. Almadén cinnabar ore δ202Hg varied from − 0.92 to 0.15‰ (mean of − 0.56‰, σ = 0.35‰, n = 7), whereas calcine was isotopically heavier and δ202Hg ranged from − 0.03‰ to 1.01‰ (mean of 0.43‰, σ = 0.44‰, n = 8). The average δ202Hg enrichment of 0.99‰ between cinnabar ore and calcines generated during ore retorting indicated Hg isotopic mass dependent fractionation (MDF). Mass independent fractionation (MIF) was not observed in any of the samples in this study. Laboratory retorting experiments of cinnabar also were carried out to evaluate Hg isotopic fractionation of products generated during retorting such as calcine, Hg0(L), and Hg0(g). Calcine and Hg0(L) generated during these retorting experiments showed an enrichment in δ202Hg of as much as 1.90‰ and 0.67‰, respectively, compared to the original cinnabar ore. The δ202Hg for Hg0(g) generated during the retorting experiments was as much as 1.16‰ isotopically lighter compared to cinnabar, thus, when cinnabar ore was roasted, the resultant calcines formed were isotopically heavier, whereas the Hg0(g) generated was isotopically lighter in Hg isotopes.

A cross-sectional survey on knowledge and perceptions of health risks associated with arsenic and mercury contamination from artisanal gold mining in Tanzania

PubMed Central

2013-01-01

Background An estimated 0.5 to 1.5 million informal miners, of whom 30-50% are women, rely on artisanal mining for their livelihood in Tanzania. Mercury, used in the processing gold ore, and arsenic, which is a constituent of some ores, are common occupational exposures that frequently result in widespread environmental contamination. Frequently, the mining activities are conducted haphazardly without regard for environmental, occupational, or community exposure. The primary objective of this study was to assess community risk knowledge and perception of potential mercury and arsenic toxicity and/or exposure from artisanal gold mining in Rwamagasa in northwestern Tanzania. Methods A cross-sectional survey of respondents in five sub-villages in the Rwamagasa Village located in Geita District in northwestern Tanzania near Lake Victoria was conducted. This area has a history of artisanal gold mining and many of the population continue to work as miners. Using a clustered random selection approach for recruitment, a total of 160 individuals over 18 years of age completed a structured interview. Results The interviews revealed wide variations in knowledge and risk perceptions concerning mercury and arsenic exposure, with 40.6% (n=65) and 89.4% (n=143) not aware of the health effects of mercury and arsenic exposure respectively. Males were significantly more knowledgeable (n=59, 36.9%) than females (n=36, 22.5%) with regard to mercury (x2=3.99, p<0.05). An individual’s occupation category was associated with level of knowledge (x2=22.82, p=<0.001). Individuals involved in mining (n=63, 73.2%) were more knowledgeable about the negative health effects of mercury than individuals in other occupations. Of the few individuals (n=17, 10.6%) who knew about arsenic toxicity, the majority (n=10, 58.8%) were miners. Conclusions The knowledge of individuals living in Rwamagasa, Tanzania, an area with a history of artisanal gold mining, varied widely with regard to the health hazards of mercury and arsenic. In these communities there was limited awareness of the threats to health associated with exposure to mercury and arsenic. This lack of knowledge, combined with minimal environmental monitoring and controlled waste management practices, highlights the need for health education, surveillance, and policy changes. PMID:23351708

A cross-sectional survey on knowledge and perceptions of health risks associated with arsenic and mercury contamination from artisanal gold mining in Tanzania.

PubMed

Charles, Elias; Thomas, Deborah S K; Dewey, Deborah; Davey, Mark; Ngallaba, Sospatro E; Konje, Eveline

2013-01-25

An estimated 0.5 to 1.5 million informal miners, of whom 30-50% are women, rely on artisanal mining for their livelihood in Tanzania. Mercury, used in the processing gold ore, and arsenic, which is a constituent of some ores, are common occupational exposures that frequently result in widespread environmental contamination. Frequently, the mining activities are conducted haphazardly without regard for environmental, occupational, or community exposure. The primary objective of this study was to assess community risk knowledge and perception of potential mercury and arsenic toxicity and/or exposure from artisanal gold mining in Rwamagasa in northwestern Tanzania. A cross-sectional survey of respondents in five sub-villages in the Rwamagasa Village located in Geita District in northwestern Tanzania near Lake Victoria was conducted. This area has a history of artisanal gold mining and many of the population continue to work as miners. Using a clustered random selection approach for recruitment, a total of 160 individuals over 18 years of age completed a structured interview. The interviews revealed wide variations in knowledge and risk perceptions concerning mercury and arsenic exposure, with 40.6% (n=65) and 89.4% (n=143) not aware of the health effects of mercury and arsenic exposure respectively. Males were significantly more knowledgeable (n=59, 36.9%) than females (n=36, 22.5%) with regard to mercury (x²=3.99, p<0.05). An individual's occupation category was associated with level of knowledge (x²=22.82, p=<0.001). Individuals involved in mining (n=63, 73.2%) were more knowledgeable about the negative health effects of mercury than individuals in other occupations. Of the few individuals (n=17, 10.6%) who knew about arsenic toxicity, the majority (n=10, 58.8%) were miners. The knowledge of individuals living in Rwamagasa, Tanzania, an area with a history of artisanal gold mining, varied widely with regard to the health hazards of mercury and arsenic. In these communities there was limited awareness of the threats to health associated with exposure to mercury and arsenic. This lack of knowledge, combined with minimal environmental monitoring and controlled waste management practices, highlights the need for health education, surveillance, and policy changes.

Signs and symptoms of mercury-exposed gold miners.

PubMed

Bose-O'Reilly, Stephan; Bernaudat, Ludovic; Siebert, Uwe; Roider, Gabriele; Nowak, Dennis; Drasch, Gustav

2017-03-30

Gold miners use mercury to extract gold from ore adding liquid mercury to the milled gold-containing ore. This results in a mercury-gold compound, called amalgam. Miners smelt this amalgam to obtain gold, vaporizing it and finally inhaling the toxic mercury fumes. The objective was to merge and analyze data from different projects, to identify typical signs and symptoms of chronic inorganic mercury exposure. Miners and community members from various artisanal small-scale gold mining areas had been examined (Philippines, Mongolia, Tanzania, Zimbabwe, Indonesia). Data of several health assessments were pooled. Urine, blood and hair samples were analyzed for mercury (N = 1252). Questionnaires, standardized medical examinations and neuropsychological tests were used. Participants were grouped into: Controls (N = 209), living in an exposed area (N = 408), working with mercury as panners (N = 181), working with mercury as amalgam burners (N = 454). Chi² test, linear trend test, Mann-Whitney test, Kruskal-Wallis test, correlation coefficient, Spearman's rho, and analysis of variance tests were used. An algorithm was used to define participants with chronic mercury intoxication. Mean mercury concentrations in all exposed subgroups were elevated and above threshold limits, with amalgam burners showing highest levels. Typical symptoms of chronic metallic mercury intoxication were tremor, ataxia, coordination problems, excessive salivation and metallic taste. Participants from the exposed groups showed poorer results in different neuropsychological tests in comparison to the control group. Fifty-four percent of the high-exposed group (amalgam burners) were diagnosed as being mercury-intoxicated, compared to 0% within the control group (Chi² p < 0.001). Chronic mercury intoxication, with tremor, ataxia and other neurological symptoms together with a raised body burden of mercury was clinically diagnosed in exposed people in artisanal small-scale mining areas. The mercury exposure needs to be urgently reduced. Health care systems need to be prepared for this emerging problem of chronic mercury intoxication among exposed people. Int J Occup Med Environ Health 2017;30(2):249-269. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Mercury in soil gas and air--A potential tool in mineral exploration

USGS Publications Warehouse

McCarthy, Joseph Howard; Vaughn, W.W.; Learned, R.E.; Meuschke, J.L.

1969-01-01

The mercury content in soil gas and in the atmosphere was measured in several mining districts to test the possibility that the mercury content in the atmosphere is higher over ore deposits than over barren ground. At Cortez, Nev., the distribution of anorhalous amounts of mercury in the air collected at ground level (soil gas) correlates well with the distribution of gold-bearing rocks that are covered by as much as 100 feet of gravel. The mercury content in the atmosphere collected at an altitude of 200 feet by an aircraft was 20 times background over a mercury posit and 10 times background over two porphyry copper deposits. Measurement of mercury in soil gas and air may prove to be a valuable exploration tool.

Mercury - Its occurrence and economic trends

USGS Publications Warehouse

Bailey, Edgar H.; Smith, Roscoe M.

1964-01-01

price will be a predictable increase in production. If the price averages $300 a flask for 1 year or more, annual production may increase to a rate of 30,000-35,000 flasks in 1966 or 1967. If the price averages $400 a flask, production may increase to 45,000-50,000 flasks a year after a timelag of two or three years. New ore bodies would have to be found however, to attain these rates of production, and the mining of lower grade ores would be needed to sustain them for more than a few years. By 1966 the U.S. economy will require at least 67 000 flasks, and the domestic demand for mercury thereafter will continue to increase. The probability that domestic mines will continue to supply a fourth or more of the domestic consumption is dependent upon the price of mercury for the next few years. The outlook for the long-term supply is reassuring, but it is dependent, not only upon price, but upon continued progress in new techniques of discovery.

Mercury mine drainage and processes that control its environmental impact

USGS Publications Warehouse

Rytuba, J.J.

2000-01-01

Mine drainage from mercury mines in the California Coast Range mercury mineral belt is an environmental concern because of its acidity and high sulfate, mercury, and methylmercury concentrations. Two types of mercury deposits are present in the mineral belt, silica-carbonate and hot-spring type. Mine drainage is associated with both deposit types but more commonly with the silica-carbonate type because of the extensive underground workings present at these mines. Mercury ores consisting primarily of cinnabar were processed in rotary furnaces and retorts and elemental mercury recovered from condensing systems. During the roasting process mercury phases more soluble than cinnabar are formed and concentrated in the mine tailings, commonly termed calcines. Differences in mineralogy and trace metal geochemistry between the two deposit types are reflected in mine drainage composition. Silica-carbonate type deposits have higher iron sulfide content than hot- spring type deposits and mine drainage from these deposits may have extreme acidity and very high concentrations of iron and sulfate. Mercury and methylmercury concentrations in mine drainage are relatively low at the point of discharge from mine workings. The concentration of both mercury species increases significantly in mine drainage that flows through and reacts with calcines. The soluble mercury phases in the calcines are dissolved and sulfate is added such that methylation of mercury by sulfate reducing bacteria is enhanced in calcines that are saturated with mine drainage. Where mercury mine drainage enters and first mixes with stream water, the addition of high concentrations of mercury and sulfate generates a favorable environment for methylation of mercury. Mixing of oxygenated stream water with mine drainage causes oxidation of dissolved iron(II) and precipitation of iron oxyhydroxide that accumulates in the streambed. Both mercury and methylmercury are strongly adsorbed onto iron oxyhydroxide over the pH range of 3.2-7.1 in streams impacted by mine drainage. The dissolved fraction of both mercury species is depleted and concentrated in iron oxyhydroxide such that the amount of iron oxyhydroxide in the water column reflects the concentration of mercury species. In streams impacted by mine drainage, mercury and methylmercury are transported and adsorbed onto particulate phases. During periods of low stream flow, fine-grained iron hydroxide sediment accumulates in the bed load of the stream and adsorbs mercury and methylmercury such that both forms of mercury become highly enriched in the iron oxyhydroxide sediment. During high-flow events, mercury- and methylmercury-enriched iron hydroxide sediment is transported into larger aquatic systems producing a high flux of bioavailable mercury. (C) 2000 Elsevier Science B.V.

Total mercury loadings in sediment from gold mining and conservation areas in Guyana.

PubMed

Howard, Joniqua; Trotz, Maya A; Thomas, Ken; Omisca, Erlande; Chiu, Hong Ting; Halfhide, Trina; Akiwumi, Fenda; Michael, Ryan; Stuart, Amy L

2011-08-01

The Low Carbon Development Strategy proposed in June 2009 by the government of Guyana in response to the Reducing Emissions from Deforestation and Forest Degradation in Developing Countries program has triggered evaluation of forest-related activities, thereby acting as a catalyst for improvements in Guyana's small- to medium-scale gold mining industry. This has also shed light on areas committed to conservation, something that has also been handled by Non Governmental Organizations. This paper compares water quality and mercury concentrations in sediment from four main areas in Guyana, two that are heavily mined for gold using mercury amalgamation methods (Arakaka and Mahdia) and two that are considered conservation areas (Iwokrama and Konashen). Fifty-three sediment and soil mercury loadings ranged from 29 to 1,200 ng/g and averaged 215 ± 187 ng/g for all sites with similar averages in conservation and mining areas. Sediment loadings are within the range seen in French Guiana and Suriname, but conservation area samples had higher loadings than the corresponding uncontaminated baselines. Type of ore and location in the mining process seemed to influence mercury loadings. Mercury sediment loadings were slightly positively correlated with pH (correlation coefficient = 0.2; p value < 0.001) whereas no significant correlations were found with dissolved oxygen or turbidity.

Metallogeny, exploitation and environmental impact of the Mt. Amiata mercury ore district (Southern Tuscany, Italy)

USGS Publications Warehouse

Rimondi, V.; Chiarantini, L.; Lattanzi, P.; Benvenuti, M.; Beutel, M.; Colica, A.; Costagliola, P.; Di Benedetto, F.; Gabbani, G.; Gray, John E.; Pandeli, E.; Pattelli, G.; Paolieri, M.; Ruggieri, G.

2015-01-01

Results of our studies indicate that the Mt. Amiata region is at present a source of Hg of remarkable environmental concern at the local, regional (Tiber River), and Mediterranean scales. Ongoing studies are aimed to a more detailed quantification of the Hg mass load input to the Mediterranean Sea, and to unravel the processes concerning Hg transport and fluid dynamics.                   

Mercury Exposure Assessment and Spatial Distribution in A Ghanaian Small-Scale Gold Mining Community

PubMed Central

Rajaee, Mozhgon; Long, Rachel N.; Renne, Elisha P.; Basu, Niladri

2015-01-01

Mercury is utilized worldwide in artisanal and small-scale gold mining (ASGM) and may pose a risk for miners and mining communities. While a number of studies have characterized mercury in ASGM communities, most have focused on a single media and few have taken a holistic approach. Here, a multiple media exposure assessment and cross-sectional study of mercury was conducted in 2010 through 2012 in northeast Ghana with a small-scale gold mining community, Kejetia, a subsistence farming community, Gorogo, and an urban ASGM gold refinery in Bolgatanga. The objective was to assess mercury in a range of human (urine and hair) and ecological (household soil, sediment, fish, and ore) samples to increase understanding of mercury exposure pathways. All participants were interviewed on demographics, occupational and medical histories, and household characteristics. Participants included 90 women of childbearing age and 97 adults from Kejetia and 75 adults from Gorogo. Median total specific gravity-adjusted urinary, hair, and household soil mercury were significantly higher in Kejetia miners (5.18 µg/L, 0.967 µg/g, and 3.77 µg/g, respectively) than Kejetia non-miners (1.18 µg/L, 0.419 µg/g, and 2.00 µg/g, respectively) and Gorogo participants (0.154 µg/L, 0.181 µg/g, and 0.039 µg/g) in 2011. Sediment, fish, and ore Hg concentrations were below guideline values. Median soil mercury from the Bolgatanga refinery was very high (54.6 µg/g). Estimated mean mercury ingestion for Kejetia adults from soil and dust exceeded the U.S. Environmental Protection Agency reference dose (0.3 µg Hg/kg·day) for pica (0.409 µg Hg/kg·day) and geophagy (20.5 µg Hg/kg·day) scenarios. Most participants with elevated urinary and household soil mercury were miners, but some non-miners approached and exceeded guideline values, suggesting a health risk for non-mining residents living within these communities. PMID:26340636

Occupational and environmental mercury exposure among small-scale gold miners in the Talensi-Nabdam District of Ghana’s Upper East region

PubMed Central

Paruchuri, Yasaswi; Siuniak, Amanda; Johnson, Nicole; Levin, Elena; Mitchell, Katherine; Goodrich, Jaclyn M.; Renne, Elisha P.; Basu, Niladri

2014-01-01

Mercury use in small-scale gold mining is ubiquitous across Ghana but little is known about the extent to which such activities have contaminated community residents and miners. Here, occupational exposures to elemental mercury (via urine sampling) and dietary exposures to methylmercury (via hair sampling) were assessed among 120 participants recruited from a mining community located in the Talensi-Nabdam District of Ghana’s Upper East region during summer 2009. More than one-fifth of the participants had moderately high levels of urinary mercury (>10 µg/L) and 5% had urine mercury levels that exceeded the WHO guideline value of 50 µg/L. When participants were stratified according to occupation, those active in the mining industry had the highest mercury levels. Specifically, individuals that burned amalgam had urine mercury levels (median: 43.8 µg/L; mean ± SD: 171.1 ± 296.5 µg/L; n=5) significantly higher than median values measured in mechanical operators (11.6 µg/L, n=4), concession managers/owners (5.6 µg/L, n=11), excavators that blast and chisel ore (4.9 µg/L, n=33), individuals that sift and grind crushed ore (2.2 µg/L, n=47), support workers (0.5 µg/L, n=14), and those with no role in the mining sector (2.5 µg/L, n=6). There was a significant positive spearman correlation between fish consumption and hair mercury levels (r = 0.30) but not with urine mercury (r = 0.18) though further studies are needed to document which types of fish are consumed as well as portion sizes. Given that 200,000 people in Ghana are involved in the small-scale gold mining industry and that the numbers are expected to grow in Ghana and many other regions of the world, elucidating mercury exposure pathways in such communities is important to help shape policies and behaviors that may minimize health risks. PMID:20875913

Mercury Exposure Assessment and Spatial Distribution in A Ghanaian Small-Scale Gold Mining Community.

PubMed

Rajaee, Mozhgon; Long, Rachel N; Renne, Elisha P; Basu, Niladri

2015-09-01

Mercury is utilized worldwide in artisanal and small-scale gold mining (ASGM) and may pose a risk for miners and mining communities. While a number of studies have characterized mercury in ASGM communities, most have focused on a single media and few have taken a holistic approach. Here, a multiple media exposure assessment and cross-sectional study of mercury was conducted in 2010 through 2012 in northeast Ghana with a small-scale gold mining community, Kejetia, a subsistence farming community, Gorogo, and an urban ASGM gold refinery in Bolgatanga. The objective was to assess mercury in a range of human (urine and hair) and ecological (household soil, sediment, fish, and ore) samples to increase understanding of mercury exposure pathways. All participants were interviewed on demographics, occupational and medical histories, and household characteristics. Participants included 90 women of childbearing age and 97 adults from Kejetia and 75 adults from Gorogo. Median total specific gravity-adjusted urinary, hair, and household soil mercury were significantly higher in Kejetia miners (5.18 µg/L, 0.967 µg/g, and 3.77 µg/g, respectively) than Kejetia non-miners (1.18 µg/L, 0.419 µg/g, and 2.00 µg/g, respectively) and Gorogo participants (0.154 µg/L, 0.181 µg/g, and 0.039 µg/g) in 2011. Sediment, fish, and ore Hg concentrations were below guideline values. Median soil mercury from the Bolgatanga refinery was very high (54.6 µg/g). Estimated mean mercury ingestion for Kejetia adults from soil and dust exceeded the U.S. Environmental Protection Agency reference dose (0.3 µg Hg/kg·day) for pica (0.409 µg Hg/kg·day) and geophagy (20.5 µg Hg/kg·day) scenarios. Most participants with elevated urinary and household soil mercury were miners, but some non-miners approached and exceeded guideline values, suggesting a health risk for non-mining residents living within these communities.

Mercury

USGS Publications Warehouse

Franson, J.C.

1999-01-01

Mercury has been used by humans for over 2,000 years and was associated with premature deaths of cinnabar (mercuric sulfide) miners as early as 700 B.C. More recent human poisonings have been related to agricultural and industrial uses of mercury. One of the best documented of these cases occurred in the 1950s in Minamata Bay, Japan, when mercury was discharged into the environment and accumulated in fish and shellfish used as human food. In addition to human poisonings, mercury poisoning or toxicosis has been identified in many other species.Mercury is sometimes used to recover gold from stream sediments, and it may pose hazards to wildlife if it is released to the environment during ore recovery. Fungicidal treatment of seeds with mercury was common in the 1950s and 1960s, but this agricultural practice has been largely halted in the Northern Hemisphere.

Resource estimation from historical data: Mercury, a test case

USGS Publications Warehouse

Cargill, S.M.; Root, D.H.; Bailey, E.H.

1980-01-01

A simple technique based on historical records of tonnage and grade of ore produced provides a means for calculating how much of a mineral product will be available in the future at various average grades. Estimates made on this basis are independent of geologic considerations or changing economic and political factors, although they are based on mining history, which was largely determined by these factors. The relatively minor element, mercury, was used for the test case reported here, but the method has been found applicable to forecasts of resources for other mineral products. Mercury resources available in ore in which the average grade is as low as 0.1% are estimated to be 53 ??106kg (1.5 ??106flasks) for the United States and 1551 ??106kg (45 ??106flasks) for the world; this amount is more than adequate to meet predicted demand to the year 2000. The expectable price of mercury in 1978 dollars at this 0.1% grade is projected to be $58.75 per kg ($2,025 per flask), but at a 10% annual inflation rate, it would be more than $12,000 per flask. To satisfy just the projected U.S. demand for mercury by 2000, the price is calculated to be $48.96 per kg ($1,688 per flask) in 1978 dollars at an average annual grade of 0.12%. ?? 1980 Plenum Publishing Corporation.

Evidence of transboundary mercury and other pollutants in the Puyango-Tumbes River basin, Ecuador-Peru.

PubMed

Marshall, Bruce G; Veiga, Marcello M; Kaplan, Robert J; Adler Miserendino, Rebecca; Schudel, Gary; Bergquist, Bridget A; Guimarães, Jean R D; Sobral, Luis G S; Gonzalez-Mueller, Carolina

2018-04-25

In Portovelo in southern Ecuador, 87 gold processing centers along the Puyango-Tumbes River produce an estimated 6 tonnes of gold per annum using a combination of mercury amalgamation and/or cyanidation and processing poly-metallic ores. We analysed total Hg, Hg isotopes, total arsenic, cadmium, copper, lead and zinc in water and sediment along the Puyango in 2012-2014. The highest total mercury (THg) concentrations in sediments were found within a 40 km stretch downriver from the processing plants, with levels varying between 0.78-30.8 mg kg-1 during the dry season and 1.80-70.7 mg kg-1 during the wet season, with most concentrations above the CCME (Canadian Council of Ministers of the Environment) Probable Effect Level (PEL) of 0.5 mg kg-1. Data from mercury isotopic analyses support the conclusion that mercury use during gold processing in Portovelo is the source of Hg pollution found downstream in the Tumbes Delta in Peru, 160 km away. The majority of the water and sediment samples collected from the Puyango-Tumbes River had elevated concentrations of, arsenic, cadmium, copper, lead and zinc exceeding the CCME thresholds for the Protection of Aquatic Life. At monitoring points immediately below the processing plants, total dissolved concentrations of these metals exceeded the thresholds by 156-3567 times in surface waters and by 19-740 times in sediment. The results illustrate a significant transboundary pollution problem involving Hg and other toxic metals, amplified by the fact that the Puyango-Tumbes River is the only available water source in the semi-arid region of northern Peru.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elias, D.F.; Corbin, W.E.

Mercury, or quicksilver, and its major ore cinnabar (HgS) have been known for thousands of years. Health effects from mercury such as dementia were known as early as the late 19th century ({open_quotes}mad as a hatter{close_quotes}). In the 1960`s and 1970`s, reported levels of mercury in tuna reawakened public awareness of mercury pollution. In the 1970`s, major epidemics of acute mercury poisoning were reported in Japan and Iraq. These incidents highlighted the extreme health risks, such as kidney damage, birth defects, and death, associated with severe mercury poisoning. Fetuses and young children are particularly vulnerable since mercury poisoning can damagemore » growing neural tissues. Recently, the perception of mercury as a dangerous pollutant has been on the rise. Advisories warning the public to avoid or reduce the consumption of freshwater fish caught in specific waterbodies due to mercury contamination have been issued in numerous states. The discovery of mercury in {open_quotes}pristine{close_quotes} lakes in the United States, Canada, and Scandinavia, remote from industry and any known mercury sources, has focused attention on atmospheric emissions of mercury as potential significant sources of mercury.« less

Gaseous Oxidized Mercury Flux from Substrates Associated with Industrial Scale Gold Mining in Nevada, USA

NASA Astrophysics Data System (ADS)

Miller, M. B.

2015-12-01

Gaseous elemental and oxidized mercury (Hg) fluxes were measured in a laboratory setting from substrate materials derived from industrial-scale open pit gold mining operations in Nevada, USA. Mercury is present in these substrates at a range of concentrations (10 - 40000 ng g-1), predominantly of local geogenic origin in association with the mineralized gold ores, but altered and redistributed to a varying degree by subsequent ore extraction and processing operations, including deposition of Hg recently emitted to the atmosphere from large point sources on the mines. Waste rock, heap leach, and tailings material usually comprise the most extensive and Hg emission relevant substrate surfaces. All three of these material types were collected from active Nevada mine sites in 2010 for previous research, and have since been stored undisturbed at the University of Nevada, Reno. Gaseous elemental Hg (GEM) flux was previously measured from these materials under a variety of conditions, and was re-measured in this study, using Teflon® flux chambers and Tekran® 2537A automated ambient air analyzers. GEM flux from dry undisturbed materials was comparable between the two measurement periods. Gaseous oxidized Hg (GOM) flux from these materials was quantified using an active filter sampling method that consisted of polysulfone cation-exchange membranes deployed in conjunction with the GEM flux apparatus. Initial measurements conducted within greenhouse laboratory space indicate that in dry conditions GOM is deposited to relatively low Hg cap and leach materials, but may be emitted from the much higher Hg concentration tailings material.

40 CFR 440.44 - New source performance standards (NSPS).

Code of Federal Regulations, 2011 CFR

2011-07-01

... attainable by the application of the best available demonstrated technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines, either open pit or underground, that produce mercury ores...

Geological structure and prospects of noble metal ore mineralization of the Khayrkhan gabbroid massif (Western Mongolia)

NASA Astrophysics Data System (ADS)

Kurumshieva, K. R.; Gertner, I. F.; Tishin, P. A.

2017-12-01

An analysis of the distribution of noble metals in zones of sulfide mineralization makes it possible to justify the isolation of four ore-bearing horizons with a specific geochemical zonation. A rise in the gold content relative to palladium and platinum is observed from the bottom upwards along the section of the stratified series of gabbroids. The study of the mineral phases of sulphides and the noble minerals itself indicates the evolution of hydrothermal solutions, which determines the different activity and mobility of the fluid (mercury, tellurium, sulfur) and ore (copper, nickel, iron, platinum, gold and silver) components.

Estimating usable resources from historical industry data.

USGS Publications Warehouse

Cargill, S.M.; Root, D.H.; Bailey, E.H.

1981-01-01

The commodities considered are mercury, copper and its byproducts gold and silver, and petroleum; the production and discovery data are for the US. The results indicate that the cumulative return per unit of effort, herein measured as grade of metal ores and discovery rate of recoverable petroleum, is proportional to a negative power of total effort expended, herein measured as total ore mined and total exploratory wells or footage drilled. This power relationship can be extended to some limiting point (a lower ore grade or a maximum number of exploratory wells or footage), and the apparent quantity of available remaining resource at that limit can be calculated. -from Authors

Optimization of gold ore Sumbawa separation using gravity method: Shaking table

NASA Astrophysics Data System (ADS)

Ferdana, Achmad Dhaefi; Petrus, Himawan Tri Bayu Murti; Bendiyasa, I. Made; Prijambada, Irfan Dwidya; Hamada, Fumio; Sachiko, Takahi

2018-04-01

Most of artisanal small gold mining in Indonesia has been using amalgamation method, which caused negative impact to the environment around ore processing area due to the usage of mercury. One of the more environmental-friendly method for gold processing is gravity method. Shaking table is one of separation equipment of gravity method used to increase concentrate based on difference of specific gravity. The optimum concentration result is influenced by several variables, such as rotational speed shaking, particle size and deck slope. In this research, the range of rotational speed shaking was between 100 rpm and 200 rpm, the particle size was between -100 + 200 mesh and -200 + 300 mesh and deck slope was between 3° and 7°. Gold concentration in concentrate was measured by EDX. The result shows that the optimum condition is obtained at a shaking speed of 200 rpm, with a slope of 7° and particle size of -100 + 200 mesh.

Mercury isotope constraints on the source for sediment-hosted lead-zinc deposits in the Changdu area, southwestern China

NASA Astrophysics Data System (ADS)

Xu, Chunxia; Yin, Runsheng; Peng, Jiantang; Hurley, James P.; Lepak, Ryan F.; Gao, Jianfeng; Feng, Xinbin; Hu, Ruizhong; Bi, Xianwu

2018-03-01

The Lanuoma and Cuona sediment-hosted Pb-Zn deposits hosted by Upper Triassic limestone and sandstone, respectively, are located in the Changdu area, SW China. Mercury concentrations and Hg isotopic compositions from sulfide minerals and potential source rocks (e.g., the host sedimentary rocks and the metamorphic basement) were investigated to constrain metal sources and mineralization processes. In both deposits, sulfide minerals have higher mercury (Hg) concentrations (0.35 to 1185 ppm) than the metamorphic basement rocks (0.05 to 0.15 ppm) and sedimentary rocks (0.02 to 0.08 ppm). Large variations of mass-dependent fractionation (3.3‰ in δ202Hg) and mass-independent fractionation (0.3‰ in Δ199Hg) of Hg isotopes were observed. Sulfide minerals have Hg isotope signatures that are similar to the hydrothermal altered rocks around the deposit, and similar to the metamorphic basement, but different from barren sedimentary rocks. The variation of Δ199Hg suggests that Hg in sulfides was mainly derived from the underlying metamorphic basement. Mercury isotopes could be a geochemical tracer in understanding metal sources in hydrothermal ore deposits.

Occupational and environmental mercury exposure among small-scale gold miners in the Talensi-Nabdam District of Ghana's Upper East region.

PubMed

Paruchuri, Yasaswi; Siuniak, Amanda; Johnson, Nicole; Levin, Elena; Mitchell, Katherine; Goodrich, Jaclyn M; Renne, Elisha P; Basu, Niladri

2010-11-15

Mercury use in small-scale gold mining is ubiquitous across Ghana but little is known about the extent to which such activities have contaminated community residents and miners. Here, occupational exposures to elemental mercury (via urine sampling) and dietary exposures to methylmercury (via hair sampling) were assessed among 120 participants recruited from a mining community located in the Talensi-Nabdam District of Ghana's Upper East region during summer 2009. More than one-fifth of the participants had moderately high levels of urinary mercury (>10μg/L) and 5% had urine mercury levels that exceeded the WHO guideline value of 50μg/L. When participants were stratified according to occupation, those active in the mining industry had the highest mercury levels. Specifically, individuals that burned amalgam had urine mercury levels (median: 43.8μg/L; mean ± SD: 171.1±296.5μg/L; n=5) significantly higher than median values measured in mechanical operators (11.6μg/L, n=4), concession managers/owners (5.6μg/L, n=11), excavators that blast and chisel ore (4.9μg/L, n=33), individuals that sift and grind crushed ore (2.2μg/L, n=47), support workers (0.5μg/L, n=14), and those with no role in the mining sector (2.5μg/L, n=6). There was a significant positive Spearman correlation between fish consumption and hair mercury levels (r=0.30) but not with urine mercury (r=0.18) though further studies are needed to document which types of fish are consumed as well as portion sizes. Given that 200,000 people in Ghana are involved in the small-scale gold mining industry and that the numbers are expected to grow in Ghana and many other regions of the world, elucidating mercury exposure pathways in such communities is important to help shape policies and behaviors that may minimize health risks. Copyright © 2010 Elsevier B.V. All rights reserved.

Advanced mercury removal from gold leachate solutions prior to gold and silver extraction: a field study from an active gold mine in Peru.

PubMed

Matlock, Matthew M; Howerton, Brock S; Van Aelstyn, Mike A; Nordstrom, Fredrik L; Atwood, David A

2002-04-01

Mercury contamination in the Gold-Cyanide Process (GCP) is a serious health and environmental problem. Following the heap leaching of gold and silver ores with NaCN solutions, portions of the mercury-cyano complexes often adhere to the activated carbon (AC) used to extract the gold. During the electrowinning and retorting steps, mercury can be (and often is) emitted to the air as a vapor. This poses a severe health hazard to plant workers and the local environment. Additional concerns relate to the safety of workers when handling the mercury-laden AC. Currently, mercury treatment from the heap leach solution is nonexistent. This is due to the fact that chelating ligands which can effectively work under the adverse pH conditions (as present in the heap leachate solutions) do not exist. In an effort to economically and effectively treat the leachate solution prior to passing over the AC, a dipotassium salt of 1,3-benzenediamidoethanethiol (BDET2-) has been developed to irreversibly bind and precipitate the mercury. The ligand has proven to be highly effective by selectively reducing mercury levels from average initial concentrations of 34.5 ppm (parts per million) to 0.014 ppm within 10 min and to 0.008 ppm within 15 min. X-ray powder diffraction (XRD), proton nuclear magnetic resonance (1H NMR), Raman, and infrared (IR) spectroscopy demonstrate the formation of a mercury-ligand compound, which remains insoluble over pH ranges of 0.0-14.0. Leachate samples from an active gold mine in Peru have been analyzed using cold vapor atomic fluorescence (CVAF) and inductively coupled plasma optical emission spectroscopy (ICP-OES) for metal concentrations before and after treatment with the BDET2- ligand.

Physical, chemical and antimicrobial characterization of copper-bearing material

NASA Astrophysics Data System (ADS)

Li, Bowen; Hwang, Jiann-Yang; Drelich, Jaroslaw; Popko, Domenic; Bagley, Susan

2010-12-01

Arsenic, cadmium, copper, mercury, silver, and zinc are elements with strong antimicrobial properties. Among them, copper is more environmentally friendly and has both good antibacterial and antifungal properties. It has been shown that copper can even be effective against new viruses such as avian influenza (H5N1). Development of copper-bearing materials for various applications, therefore, is receiving increased attention. The Keweenaw Peninsula of Michigan was the largest native copper mining regions of North America at the turn of the 20th century. Copper was extracted by mining the copper-rich basaltic rock, and steamdriven stamp mills were used to process a great volume of low-grade ores, resulting in huge amounts of crushed waste ore called stamp sands. Approximately 500 million tons of stamp sand were discarded. This material is investigated in this study as an example for the development of antimicrobial materials.

Mercury methylation at mercury mines in the Humboldt River Basin, Nevada, USA

USGS Publications Warehouse

Gray, J.E.; Crock, J.G.; Lasorsa, B.K.

2002-01-01

Total Hg and methylmercury concentrations were measured in mine-waste calcines (retorted ore), sediment, and water samples collected in and around abandoned mercury mines in western Nevada to evaluate Hg methylation at the mines and in the Humboldt River Basin. Mine-waste calcines contain total Hg concentrations as high as 14 000 ??g g-1. Stream-sediment samples collected within 1 km of the mercury mines contain total Hg concentrations as high as 170 ??g g-1, whereas stream sediments collected at a distance >5 km from the mines, and those collected from the Humboldt River and regional baseline sites, contain total Hg concentrations 8 km from the nearest mercury mines. Our data indicate little transference of Hg and methylmercury from the sediment to the water column due to the lack of mine runoff in this desert climate.

Long-range effect of cyanide on mercury methylation in a gold mining area in southern Ecuador.

PubMed

Guimaraes, Jean Remy Davée; Betancourt, Oscar; Miranda, Marcio Rodrigues; Barriga, Ramiro; Cueva, Edwin; Betancourt, Sebastián

2011-11-01

Small-scale gold mining in Portovelo-Zaruma, Southern Equador, performed by mercury amalgamation and cyanidation, yields 9-10 t of gold/annum, resulting in annual releases of around 0.65 t of inorganic mercury and 6000 t of sodium cyanide in the local river system. The release of sediments, cyanide, mercury, and other metals present in the ore such as lead, manganese and arsenic significantly reduces biodiversity downstream the processing plants and enriches metals in bottom sediments and biota. However, methylmercury concentrations in sediments downstream the mining area were recently found to be one order of magnitude lower than upstream or in small tributaries. In this study we investigated cyanide, bacterial activity in water and sediment and mercury methylation potentials in sediments along the Puyango river watershed, measured respectively by in-situ spectrophotometry and incubation with (3)H-leucine and (203)Hg(2+). Free cyanide was undetectable (<1 μg·L(-1)) upstream mining activities, reached 280 μg·L(-1) a few km downstream the processing plants area and was still detectable about 100 km downstream. At stations with detectable free cyanide in unfiltered water, 50% of it was dissolved and 50% associated to suspended particles. Bacterial activity and mercury methylation in sediment showed a similar spatial pattern, inverse to the one found for free cyanide in water, i.e. with significant values in pristine upstream sampling points (respectively 6.4 to 22 μgC·mg wet weight(-1)·h(-1) and 1.2 to 19% of total (203) Hg·gdry weight(-1)·day(-1)) and undetectable downstream the processing plants, returning to upstream values only in the most distant downstream stations. The data suggest that free cyanide oxidation was slower than would be expected from the high water turbulence, resulting in a long-range inhibition of bacterial activity and hence mercury methylation. The important mercury fluxes resultant from mining activities raise concerns about its biomethylation in coastal areas where many mangrove areas have been converted to shrimp farming. Copyright © 2011. Published by Elsevier B.V.

Linking geological and health sciences to assess childhood lead poisoning from artisanal gold mining in Nigeria.

PubMed

Plumlee, Geoffrey S; Durant, James T; Morman, Suzette A; Neri, Antonio; Wolf, Ruth E; Dooyema, Carrie A; Hageman, Philip L; Lowers, Heather A; Fernette, Gregory L; Meeker, Gregory P; Benzel, William M; Driscoll, Rhonda L; Berry, Cyrus J; Crock, James G; Goldstein, Harland L; Adams, Monique; Bartrem, Casey L; Tirima, Simba; Behbod, Behrooz; von Lindern, Ian; Brown, Mary Jean

2013-06-01

In 2010, Médecins Sans Frontières discovered a lead poisoning outbreak linked to artisanal gold processing in northwestern Nigeria. The outbreak has killed approximately 400 young children and affected thousands more. Our aim was to undertake an interdisciplinary geological- and health-science assessment to clarify lead sources and exposure pathways, identify additional toxicants of concern and populations at risk, and examine potential for similar lead poisoning globally. We applied diverse analytical methods to ore samples, soil and sweep samples from villages and family compounds, and plant foodstuff samples. Natural weathering of lead-rich gold ores before mining formed abundant, highly gastric-bioaccessible lead carbonates. The same fingerprint of lead minerals found in all sample types confirms that ore processing caused extreme contamination, with up to 185,000 ppm lead in soils/sweep samples and up to 145 ppm lead in plant foodstuffs. Incidental ingestion of soils via hand-to-mouth transmission and of dusts cleared from the respiratory tract is the dominant exposure pathway. Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways. Although young children suffered the most immediate and severe consequences, results indicate that older children, adult workers, pregnant women, and breastfed infants are also at risk for lead poisoning. Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats. Results inform ongoing efforts in Nigeria to assess lead contamination and poisoning, treat victims, mitigate exposures, and remediate contamination. Ore deposit geology, pre-mining weathering, and burgeoning artisanal mining may combine to cause similar lead poisoning disasters elsewhere globally.

Linking Geological and Health Sciences to Assess Childhood Lead Poisoning from Artisanal Gold Mining in Nigeria

PubMed Central

Durant, James T.; Morman, Suzette A.; Neri, Antonio; Wolf, Ruth E.; Dooyema, Carrie A.; Hageman, Philip L.; Lowers, Heather A.; Fernette, Gregory L.; Meeker, Gregory P.; Benzel, William M.; Driscoll, Rhonda L.; Berry, Cyrus J.; Crock, James G.; Goldstein, Harland L.; Adams, Monique; Bartrem, Casey L.; Tirima, Simba; Behbod, Behrooz; von Lindern, Ian; Brown, Mary Jean

2013-01-01

Background: In 2010, Médecins Sans Frontières discovered a lead poisoning outbreak linked to artisanal gold processing in northwestern Nigeria. The outbreak has killed approximately 400 young children and affected thousands more. Objectives: Our aim was to undertake an interdisciplinary geological- and health-science assessment to clarify lead sources and exposure pathways, identify additional toxicants of concern and populations at risk, and examine potential for similar lead poisoning globally. Methods: We applied diverse analytical methods to ore samples, soil and sweep samples from villages and family compounds, and plant foodstuff samples. Results: Natural weathering of lead-rich gold ores before mining formed abundant, highly gastric-bioaccessible lead carbonates. The same fingerprint of lead minerals found in all sample types confirms that ore processing caused extreme contamination, with up to 185,000 ppm lead in soils/sweep samples and up to 145 ppm lead in plant foodstuffs. Incidental ingestion of soils via hand-to-mouth transmission and of dusts cleared from the respiratory tract is the dominant exposure pathway. Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways. Although young children suffered the most immediate and severe consequences, results indicate that older children, adult workers, pregnant women, and breastfed infants are also at risk for lead poisoning. Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats. Conclusions: Results inform ongoing efforts in Nigeria to assess lead contamination and poisoning, treat victims, mitigate exposures, and remediate contamination. Ore deposit geology, pre-mining weathering, and burgeoning artisanal mining may combine to cause similar lead poisoning disasters elsewhere globally. PMID:23524139

Linking geology and health sciences to assess childhood lead poisoning from artisanal gold mining in Nigeria

USGS Publications Warehouse

Plumlee, Geoffrey S.; Durant, James T.; Morman, Suzette A.; Neri, Antonio; Wolf, Ruth E.; Dooyema, Carrie A.; Hageman, Philip L.; Lowers, Heather; Fernette, Gregory L.; Meeker, Gregory P.; Benzel, William M.; Driscoll, Rhonda L.; Berry, Cyrus J.; Crock, James G.; Goldstein, Harland L.; Adams, Monique; Bartrem, Casey L.; Tirima, Simba; Behrooz, Behbod; von Lindern, Ian; Brown, Mary Jean

2013-01-01

Background: In 2010, Médecins Sans Frontières discovered a lead poisoning outbreak linked to artisanal gold processing in northwestern Nigeria. The outbreak has killed approximately 400 young children and affected thousands more. Objectives: Our aim was to undertake an interdisciplinary geological- and health-science assessment to clarify lead sources and exposure pathways, identify additional toxicants of concern and populations at risk, and examine potential for similar lead poisoning globally. Methods: We applied diverse analytical methods to ore samples, soil and sweep samples from villages and family compounds, and plant foodstuff samples. Results: Natural weathering of lead-rich gold ores before mining formed abundant, highly gastric-bioaccessible lead carbonates. The same fingerprint of lead minerals found in all sample types confirms that ore processing caused extreme contamination, with up to 185,000 ppm lead in soils/sweep samples and up to 145 ppm lead in plant foodstuffs. Incidental ingestion of soils via hand-to-mouth transmission and of dusts cleared from the respiratory tract is the dominant exposure pathway. Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways. Although young children suffered the most immediate and severe consequences, results indicate that older children, adult workers, pregnant women, and breastfed infants are also at risk for lead poisoning. Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats. Conclusions: Results inform ongoing efforts in Nigeria to assess lead contamination and poisoning, treat victims, mitigate exposures, and remediate contamination. Ore deposit geology, pre-mining weathering, and burgeoning artisanal mining may combine to cause similar lead poisoning disasters elsewhere globally.

Estimating usable resources from historical industry data

USGS Publications Warehouse

Cargill, S.M.; Root, D.H.; Bailey, E.H.

1981-01-01

Historical production statistics are used to predict the quantity of remaining usable resources. The commodities considered are mercury, copper and its byproducts gold and silver, and petroleum; the production and discovery data are for the United States. The results of the study indicate that the cumulative return per unit of effort, herein measured as grade of metal ores and discovery rate of recoverable petroleum, is proportional to a negative power of total effort expended, herein measured as total ore mined and total exploratory wells or footage drilled. This power relationship can be extended to some limiting point (a lower ore grade or a maximum number of exploratory wells or footage), and the apparent quantity of available remaining resource at that limit can be calculated. For mercury ore of grades at and above 0.1 percent, the remaining usable resource in the United States is calculated to be 54 million kg (1,567,000 flasks). For copper ore of grades at and above 0.2 percent, the remaining usable copper resource is calculated to be 270 million metric tons (298 million short tons); remaining resources of its by-products gold and silver are calculated to be 3,656 metric tons (118 million troy ounces) and 64,676 metric tons (2,079 million troy ounces), respectively. The undiscovered recoverable crude oil resource in the conterminous United States, at 3 billion feet of additional exploratory drilling, is calculated to be nearly 37.6 billion barrels; the undiscovered recoverable petroleum resource in the Permian basin of western Texas and southeastern New Mexico, at 300 million feet of additional exploratory drilling or 50,000 additional exploratory wells, is calculated to be about 6.2 billion BOE (barrels of oil equivalent).

Distribution of mercury species and mercury isotope ratios in soils and river suspended matter of a mercury mining area.

PubMed

Baptista-Salazar, Carluvy; Hintelmann, Holger; Biester, Harald

2018-04-25

Mercury (Hg) released by mining activities can be dispersed in the environment, where it is subject to species transformations. Hg isotope ratios have been used to track sources in Hg contaminated areas, although it is unclear to what extent variations in δ-values are attributed to distinct Hg species. Hg was mined as Hg sulphide (cinnabar) in Idrija, Slovenia for centuries. Sediments are loaded with mining-residues (cinnabar and calcine), whereas contaminated soils mainly contain Hg bound to natural organic matter (NOM-Hg) related to atmospheric Hg deposition. Hg released from soils and sediments is transported as suspended matter (SM) in the Idrijca river to the Gulf of Trieste (GT), Italy. We determine Hg isotope ratios in river SM, sediments and soils from the Idrijca-catchment to decipher the Hg isotope ratio variability related to Hg species distribution in different grain-size fractions. δ202Hg values of SM collected from tributaries corresponded to those found in soils ranging from -2.58 to 0.19‰ and from -2.27 to -0.88‰, respectively. Speciation measurements reveal that fine fractions (0.45-20 μm) are dominated by NOM-Hg, while larger fractions contain more cinnabar. More negative δ202Hg values were related to higher proportions of NOM-Hg, which are predominant in soils and SM. Rain events increase SM-loads in the river, mainly due to resuspension of coarse grain-size fractions of bottom sediments bearing larger proportions of cinnabar, which leads to more positive δ202Hg values. The large magnitude of variation in δ202Hg and the smaller magnitude of variation in Δ199Hg (-0.37 to 0.09‰) are likely related to fractionation during ore roasting. Soil samples with high NOM-Hg content show more negative δ202Hg values and larger variation of Δ199Hg. More negative δ202Hg values in GT sediments were rather linked to distant sedimentation of soil derived NOM-Hg than to sedimentation of autochthonous marine material. Heterogeneity in the Idrija ore and ore processing likely produce large variations in the Hg isotopic composition of cinnabar and released metallic Hg, which complicate the differentiation of Hg sources. Combining Hg isotope measurements with solid phase Hg speciation reveals that Hg isotope ratios rather indicate different Hg species and are not necessarily symptomatic for Hg pollution sources.

Mercury transformation and speciation in flue gases from anthropogenic emission sources: a critical review

NASA Astrophysics Data System (ADS)

Zhang, L.; Wang, S. X.; Wu, Q. R.; Wang, F. Y.; Lin, C.-J.; Zhang, L. M.; Hui, M. L.; Hao, J. M.

2015-11-01

Mercury transformation mechanisms and speciation profiles are reviewed for mercury formed in and released from flue gases of coal-fired boilers, non-ferrous metal smelters, cement plants, iron and steel plants, municipal solid waste incinerators, and biomass burning. Mercury in coal, ores and other raw materials is released to flue gases in the form of Hg0 during combustion or smelting in boilers, kilns or furnaces. Decreasing temperature from over 800 °C to below 300 °C in flue gases leaving boilers, kilns or furnaces promotes homogeneous and heterogeneous oxidation of gaseous elemental mercury (Hg0) to gaseous divalent mercury (Hg2+), with a portion of Hg2+ adsorbed onto fly ash to form particulate-bound mercury (Hgp). Halogen is the primary oxidizer for Hg0 in flue gases, and active components (e.g.,TiO2, Fe2O3, etc.) on fly ash promote heterogeneous oxidation and adsorption processes. In addition to mercury removal, mercury transformation also occurs when passing through air pollution control devices (APCDs), affecting the mercury speciation in flue gases. In coal-fired power plants, selective catalytic reduction (SCR) system promotes mercury oxidation by 34-85 %, electrostatic precipitator (ESP) and fabric filter (FF) remove over 99 % of Hgp, and wet flue gas desulfurization system (WFGD) captures 60-95 % of Hg2+. In non-ferrous metal smelters, most Hg0 is converted to Hg2+ and removed in acid plants (APs). For cement clinker production, mercury cycling and operational conditions promote heterogeneous mercury oxidation and adsorption. The mercury speciation profiles in flue gases emitted to the atmosphere are determined by transformation mechanisms and mercury removal efficiencies by various APCDs. For all the sectors reviewed in this study, Hgp accounts for less than 5 % in flue gases. In China, mercury emission has a higher fraction (66-82 % of total mercury) in flue gases from coal combustion, in contrast to a greater Hg2+ fraction (29-90 %) from non-ferrous metal smelting, cement and iron/steel production. The higher Hg2+ fractions shown here than previous estimates may imply stronger local environmental impacts than previously thought, caused by mercury emissions in East Asia. Future research should focus on determining mercury speciation in flue gases from iron and steel plants, waste incineration and biomass burning, and on elucidating the mechanisms of mercury oxidation and adsorption in flue gases.

Mercury transformation and speciation in flue gases from anthropogenic emission sources: a critical review

NASA Astrophysics Data System (ADS)

Zhang, Lei; Wang, Shuxiao; Wu, Qingru; Wang, Fengyang; Lin, Che-Jen; Zhang, Leiming; Hui, Mulin; Yang, Mei; Su, Haitao; Hao, Jiming

2016-02-01

Mercury transformation mechanisms and speciation profiles are reviewed for mercury formed in and released from flue gases of coal-fired boilers, non-ferrous metal smelters, cement plants, iron and steel plants, waste incinerators, biomass burning and so on. Mercury in coal, ores, and other raw materials is released to flue gases in the form of Hg0 during combustion or smelting in boilers, kilns or furnaces. Decreasing temperature from over 800 °C to below 300 °C in flue gases leaving boilers, kilns or furnaces promotes homogeneous and heterogeneous oxidation of Hg0 to gaseous divalent mercury (Hg2+), with a portion of Hg2+ adsorbed onto fly ash to form particulate-bound mercury (Hgp). Halogen is the primary oxidizer for Hg0 in flue gases, and active components (e.g., TiO2, Fe2O3, etc.) on fly ash promote heterogeneous oxidation and adsorption processes. In addition to mercury removal, mercury transformation also occurs when passing through air pollution control devices (APCDs), affecting the mercury speciation in flue gases. In coal-fired power plants, selective catalytic reduction (SCR) system promotes mercury oxidation by 34-85 %, electrostatic precipitator (ESP) and fabric filter (FF) remove over 99 % of Hgp, and wet flue gas desulfurization system (WFGD) captures 60-95 % of Hg2+. In non-ferrous metal smelters, most Hg0 is converted to Hg2+ and removed in acid plants (APs). For cement clinker production, mercury cycling and operational conditions promote heterogeneous mercury oxidation and adsorption. The mercury speciation profiles in flue gases emitted to the atmosphere are determined by transformation mechanisms and mercury removal efficiencies by various APCDs. For all the sectors reviewed in this study, Hgp accounts for less than 5 % in flue gases. In China, mercury emission has a higher Hg0 fraction (66-82 % of total mercury) in flue gases from coal combustion, in contrast to a greater Hg2+ fraction (29-90 %) from non-ferrous metal smelting, cement and iron and/or steel production. The higher Hg2+ fractions shown here than previous estimates may imply stronger local environmental impacts than previously thought, caused by mercury emissions in East Asia. Future research should focus on determining mercury speciation in flue gases from iron and steel plants, waste incineration and biomass burning, and on elucidating the mechanisms of mercury oxidation and adsorption in flue gases.

Mercury and methylmercury contents in mine-waste calcine, water, and sediment collected from the Palawan Quicksilver mine, Philippines

USGS Publications Warehouse

Gray, J.E.; Greaves, I.A.; Bustos, D.M.; Krabbenhoft, D.P.

2003-01-01

The Palawan Quicksilver mine, Philippines, produced about 2,900 t of mercury during mining of cinnabar ore from 1953 to 1976. More than 2,000,000 t of mine-waste calcines (retorted ore) were produced during mining, much of which were used to construct a jetty in nearby Honda Bay. Since 1995, high Hg contents have been found in several people living near the mine, and 21 of these people were treated for mercury poisoning. Samples of mine-waste calcine contain high total Hg concentrations ranging from 43-660 ??g/g, whereas total Hg concentrations in sediment samples collected from a mine pit lake and local stream vary from 3.7-400 ??g/g. Mine water flowing through the calcines is acidic, pH 3.1-4.3, and total Hg concentrations ranging from 18-31 ??g/l in this water significantly exceed the 1.0-??g/l drinking water standard for Hg recommended by the World Health Organization (WHO). Total Hg contents are generally lower in water samples collected from surrounding domestic wells, the mine pit lake, Honda Bay, and the nearby stream, varying from 0.008-1.4 ??g/l. Methylmercury concentrations in water draining mine calcines range from <0.02-1.4 ng/l, but methylmercury is highest in the pit lake water, ranging from 1.7-3.1 ng/l. Mercury methylation at the Palawan mine is similar to or higher than that found in other mercury mines worldwide. Much of the methylmercury generated in Palawan mine-waste calcines and those in Honda Bay is transferred to water, and then to marine fish and seafood. A food source pathway of Hg to humans is most likely in this coastal, high fish-consuming population.

Publications - SR 53 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

Group; Lead; Limestone; Lode; Marble; Mercury; Mesozoic; Metallurgy; Metamorphic Rocks; Mineral Pluton; Nickel; Nikolai Greenstone; Noatak Sandstone; Nome Group; Nuggets; Orca Group; Ordovician; Ores ; Paleozoic; Palladium; Pennsylvanian; Placer; Platinum; Platinum Group Elements; Plutonic; Plutonic Hosted

Geochemistry of selected mercury mine-tailings in the Parkfield Mercury District, California

USGS Publications Warehouse

Rytuba, James J.; Kotlyar, Boris B.; Wilkerson, Gregg; Olson, Jerry

2001-01-01

The Parkfield mercury district is located in the southern part of the California Coast Range mercury mineral belt and contains three silica-carbonate-type mercury deposits that have had significant mercury production. Mercury was first produced in the district in 1873, but the main period of production occurred from 1915-1922. Total production from the district is about 5,000 flasks of mercury (a flask equals 76 pounds of mercury) with most production coming from the Patriquin mine (1,875 flasks), and somewhat less from the King (1,600 flasks) and Dawson (1,470 flasks) mines. Several other small prospects and mines occur in the district but only minor production has come from them. In 1969, Phelan Sulphur Company carried out mineral exploration at the King mine and announced the discovery of 55,000 tons of mercury ore with an average grade of 5.2 pounds per ton. The King mine is located on federal land administered by the U.S. Bureau of Land Management. Several other parcels of federal land are present adjacent to other mines and prospects in the Parkfield district. An environmental assessment of mine sites on and adjacent to federal land was carried out to determine the amount of mercury and other trace metals present in mine wastes and in sediments from streams impacted by past mining.

Critical elements in Carlin, epithermal, and orogenic gold deposits

USGS Publications Warehouse

Goldfarb, Richard J.; Hofstra, Albert H.; Simmons, Stuart F.

2016-01-01

Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered, although typically in small amounts, by historic mining activities. These elements include As, Bi, Hg, In, Sb, Se, Te, Tl, and W. Most of these elements are now solely recovered as by-products from the milling of large-tonnage, base metal-rich ore deposits, such as porphyry and volcanogenic massive sulfide deposits.A combination of dominance of the world market by a single country for a single commodity and a growing demand for many of the critical to near-critical elements could lead to future recovery of such elements from select epithermal, orogenic, or Carlin-type gold deposits. Antimony continues to be recovered from some orogenic gold deposits and tellurium could potentially be a primary commodity from some such deposits. Tellurium and indium in sphalerite-rich ores have been recovered in the past and could be future commodities recovered from epithermal ores. Carlin-type gold deposits in Nevada are enriched in and may be a future source for As, Hg, Sb, and/or Tl. Some of the Devonian carbonaceous host rocks in the Carlin districts are sufficiently enriched in many trace elements, including Hg, Se, and V, such that they also could become resources. Thallium may be locally enriched to economic levels in Carlin-type deposits and it has been produced from Carlin-like deposits elsewhere in the world (e.g., Alsar, southern Macedonia; Lanmuchang, Guizhou province, China). Mercury continues to be recovered from shallow-level epithermal deposits, as well as a by-product of many Carlin-type deposits where refractory ore is roasted to oxidize carbon and pyrite, and mercury is then captured in air pollution control devices.

ASSESSING AND MANAGING MERCURY FROM HISTORIC AND CURRENT MINING ACTIVITIES

EPA Science Inventory

Mining activities in the US (not counting coal) produce between one and two billion tons of mine waste annually. Since many of the ore mines involve sulfide minerals, the production of acid mine drainage (AMD) is a common problem from these abandoned mine sites. The combination o...

Multielemental analysis of Migori (Southwest, Kenya) artisanal gold mine ores and sediments by EDX-ray fluorescence technique: implications of occupational exposure and environmental impact.

PubMed

Odumo, O B; Mustapha, A O; Patel, J P; Angeyo, H K

2011-05-01

The results of heavy element profiling of the gold ores and sediments associated with the artisanal gold mining activities of the Migori gold belt of Southwestern Nyanza, Kenya, were reported in this paper. The analysis was made to assess the occupational exposure of the miners as well as to investigate the environmental impact of toxic heavy metals. Gold ores and sediments from the artisanal gold processing were sampled in four artisanal gold mining areas: Osiri A, Osiri B, Mikei and Macalder (Makalda) and analyzed for heavy elemental content using (109)Cd radioisotope excited EDXRF spectrometry technique. Analysis consisted of direct irradiating of sample pellets. The concentrations of major elements detected were: titanium (711.41-10,766.67 mg/kg); cobalt (82.65-1,010.00 mg/kg); zinc (29.90-63,210 mg/kg); arsenic (29.30-8,246.59 mg/kg); gold (14.07-73.48 mg/kg); lead (16.31-14,999.40 mg/kg) and mercury (16.10-149.93 mg/kg). The average concentration of the heavy toxic metals i.e. arsenic, lead, titanium and zinc were found to be above 50 mg/Kg as recommended by World Health Organization. © Springer Science+Business Media, LLC 2011

Geochemical investigation of potentially harmful elements in household dust from a mercury-contaminated site, the town of Idrija (Slovenia).

PubMed

Bavec, Špela; Gosar, Mateja; Miler, Miloš; Biester, Harald

2017-06-01

A comprehensive geochemical investigation of potentially harmful elements (PHEs) in household dust from the town of Idrija (Slovenia), once a world-famous Hg mining town that is now seriously polluted, was performed for the first time. After aqua regia digestion, the content of mercury (Hg), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), molybdenum (Mo), nickel (Ni), lead (Pb) and zinc (Zn) was measured. PHE-bearing particles were recognised and observed by scanning electron microscopy and energy-dispersive spectrometry before and after exposure to simulated stomach acid (SSA). Mercury binding forms were identified by Hg thermal desorption technique and gastric bioaccessible Hg was estimated after SSA extraction by ICP-MS. With regard to rural and urban background values for Slovenia, high Hg content (6-120 mg/kg) and slightly elevated As content (1-13 mg/kg) were found. Mercury pollution is a result of past mining and ore processing activities. Arsenic content is potentially associated with As enrichment in local soils. Four Hg binding forms were identified: all samples contained Hg bound to the dust matrix, 14 samples contained cinnabar, two samples contained metallic Hg (Hg 0 ), and one sample assumingly contained mercury oxide. After exposure to SSA, Hg-bearing phases showed no signs of dissolution, while other PHE-bearing phases were significantly morphologically and/or chemically altered. Estimated gastric Hg bioaccessibility was low (<0.006-0.09 %), which is in accordance with identified Hg binding forms and high organic carbon content (15.9-31.5 %) in the dust samples.

Binding of Vapour-Phase Mercury (Hg0) on Chemically Treated Bauxite Residues (Red Mud)

EPA Science Inventory

In this study, Hg capture using red mud, seawater-neutralized red mud, and acid-treated red mud is evaluated and compared to other, more conventional sorbent materials. Red mud (also known as bauxite residue) is a by-product of extracting alumina from ground bauxite ore by treati...

A preliminary study on health effects in villagers exposed to mercury in a small-scale artisanal gold mining area in Indonesia.

PubMed

Bose-O'Reilly, Stephan; Schierl, Rudolf; Nowak, Dennis; Siebert, Uwe; William, Jossep Frederick; Owi, Fradico Teorgi; Ir, Yuyun Ismawati

2016-08-01

Cisitu is a small-scale gold mining village in Indonesia. Mercury (Hg) is used to extract gold from ore, heavily polluting air, soil, fish and rice paddy fields with Hg. Rice in Cisitu is burdened with mercury. The main staple food of the inhabitants of Cisitu is this polluted rice. Villagers were concerned that the severe diseases they observed in the community might be related to their mining activities, including high mercury exposure. Case report of the medical examinations and the mercury levels in urine and hair of 18 people with neurological symptoms. Typical signs and symptoms of chronic mercury intoxication were found (excessive salivation, sleep disturbances, tremor, ataxia, dysdiadochokinesia, pathological coordination tests, gray to bluish discoloration of the oral cavity and proteinuria). Mercury levels in urine were increased in eight patients (>7µg Hg/L urine). All 18 people had increased hair levels (>1µg Hg/g hair). 15 patients exhibited several, and sometimes numerous, symptoms in addition to having moderately to highly elevated levels of mercury in their specimens. These patients were classified as intoxicated. The situation in Cisitu is special, with rice paddy fields being irrigated with mercury-contaminated water and villagers consuming only local food, especially mercury-contaminated rice. Severe neurological symptoms and increased levels of mercury in urine and hair support are possibly caused by exposure to inorganic mercury in air, and the consumption of mercury-contaminated fish and rice. The mercury exposure needs to be reduced and treatment provided. Further research is needed to test the hypothesis that mercury-contaminated rice from small-scale gold mining areas might cause mercury intoxication. Copyright © 2016 Elsevier Inc. All rights reserved.

Characterisation and Processing of Some Iron Ores of India

NASA Astrophysics Data System (ADS)

Krishna, S. J. G.; Patil, M. R.; Rudrappa, C.; Kumar, S. P.; Ravi, B. P.

2013-10-01

Lack of process characterization data of the ores based on the granulometry, texture, mineralogy, physical, chemical, properties, merits and limitations of process, market and local conditions may mislead the mineral processing entrepreneur. The proper implementation of process characterization and geotechnical map data will result in optimized sustainable utilization of resource by processing. A few case studies of process characterization of some Indian iron ores are dealt with. The tentative ascending order of process refractoriness of iron ores is massive hematite/magnetite < marine black iron oxide sands < laminated soft friable siliceous ore fines < massive banded magnetite quartzite < laminated soft friable clayey aluminous ore fines < massive banded hematite quartzite/jasper < massive clayey hydrated iron oxide ore < manganese bearing iron ores massive < Ti-V bearing magnetite magmatic ore < ferruginous cherty quartzite. Based on diagnostic process characterization, the ores have been classified and generic process have been adopted for some Indian iron ores.

Mercury Slovenian soils: High, medium and low sample density geochemical maps

NASA Astrophysics Data System (ADS)

Gosar, Mateja; Šajn, Robert; Teršič, Tamara

2017-04-01

Regional geochemical survey was conducted in whole territory of Slovenia (20273 km2). High, medium and low sample density surveys were compared. High sample density represented the regional geochemical data set supplemented by local high-density sampling data (irregular grid, n=2835). Medium-density soil sampling was performed in a 5 x 5 km grid (n=817) and low-density geochemical survey was conducted in a sampling grid 25 x 25 km (n=54). Mercury distribution in Slovenian soils was determined with models of mercury distribution in soil using all three data sets. A distinct Hg anomaly in western part of Slovenia is evident on all three models. It is a consequence of 500-years of mining and ore processing in the second largest mercury mine in the world, the Idrija mine. The determined mercury concentrations revealed an important difference between the western and the eastern parts of the country. For the medium scale geochemical mapping is the median value (0.151 mg /kg) for western Slovenia almost 2-fold higher than the median value (0.083 mg/kg) in eastern Slovenia. Besides the Hg median for the western part of Slovenia exceeds the Hg median for European soil by a factor of 4 (Gosar et al., 2016). Comparing these sample density surveys, it was shown that high sampling density allows the identification and characterization of anthropogenic influences on a local scale, while medium- and low-density sampling reveal general trends in the mercury spatial distribution, but are not appropriate for identifying local contamination in industrial regions and urban areas. The resolution of the pattern generated is the best when the high-density survey on a regional scale is supplemented with the geochemical data of the high-density surveys on a local scale. References: Gosar, M, Šajn, R, Teršič, T. Distribution pattern of mercury in the Slovenian soil: geochemical mapping based on multiple geochemical datasets. Journal of geochemical exploration, 2016, 167/38-48.

Source identification and mass balance studies of mercury in Lake An-dong, S. Korea

NASA Astrophysics Data System (ADS)

Han, J.; Byeon, M.; Yoon, J.; Park, J.; Lee, M.; Huh, I.; Na, E.; Chung, D.; Shin, S.; Kim, Y.

2009-12-01

In this study, mercury and methylmercury were measured in atmospheric, tributary, open-lake water column, sediment, planktons and fish samples in the catchments area of Lake An-dong, S. Korea. Lake An-dong, an artificial freshwater lake is located on the upstream of River Nak-dong. It has 51.5 km2 of open surface water and 1.33 year of hydraulic residence time. It is a source of drinking water for 0.3 million S. Koreans. Recently, the possibilities of its mercury contamination became an issue since current studies showed that the lake had much higher mercury level in sediment and certain freshwater fish species than any other lakes in S. Korea. This catchments area has the possibilities of historical mercury pollution by the location of more than 50 abandoned gold mines and Young-poong zinc smelter. The objective of this study was to develop a mercury mass balance and identify possible mercury sources in the lake. The results of this study are thus expected to offer valuable insights for the sources of mercury loading through the watershed. In order to estimate the mercury flux, TGM, RGM and particulate mercury were measured using TEKRAN 2537 at the five sites surrounding Lake An-dong from May, 2009 with wet and dry deposition. The fate and transport of mercury in water body were predicted by using EFDC (Environmental Dynamic Fluid Code) and Mercury module in WASP7 (Water quality analysis program) after subsequent distribution into water body, sediments, followed by bioaccumulation and ultimate uptake by humans. The mercury mass balance in Young-poong zinc smelter was also pre-estimated by measuring mercury content in zinc ores, emission gases, sludge, wastewater and products.

Factors Affecting Elevated Arsenic and Methyl Mercury Concentrations in Small Shield Lakes Surrounding Gold Mines near the Yellowknife, NT, (Canada) Region

PubMed Central

Houben, Adam James; D’Onofrio, Rebecca; Kokelj, Steven V; Blais, Jules M

2016-01-01

Gold mines in the Yellowknife, NT, region—in particular, the Giant Mine—operated from 1949–99, releasing 237,000 tonnes of waste arsenic trioxide (As2O3) dust, among other compounds, from gold ore extraction and roasting processes. For the first time, we show the geospatial distribution of roaster-derived emissions of several chemical species beyond the mine property on otherwise undisturbed taiga shield lakes within a 25 km radius of the mine, 11 years after its closing. Additionally, we demonstrate that underlying bedrock is not a significant source for the elevated concentrations in overlying surface waters. Aquatic arsenic (As) concentrations are well above guidelines for drinking water (10 μg/L) and protection for aquatic life (5 μg/L), ranging up to 136 μg/L in lakes within 4 km from the mine, to 2.0 μg/L in lakes 24 km away. High conversion ratios of methyl mercury were shown in lakes near the roaster stack as well, with MeHg concentrations reaching 44% of total mercury. The risk of elevated exposures by these metals is significant, as many lakes used for recreation and fishing near the City of Yellowknife are within this radius of elevated As and methyl Hg concentrations. PMID:27050658

Mercury in breast milk - a health hazard for infants in gold mining areas?

PubMed

Bose-O'Reilly, Stephan; Lettmeier, Beate; Roider, Gabriele; Siebert, Uwe; Drasch, Gustav

2008-10-01

Breast-feeding can be a source of mercury exposure for infants. The main concern up to now is methyl-mercury exposure of women at child-bearing age. Certain fish species have high levels of methyl-mercury leading to consumer's advisory guidelines in regard of fish consumption to protect infants from mercury exposure passing through breast milk. Little is known about the transfer of inorganic mercury passing through breast milk to infants. Epidemiological studies showed negative health effects of inorganic mercury in gold mining areas. Small-scale gold miners use mercury to extract the gold from the ore. Environmental and health assessments of gold mining areas in Indonesia, Tanzania and Zimbabwe showed a high exposure with inorganic mercury in these gold mining areas, and a negative health impact of the exposure to the miners and the communities. This paper reports about the analysis and the results of 46 breast milk samples collected from mercury-exposed mothers. The median level of 1.87mug/l is fairly high compared to other results from literature. Some breast milk samples showed very high levels of mercury (up to 149mug/l). Fourteen of the 46 breast milk samples exceed 4mug/l which is considered to be a "high" level. US EPA recommends a "Reference Dose" of 0.3mug inorganic mercury/kg body weight/day [United States Environmental Protection Agency, 1997. Volume V: Health Effects of Mercury and Mercury Compounds. Study Report EPA-452/R-97-007: US EPA]. Twenty-two of the 46 children from these gold mining areas had a higher calculated total mercury uptake. The highest calculated daily mercury uptake of 127mug exceeds by far the recommended maximum uptake of inorganic mercury. Further systematic research of mercury in breast milk from small-scale gold mining areas is needed to increase the knowledge about the bio-transfer of mercury from mercury vapour-exposed mothers passing through breast milk to the breast-fed infant.

A biographical memoir of Donald Edward White

USGS Publications Warehouse

Muffler, L. J. Patrick

2016-01-01

Donald E. White was a leading scientist for the U.S. Geological Survey, where his career was devoted almost entirely to the study of hydrothermal processes in the Earth’s crust, from the dual perspectives of active geothermal systems and of extinct hydrothermal systems now represented only by ore deposits and alteration patterns. White was devoted to analyzing the mechanisms by which ore-forming metals are concentrated, transported, and deposited. His early work on antimony deposits and on mercury transport led to the understanding that these elements, as well as some precious metals, were concentrated in hydrothermal convection systems characterized by dilute chloride waters of predominantly meteoric origin. He concluded, on the other hand, that base metals required more concentrated brines, as was impressively confirmed in the early 1960s by the discovery of the metal-rich fluids of the Salton Sea geothermal system and subsequently by the recognition of sulfide-depositing hydrothermal systems on the sea floor. His studies of active hot-spring systems elucidated the principles of geyser activity and provided the scientific foundation for research programs aimed at the understanding of geothermal systems throughout the world.

Some limitations on the possible composition of the ore-forming fluid

USGS Publications Warehouse

Barton, Paul B.

1956-01-01

The activity rations of various important anions (S, CO3, SO4, OH, F, and Cl) in hydrothermal solutions at the time of deposition are evaluated using a simple thermodynamic technique. The rations are interpreted in the light of the mineralogy of ore deposits and limites are placed on the variability of each ratio in hydrothermal solutions. All of the calculations are made for 25°C and cautious extrapolation to higher temperatures seems justified; however, additional data for elevated temperatures and pressures are needed before more than approximate values may be assigned to these ratios in the ore-forming fluid. The calculated partial pressure of CO2 in the ore fluid is generally less than one atmosphere, which suggests that a dense CO2 phase cannot be considered an importatn ore fluid for most deposits. The partial pressure of H2S is usually less than 10-4 atmospheres which makes it extremely difficult to defend the heory that metals (other than the easily complexible mercury, arsenic, antimony, and perhaps fols and silver) are transported in quantity as complex sulfide and hydrosulfides. The sulfate to sulfide ration is such that the oxidation potential at the time of deposition is defined by the following equation: Eh (in volts) = 0.22 ± 0.04 - 0.059 pH.

Distribution, speciation, and transport of mercury in stream-sediment, stream-water, and fish collected near abandoned mercury mines in southwestern Alaska, USA

USGS Publications Warehouse

Gray, J.E.; Theodorakos, P.M.; Bailey, E.A.; Turner, R.R.

2000-01-01

Concentrations of total Hg, Hg (II), and methylmercury were measured in stream-sediment, stream-water, and fish collected downstream from abandoned mercury mines in south-western Alaska to evaluate environmental effects to surrounding ecosystems. These mines are found in a broad belt covering several tens of thousands of square kilometers, primarily in the Kuskokwim River basin. Mercury ore is dominantly cinnabar (HgS), but elemental mercury (Hg(o)) is present in ore at one mine and near retorts and in streams at several mine sites. Approximately 1400 t of mercury have been produced from the region, which is approximately 99% of all mercury produced from Alaska. These mines are not presently operating because of low prices and low demand for mercury. Stream-sediment samples collected downstream from the mines contain as much as 5500 ??g/g Hg. Such high Hg concentrations are related to the abundance of cinnabar, which is highly resistant to physical and chemical weathering, and is visible in streams below mine sites. Although total Hg concentrations in the stream-sediment samples collected near mines are high, Hg speciation data indicate that concentrations of Hg (II) are generally less than 5%, and methylmercury concentrations are less than 1% of the total Hg. Stream waters below the mines are neutral to slightly alkaline (pH 6.8-8.4), which is a result of the insolubility of cinnabar and the lack of acid- generating minerals such as pyrite in the deposits. Unfiltered stream-water samples collected below the mines generally contain 500-2500 ng/l Hg; whereas, corresponding stream-water samples filtered through a 0.45-??m membrane contain less than 50 ng/l Hg. These stream-water results indicate that most of the Hg transported downstream from the mines is as finely- suspended material rather than dissolved Hg. Mercury speciation data show that concentrations of Hg (II) and methylmercury in stream-water samples are typically less than 22 ng/l, and generally less than 5% of the total Hg. Muscle samples of fish collected downstream from mines contain as much as 620 ng/g Hg (wet wt.), of which 90-100% is methylmercury. Although these Hg concentrations are several times higher than that in fish collected from regional baseline sites, the concentration of Hg in fish is below the 1000 ng/g action level for edible fish established by the US Food and Drug Administration (FDA). Salmon contain less than 100 ng/g Hg, which are among the lowest Hg contents observed for fish in the study, and well below the FDA action level. (C) 2000 Elsevier Science B.V.

Distribution of total and methyl mercury in sediments along Steamboat Creek (Nevada, USA)

USGS Publications Warehouse

Stamenkovic, J.; Gustin, M.S.; Marvin-DiPasquale, M. C.; Thomas, B.A.; Agee, J.L.

2004-01-01

In the late 1800s, mills in the Washoe Lake area, Nevada, used elemental mercury to remove gold and silver from the ores of the Comstock deposit. Since that time, mercury contaminated waste has been distributed from Washoe Lake, down Steamboat Creek, and to the Truckee River. The creek has high mercury concentrations in both water and sediments, and continues to be a constant source of mercury to the Truckee River. The objective of this study was to determine concentrations of total and methyl mercury (MeHg) in surface sediments and characterize their spatial distribution in the Steamboat Creek watershed. Total mercury concentrations measured in channel and bank sediments did not decrease downstream, indicating that mercury contamination has been distributed along the creek's length. Total mercury concentrations in sediments (0.01-21.43 ??g/g) were one to two orders of magnitude higher than those in pristine systems. At 14 out of 17 sites, MeHg concentrations in streambank sediments were higher than the concentrations in the channel, suggesting that low banks with wet sediments might be important sites of mercury methylation in this system. Both pond/wetland and channel sites exhibited high potential for mercury methylation (6.4-30.0 ng g-1 day-1). Potential methylation rates were positively correlated with sulfate reduction rates, and decreased as a function of reduced sulfur and MeHg concentration in the sediments. Potential demethylation rate appeared not to be influenced by MeHg concentration, sulfur chemistry, DOC, sediment grain size or other parameters, and showed little variation across the sites (3.7-7.4 ng g-1 day-1). ?? 2003 Elsevier B.V. All rights reserved.

Applicability of two mobile analysers for mercury in urine in small-scale gold mining areas.

PubMed

Baeuml, Jennifer; Bose-O'Reilly, Stephan; Lettmeier, Beate; Maydl, Alexandra; Messerer, Katalin; Roider, Gabriele; Drasch, Gustav; Siebert, Uwe

2011-12-01

Mercury is still used in developing countries to extract gold from the ore in small-scale gold mining areas. This is a major health hazard for people living in mining areas. The concentration of mercury in urine was analysed in different mining areas in Zimbabwe, Indonesia and Tanzania. First the urine samples were analysed by CV-AAS (cold vapour atomic absorption spectrometry) during the field projects with a mobile mercury analyser (Lumex(®) or Seefelder(®)) and secondly, in a laboratory with a stationary CV-AAS mercury analyser (PerkinElmer(®)). Caused by the different systems (reduction agent either SnCl(2) (Lumex(®) or Seefelder(®))) or NaBH(4) (PerkinElmer(®)), with the mobile analysers only the inorganic mercury was obtained and with the stationary system the total mercury concentration was measured. The aims of the study were whether the results obtained in field with the mobile equipments can be compared with the stationary reference method in the laboratory and allow the application of these mobile analysers in screening studies on concerned populations to select those, who are exposed to critical mercury levels. Overall, the concentrations obtained with the two mobile systems were approximately 25% lower than determined with the stationary system. Nevertheless, both mobile systems seem to be very useful for screening of volunteers in field. Moreover, regional staff may be trained on such analysers to perform screening tests by themselves. Copyright © 2011 Elsevier GmbH. All rights reserved.

Environmental geochemistry of abandoned mercury mines in West-Central Nevada, USA

USGS Publications Warehouse

Gray, J.E.; Crock, J.G.; Fey, D.L.

2002-01-01

The Humboldt River is a closed basin and is the longest river in Nevada. Numerous abandoned Hg mines are located within the basin, and because Hg is a toxic heavy metal, the potential transport of Hg from these mines into surrounding ecosystems, including the Humboldt River, is of environmental concern Samples of ore, sediment, water, calcines (roasted ore), and leachates of the calcines were analyzed for Hg and other heavy metals to evaluate geochemical dispersion from the mines. Cinnabar-bearing ore samples collected from the mines contain highly elevated Hg concentrations, up to 6.9 %, whereas calcines collected from the mines contain up to 2000 mg Hg/kg. Stream-sediment samples collected within 1 km of the mines contain as much as 170 mg Hg/kg, but those collected distal from the mines (> 5 km) contain 8 km from the Humboldt River, and Hg is transported and diluted through a large volume of pediment before it reaches the Humboldt River. ?? 2002 Elsevier Science Ltd. All rights reserved.

The Mercury Problem in Artisanal and Small-Scale Gold Mining.

PubMed

Esdaile, Louisa J; Chalker, Justin M

2018-05-11

Mercury-dependent artisanal and small-scale gold mining (ASGM) is the largest source of mercury pollution on Earth. In this practice, elemental mercury is used to extract gold from ore as an amalgam. The amalgam is typically isolated by hand and then heated-often with a torch or over a stove-to distill the mercury and isolate the gold. Mercury release from tailings and vaporized mercury exceed 1000 tonnes each year from ASGM. The health effects on the miners are dire, with inhaled mercury leading to neurological damage and other health issues. The communities near these mines are also affected due to mercury contamination of water and soil and subsequent accumulation in food staples, such as fish-a major source of dietary protein in many ASGM regions. The risks to children are also substantial, with mercury emissions from ASGM resulting in both physical and mental disabilities and compromised development. Between 10 and 19 million people use mercury to mine for gold in more than 70 countries, making mercury pollution from ASGM a global issue. With the Minamata Convention on Mercury entering force this year, there is political motivation to help overcome the problem of mercury in ASGM. In this effort, chemists can play a central role. Here, the problem of mercury in ASGM is reviewed with a discussion on how the chemistry community can contribute solutions. Introducing portable and low-cost mercury sensors, inexpensive and scalable remediation technologies, novel methods to prevent mercury uptake in fish and food crops, and efficient and easy-to-use mercury-free mining techniques are all ways in which the chemistry community can help. To meet these challenges, it is critical that new technologies or techniques are low-cost and adaptable to the remote and under-resourced areas in which ASGM is most common. The problem of mercury pollution in ASGM is inherently a chemistry problem. We therefore encourage the chemistry community to consider and address this issue that affects the health of millions of people. © 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Geology and ore deposits of the McDermitt Caldera, Nevada-Oregon

USGS Publications Warehouse

Rytuba, James J.

1976-01-01

The McDermitt caldera is a Miocene collapse structure along the Nevada-Oregon border. The oval-shaped caldera is bounded by arcuate normal faults on the north and south and by rhyolite ring domes on the west. Precollapse ash-flow tuffs exposed within the south caldera rim consist of three cooling units and are peralkaline in composition. Refractive indexes of nonhydrated glasses from basal vitrophyres of the. units range from 1.493 to 1.503 and are typical of comendites. Post-collapse intracaldera rocks consist of tuffaceous lake sediments, rhyolite flows and domes, and ash-flow tuffs. Within the caldera are the mercury mines of Bretz, Cordero, McDermitt, Opalite, and Ruja and the Moonlight uranium mine. The mercury mines are adjacent to ring fracture faults, and the uranium mine and other uranium occurrences are located within rhyolite ring domes. Fluid inclusions in quartz indicate a deposition temperature of 340?C for the uranium deposit and 200?C for the mercury deposits. The mercury deposits formed at shallow depth by replacement of lakebed sediments and volcanic rocks.

Prevalence and Risk Factors of Elevated Blood Lead in Children in Gold Ore Processing Communities, Zamfara, Nigeria, 2012.

PubMed

Kaufman, John A; Brown, Mary Jean; Umar-Tsafe, Nasir T; Adbullahi, Muhammad Bashir; Getso, Kabiru I; Kaita, Ibrahim M; Sule, Binta Bako; Ba'aba, Ahmed; Davis, Lora; Nguku, Patrick M; Sani-Gwarzo, Nasir

2016-09-01

In March 2010, Medecins Sans Frontieres/Doctors Without Borders detected an outbreak of acute lead poisoning in Zamfara State, northwestern Nigeria, linked to low-technology gold ore processing. The outbreak killed more than 400 children ≤5 years of age in the first half of 2010 and has left more than 2,000 children with permanent disabilities. The aims of this study were to estimate the statewide prevalence of children ≤5 years old with elevated blood lead levels (BLLs) in gold ore processing and non-ore-processing communities, and to identify factors associated with elevated blood lead levels in children. A representative, population-based study of ore processing and non-ore-processing villages was conducted throughout Zamfara in 2012. Blood samples from children, outdoor soil samples, indoor dust samples, and survey data on ore processing activities and other lead sources were collected from 383 children ≤5 years old in 383 family compounds across 56 villages. 17.2% of compounds reported that at least one member had processed ore in the preceding 12 months (95% confidence intervals (CI): 9.7, 24.7). The prevalence of BLLs ≥10 µg/dL in children ≤5 years old was 38.2% (95% CI: 26.5, 51.4) in compounds with members who processed ore and 22.3% (95% CI: 17.8, 27.7) in compounds where no one processed ore. Ore processing activities were associated with higher lead concentrations in soil, dust, and blood samples. Other factors associated with elevated BLL were a child's age and sex, breastfeeding, drinking water from a piped tap, and exposure to eye cosmetics. Childhood lead poisoning is widespread in Zamfara State in both ore processing and non-ore-processing settings, although it is more prevalent in ore processing areas. Although most children's BLLs were below the recommended level for chelation therapy, environmental remediation and use of safer ore processing practices are needed to prevent further exposures. Obtained. The study protocol was approved by the US Centers for Disease Control Institutional Review Board-A and the National Health Research Ethics Committee of Nigeria. The authors declare no competing financial interests.

Stream-sediment geochemistry in mining-impacted streams: Prichard, Eagle, and Beaver creeks, northern Coeur d'Alene Mining District, northern Idaho

USGS Publications Warehouse

Box, Stephen E.; Wallis, John C.; Briggs, Paul H.; Brown, Zoe Ann

2005-01-01

This report presents the results of one aspect of an integrated watershed-characterization study that was undertaken to assess the impacts of historical mining and milling of silver-lead-zinc ores on water and sediment composition and on aquatic biota in streams draining the northern part of the Coeur d?Alene Mining District in northern Idaho. We present the results of chemical analyses of 62 samples of streambed sediment, 19 samples of suspended sediment, 23 samples of streambank soil, and 29 samples of mine- and mill-related artificial- fill material collected from the drainages of Prichard, Eagle, and Beaver Creeks, all tributaries to the North Fork of the Coeur d?Alene River. All samples were sieved into three grain-size fractions (<0.063, 0.063?0.25, and 0.25?1.0 mm) and analyzed for 40 elements after four-acid digestion by inductively coupled plasma atomic-emission spectrometry and for mercury by continuous- flow cold-vapor atomic-absorption spectrometry in the U.S. Geological Survey laboratory in Denver, Colo. Historical mining of silver-lead-zinc ores in the headwater reaches of the Prichard Creek, Eagle Creek, and Beaver Creek drainages has resulted in enrichments of lead, zinc, mercury, arsenic, cadmium, silver, copper, cobalt, and, to a lesser extent, iron and manganese in streambed sediment. Using samples collected from the relatively unimpacted West Fork of Eagle Creek as representative of background compositions, streambed sediment in the vicinity of the mines and millsites has Pb and Zn contents of 20 to 100 times background values, decreasing to 2 to 5 times background values at the mouth of the each stream, 15 to 20 km downstream. Lesser enrichments (<10 times background values) of mercury and arsenic also are generally associated with, and decrease downstream from, historical silver-lead-zinc mining in the drainages. However, enrichments of arsenic and, to a lesser extent, mercury also are areally associated with the lode gold deposits along Prichard Creek near Murray, which were not studied here. Metal contents in samples of unfractionated suspended sediment collected during a high-flow event in April 2000 are generally similar to, but slightly higher than, those in the fine (<0.063- mm grain size) fraction of streambed sediment from the same sampling site. Although metal enrichment in streambed sediment typically begins adjacent to the mine portals and their associated mine-waste rock dumps, volumetrically larger inputs of metal-enriched materials were contributed by the ore-concentration millsites and their associated, more finely ground, more metal rich mill-tailings impoundments.

Multi-Criteria selection of technology for processing ore raw materials

NASA Astrophysics Data System (ADS)

Gorbatova, E. A.; Emelianenko, E. A.; Zaretckii, M. V.

2017-10-01

The development of Computer-Aided Process Planning (CAPP) for the Ore Beneficiation process is considered. The set of parameters to define the quality of the Ore Beneficiation process is identified. The ontological model of CAPP for the Ore Beneficiation process is described. The hybrid choice method of the most appropriate variant of the Ore Beneficiation process based on the Logical Conclusion Rules and the Fuzzy Multi-Criteria Decision Making (MCDM) approach is proposed.

The Mercury Problem in Artisanal and Small‐Scale Gold Mining

PubMed Central

2018-01-01

Abstract Mercury‐dependent artisanal and small‐scale gold mining (ASGM) is the largest source of mercury pollution on Earth. In this practice, elemental mercury is used to extract gold from ore as an amalgam. The amalgam is typically isolated by hand and then heated—often with a torch or over a stove—to distill the mercury and isolate the gold. Mercury release from tailings and vaporized mercury exceed 1000 tonnes each year from ASGM. The health effects on the miners are dire, with inhaled mercury leading to neurological damage and other health issues. The communities near these mines are also affected due to mercury contamination of water and soil and subsequent accumulation in food staples, such as fish—a major source of dietary protein in many ASGM regions. The risks to children are also substantial, with mercury emissions from ASGM resulting in both physical and mental disabilities and compromised development. Between 10 and 19 million people use mercury to mine for gold in more than 70 countries, making mercury pollution from ASGM a global issue. With the Minamata Convention on Mercury entering force this year, there is political motivation to help overcome the problem of mercury in ASGM. In this effort, chemists can play a central role. Here, the problem of mercury in ASGM is reviewed with a discussion on how the chemistry community can contribute solutions. Introducing portable and low‐cost mercury sensors, inexpensive and scalable remediation technologies, novel methods to prevent mercury uptake in fish and food crops, and efficient and easy‐to‐use mercury‐free mining techniques are all ways in which the chemistry community can help. To meet these challenges, it is critical that new technologies or techniques are low‐cost and adaptable to the remote and under‐resourced areas in which ASGM is most common. The problem of mercury pollution in ASGM is inherently a chemistry problem. We therefore encourage the chemistry community to consider and address this issue that affects the health of millions of people. PMID:29314284

Sediment-water interactions affecting dissolved-mercury distributions in Camp Far West Reservoir, California

USGS Publications Warehouse

Kuwabara, James S.; Alpers, Charles N.; Marvin-DiPasquale, Mark; Topping, Brent R.; Carter, James L.; Stewart, A. Robin; Fend, Steven V.; Parcheso, Francis; Moon, Gerald E.; Krabbenhoft, David P.

2003-01-01

Field and laboratory studies were conducted in April and November 2002 to provide the first direct measurements of the benthic flux of dissolved (0.2-micrometer filtered) mercury species (total and methylated forms) between the bottom sediment and water column at three sampling locations within Camp Far West Reservoir, California: one near the Bear River inlet to the reservoir, a second at a mid-reservoir site of comparable depth to the inlet site, and the third at the deepest position in the reservoir near the dam (herein referred to as the inlet, midreservoir and near-dam sites, respectively; Background, Fig. 1). Because of interest in the effects of historic hydraulic mining and ore processing in the Sierra Nevada foothills just upstream of the reservoir, dissolved-mercury species and predominant ligands that often control the mercury speciation (represented by dissolved organic carbon, and sulfides) were the solutes of primary interest. Benthic flux, sometimes referred to as internal recycling, represents the transport of dissolved chemical species between the water column and the underlying sediment. Because of the affinity of mercury to adsorb onto particle surfaces and to form insoluble precipitates (particularly with sulfides), the mass transport of mercury in mining-affected watersheds is typically particle dominated. As these enriched particles accumulate at depositional sites such as reservoirs, benthic processes facilitate the repartitioning, transformation, and transport of mercury in dissolved, biologically reactive forms (dissolved methylmercury being the most bioavailable for trophic transfer). These are the forms of mercury examined in this study. In contrast to typical scientific manuscripts, this report is formatted in a pyramid-like structure to serve the needs of diverse groups who may be interested in reviewing or acquiring information at various levels of technical detail (Appendix 1). The report enables quick transitions between the initial summary information (figuratively at the top of the pyramid) and the later details of methods or results (figuratively towards the base of the pyramid) using hyperlinks to supporting figures and tables, and an electronically linked Table of Contents. During two sampling events, two replicate sediment cores (Coring methods; Fig. 2) from each of three reservoir locations (Fig. 1) were used in incubation experiments to provide flux estimates and benthic biological characterizations. Incubation of these cores provided ?snapshots? of solute flux across the sediment-water interface in the reservoir, under benthic, environmental conditions representative of the time and place of collection. Ancillary data, including nutrient and ligand fluxes, were gathered to provide a water-quality framework from which to compare the results for mercury. The following major observations from interdependent physical, biological, and chemical data were made:

Macroscopic and microscopic observations of particle-facilitated mercury transport from New Idria and Sulphur Bank mercury mine tailings

USGS Publications Warehouse

Lowry, G.V.; Shaw, S.; Kim, C.S.; Rytuba, J.J.; Brown, Gordon E.

2004-01-01

Mercury (Hg) release from inoperative Hg mines in the California Coast Range has been documented, but little is known about the release and transport mechanisms. In this study, tailings from Hg mines located in different geologic settings-New Idria (NI), a Si-carbonate Hg deposit, and Sulphur Bank (SB), a hot-spring Hg deposit-were characterized, and particle release from these wastes was studied in column experiments to (1) investigate the mechanisms of Hg release from NI and SB mine wastes, (2) determine the speciation of particle-bound Hg released from the mine wastes, and (3) determine the effect of calcinations on Hg release processes. The physical and chemical properties of tailings and the colloids released from them were determined using chemical analyses, selective chemical extractions, XRD, SEM, TEM, and X-ray absorption spectroscopy techniques. The total Hg concentration in tailings increased with decreasing particle size in NI and SB calcines (roasted ore), but reached a maximum at an intermediate particle size in the SB waste rock (unroasted ore). Hg in the tailings exists predominantly as low-solubility HgS (cinnabar and metacinnabar), with NI calcines having >50% HgS, SB calcines having >89% HgS, and SB waste rock having ???100% HgS. Leaching experiments with a high-ionic-strength solution (0.1 M NaCl) resulted in a rapid but brief release of soluble and particulate Hg. Lowering the ionic strength of the leach solution (0.005 M NaCl) resulted in the release of colloidal Hg from two of the three mine wastes studied (NI calcines and SB waste rock). Colloid-associated Hg accounts for as much as 95% of the Hg released during episodic particle release. Colloids generated from the NI calcines are produced by a breakup and release mechanism and consist of hematite, jarosite/alunite, and Al-Si gel with particle sizes of 10-200 nm. ATEM and XAFS analyses indicate that the majority (???78%) of the mercury is present in the form of HgS. SB calcines also produced HgS colloids. The colloids generated from the SB waste rock were heterogeneous and varied in composition according to the column influent composition. ATEM and XAFS results indicate that Hg is entirely in the HgS form. Data from this study identify colloidal HgS as the dominant transported form of Hg from these mine waste materials.

Statistical studies of selected trace elements with reference to geology and genesis of the Carlin gold deposit, Nevada

USGS Publications Warehouse

Harris, Michael; Radtke, Arthur S.

1976-01-01

Linear regression and discriminant analyses techniques were applied to gold, mercury, arsenic, antimony, barium, copper, molybdenum, lead, zinc, boron, tellurium, selenium, and tungsten analyses from drill holes into unoxidized gold ore at the Carlin gold mine near Carlin, Nev. The statistical treatments employed were used to judge proposed hypotheses on the origin and geochemical paragenesis of this disseminated gold deposit.

In Vitro Studies Evaluating Leaching of Mercury from Mine Waste Calcine Using Simulated Human Body Fluids

PubMed Central

2010-01-01

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almadén, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 μg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 μg of Hg leached/g), serum-based fluid (as much as 1600 μg of Hg leached/g), and water of pH 5 (as much as 880 μg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway. PMID:20491469

In vitro studies evaluating leaching of mercury from mine waste calcine using simulated human body fluids.

PubMed

Gray, John E; Plumlee, Geoffrey S; Morman, Suzette A; Higueras, Pablo L; Crock, James G; Lowers, Heather A; Witten, Mark L

2010-06-15

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almaden, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 microg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 microg of Hg leached/g), serum-based fluid (as much as 1600 microg of Hg leached/g), and water of pH 5 (as much as 880 microg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway.

In vitro studies evaluating leaching of mercury from mine waste calcine using simulated human body fluids

USGS Publications Warehouse

Gray, John E.; Plumlee, Geoffrey S.; Morman, Suzette A.; Higueras, Pablo L.; Crock, James G.; Lowers, Heather A.; Witten, Mark L.

2010-01-01

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almadén, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 μg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 μg of Hg leached/g), serum-based fluid (as much as 1600 μg of Hg leached/g), and water of pH 5 (as much as 880 μg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway.

Prevalence and Risk Factors of Elevated Blood Lead in Children in Gold Ore Processing Communities, Zamfara, Nigeria, 2012

PubMed Central

Kaufman, John A.; Brown, Mary Jean; Umar-Tsafe, Nasir T.; Adbullahi, Muhammad Bashir; Getso, Kabiru I.; Kaita, Ibrahim M.; Sule, Binta Bako; Ba’aba, Ahmed; Davis, Lora; Nguku, Patrick M.; Sani-Gwarzo, Nasir

2018-01-01

Background In March 2010, Medecins Sans Frontieres/Doctors Without Borders detected an outbreak of acute lead poisoning in Zamfara State, northwestern Nigeria, linked to low-technology gold ore processing. The outbreak killed more than 400 children ≤5 years of age in the first half of 2010 and has left more than 2,000 children with permanent disabilities. Objectives The aims of this study were to estimate the statewide prevalence of children ≤5 years old with elevated blood lead levels (BLLs) in gold ore processing and non-ore-processing communities, and to identify factors associated with elevated blood lead levels in children. Methods A representative, population-based study of ore processing and non-ore-processing villages was conducted throughout Zamfara in 2012. Blood samples from children, outdoor soil samples, indoor dust samples, and survey data on ore processing activities and other lead sources were collected from 383 children ≤5 years old in 383 family compounds across 56 villages. Results 17.2% of compounds reported that at least one member had processed ore in the preceding 12 months (95% confidence intervals (CI): 9.7, 24.7). The prevalence of BLLs ≥10 µg/dL in children ≤5 years old was 38.2% (95% CI: 26.5, 51.4) in compounds with members who processed ore and 22.3% (95% CI: 17.8, 27.7) in compounds where no one processed ore. Ore processing activities were associated with higher lead concentrations in soil, dust, and blood samples. Other factors associated with elevated BLL were a child’s age and sex, breastfeeding, drinking water from a piped tap, and exposure to eye cosmetics. Conclusions Childhood lead poisoning is widespread in Zamfara State in both ore processing and non-ore-processing settings, although it is more prevalent in ore processing areas. Although most children’s BLLs were below the recommended level for chelation therapy, environmental remediation and use of safer ore processing practices are needed to prevent further exposures. Patient consent Obtained Ethics approval The study protocol was approved by the US Centers for Disease Control Institutional Review Board-A and the National Health Research Ethics Committee of Nigeria. Competing Interests The authors declare no competing financial interests. PMID:29416933

Mining legacy across a wetland landscape: high mercury in Upper Peninsula (Michigan) rivers, lakes, and fish.

PubMed

Kerfoot, W Charles; Urban, Noel R; McDonald, Cory P; Zhang, Huanxin; Rossmann, Ronald; Perlinger, Judith A; Khan, Tanvir; Hendricks, Ashley; Priyadarshini, Mugdha; Bolstad, Morgan

2018-04-25

A geographic enigma is that present-day atmospheric deposition of mercury in the Upper Peninsula of Michigan is low (48%) and that regional industrial emissions have declined substantially (ca. 81% reduction) relative to downstate. Mercury levels should be declining. However, state (MDEQ) surveys of rivers and lakes revealed elevated total mercury (THg) in Upper Peninsula waters and sediment relative to downstate. Moreover, Western Upper Peninsula (WUP) fish possess higher methyl mercury (MeHg) levels than Northern Lower Peninsula (NLP) fish. A contributing explanation for elevated THg loading is that a century ago the Upper Peninsula was a major industrial region, centered on mining. Many regional ores (silver, copper, zinc, massive sulfides) contain mercury in part per million concentrations. Copper smelters and iron furnace-taconite operations broadcast mercury almost continuously for 140 years, whereas mills discharged tailings and old mine shafts leaked contaminated water. We show that mercury emissions from copper and iron operations were substantial (60-650 kg per year) and dispersed over relatively large areas. Moreover, lake sediments in the vicinity of mining operations have higher THg concentrations. Sediment profiles from the Keweenaw Waterway show that THg accumulation increased 50- to 400-fold above modern-day atmospheric deposition levels during active mining and smelting operations, with lingering MeHg effects. High MeHg concentrations are geographically correlated with low pH and dissolved organic carbon (DOC), a consequence of biogeochemical cycling in wetlands, characteristic of the Upper Peninsula. DOC can mobilize metals and elevate MeHg concentrations. We argue that mercury loading from mining is historically superimposed upon strong regional wetland effects, producing a combined elevation of both THg and MeHg in the Western Upper Peninsula.

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... process alone or in conjunction with other processes, for the beneficiation of copper, lead, zinc, gold, silver, or molybdenum ores, or any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach processes to extract copper from ores or ore waste materials; and (4) Mills...

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... process alone or in conjunction with other processes, for the beneficiation of copper, lead, zinc, gold, silver, or molybdenum ores, or any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach processes to extract copper from ores or ore waste materials; and (4) Mills...

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... process alone or in conjunction with other processes, for the beneficiation of copper, lead, zinc, gold, silver, or molybdenum ores, or any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach processes to extract copper from ores or ore waste materials; and (4) Mills...

Mercury in soil and perennial plants in a mining-affected urban area from Northwestern Romania.

PubMed

Senilă, Marin; Levei, Erika A; Senilă, Lăcrimioara R; Oprea, Gabriela M; Roman, Cecilia M

2012-01-01

The mercury (Hg) concentrations were evaluated in soils and perennial plants sampled in four districts of Baia Mare city, a historical mining and ore processing center in Northwestern Romania. The results showed that the Hg concentration exceeded the guideline value of 1.0 mg kg(-1) dry weight (dw) established by the Romanian Legislation, in 24 % of the analyzed soil samples, while the median Hg concentration (0.70 mg kg(-1) dw) was lower than the guideline value. However, Hg content in soil was generally higher than typical values in soils from residential and agricultural areas of the cities all over the world. The median Hg concentration was 0.22 mg kg(-1) dw in the perennial plants, and exceeded the maximum level of Hg (0.10 mg kg(-1)) established by European Directive 2002/32/EC for plants used in animal feed in order to prevent its transfer and further accumulation in the higher levels of food chain. No significant correlations were found between soil Hg and other analyzed metals (Cd, Cu, Pb, Zn) resulted from the non-ferrous smelting activities, probably due to the different physicochemical properties, that led to different dispersion patterns.

Mercury exposure and effects on cavity-nesting birds from the Carson River, Nevada

USGS Publications Warehouse

Custer, Christine M.; Custer, T.W.; Hill, E.F.

2007-01-01

Mercury (Hg) concentrations were 15-40 times higher in the eggs and livers of tree swallows (Tachycineta bicolor) and house wrens (Troglodytes aedon) that nested along the Carson River at and below Dayton, Nevada than in the same species above the mining-impacted areas. Hg contamination was mainly the result of processing mills in the 1800s that used Hg to separate gold and silver from ore. The exposure pattern of tree swallows and house wrens along the Carson River was consistent with their trophic status (i.e., lower levels in liver tissue of aquatic insectivores than in piscivorous birds nesting nearby). Even though they are aquatic insectivores, tree swallows and house wrens were exposed to the same amount of Hg as piscivores in the Florida Everglades; this indicated the extreme level of Hg contamination in the Carson River. Only 70-74% of the eggs hatched. This was less than the nationwide average for these two species that generally hatch ???85% of eggs. Although the sample size was small, Hg might be impacting reproductive end points in cavity-nesting birds from the Carson River. Other trace elements were present at background concentrations. ?? 2006 Springer Science+Business Media, Inc.

Small-scale studies of roasted ore waste reveal extreme ranges of stable mercury isotope signatures

NASA Astrophysics Data System (ADS)

Smith, Robin S.; Wiederhold, Jan G.; Jew, Adam D.; Brown, Gordon E.; Bourdon, Bernard; Kretzschmar, Ruben

2014-07-01

Active and closed Hg mines are significant sources of Hg contamination to the environment, mainly due to large volumes of mine waste material disposed of on-site. The application of Hg isotopes as source tracer from such contaminated sites requires knowledge of the Hg isotope signatures of different materials potentially released to the environment. Previous work has shown that calcine, the waste residue of the on-site ore roasting process, can exhibit distinct Hg isotope signatures compared with the primary ore. Here, we report results from a detailed small-scale study of Hg isotope variations in calcine collected from the closed New Idria Hg mine, San Benito County, CA, USA. The calcine samples exhibited different internal layering features which were investigated using optical microscopy, micro X-ray fluorescence, micro X-ray absorption spectroscopy (μ-XAS), and stable Hg isotope analysis. Significant Fe, S, and Hg concentration gradients were found across the different internal layers. Isotopic analyses revealed an extreme variation with pronounced isotopic gradients across the internal layered features. Overall, δ202Hg (±0.10‰, 2 SD) describing mass-dependent fractionation (MDF) ranged from -5.96 to 14.49‰, which is by far the largest range of δ202Hg values reported for any environmental sample. In addition, Δ199Hg (±0.06‰, 2 SD) describing mass-independent fractionation (MIF) ranged from -0.17 to 0.21‰. The μ-XAS analyses suggested that cinnabar and metacinnabar are the dominant Hg-bearing phases in the calcine. Our results demonstrate that the incomplete roasting of HgS ores in Hg mines can cause extreme mass-dependent Hg isotope fractionations at the scale of individual calcine pieces with enrichments in both light and heavy Hg isotopes relative to the primary ore signatures. This finding has important implications for the application of Hg isotopes as potential source tracers for Hg released to the environment from closed Hg mines and highlights the need for detailed source signature identification.

Mercury and arsenic in the gold mining regions of the Ankobra River basin in Ghana

NASA Astrophysics Data System (ADS)

Bannerman, W.; Potin-Gautier, M.; Amoureux, D.; Tellier, S.; Rambaud, A.; Babut, M.; Adimado, A.; Beinhoff, C.

2003-05-01

The river Ankobra flows through the principal gold mining centres in Western Ghana, draining a total area of 8272 km^2 to join the Atlantic ocean. Mercury is used by thousands of small-scale miners in the region to amalgamate gold. Ores mined in some deep shafts and surface mines are arsenopyrites and the region is marked by the presence of heaps of arsenic - rich mine tailings from both past and recent activities. This study was conducted to assess the impact of mining activities on the distribution and speciation of arsenic and mercury in the aquatic environment of the Ankobra River. In all, water (filtered and non-filtered) and bed sediments were collected from various locations within the watershed. Principal parameters investigated include total mercury, arsenic (III), arsenic (V), monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). Seasonal and spatial variations of these parameters were investigated. Quality control systems were adopted at both the environmental and analytical stages of the study. ln general, areas close to the mining centres are the most pollilited. As (V)/As (III) ratios in water are reversed after the first 100-km of the river length with the onset of industrial influence downstream.

Idea of Identification of Copper Ore with the Use of Process Analyser Technology Sensors

NASA Astrophysics Data System (ADS)

Jurdziak, Leszek; Kaszuba, Damian; Kawalec, Witold; Król, Robert

2016-10-01

The Polish resources of the copper ore exploited by the KGHM S.A. underground mines are considered as one of the most complex in the world and - consequently - the most difficult to be processed. The ore consists of three lithology forms: dolomites, shales and sandstones but in different proportions which has a significant impact on the effectiveness of the grinding and flotation processes. The lithological composition of the ore is generally recognised in-situ but after being mined it is blended on its long way from various mining fields to the processing plant by the complex transportation system consisting of belt conveyors with numerous switching points, ore bunkers and shafts. Identification of the lithological composition of the ore being supplied to the processing plant should improve the adjustments of the ore processing machinery equipment aiming to decrease the specific processing (mainly grinding) energy consumption as well as increase the metal recovery. The novel idea of Process Analyser Technology (PAT) sensors - information carrying pellets, dropped into the transported or processed bulk material which can be read directly when needed - is investigated for various applications within the DISIRE project (a part of the SPIRE initiative, acting under the Horizon2020 framework program) and here is adopted for implementing the annotation the transported copper ore for the needs of ore processing plants control. The identification of the lithological composition of ore blended on its way to the processing plant can be achieved by an information system consisting of pellets that keep the information about the original location of the portions of conveyed ore, the digital, geological database keeping the data of in-situ lithology and the simulation models of the transportation system, necessary to evaluate the composition of the blended ore. The assumptions of the proposed solution and the plan of necessary in-situ tests (with the special respect to harsh environment of

On the origin of the livingstonite deposits at Huitzuco, Guerrero, Mexico

USGS Publications Warehouse

Tunell, G.; Learned, R.E.; Lawrence, E.F.

1976-01-01

Livingstonite is the principal ore mineral in the deposits of the Huitzuco District in the State of Guerrero, Mexico. The ore is found in the lower part of the Morelos Formation, which consists of a thick bed of sedimentary anhydrite containing lenses of dolomite and dolomite breccia. In the unweathered ore practically all the mercury is in the livingstonite, whereas the antimony occurs partly in the livingstonite and partly in stibnite. Native sulfur forms pockets as much as 30 centimeters in diameter in the ore and is also found in gypsum on the surface away from the ore. It appears that the deposition of livingstonite, rather than of the combination of cinnabar and stibnite that is more usual in other districts, was caused by the native sulfur present in considerable quantity scattered through the sedimentary dolomite and anhydrite above, below, and in the ore. Since the formula of livingstonite is actually HgSb4S8 (not HgSb4S7 as was previously supposed), it is not stable in solutions containing only HgS, Sb2S3, Na2S, and H2O. It has been proved by one of us, experimentally, that in order to form livingstonite, the solutions must contain elemental sulfur in addition to HgS, Sb2S3, Na2S, and H2O. In such solutions the solubility of mercuric sulfide is extremely low. However, the problem of transport is overcome if the elemental sulfur is already present in the wall rock. In that case, the reaction of the elemental sulfur with a solution containing mercuric sulfide and antimony sulfide, but not saturated with either, would precipitate livingstonite, as was proved by our experimental work. ?? 1976 Springer-Verlag.

Process for recovering hydrocarbons from a diatomite-type ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, B.W.

1983-02-15

A process for recovering hydrocarbons from a diatomite-type ore which comprises contacting the diatomite ore with a C/sub 4/-C/sub 10/ alcohol and thereafter contacting the diatomite ore-alcohol mixture with an aqueous alkaline solution to separate a hydrocarbon-alcohol phase and an alkaline aqueous phase containing the stripped diatomite ore. Thereafter, the alcohol is distilled off from the hydrocarbon phase and recycled back into the initial process.

Disposal and improvement of contaminated by waste extraction of copper mining in chile

NASA Astrophysics Data System (ADS)

Naranjo Lamilla, Pedro; Blanco Fernández, David; Díaz González, Marcos; Robles Castillo, Marcelo; Decinti Weiss, Alejandra; Tapia Alvarez, Carolina; Pardo Fabregat, Francisco; Vidal, Manuel Miguel Jordan; Bech, Jaume; Roca, Nuria

2016-04-01

This project originated from the need of a mining company, which mines and processes copper ore. High purity copper is produced with an annual production of 1,113,928 tons of concentrate to a law of 32%. This mining company has generated several illegal landfills and has been forced by the government to make a management center Industrial Solid Waste (ISW). The forecast volume of waste generated is 20,000 tons / year. Chemical analysis established that the studied soil has a high copper content, caused by nature or from the spread of contaminants from mining activities. Moreover, in some sectors, soil contamination by mercury, hydrocarbons and oils and fats were detected, likely associated with the accumulation of waste. The waters are also impacted by mining industrial tasks, specifically copper ores, molybdenum, manganese, sulfates and have an acidic pH. The ISW management center dispels the pollution of soil and water and concentrating all activities in a technically suitable place. In this center the necessary guidelines for the treatment and disposal of soil contamination caused by uncontrolled landfills are given, also generating a leachate collection system and a network of fluid monitoring physicochemical water quality and soil environment. Keywords: Industrial solid waste, soil contamination, Mining waste

Solvent extraction of diatomite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, W.

1984-07-24

There is provided a method of extracting hydrocarbons from a diatomite ore. The particle size of the ore is first reduced to form a processed ore. The processed ore is then mixed with a substantially irregular granular material to form an unstratified ore mixture having increased permeability to an extracting solvent. The unstratified ore mixture is then permeated with an extracting solvent to obtain a hydrocarbon-solvent stream from which hydrocarbons are subsequently separated. The irregular granular material may be sand.

Explosion-assisted preparation of dispersed gold-bearing different-grade ore for selective mining

NASA Astrophysics Data System (ADS)

Trubachev, AI; Zykov, NV

2017-02-01

It is found that there are transient zones (between quality and off-quality ore areas) with the respective content of useful component in an ore body, and a variant of explosive treatment of such zones before the selective mining is put forward. Practicability of two processing technologies is evaluated: processing of high-grade and low-grade ore from the transient zones and heap leaching of metals from the low-grade and impoverished ore. Open mining technology is conventional truck-and-shovel scheme, with distributed ore flows to processing plant and (or) to heap leaching, which generally enhances the mine efficiency.

The Problem of Preconcentration of Uranium Ores by Physical Processes; LES PROBLEMES DE LA PRECONCENTRATION DES MINERAIS D'URANIUM PAR VOIE PHYSIQUE. LE TRIAGE ELECTRONIQUE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vuchot, L.; Ginocchio, A. et al.

1959-10-31

As uranium ores, like most other ores, are not definite substances which can be treated directly for the production of the metal, the ores must be concentrated. The common physical processes used for all ores, such as sieving, gravimetric separation, flotation, electromagnetic separation, and electrostatic separation, are applicable to the beneficiation of uranium. The radioactivity of uranium ores has led to a radiometric method for the concentration. This method is described in detail. As an example, the preconcentration of Forez ores is discussed. (J.S.R.)

Intensification of the Reverse Cationic Flotation of Hematite Ores with Optimization of Process and Hydrodynamic Parameters of Flotation Cell

NASA Astrophysics Data System (ADS)

Poperechnikova, O. Yu; Filippov, L. O.; Shumskaya, E. N.; Filippova, I. V.

2017-07-01

The demand of high grade iron ore concentrates is a major issue due to the depletion of rich iron-bearing ores and high competitiveness in the iron ore market. Iron ore production is forced out to upgrade flowsheets to decrease the silica content in the pelettes. Different types of ore have different mineral composition and texture-structural features which require different mineral processing methods and technologies. The paper presents a comparative study of the cationic and anionic flotation routes to process a fine-grain oxidized iron ore. The modified carboxymethyl cellulose was found as the most efficient depressant in reverse cationic flotation. The results of flotation optimization of hematite ores using matrix of second-order center rotatable uniform design allowed to define the collector concentration, impeller rotation speed and air flowrate as the main flotation parameters impacting on the iron ore concentrate quality and iron recovery in a laboratory flotation machine. These parameters have been selected as independent during the experiments.

Temporal and Spatial Distribution of Selected Species of Mercury, Carson River Superfund Site, Nevada

NASA Astrophysics Data System (ADS)

Thodal, C.; Morway, E. D.

2015-12-01

The Carson River Mercury Site in western Nevada was added to the US Environmental Protection Agency (USEPA) "Superfund" List in 1990 due to contamination from mercury used to amalgamate silver and gold from Comstock Lode ores milled during the late 1800s. The U.S. Geological Survey (USGS) has monitored concentrations of suspended sediment (SS), total mercury (THg) and methylmercury (MeHg) as well as streamflow upstream and downstream of Lahontan Reservoir since 1997 in support of USEPA Remedial Investigations. Differences between inflow and outflow concentrations indicate that nearly 90 percent of SS and unfiltered THg, and at least 50 percent of unfiltered MeHg and filtered (<0.45 μm) THg and MeHg is retained in the reservoir. However, outflow MeHg concentrations exceeded mean inflow concentration (2.9 nanograms per liter; ng/L) in 10 of 135 samples, indicating augmented mercury methylation. During August 2010 and June-September 2011, limnological profiles were measured and water samples collected from discrete depths in each of the reservoir's 3 sub-basins, the inflow delta and 2 shallow and rarely inundated overflow basins to investigate mercury distribution and methylation. In most samples, MeHg concentrations were less than 5 ng/L and increased by less than 1 ng/L in deeper samples. After temperature, oxygen, and Eh profiles indicated thermal stratification in the deep (~25 m) lower basin, samples from the top 1 m still had less than 2 ng/L MeHg but samples collected from 2 m above the sediment-water interface yielded concentrations as high as 220 ng/L in filtered water samples, accounting for 100 percent of filtered and 65 percent of unfiltered THg concentrations in concurrently-sampled water. We hypothesize that anoxic conditions and decomposition of mercury-contaminated plankton and sulfate-reduction in the hypolimnion provide carbon and mercury necessary for mercury methylation that exceeds diffusion from bottom sediment.

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2014 CFR

2014-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2011 CFR

2011-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2012 CFR

2012-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2013 CFR

2013-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

Children's personal exposure to PM10 and associated metals in urban, rural and mining activity areas.

PubMed

Hinwood, Andrea; Callan, Anna C; Heyworth, Jane; McCafferty, Peter; Sly, Peter D

2014-08-01

There has been limited study of children's personal exposure to PM10 and associated metals in rural and iron ore mining activity areas where PM10 concentrations can be very high. We undertook a small study of 70 children where 13 children were recruited in an area of iron ore mining processing and shipping, 15 children from an area in the same region with no mining activities, and 42 children in an urban area. Each child provided a 24h personal exposure PM10 sample, a first morning void urine sample, a hair sample, time activity diary, and self administered questionnaire. Children's 24h personal PM10 concentrations were low (median of 28 μg m(-3) in the mining area; 48 μg m(-3) in the rural area and 45 μg m(-3) in the urban area) with corresponding outdoor PM10 concentrations also low. Some very high personal PM10 concentrations were recorded for individuals (>300 μg m(-3)) with the highest concentrations recorded in the mining and rural areas in the dry season. PM10 concentrations were highly variable. Hair aluminium, cadmium and manganese concentrations were higher in the iron ore activity area, while hair mercury, copper and nickel concentrations were higher in the urban area. Factors such as season and ventilation appear to be important but this study lacked power to confirm this. These results need to be confirmed by a larger study and the potential for absorption of the metals needs to be established along with the factors that increase exposures and the potential for health risks arising from exposure. Copyright © 2014 Elsevier Ltd. All rights reserved.

The burden of chronic mercury intoxication in artisanal small-scale gold mining in Zimbabwe: data availability and preliminary estimates.

PubMed

Steckling, Nadine; Bose-O'Reilly, Stephan; Pinheiro, Paulo; Plass, Dietrich; Shoko, Dennis; Drasch, Gustav; Bernaudat, Ludovic; Siebert, Uwe; Hornberg, Claudia

2014-12-13

Artisanal small-scale gold mining (ASGM) is a poverty-driven activity practiced in over 70 countries worldwide. Zimbabwe is amongst the top ten countries using large quantities of mercury to extract gold from ore. This analysis was performed to check data availability and derive a preliminary estimate of disability-adjusted life years (DALYs) due to mercury use in ASGM in Zimbabwe. Cases of chronic mercury intoxication were identified following an algorithm using mercury-related health effects and mercury in human specimens. The sample prevalence amongst miners and controls (surveyed by the United Nations Industrial Development Organization in 2004 and the University of Munich in 2006) was determined and extrapolated to the entire population of Zimbabwe. Further epidemiological and demographic data were taken from the literature and missing data modeled with DisMod II to quantify DALYs using the methods from the Global Burden of Disease (GBD) 2004 update published by the World Health Organization (WHO). While there was no disability weight (DW) available indicating the relative disease severity of chronic mercury intoxication, the DW of a comparable disease was assigned by following the criteria 1) chronic condition, 2) triggered by a substance, and 3) causing similar health symptoms. Miners showed a sample prevalence of 72% while controls showed no cases of chronic mercury intoxication. Data availability is very limited why it was necessary to model data and make assumptions about the number of exposed population, the definition of chronic mercury intoxication, DW, and epidemiology. If these assumptions hold, the extrapolation would result in around 95,400 DALYs in Zimbabwe's total population in 2004. This analysis provides a preliminary quantification of the mercury-related health burden from ASGM based on the limited data available. If the determined assumptions hold, chronic mercury intoxication is likely to have been one of the top 20 hazards for population health in Zimbabwe in 2004 when comparing with more than 130 categories of diseases and injuries quantified in the WHO's GBD 2004 update. Improving data quality would allow more accurate estimates. However, the results highlight the need to reduce a burden which could be entirely avoided.

Spatial distribution of chemical constituents in the Kuskokwim River, Alaska

USGS Publications Warehouse

Wang, Bronwen

1999-01-01

The effects of lithologic changes on the water quality of the Kuskokwim River, Alaska, were evaluated by the U.S. Geological Survey in June 1997. Water, suspended sediments, and bed sediments were sampled from the Kusko-kwim River and from three tributaries, the Holitna River, Red Devil Creek, and Crooked Creek. Dissolved boron, chromium, copper, manganese, zinc, aluminum, lithium, barium, iron, antimony, arsenic, mercury, and strontium were detected. Dissolved manganese and iron concentrations were three and four times higher in the Holitna River than in the Kusko-kwim River. Finely divided ferruginous materials found in the graywacke and shale units of the Kuskokwim Group are the probable source of the iron. The highest concentrations of dissolved strontium and barium were found at McGrath, and the limestone present in the upper basin was the most probable source of strontium. The total mercury concentrations on the Kuskokwim River decreased downstream from McGrath. Dissolved mercury was 24 to 32 percent of the total concentration. The highest concentrations of total mercury, and of dissolved antimony and arsenic were found in Red Devil Creek. The higher concentrations from Red Devil Creek did not affect the main stem mercury transport because the tributary was small relative to the Kuskokwim River. In Red Devil Creek, total mercury exceeded the concentration at which the U.S. Environmental Protection Agency (USEPA) indicates that aquatic life is affected and dissolved arsenic exceeded the USEPA's drinking-water standard. Background mercury and antimony concentrations in bed sediments ranged from 0.09 to 0.15 micrograms per gram for mercury and from 1.6 to 2.1 micrograms per gram for antimony. Background arsenic concentrations were greater than 27 micrograms per gram. Sites near the Red Devil mercury mine had mercury and antimony concentrations greater than background concentrations. These concentrations probably reflect the proximity to the ore body and past mining. Crooked Creek had mercury concentrations greater than the background concentration. The transport of suspended sediment-associated trace elements was lower for all elements in the lower river than in the upper river, indicating storage of sediments and their associated metals within the river system.

Fail-Safe Pressure Plug

NASA Technical Reports Server (NTRS)

Svejkovsky, Paul A.

1993-01-01

Protective plug resists slowly built-up pressure or automatically releases itself if pressure rises suddenly. Seals out moisture at pressures ranging from 50 micrometers of mercury to 200 pounds per square inch. Designed to seal throat of 38 Reaction Control Thrusters on Space Shuttle protecting internal components from corrosion. Plug conforms to contour of nozzle throat, where O-ring forms pressure seal. After plug inserted, cover attached by use of cover-fitting assembly. Modified versions useful in protecting engines, pumps, reaction vessels, and other industrial equipment during shipment and maintenance.

Holistic processing, contact, and the other-race effect in face recognition.

PubMed

Zhao, Mintao; Hayward, William G; Bülthoff, Isabelle

2014-12-01

Face recognition, holistic processing, and processing of configural and featural facial information are known to be influenced by face race, with better performance for own- than other-race faces. However, whether these various other-race effects (OREs) arise from the same underlying mechanisms or from different processes remains unclear. The present study addressed this question by measuring the OREs in a set of face recognition tasks, and testing whether these OREs are correlated with each other. Participants performed different tasks probing (1) face recognition, (2) holistic processing, (3) processing of configural information, and (4) processing of featural information for both own- and other-race faces. Their contact with other-race people was also assessed with a questionnaire. The results show significant OREs in tasks testing face memory and processing of configural information, but not in tasks testing either holistic processing or processing of featural information. Importantly, there was no cross-task correlation between any of the measured OREs. Moreover, the level of other-race contact predicted only the OREs obtained in tasks testing face memory and processing of configural information. These results indicate that these various cross-race differences originate from different aspects of face processing, in contrary to the view that the ORE in face recognition is due to cross-race differences in terms of holistic processing. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

Mineralogical and geochemical features of the alteration processes of magmatic ores in the Beni Bousera ultramafic massif (north Morocco)

NASA Astrophysics Data System (ADS)

Hajjar, Zaineb; Gervilla, Fernando; Essaifi, Abderrahim; Wafik, Amina

2017-08-01

The Beni Bousera ultramafic massif (Internal Rif, Morocco) is characterized by the presence of two types of small-scale magmatic mineralizations (i) a mineralization consisting mainly of chromite and Ni arsenides associated to orthopyroxene and cordierite (Cr-Ni ores), and (ii) a mineralization mainly composed of magmatic Fe-Ni-Cu sulfides containing variable amounts of graphite and chromite associated to phlogopite, clinopyroxène and plagioclase (S-G ores). Theses ores underwent High-T (450-550 °C) and Low-T (150-300 °C) alteration processes. The High-T alteration processes are tentatively related to intrusion of leucogranite dykes. They are preserved in the Galaros Cr-Ni ore deposit where nickeline is partly dissolved and transformed to maucherite, and orthopyroxene alters to phlogopite. Ni and Co were mobilized to the fluid phase, rising up their availability and promoting their diffusion into chromite and phlogopite, which have significantly higher contents in Ni and Co in phlogopite-rich ores than in orthopyroxene- and nickeline-rich ones. The Low-T alteration processes are related to serpentinization/weathering spatially associated with a regional shear zone. They affected both the Cr-Ni and S-G ores. In the Cr-Ni ores, Ni-arsenides were completely leached out while chromite is fractured within a matrix of chlorite, vermiculite and Ni-rich serpentine. In S-G ores, the silicates were altered into amphibole, Fe-rich chlorite and pectolite in clinopyroxene- and plagioclase-bearing ores while sulfides were completely leached out in phlogopite-bearing ores where iron oxides and hydroxides, and Fe-rich vermiculite were deposited. Chromite composition is not affected by the Low-T alteration processes.

Impact of microbial communities from tropical soils on the mobilization of trace metals during dissolution of cinnabar ore.

PubMed

Balland-Bolou-Bi, Clarisse; Turc, Benjamin; Alphonse, Vanessa; Bousserrhine, Noureddine

2017-06-01

Biodissolution experiments on cinnabar ore (mercury sulphide and other sulphide minerals, such as pyrite) were performed with microorganisms extracted directly from soil. These experiments were carried out in closed systems under aerobic and anaerobic conditions with 2 different soils sampled in French Guyana. The two main objectives of this study were (1) to quantify the ability of microorganisms to mobilize metals (Fe, Al, Hg) during the dissolution of cinnabar ore, and (2) to identify the links between the type and chemical properties of soils, environmental parameters such as season and the strategies developed by indigenous microorganisms extracted from tropical natural soils to mobilize metals. Results indicate that microbial communities extracted directly from various soils are able to (1) survive in the presence of cinnabar ore, as indicated by consumption of carbon sources and, (2) leach Hg from cinnabar in oxic and anoxic dissolution experiments via the acidification of the medium and the production of low molecular mass organic acids (LMMOAs). The dissolution rate of cinnabar in aerobic conditions with microbial communities ranged from 4.8×10 -4 to 2.6×10 -3 μmol/m 2 /day and was independent of the metabolites released by the microorganisms. In addition, these results suggest an indirect action by the microorganisms in the cinnabar dissolution. Additionally, because iron is a key element in the dynamics of Hg, microbes were stimulated by the presence of this metal, and microbes released LMMOAs that leached iron from iron-bearing minerals, such as pyrite and oxy-hydroxide of iron, in the mixed cinnabar ore. Copyright © 2016. Published by Elsevier B.V.

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold... gold bearing ores from placer deposits; and (2) The beneficiation processes which use gravity... applicable to any mines or beneficiation processes which process less than 1500 cubic yards (cu yd) of ore...

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

Chromite Ore from the Transvaal Region of South Africa

EPA Pesticide Factsheets

In 2001, EPA finalized a rule to to delete both chromite ore mined in the Transvaal Region of South Africa and the unreacted ore component of the chromite ore processing residue (COPR) from TRI reporting requirements.

Fiber size and number in workers exposed to processed chrysotile asbestos, chrysotile miners, and the general population

DOE Office of Scientific and Technical Information (OSTI.GOV)

Churg, A.; Wiggs, B.

1986-01-01

We analyzed chrysotile and chrysotile-associated amphibole (largely tremolite) asbestos fibers in 21 workers exposed to various types of processed (milled) chrysotile ore, 20 long-term chrysotile miners, and 20 members of the general population (controls). Significantly greater amounts of both chrysotile and tremolite were found in processed-ore workers and miners than in controls. On average, the mean fiber lengths and aspect ratios for the mining and processed-ore-exposed workers were similar and were significantly greater than the values seen in the controls; within the processed-ore group, there was a marked variation in these parameters, and some workers appeared to be exposed tomore » fairly long, thin fibers. It was found empirically that the fiber size data, and to a lesser extent the concentration data, could be used to classify workers accurately into those with processed-ore exposure and controls. We conclude that fiber sizes in the lungs of processed-ore-exposed workers are similar to those of chrysotile miners and are considerably longer than those found in the general population; some processed-ore workers have longer fibers which might be responsible for higher disease incidences in certain working groups; tremolite accompanies chrysotile in a variable proportion of workers exposed to processed chrysotile products and might be important in the genesis of mesothelioma in such workers; and mineralogic analysis will usually detect exposure even when chrysotile has largely disappeared from lung tissue.« less

Stochastic production phase design for an open pit mining complex with multiple processing streams

NASA Astrophysics Data System (ADS)

Asad, Mohammad Waqar Ali; Dimitrakopoulos, Roussos; van Eldert, Jeroen

2014-08-01

In a mining complex, the mine is a source of supply of valuable material (ore) to a number of processes that convert the raw ore to a saleable product or a metal concentrate for production of the refined metal. In this context, expected variation in metal content throughout the extent of the orebody defines the inherent uncertainty in the supply of ore, which impacts the subsequent ore and metal production targets. Traditional optimization methods for designing production phases and ultimate pit limit of an open pit mine not only ignore the uncertainty in metal content, but, in addition, commonly assume that the mine delivers ore to a single processing facility. A stochastic network flow approach is proposed that jointly integrates uncertainty in supply of ore and multiple ore destinations into the development of production phase design and ultimate pit limit. An application at a copper mine demonstrates the intricacies of the new approach. The case study shows a 14% higher discounted cash flow when compared to the traditional approach.

Relation of ERTS-1 detected geologic structure to known economic ore deposits

NASA Technical Reports Server (NTRS)

Rich, E. I.

1973-01-01

A preliminary analysis of ERTS-1 imagery of the Northern Coast Ranges and Sacramento Valley, California, has disclosed a potentially important fracture system which may be one of the controlling factors in the location of known mercury deposits in the Coast Ranges and which appears to be associated with some of the oil and gas fields within the Sacramento Valley. Recognition of this fracture system may prove to be an extremely useful exploration tool, hence careful analysis of subsequent ERTS imagery might delineate areas for field evaluation.

On prediction and discovery of lunar ores

NASA Technical Reports Server (NTRS)

Haskin, Larry A.; Colson, Russell O.; Vaniman, David

1991-01-01

Sampling of lunar material and remote geochemical, mineralogical, and photogeologic sensing of the lunar surface, while meager, provide first-cut information about lunar composition and geochemical separation processes. Knowledge of elemental abundances in known lunar materials indicates which common lunar materials might serve as ores if there is economic demand and if economical extraction processes can be developed, remote sensing can be used to extend the understanding of the Moon's major geochemical separations and to locate potential ore bodies. Observed geochemical processes might lead to ores of less abundant elements under extreme local conditions.

Removal of mercury from coal via a microbial pretreatment process

DOEpatents

Borole, Abhijeet P [Knoxville, TN; Hamilton, Choo Y [Knoxville, TN

2011-08-16

A process for the removal of mercury from coal prior to combustion is disclosed. The process is based on use of microorganisms to oxidize iron, sulfur and other species binding mercury within the coal, followed by volatilization of mercury by the microorganisms. The microorganisms are from a class of iron and/or sulfur oxidizing bacteria. The process involves contacting coal with the bacteria in a batch or continuous manner. The mercury is first solubilized from the coal, followed by microbial reduction to elemental mercury, which is stripped off by sparging gas and captured by a mercury recovery unit, giving mercury-free coal. The mercury can be recovered in pure form from the sorbents via additional processing.

Create a Consortium and Develop Premium Carbon Products from Coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frank Rusinko; John Andresen; Jennifer E. Hill

2006-01-01

The objective of these projects was to investigate alternative technologies for non-fuel uses of coal. Special emphasis was placed on developing premium carbon products from coal-derived feedstocks. A total of 14 projects, which are the 2003 Research Projects, are reported herein. These projects were categorized into three overall objectives. They are: (1) To explore new applications for the use of anthracite in order to improve its marketability; (2) To effectively minimize environmental damage caused by mercury emissions, CO{sub 2} emissions, and coal impounds; and (3) To continue to increase our understanding of coal properties and establish coal usage in non-fuelmore » industries. Research was completed in laboratories throughout the United States. Most research was performed on a bench-scale level with the intent of scaling up if preliminary tests proved successful. These projects resulted in many potential applications for coal-derived feedstocks. These include: (1) Use of anthracite as a sorbent to capture CO{sub 2} emissions; (2) Use of anthracite-based carbon as a catalyst; (3) Use of processed anthracite in carbon electrodes and carbon black; (4) Use of raw coal refuse for producing activated carbon; (5) Reusable PACs to recycle captured mercury; (6) Use of combustion and gasification chars to capture mercury from coal-fired power plants; (7) Development of a synthetic coal tar enamel; (8) Use of alternative binder pitches in aluminum anodes; (9) Use of Solvent Extracted Carbon Ore (SECO) to fuel a carbon fuel cell; (10) Production of a low cost coal-derived turbostratic carbon powder for structural applications; (11) Production of high-value carbon fibers and foams via the co-processing of a low-cost coal extract pitch with well-dispersed carbon nanotubes; (12) Use of carbon from fly ash as metallurgical carbon; (13) Production of bulk carbon fiber for concrete reinforcement; and (14) Characterizing coal solvent extraction processes. Although some of the projects funded did not meet their original goals, the overall objectives of the CPCPC were completed as many new applications for coal-derived feedstocks have been researched. Future research in many of these areas is necessary before implementation into industry.« less

Biomining: metal recovery from ores with microorganisms.

PubMed

Schippers, Axel; Hedrich, Sabrina; Vasters, Jürgen; Drobe, Malte; Sand, Wolfgang; Willscher, Sabine

2014-01-01

Biomining is an increasingly applied biotechnological procedure for processing of ores in the mining industry (biohydrometallurgy). Nowadays the production of copper from low-grade ores is the most important industrial application and a significant part of world copper production already originates from heap or dump/stockpile bioleaching. Conceptual differences exist between the industrial processes of bioleaching and biooxidation. Bioleaching is a conversion of an insoluble valuable metal into a soluble form by means of microorganisms. In biooxidation, on the other hand, gold is predominantly unlocked from refractory ores in large-scale stirred-tank biooxidation arrangements for further processing steps. In addition to copper and gold production, biomining is also used to produce cobalt, nickel, zinc, and uranium. Up to now, biomining has merely been used as a procedure in the processing of sulfide ores and uranium ore, but laboratory and pilot procedures already exist for the processing of silicate and oxide ores (e.g., laterites), for leaching of processing residues or mine waste dumps (mine tailings), as well as for the extraction of metals from industrial residues and waste (recycling). This chapter estimates the world production of copper, gold, and other metals by means of biomining and chemical leaching (bio-/hydrometallurgy) compared with metal production by pyrometallurgical procedures, and describes new developments in biomining. In addition, an overview is given about metal sulfide oxidizing microorganisms, fundamentals of biomining including bioleaching mechanisms and interface processes, as well as anaerobic bioleaching and bioleaching with heterotrophic microorganisms.

Dephosphorization of High-Phosphorus Iron Ore Using Different Sources of Aspergillus niger Strains.

PubMed

Xiao, Chunqiao; Wu, Xiaoyan; Chi, Ruan

2015-05-01

High-phosphorus iron ore is traditionally dephosphorized by chemical process with inorganic acids. However, this process is not recommended nowadays because of its high cost and consequent environmental pollution. With the current tendency for development of a low-cost and eco-friendly process, dephosphorization of high-phosphorus iron ore through microbial process with three different sources of Aspergillus niger strains was studied in this study. Results show that the three strains of A. niger could grow well in the broth, and effectively remove phosphate from high-phosphorus iron ore during the experiments. Meanwhile, the total iron in the broth was also increased. Acidification of the broth seemed to be the major mechanism for the dephosphorization by these strains. High-pressure liquid chromatography analysis indicated that various organic acids were secreted in the broth, which caused a significant drop of the broth pH. Scanning electron microscopy of ore residues revealed that the high-phosphorus iron ore was obviously destroyed by the actions of these strains. Ore residues by energy-dispersive X-ray microanalysis and Fourier transform infrared spectroscopy indicated that the phosphate was obviously removed from the high-phosphorus iron ore. The optimization of the dephosphorization by these strains was also investigated, and the maximum percentages of phosphate removal were recorded at temperature 27-30 °C, initial pH 5.0-6.5, particle size 0.07-0.1 mm, and pulp density of 2-3% (w/v), respectively. The fungus A. niger was found to have good potential for the dephosphorization of high-phosphorus iron ore, and this microbial process seems to be economic and effective in the future industrial application.

Mercury speciation in the Mt. Amiata mining district (Italy): interplay between urban activities and mercury contamination

USGS Publications Warehouse

Rimondi, Valentina; Bardelli, Fabrizio; Benvenuti, Marco; Costagliola, Pilario; Gray, John E.; Lattanzi, Pierfranco

2014-01-01

A fundamental step to evaluate the biogeochemical and eco-toxicological significance of Hg dispersion in the environment is to determine speciation of Hg in solid matrices. In this study, several analytical techniques such as scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), sequential chemical extractions (SCEs), and X-ray absorption spectroscopy (XANES) were used to identify Hg compounds and Hg speciation in samples collected from the Mt. Amiata Hg mining district, southern Tuscany, Italy. Different geological materials, such as mine waste calcine (retorted ore), soil, stream sediment, and stream water suspended particulate matter were analyzed. Results show that the samples were generally composed of highly insoluble Hg compounds such as sulphides (HgS, cinnabar and metacinnabar), and more soluble Hg halides such as those associated with the mosesite group. Other moderately soluble Hg compounds, HgCl2, HgO and Hg0, were also identified in stream sediments draining the mining area. The presence of these minerals suggests active and continuous runoff of soluble Hg compounds from calcines, where such Hg compounds form during retorting, or later in secondary processes. Specifically, we suggest that, due to the proximity of Hg mines to the urban center of Abbadia San Salvatore, the influence of other anthropogenic activities was a key factor for Hg speciation, resulting in the formation of unusual Hg-minerals such as mosesite.

PROCESS FOR THE CONCENTRATION OF ORES CONTAINING GOLD AND URANIUM

DOEpatents

Gaudin, A.M.; Dasher, J.

1958-06-10

ABS>A process is described for concentrating certain low grade uranium and gold bearing ores, in which the gangue is mainly quartz. The production of the concentrate is accomplished by subjecting the crushed ore to a froth floatation process using a fatty acid as a collector in conjunction with a potassium amyl xanthate collector. Pine oil is used as the frothing agent.

Silicophosphate Sorbents, Based on Ore-Processing Plants' Waste in Kazakhstan

ERIC Educational Resources Information Center

Kubekova, Sholpan N.; Kapralova, Viktoria I.; Telkov, Shamil A.

2016-01-01

The problem of ore-processing plants' waste and man-made mineral formations (MMF) disposal is very important for the Republic of Kazakhstan. The research of various ore types (gold, polymetallic, iron-bearing) MMF from a number of Kazakhstan's deposits using a complex physical and chemical methods showed, that the waste's main components are…

Production of Titanium Metal by an Electrochemical Molten Salt Process

NASA Astrophysics Data System (ADS)

Fatollahi-Fard, Farzin

Titanium production is a long and complicated process. What we often consider to be the standard method of primary titanium production (the Kroll process), involves many complex steps both before and after to make a useful product from titanium ore. Thus new methods of titanium production, especially electrochemical processes, which can utilize less-processed feedstocks have the potential to be both cheaper and less energy intensive than current titanium production processes. This project is investigating the use of lower-grade titanium ores with the electrochemical MER process for making titanium via a molten salt process. The experimental work carried out has investigated making the MER process feedstock (titanium oxycarbide) with natural titanium ores--such as rutile and ilmenite--and new ways of using the MER electrochemical reactor to "upgrade" titanium ores or the titanium oxycarbide feedstock. It is feasible to use the existing MER electrochemical reactor to both purify the titanium oxycarbide feedstock and produce titanium metal.

Characteristics of Crushing Energy and Fractal of Magnetite Ore under Uniaxial Compression

NASA Astrophysics Data System (ADS)

Gao, F.; Gan, D. Q.; Zhang, Y. B.

2018-03-01

The crushing mechanism of magnetite ore is a critical theoretical problem on the controlling of energy dissipation and machine crushing quality in ore material processing. Uniaxial crushing tests were carried out to research the deformation mechanism and the laws of the energy evolution, based on which the crushing mechanism of magnetite ore was explored. The compaction stage and plasticity and damage stage are two main compression deformation stages, the main transitional forms from inner damage to fracture are plastic deformation and stick-slip. In the process of crushing, plasticity and damage stage is the key link on energy absorption for that the specimen tends to saturate energy state approaching to the peak stress. The characteristics of specimen deformation and energy dissipation can synthetically reply the state of existed defects inner raw magnetite ore and the damage process during loading period. The fast releasing of elastic energy and the work done by the press machine commonly make raw magnetite ore thoroughly broken after peak stress. Magnetite ore fragments have statistical self-similarity and size threshold of fractal characteristics under uniaxial squeezing crushing. The larger ratio of releasable elastic energy and dissipation energy and the faster energy change rate is the better fractal properties and crushing quality magnetite ore has under uniaxial crushing.

Long-Term Planning for Open Pits for Mining Sulphide-Oxide Ores in Order to Achieve Maximum Profit

NASA Astrophysics Data System (ADS)

Kržanović, Daniel; Conić, Vesna; Stevanović, Dejan; Kolonja, Božo; Vaduvesković, Jovan

2017-12-01

Profitable exploitation of mineralised material from the earth's crust is a complex and difficult task that depends on a comprehensive planning process. Answering the question of how to plan production depends on the geometry of the deposit, as well as the concentration, distribution, and type of minerals in it. The complex nature of mineral deposits largely determines the method of exploitation and profitability of mining operations. In addition to unit operating costs and metal prices, the optimal recovery of and achievement of maximum profit from deposits of sulphide-oxide ores also depend, to a significant extent, on the level of technological recovery achieved in the ore processing procedure. Therefore, in defining a long-term development strategy for open pits, special attention must be paid to the selection of an optimal procedure for ore processing in order to achieve the main objective: maximising the Net Present Value (NPV). The effect of using two different processes, flotation processing and hydrometallurgical methods (bioleaching acid leaching), on determining the ultimate pit is shown in the case of the Kraku Bugaresku-Cementacija sulphide-oxide ore deposit in eastern Serbia. Analysis shows that the application of hydrometallurgical methods of processing sulphide-oxide ore achieved an increase in NPV of 20.42%.

NOVEL BINDERS AND METHODS FOR AGGLOMERATION OF ORE

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.K. Kawatra; T.C. Eisele; J.A. Gurtler

2005-04-01

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not breakdown during processing. However, for many important metal extraction processes there are no binders known that will workmore » satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process. As a result, operators of many facilities see large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; J. A. Gurtler

2004-03-31

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily. A primary example of this is copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process. As a result, operators of acidic heap-leach facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of other agglomeration applications, particularly advanced primary ironmaking.« less

Experimenting With Ore: Creating the Taconite Process; flow chart of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Experimenting With Ore: Creating the Taconite Process; flow chart of process - Mines Experiment Station, University of Minnesota, Twin Cities Campus, 56 East River Road, Minneapolis, Hennepin County, MN

Childhood lead poisoning associated with gold ore processing: a village-level investigation-Zamfara State, Nigeria, October-November 2010.

PubMed

Lo, Yi-Chun; Dooyema, Carrie A; Neri, Antonio; Durant, James; Jefferies, Taran; Medina-Marino, Andrew; de Ravello, Lori; Thoroughman, Douglas; Davis, Lora; Dankoli, Raymond S; Samson, Matthias Y; Ibrahim, Luka M; Okechukwu, Ossai; Umar-Tsafe, Nasir T; Dama, Alhassan H; Brown, Mary Jean

2012-10-01

During May-June 2010, a childhood lead poisoning outbreak related to gold ore processing was confirmed in two villages in Zamfara State, Nigeria. During June-September of that year, villages with suspected or confirmed childhood lead poisoning continued to be identified in Zamfara State. We investigated the extent of childhood lead poisoning [≥ 1 child with a blood lead level (BLL) ≥ 10 µg/dL] and lead contamination (≥ 1 soil/dust sample with a lead level > 400 parts per million) among villages in Zamfara State and identified villages that should be prioritized for urgent interventions. We used chain-referral sampling to identify villages of interest, defined as villages suspected of participation in gold ore processing during the previous 12 months. We interviewed villagers, determined BLLs among children < 5 years of age, and analyzed soil/dust from public areas and homes for lead. We identified 131 villages of interest and visited 74 (56%) villages in three local government areas. Fifty-four (77%) of 70 villages that completed the survey reported gold ore processing. Ore-processing villages were more likely to have ≥ 1 child < 5 years of age with lead poisoning (68% vs. 50%, p = 0.17) or death following convulsions (74% vs. 44%, p = 0.02). Soil/dust contamination and BLL ≥ 45 µg/dL were identified in ore-processing villages only [50% (p < 0.001) and 15% (p = 0.22), respectively]. The odds of childhood lead poisoning or lead contamination was 3.5 times as high in ore-processing villages than the other villages (95% confidence interval: 1.1, 11.3). Childhood lead poisoning and lead contamination were widespread in surveyed areas, particularly among villages that had processed ore recently. Urgent interventions are required to reduce lead exposure, morbidity, and mortality in affected communities.

Childhood Lead Poisoning Associated with Gold Ore Processing: a Village-Level Investigation—Zamfara State, Nigeria, October–November 2010

PubMed Central

Lo, Yi-Chun; Dooyema, Carrie A.; Neri, Antonio; Durant, James; Jefferies, Taran; Medina-Marino, Andrew; de Ravello, Lori; Thoroughman, Douglas; Davis, Lora; Dankoli, Raymond S.; Samson, Matthias Y.; Ibrahim, Luka M.; Okechukwu, Ossai; Umar-Tsafe, Nasir T.; Dama, Alhassan H.

2012-01-01

Background: During May–June 2010, a childhood lead poisoning outbreak related to gold ore processing was confirmed in two villages in Zamfara State, Nigeria. During June–September of that year, villages with suspected or confirmed childhood lead poisoning continued to be identified in Zamfara State. Objectives: We investigated the extent of childhood lead poisoning [≥ 1 child with a blood lead level (BLL) ≥ 10 µg/dL] and lead contamination (≥ 1 soil/dust sample with a lead level > 400 parts per million) among villages in Zamfara State and identified villages that should be prioritized for urgent interventions. Methods: We used chain-referral sampling to identify villages of interest, defined as villages suspected of participation in gold ore processing during the previous 12 months. We interviewed villagers, determined BLLs among children < 5 years of age, and analyzed soil/dust from public areas and homes for lead. Results: We identified 131 villages of interest and visited 74 (56%) villages in three local government areas. Fifty-four (77%) of 70 villages that completed the survey reported gold ore processing. Ore-processing villages were more likely to have ≥ 1 child < 5 years of age with lead poisoning (68% vs. 50%, p = 0.17) or death following convulsions (74% vs. 44%, p = 0.02). Soil/dust contamination and BLL ≥ 45 µg/dL were identified in ore-processing villages only [50% (p < 0.001) and 15% (p = 0.22), respectively]. The odds of childhood lead poisoning or lead contamination was 3.5 times as high in ore-processing villages than the other villages (95% confidence interval: 1.1, 11.3). Conclusion: Childhood lead poisoning and lead contamination were widespread in surveyed areas, particularly among villages that had processed ore recently. Urgent interventions are required to reduce lead exposure, morbidity, and mortality in affected communities. PMID:22766030

Face format at encoding affects the other-race effect in face memory.

PubMed

Zhao, Mintao; Hayward, William G; Bülthoff, Isabelle

2014-08-07

Memory of own-race faces is generally better than memory of other-races faces. This other-race effect (ORE) in face memory has been attributed to differences in contact, holistic processing, and motivation to individuate faces. Since most studies demonstrate the ORE with participants learning and recognizing static, single-view faces, it remains unclear whether the ORE can be generalized to different face learning conditions. Using an old/new recognition task, we tested whether face format at encoding modulates the ORE. The results showed a significant ORE when participants learned static, single-view faces (Experiment 1). In contrast, the ORE disappeared when participants learned rigidly moving faces (Experiment 2). Moreover, learning faces displayed from four discrete views produced the same results as learning rigidly moving faces (Experiment 3). Contact with other-race faces was correlated with the magnitude of the ORE. Nonetheless, the absence of the ORE in Experiments 2 and 3 cannot be readily explained by either more frequent contact with other-race faces or stronger motivation to individuate them. These results demonstrate that the ORE is sensitive to face format at encoding, supporting the hypothesis that relative involvement of holistic and featural processing at encoding mediates the ORE observed in face memory. © 2014 ARVO.

Stable mercury isotope ratios as tracers for Hg cycling at the inoperative New Idria Hg mine, California

NASA Astrophysics Data System (ADS)

Wiederhold, J. G.; Jew, A. D.; Brown, G. E.; Bourdon, B.; Kretzschmar, R.

2010-12-01

The seven stable isotopes of Hg are fractionated in the environment as a result of mass-dependent (MDF) and mass-independent (MIF) fractionation processes that can be studied in parallel by analyzing the ratios of even and odd mass Hg isotopes. MDF and MIF Hg isotope signatures of natural samples may provide a new tool to trace sources and transformations in environmental Hg cycling. However, the mechanisms controlling the extent of kinetic and equilibrium Hg isotope fractionations are still only partially understood. Thus, development of this promising tracer requires experimental calibration of relevant fractionation factors as well as assessment of natural variations of Hg isotope ratios under different environmental conditions. The inoperative Hg mine in New Idria (California, USA) represents an ideal case study to explore Hg isotope fractionation during Hg transformation and transport processes. More than a century of Hg mining and on-site thermal refining to obtain elemental Hg until 1972 produced large volumes of contaminated mine wastes which now represent sources of Hg pollution for the surrounding ecosystems. Here, we present Hg isotope data from various materials collected at New Idria using Cold-Vapor-MC-ICPMS with a long-term δ202Hg reproducibility of ±0.1‰ (2SD). Uncalcined mine waste samples were isotopically similar to NIST-3133 and did not exhibit any MIF signatures. In contrast, calcine samples, which represent the residue of the thermal ore processing at 700°C, had significantly heavier δ202Hg values of up to +1.5‰. In addition, we observed small negative MIF anomalies of the odd-mass Hg isotopes in the calcine samples, which could be caused either by nuclear volume fractionation or a magnetic isotope effect during or after the roasting process. The mass-dependent enrichment of heavy Hg isotopes in the calcine materials indicates that light Hg isotopes were preferentially removed during the roasting process, in agreement with a previous study by Stetson et al. (ES&T, 2009, 43:7331-7336). In order to further elucidate the Hg isotope signatures of the New Idria samples, we performed a three-step sequential extraction procedure to separate different Hg pools. The calcine samples exhibited a higher proportion of leachable Hg phases compared with the unrefined ore waste samples. The most soluble Hg pool (HAc/HCl, pH 2) had a significantly heavier MDF and more negative MIF signature than the bulk calcine samples, suggesting that the dissolution of more soluble Hg phases from calcine materials results in an enhanced flux of leached Hg which is isotopically distinct from the original ore. Moreover, this finding demonstrates that the Hg isotope fractionation during the ore roasting cannot be solely explained by a kinetic Rayleigh-type process which removes light Hg isotopes, but must additionally involve the formation of isotopically heavy secondary Hg phases in the calcine. The analysis of additional samples will enable us to test this hypothesis and to gain further insights into the applicability of stable Hg isotope ratios as source and process tracers in Hg-contaminated environments.

Mercury Methylation at Mercury Mines In The Humboldt River Basin, Nevada, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gray, John E.; Crock, James G.; Lasorsa, Brenda K.

2002-12-01

Total Hg and methylmercury concentrations were measured in mine-waste calcines (retorted ore), sediment, and water samples collected in and around abandoned mercury mines in western Nevada to evaluate Hg methylation at the mines and in the Humboldt River basin. Mine-waste calcines contain total Hg concentrations as high as 14 000?g/g. Stream-sediment samples collected within 1 km of the mercury mines contain total Hg concentrations as high as 170?g/g, whereas stream sediments collected>5 km from the mines, and those collected from the Humboldt River and regional baseline sites, contain total Hg concentrations<0.5?g/g. Similarly, methylmercury concentrations in mine-waste calcines are locally asmore » high as 96 ng/g, but methylmercury contents in stream-sediments collected downstream from the mines and from the Humboldt River are lower, ranging from<0.05 to 0.95 ng/g. Stream-water samples collected below two mines studied contain total Hg concentrations ranging from 6 to 2000 ng/L, whereas total Hg in Humboldt River water was generally lower ranging from 2.1 to 9.0 ng/L. Methylmercury concentrations in the Humboldt River water were the lowest in this study (<0.02-0.27 ng/L). Although total Hg and methylmercury concentrations are locally high in mine-waste calcines, there is significant dilution of Hg and lower Hg methylation down gradient from the mines, especially in the sediments and water collected from the Humboldt River, which is> 8 km from any mercury mines. Our data indicate little transference of Hg and methylmercury from the sediment to the water column due to the lack of mine runoff in this desert climate.« less

Nanocrystalline Iron-Ore-Based Catalysts for Fischer-Tropsch Synthesis.

PubMed

Yong, Seok; Park, Ji Chan; Lee, Ho-Tae; Yang, Jung-Il; Hong, SungJun; Jung, Heon; Chun, Dong Hyun

2016-02-01

Nanocrystalline iron ore particles were fabricated by a wet-milling process using an Ultra Apex Mill, after which they were used as raw materials of iron-based catalysts for low-temperature Fischer-Tropsch synthesis (FTS) below 280 degrees C, which usually requires catalysts with a high surface area, a large pore volume, and a small crystallite size. The wet-milling process using the Ultra Apex Mill effectively destroyed the initial crystallite structure of the natural iron ores of several tens to hundreds of nanometers in size, resulting in the generation of nanocrystalline iron ore particles with a high surface area and a large pore volume. The iron-ore-based catalysts prepared from the nanocrystalline iron ore particles effectively catalyzed the low-temperature FTS, displaying a high CO conversion (about 90%) and good C5+ hydrocarbon productivity (about 0.22 g/g(cat)(-h)). This demonstrates the feasibility of using the iron-ore-based catalysts as inexpensive and disposable catalysts for the low-temperature FTS.

Blasting preparation for selective mining of complex structured ore deposition

NASA Astrophysics Data System (ADS)

Marinin, M. A.; Dolzhikov, V. V.

2017-10-01

Technological features of ore mining in the open pit development for processing of complex structured ore deposit of steeply falling occurrence have been considered. The technological schemes of ore bodies mining under different conditions of occurrence, consistency and capacity have been considered and offered in the paper. These technologies permit to reduce losses and dilution, but to increase the completeness and quality of mined ore. A method of subsequent selective excavation of ore bodies has been proposed. The method is based on the complex use of buffer-blasting technology for the muck mass and the principle of trim blasting at ore-rock junctions.

Bacterio-electric leaching of metals

DOEpatents

Lazaroff, Norman; Dugan, Patrick R.

1992-07-07

The separation of cationic materials from an ore body is assisted by the application of an electric potential, and resulting current, to the ore body, in association with iron or sulphur oxidizing bacteria. The combined process induces migration of cationic metals to a cathode suspended within the ore body so that the cationic metal can be preferentially separated from the ore body.

Bacterio-electric leaching of metals

DOEpatents

Lazaroff, Norman; Dugan, Patrick R.

1992-01-01

The separation of cationic materials from an ore body is assisted by the application of an electric potential, and resulting current, to the ore body, in association with iron or sulphur oxidizing bacteria. The combined process induces migration of cationic metals to a cathode suspended within the ore body so that the cationic metal can be preferentially separated from the ore body.

Biogeochemistry of mercury in soils and sediments in a mining-impacted watershed, California

NASA Astrophysics Data System (ADS)

Holloway, J. M.; Goldhaber, M. B.

2004-12-01

The East Davis Creek watershed, located in the California Coast Ranges, is host to historic mines that provided mercury for recovery of gold in the Sierra Nevada goldfields in the mid-to-late 1800s. Bedrock in this watershed includes marine sedimentary rock, serpentinite, and hydrothermally altered serpentinite. Cinnabar (HgS) found in the altered serpentinite is the primary ore mineral for mercury. We evaluated the hypothesis that mercury is sequestered in soil organic matter downstream from source areas, releasing a fraction as water-soluble methylmercury. Microbial biomass and the presence of sulfur-reducing bacteria implicated in mercury methylation were quantified using phospholipid fatty acid (PLFA) data. Methylation incubations were performed on soil and sediment inoculated with water from Davis Creek Reservoir and sealed in glass containers under an anoxic headspace for 21 days. Methylmercury was measured on extracts of the soils at the start and at the end of the incubation period. Two sources of mercury to stream sediments, a soil with an altered serpentinite parent and mine tailings, were incubated. Stream sediment, an overbank deposit soil and a wetland soil forming from these sediments were also incubated. The overbank deposit soil is periodically flooded. The wetland soil around the edge of Davis Creek Reservoir is perennially saturated with water. The altered serpentinite soil and mine tailings had the highest total mercury concentrations (170 and 150 ng Hg /g, respectively). Total mercury concentrations in stream sediments are low (¡Ü1 ng Hg/g), with higher mercury concentrations in the overbank (3 ng/g) and wetland soils (18 ng Hg/g). Mercury leached from altered serpentinite soils and mine tailings may be transported downstream and sequestered through sorption to organic matter in the overbank and wetland soils. PLFA biomarkers for Desulfobacter (10Me16:0) and Desulfovibrio (i17:1) were present in all incubated materials, with lower concentrations in mine tailings and stream sediment relative to the three soils examined. Methylmercury was initially present in greater concentrations in the overbank deposit (23 ng HgMe/g) soils. The elevated methyl mercury in the overbank deposit soil may be due to the greater biomass of sulfur reducing bacteria indicated by the 10Me16:0 and i17:1 biomarkers. During the 21-day incubation, methylmercury increased from 0.6 to 15 ng HgMe/g in the wetland soil concomitantly with sulfate decreasing from 130 to 7.0 mg SO4=/g. Methylmercury concentrations did not change appreciably in the other soils, although sulfate decreased from 19 to 2.0 mg SO4=/g in the overbank deposit soil. These data suggest that overbank deposits and wetland soils sequester mercury leached from upstream sources, with a fraction of this mercury released through microbial methylation.

Beneficiation and leaching study of a muti-Au carrier and low grade refractory gold ore

NASA Astrophysics Data System (ADS)

Li, W. J.; Song, Y. S.; Chen, Y.; Cai, L. L.; Zhou, G. Y.

2017-09-01

Detailed mineralogy and beneficiation and leaching study of a muti-Au carrier, low grade refractory gold ore from a beneficiation plant in Henan Province, China, was investigated. Mineral liberation analysis, scanning electron microscopy, element phase analysis and etc. by a mineral liberation analyser were used for mineralogical characterization study of this ore. The present work describes an experimental study on the effect of traditional parameters (such as grinding fineness and reagent regimes), middling processing method and flowsheet construction on the total recovery and the assay of the floatation concentrate. Two-step floatation and part of middling combined to the floatation tailing for gold leaching process resulted in high gold grade (g.t-1) and gold recovery (%) for this refractory gold ore. This process opens the possibilities of maximizing Au grade and recoveries in a muti-Au carrier and low grade refractory gold ore where low recoveries are common.

Assessment of mercury exposure among small-scale gold miners using mercury stable isotopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sherman, Laura S., E-mail: lsaylors@umich.edu; Blum, Joel D.; Basu, Niladri

Total mercury (Hg) concentrations in hair and urine are often used as biomarkers of exposure to fish-derived methylmercury (MeHg) and gaseous elemental Hg, respectively. We used Hg stable isotopes to assess the validity of these biomarkers among small-scale gold mining populations in Ghana and Indonesia. Urine from Ghanaian miners displayed similar Δ{sup 199}Hg values to Hg derived from ore deposits (mean urine Δ{sup 199}Hg=0.01‰, n=6). This suggests that urine total Hg concentrations accurately reflect exposure to inorganic Hg among this population. Hair samples from Ghanaian miners displayed low positive Δ{sup 199}Hg values (0.23–0.55‰, n=6) and low percentages of total Hgmore » as MeHg (7.6–29%, n=7). These data suggest that the majority of the Hg in these miners' hair samples is exogenously adsorbed inorganic Hg and not fish-derived MeHg. Hair samples from Indonesian gold miners who eat fish daily displayed a wider range of positive Δ{sup 199}Hg values (0.21–1.32‰, n=5) and percentages of total Hg as MeHg (32–72%, n=4). This suggests that total Hg in the hair samples from Indonesian gold miners is likely a mixture of ingested fish MeHg and exogenously adsorbed inorganic Hg. Based on data from both populations, we suggest that total Hg concentrations in hair samples from small-scale gold miners likely overestimate exposure to MeHg from fish consumption. - Highlights: • Mercury isotopes were measured in hair and urine from small-scale gold miners. • Mercury isotopes indicate that Hg in urine comes from mining activity. • Mercury isotopes suggest Hg in hair is a mixture of fish MeHg and inorganic Hg. • A large percentage of Hg in miner’s hair is released during amalgam burning and adsorbed.« less

Modelling of the mercury loss in fluorescent lamps under the influence of metal oxide coatings

NASA Astrophysics Data System (ADS)

Santos Abreu, A.; Mayer, J.; Lenk, D.; Horn, S.; Konrad, A.; Tidecks, R.

2016-11-01

The mercury transport and loss mechanisms in the metal oxide coatings of mercury low pressure discharge fluorescent lamps have been investigated. An existing model based on a ballistic process is discussed in the context of experimental mercury loss data. Two different approaches to the modeling of the mercury loss have been developed. The first one is based on mercury transition rates between the plasma, the coating, and the glass without specifying the underlying physical processes. The second one is based on a transport process driven by diffusion and a binding process of mercury reacting to mercury oxide inside the layers. Moreover, we extended the diffusion based model to handle multi-component coatings. All approaches are applied to describe mercury loss experiments under the influence of an Al 2 O 3 coating.

NOVEL BINDERS AND METHODS FOR AGGLOMERATION OF ORE

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.K. Kawatra; T.C. Eisele; J.A. Gurtler

2004-04-01

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process, and advanced ironmaking processes, where binders must function satisfactorily over an extraordinarily large range of temperatures (from room temperature up to over 1200 C). As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching and advanced primary ironmaking.« less

MERCURY REDUCTION IN PRODUCTS AND PROCESSES: A REVIEW OF THE ELECTRICAL AND ELECTRONIC INDUSTRIES

EPA Science Inventory

The electrical and electronics industries have significantly reduced the amount of mercury from various products and processes. However, the unique electromechanical and photoelectronic properties of mercury and mercury compounds have made replacement of mercury difficult in some...

MERCURY REDUCTION IN PRODUCTS AND PROCESSES: A REVIEW OF THE ELECTRICAL AND ELECTRONIC INDUSTRIES

EPA Science Inventory

The electrical and electronics industries have significantly reduced the amount of mercury from various products and processes. owever, the unique electromechanical and photoelectronic properties of mercury and mercury compounds have made replacement of mercury difficult in some ...

Tourmaline as a recorder of ore-forming processes

USGS Publications Warehouse

Slack, John F.; Trumbull, Robert B.

2011-01-01

Tourmaline occurs in diverse types of hydrothermal mineral deposits and can be used to constrain the nature and evolution of ore-forming fl uids. Because of its broad range in composition and retention of chemical and isotopic signatures, tourmaline may be the only robust recorder of original mineralizing processes in some deposits. Microtextures and in situ analysis of compositional and isotopic variations in ore-related tourmaline provide valuable insights into hydrothermal systems in seafl oor, sedimentary, magmatic, and metamorphic environments. Deciphering the hydrothermal record in tourmaline also holds promise for aiding exploration programs in the search for new ore deposits.

Mercury emission and distribution: Potential environmental risks at a small-scale gold mining operation, Phichit Province, Thailand.

PubMed

Pataranawat, Poranee; Parkpian, Preeda; Polprasert, Chongrak; Delaune, R D; Jugsujinda, A

2007-07-01

Mercury (Hg) contamination was assessed in environment near an amalgamation gold recovery operation located at a small scale mining operation (Phanom Pha) in Phichit Province, Thailand. Total mercury (THg) concentrations was determined in water, sediment, bivalves in the aquatic environment and as dry deposition or atmospheric fallout on surface soil and leaves of Neem tree (Azadirachta indica Juss. var. siamensis Valeton) near the mining operation. THg in surface soil, Neem flowers (edible part) and rice grain in surrounding terrestrial habitat and with distance from the mining area were also evaluated for possible contamination. Potential environmental risks were evaluated using the hazard quotient equation. Hg analyses conducted in the aquatic habitat showed that THg in water, sediment and bivalves (Scabies cripata Gould) ranged from 0.4 to 4 microg L(-1), 96 to 402 microg kg(-1)dry weight (dw) and 15 to 584 microg kg(-1) wet weight (ww), respectively. High concentrations of THg in water, sediment and bivalves were observed in the receiving stream near the mining operation which was located near the Khao Chet Luk Reservoir. Whereas the THg concentration in water, sediment and bivalves from monitoring stations outside the gold mining operation (upstream and downstream), were considerably lower with the values of 0.4-0.8 microg L(-1), 96-140 microg kg(-1) dw and 88-658 microg kg(-1) dw, respectively. The elevated concentration of Hg found in the sediment near the mining operation was consistent with Hg accumulation measured in bivalves. The elevated Hg levels found in living bivalves collected from highly contaminated sites suggested that the sediment bound Hg was bioavailable. THg in surface soils, brown rice grain (Jasmine rice #105) and Neem flowers of terrestrial habitats were in the range of 16 to 180 microg kg(-1) dw, 190 to 300 microg kg(-1) dw, and 622 to 2150 microg kg(-1) dw, respectively. Elevated concentrations of mercury were found in Neem flowers with the concentration greater than 600 microg kg(-1) ww, which exceeds the maximum permissible concentration reported for biota tissue (500 microg kg(-1) ww). An evaluation of air and soil pollution near the mining operations showed high concentrations of THg in dry deposit from atmospheric fallout (139 microg m(-2) d(-1)), and in surface soil (10,564 microg kg(-1) dw) at station near where open burning of gold ore extracts using the amalgamation process occurred. High or elevated concentration of THg (1172-1301 microg kg(-1) dw) in leaves of Neem tree was also measured near the mining operations. A survey of Hg in surface soil showed elevated Hg concentrations near the site which corresponded to the elevated THg concentration in dry deposition. These results suggested that atmospheric fallout is a major source of Hg to the area surrounding the mining or gold ore extraction. Results also suggest that Hg emitted into the air (estimated to be 60-150 g d(-1)) from the gold mining activities (over the past 10 years) contaminated air, the aquatic environment, surface soil and biota in the area surrounding the gold mining operation.

Isotope effect of mercury diffusion in air

PubMed Central

Koster van Groos, Paul G.; Esser, Bradley K.; Williams, Ross W.; Hunt, James R.

2014-01-01

Identifying and reducing impacts from mercury sources in the environment remains a considerable challenge and requires process based models to quantify mercury stocks and flows. The stable isotope composition of mercury in environmental samples can help address this challenge by serving as a tracer of specific sources and processes. Mercury isotope variations are small and result only from isotope fractionation during transport, equilibrium, and transformation processes. Because these processes occur in both industrial and environmental settings, knowledge of their associated isotope effects is required to interpret mercury isotope data. To improve the mechanistic modeling of mercury isotope effects during gas phase diffusion, an experimental program tested the applicability of kinetic gas theory. Gas-phase elemental mercury diffusion through small bore needles from finite sources demonstrated mass dependent diffusivities leading to isotope fractionation described by a Rayleigh distillation model. The measured relative atomic diffusivities among mercury isotopes in air are large and in agreement with kinetic gas theory. Mercury diffusion in air offers a reasonable explanation of recent field results reported in the literature. PMID:24364380

Isotope effect of mercury diffusion in air.

PubMed

Koster van Groos, Paul G; Esser, Bradley K; Williams, Ross W; Hunt, James R

2014-01-01

Identifying and reducing impacts from mercury sources in the environment remains a considerable challenge and requires process based models to quantify mercury stocks and flows. The stable isotope composition of mercury in environmental samples can help address this challenge by serving as a tracer of specific sources and processes. Mercury isotope variations are small and result only from isotope fractionation during transport, equilibrium, and transformation processes. Because these processes occur in both industrial and environmental settings, knowledge of their associated isotope effects is required to interpret mercury isotope data. To improve the mechanistic modeling of mercury isotope effects during gas phase diffusion, an experimental program tested the applicability of kinetic gas theory. Gas-phase elemental mercury diffusion through small bore needles from finite sources demonstrated mass dependent diffusivities leading to isotope fractionation described by a Rayleigh distillation model. The measured relative atomic diffusivities among mercury isotopes in air are large and in agreement with kinetic gas theory. Mercury diffusion in air offers a reasonable explanation of recent field results reported in the literature.

Mercury Phase II Study - Mercury Behavior across the High-Level Waste Evaporator System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Crawford, C. L.; Jackson, D. G.

2016-06-17

The Mercury Program team’s effort continues to develop more fundamental information concerning mercury behavior across the liquid waste facilities and unit operations. Previously, the team examined the mercury chemistry across salt processing, including the Actinide Removal Process/Modular Caustic Side Solvent Extraction Unit (ARP/MCU), and the Defense Waste Processing Facility (DWPF) flowsheets. This report documents the data and understanding of mercury across the high level waste 2H and 3H evaporator systems.

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

Process for low mercury coal

DOEpatents

Merriam, Norman W.; Grimes, R. William; Tweed, Robert E.

1995-01-01

A process for producing low mercury coal during precombustion procedures by releasing mercury through discriminating mild heating that minimizes other burdensome constituents. Said mercury is recovered from the overhead gases by selective removal.

40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

Code of Federal Regulations, 2011 CFR

2011-07-01

... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... tank sludge 13. Mercury cell process solids 14. Recoverable levels of mercury contained in soil [59 FR...

40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

Code of Federal Regulations, 2012 CFR

2012-07-01

... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... tank sludge 13. Mercury cell process solids 14. Recoverable levels of mercury contained in soil [59 FR...

40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

Code of Federal Regulations, 2014 CFR

2014-07-01

... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... tank sludge 13. Mercury cell process solids 14. Recoverable levels of mercury contained in soil [59 FR...

40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

Code of Federal Regulations, 2010 CFR

2010-07-01

... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... tank sludge 13. Mercury cell process solids 14. Recoverable levels of mercury contained in soil [59 FR...

40 CFR Appendix Xiii to Part 266 - Mercury Bearing Wastes That May Be Processed in Exempt Mercury Recovery Units

Code of Federal Regulations, 2013 CFR

2013-07-01

... are exempt mercury-bearing materials with less than 500 ppm of 40 CFR Part 261, appendix VIII organic... tank sludge 13. Mercury cell process solids 14. Recoverable levels of mercury contained in soil [59 FR...

Technical Report on the Behavior of Trace Elements, Stable Isotopes, and Radiogenic Isotopes During the Processing of Uranium Ore to Uranium Ore Concentrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marks, N. E.; Borg, L. E.; Eppich, G. R.

2015-07-09

The goals of this SP-1 effort were to understand how isotopic and elemental signatures behave during mining, milling, and concentration and to identify analytes that might preserve geologic signatures of the protolith ores. The impurities that are preserved through the concentration process could provide useful forensic signatures and perhaps prove diagnostic of sample origin.

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; K. A. Lewandowski

2006-03-31

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily at a reasonable cost. A primary example of this is copper heap leaching, where there are no binders currently encountered in this acidic environment process. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching. The active involvement of our industrial partners will help to ensure rapid commercialization of any agglomeration technologies developed by this project.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; J. A. Gurtler

2005-09-30

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily at a reasonable cost. A primary example of this is copper heap leaching, where there are no binders currently encountered in this acidic environment process. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching. The active involvement of our industrial partners will help to ensure rapid commercialization of any agglomeration technologies developed by this project.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; K. A. Lewandowski

2006-12-31

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process, and advanced ironmaking processes, where binders must function satisfactorily over an extraordinarily large range of temperatures (from room temperature up to over 1200 C). As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching and advanced primary ironmaking. This project has identified several acid-resistant binders and agglomeration procedures that can be used for improving the energy efficiency of heap leaching, by preventing the ''ponding'' and ''channeling'' effects that currently cause reduced recovery and extended leaching cycle times. Methods have also been developed for iron ore processing which are intended to improve the performance of pellet binders, and have directly saved energy by increasing filtration rates of the pelletization feed by as much as 23%.« less

Characterization of Sumbawa manganese ore and recovery of manganese sulfate as leaching products

NASA Astrophysics Data System (ADS)

Kusumaningrum, Retno; Rahmani, Siti Astari; Widayatno, Wahyu Bambang; Wismogroho, Agus Sukarto; Nugroho, Dwi Wahyu; Maulana, Syahrizal; Rochman, Nurul Taufiqu; Amal, M. Ikhlasul

2018-05-01

The aims of this research were to study the leaching process of manganese ore which originated from Sumbawa, Indonesia and its characterization. A high grade Indonesian manganese ore from Sumbawa, West of Nusa Tenggara was characterized by X-Ray Fluorescence (XRF). The result showed composition of 78.8 % Mn, 17.77% Fe and the rest were trace elements such as Si, Co, Ti, Zn, V and Zr contents. X-Ray Diffraction analysis showed that the manganese ore was consisted of pyrolusite (MnO2), rhodonite (MnSiO3), rhodochrosite (MnCO3) and hematite (Fe2O3). Manganese ore was also analyzed by thermal analysis to observe their thermal decomposition character. In this study, sulphuric acid (H2SO4, 6 M) was deployed as leaching agent. The leaching process was performed at 90 °C for two hours with the addition of NH4OH to control pH. Recovery percentage of leaching process yielded of 87 % Mn extracted. The crystallization process result at heating temperature of 200 °C was confirmed by XRD as manganese sulfate.

Genesis of iron-apatite ores in Posht-e-Badam Block (Central Iran) using REE geochemistry

NASA Astrophysics Data System (ADS)

Mokhtari, Mir Ali Asghar; Zadeh, Ghader Hossein; Emami, Mohamad Hashem

2013-06-01

Rare earth elements in apatites of different ore types show characteristic patterns which are related to different modes of formation of the ores. Most of the apatite-bearing iron ores are associated with alkaline magmas with LREE/HREE fractionation varying from moderate to steep. Iron-apatite deposits in Posht-e-Badam Block (Central Iran) have a high concentration of REE (more than 1000 ppm up to 2.5%), and show a strong LREE/HREE ratio with a pronounced negative Eu anomaly. This REE pattern is typical of magmatic apatite and quiet distinct from sedimentary apatites (phosphorites) which have a low REE contents and Ce negative anomalies. On the other hand, they are comparable to the REE patterns of apatites in Kiruna-type iron ores in different parts of the world. The REE patterns of apatites, iron-apatite ores and iron ores are similar and only have different REE contents. This similarity indicates a genetic relation for these rocks. Most of the iron-apatite deposits in Central Iran have similar REE patterns too, which in turn show a genetic relation for all of these deposits. This similarity indicates a similar origin and processes in their genesis. There are some small intrusions around some of the iron-apatite deposits that are petrographically identified as syenite and gabbro. These intrusions also have REE patterns similar to that of iron-apatite ores. This demonstrates a genetic relation between these intrusions and iron-apatite ores. The REE patterns of apatites in different deposits of Posht-e-Badam Block iron-apatite ores show an affinity to alkaline to sub-alkaline magmas and rifting environment. The alkaline host rocks of Central Iran iron-apatite ores are clearly related to an extensional setting where rifting was important (SSE-NNW fault lines). A probable source for this large scale ore forming processes is relatively low partial melting of mantle rocks. The ores have originated by magmatic differentiation as a late phase in the volcanic cycle forming sub-surface injections or surface flows. These ores have formed during magmatism as immiscible liquids (silicate and Fe-P-rich magmatic liquids) which separated from strongly differentiated magmas aided by a large volatile and alkali element content. Separation of an iron oxide melt and the ensuing hydrothermal processes dominated by alkali metasomatism were both involved to different degrees in the formation of Posht-e-Badam Block iron-apatite deposits. We proposed that the separation of an iron oxide melt and the ensuing hydrothermal processes dominated by alkali metasomatism were both involved to different degrees in the formation of Posht-e-Badam Block iron-apatite deposits.

Arsenic and mercury contamination related to historical goldmining in the Sierra Nevada, California

USGS Publications Warehouse

Alpers, Charles N.

2017-01-01

Arsenic (As) is a naturally occurring constituent in low-sulphide gold-quartz vein deposits, the dominant deposit type for lode mines in the Sierra Nevada Foothills (SNFH) gold (Au) province of California. Concentrations of naturally occurring mercury (Hg) in the SNFH Au province are low, but extensive use and loss of elemental Hg during amalgamation processing of ore from lode and placer Au deposits led to widespread contamination of Hg in the Sierra Nevada foothills and downstream areas, such as the Sacramento–San Joaquin Delta and San Francisco Bay. This review paper provides an overview of As and Hg contamination related to historical Au mining in the Sierra Nevada of California. It summarizes the geology, mineralogy, and geochemistry of the Au deposits, and provides information on specific areas where detailed studies have been done in association with past, ongoing, and planned remediation activities related to the environmental As and Hg contamination.Arsenic is a naturally occurring constituent in low-sulphide Au-quartz vein deposits, the dominant deposit type for lode mines in the Sierra Nevada Foothills (SNFH) Au province (Ashley 2002). Because of elevated concentrations of As in accessory iron-sulphide minerals including arsenopyrite (FeAsS) and arsenian pyrite (Fe(S,As)2), As is commonly a contaminant of concern in lode Au mine waste, including waste rock and mill tailings. The principal pathways of human As exposure from mine waste include ingestion of soil or drinking water, and inhalation of dust in contaminated areas (Mitchell 2014).Concentrations of naturally occurring Hg in the SNFH Au province are low, but extensive use and loss of elemental Hg during amalgamation processing of ore from lode and placer Au deposits (Churchill 2000) led to widespread contamination of Hg in the Sierra Nevada foothills and downstream areas, such as the Sacramento–San Joaquin Delta and San Francisco Bay (Alpers et al. 2005a). Conversion of Hg to monomethylmercury (MeHg) by sulphate-reducing and iron-reducing microbes facilitates its bioaccumulation (Wiener et al. 2003). The human Hg exposure pathway of main concern is ingestion of MeHg from sport (non-commercial) fish, especially higher trophic levels such as bass species (Davis et al. 2008). Wildlife exposure to MeHg is also a concern because of chronic and reproductive effects, for example in fish-eating and invertebrate-foraging birds (e.g. Wiener et al. 2003; Eagles-Smith et al. 2009; Ackerman et al. 2016).

Iron isotope fractionation during hydrothermal ore deposition and alteration

NASA Astrophysics Data System (ADS)

Markl, Gregor; von Blanckenburg, Friedhelm; Wagner, Thomas

2006-06-01

Iron isotopes fractionate during hydrothermal processes. Therefore, the Fe isotope composition of ore-forming minerals characterizes either iron sources or fluid histories. The former potentially serves to distinguish between sedimentary, magmatic or metamorphic iron sources, and the latter allows the reconstruction of precipitation and redox processes. These processes take place during ore formation or alteration. The aim of this contribution is to investigate the suitability of this new isotope method as a probe of ore-related processes. For this purpose 51 samples of iron ores and iron mineral separates from the Schwarzwald region, southwest Germany, were analyzed for their iron isotope composition using multicollector ICP-MS. Further, the ore-forming and ore-altering processes were quantitatively modeled using reaction path calculations. The Schwarzwald mining district hosts mineralizations that formed discontinuously over almost 300 Ma of hydrothermal activity. Primary hematite, siderite and sulfides formed from mixing of meteoric fluids with deeper crustal brines. Later, these minerals were partly dissolved and oxidized, and secondary hematite, goethite and iron arsenates were precipitated. Two types of alteration products formed: (1) primary and high-temperature secondary Fe minerals formed between 120 and 300 °C, and (2) low-temperature secondary Fe minerals formed under supergene conditions (<100 °C). Measured iron isotope compositions are variable and cover a range in δ56Fe between -2.3‰ and +1.3‰. Primary hematite ( δ56Fe: -0.5‰ to +0.5‰) precipitated by mixing oxidizing surface waters with a hydrothermal fluid that contained moderately light Fe ( δ56Fe: -0.5‰) leached from the crystalline basement. Occasional input of CO 2-rich waters resulted in precipitation of isotopically light siderite ( δ56Fe: -1.4 to -0.7‰). The difference between hematite and siderite is compatible with published Fe isotope fractionation factors. The observed range in isotopic compositions can be accounted for by variable fractions of Fe precipitating from the fluid. Therefore, both fluid processes and mass balance can be inferred from Fe isotopes. Supergene weathering of siderite by oxidizing surface waters led to replacement of isotopically light primary siderite by similarly light secondary hematite and goethite, respectively. Because this replacement entails quantitative transfer of iron from precursor mineral to product, no significant isotope fractionation is produced. Hence, Fe isotopes potentially serve to identify precursors in ore alteration products. Goethites from oolitic sedimentary iron ores were also analyzed. Their compositional range appears to indicate oxidative precipitation from relatively uniform Fe dissolved in coastal water. This comprehensive iron isotope study illustrates the potential of the new technique in deciphering ore formation and alteration processes. Isotope ratios are strongly dependent on and highly characteristic of fluid and precipitation histories. Therefore, they are less suitable to provide information on Fe sources. However, it will be possible to unravel the physico-chemical processes leading to the formation, dissolution and redeposition of ores in great detail.

Process for low mercury coal

DOEpatents

Merriam, N.W.; Grimes, R.W.; Tweed, R.E.

1995-04-04

A process is described for producing low mercury coal during precombustion procedures by releasing mercury through discriminating mild heating that minimizes other burdensome constituents. Said mercury is recovered from the overhead gases by selective removal. 4 figures.

Rock Smelting of Copper Ores with Waste Heat Recovery

NASA Astrophysics Data System (ADS)

Norgate, Terry; Jahanshahi, Sharif; Haque, Nawshad

It is generally recognised that the grades of metallic ores are falling globally. This trend can be expected to increase the life cycle-based energy requirement for primary metal production due to the additional amount of material that must be handled and treated in the mining and mineral processing stages of the metal production life cycle. Rock (or whole ore) smelting has been suggested as a possible alternative processing route for low grade ores with a potentially lower energy intensity and environmental impact than traditional processing routes. In this processing route, the beneficiation stage is eliminated along with its associated energy consumption and greenhouse gas emissions, but this is partially offset by the need for more solid material to be handled and heated up to smelting temperatures. A life cycle assessment study was carried out to assess the potential energy and greenhouse gas benefits of a conceptual flowsheet of the rock smelting process, using copper ore as an example. Recovery and utilisation of waste heat in the slag (via dry slag granulation) and offgas streams from the smelting step was also included in the study, with the waste heat being utilised either for thermal applications or electricity generation.

40 CFR Table 3 to Subpart Ddddd of... - Operating Limits for Boilers and Process Heaters With Mercury Emission Limits and Boilers and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Process Heaters With Mercury Emission Limits and Boilers and Process Heaters That Choose To Comply With... Heaters With Mercury Emission Limits and Boilers and Process Heaters That Choose To Comply With the... operating limits: If you demonstrate compliance with applicable mercury and/or total selected metals...

PROCESS FOR THE RECOVERY OF METALS FROM HIGH-LIME CARNOTITE ORES

DOEpatents

Grinstead, R.R.

1959-01-20

A process is presented for recovering uranium values from a high-lime carnotite ore comprising contacting the ore dispersed in a finely divided state with a concentrated mineral acid, adding an industrial orgnnic solvent containing alkyl ontho or pyro phosphoric acids, alkyl phosphates or alkyl phosphonates so as to effect an organic phase into which the metal value is leached and then recovering the metal value from the organic phase.

The experiment of the elemental mercury was removed from natural gas by 4A molecular sieve

NASA Astrophysics Data System (ADS)

Jiang, Cong; Chen, Yanhao

2018-04-01

Most of the world's natural gas fields contain elemental mercury and mercury compounds, and the amount of mercury in natural gas is generally 1μg/m3 200μg/m3. This paper analyzes the mercury removal principle of chemical adsorption process, the characteristics and application of mercury removal gent and the factors that affect the efficiency of mercury removal. The mercury in the natural gas is adsorbed by the mercury-silver reaction of the 4 molecular sieve after the manned treatment. The limits for mercury content for natural gas for different uses and different treatment processes are also different. From the environmental protection, safety and other factors, it is recommended that the mercury content of natural gas in the pipeline is less than 28μg / m3, and the mercury content of the raw material gas in the equipment such as natural gas liquefaction and natural gas condensate recovery is less than 0.01μg/m3. This paper mainly analyzes the existence of mercury in natural gas, and the experimental research process of using 4A molecular sieve to absorb mercury in natural gas.

Effective Processing of the Iron Ores

NASA Astrophysics Data System (ADS)

Kuskov, Vadim; Kuskova, Yana; Udovitsky, Vladimir

2017-11-01

Effective technology for a complex wasteless processing of the iron ores has been designed and includes three main components (plats): comminution plant, briquette plant, pigment plant. The comminution is done per energy effective technology. Using of briquetting for ores clotting enables the costs cut and brings to a higher level of environmental safety of the process. Briquette formation can be done as a regular pressing, as an extrusion. Developed technology allows to produce high quality competitively products for metallurgy industry and red iron oxide pigments. The whole production line impacts the environment in a minimal manner.

Mercury's Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroid Space Weathering Studies

NASA Technical Reports Server (NTRS)

Dominque, Deborah L.; Chapman, Clark R.; Killen, Rosemary M.; Zurbuchen, Thomas H.; Gilbert, Jason A.; Sarantos, Menelaos; Benna, Mehdi; Slavin, James A.; Orlando, Thomas M.; Schriver, David;

Anomalous concentrations of gold, silver, and other metals in the Mill Canyon area, Cortez quadrangle, Eureka and Lander Counties, Nevada

USGS Publications Warehouse

Elliott, James E.; Wells, John David

1968-01-01

The Mill Canyon area is in the eastern part of the Cortez window of the Roberts Mountains thrust belt in the Cortez quadrangle, north-central Nevada. Gold and silver ores have been mined from fissure veins in Jurassic quartz monzonite and in the bordering Wenban Limestone of Devonian age. Geochemical data show anomalies of gold, silver, lead, zinc, copper, arsenic, antimony, mercury, and tellurium. Geologic and geochemical studies indicate that a formation favorable for gold deposition, the Roberts Mountains Limestone of Silurian age, may be found at depth near the mouth of Mill Canyon.

Mathematical modeling of the integrated process of mercury bioremediation in the industrial bioreactor.

PubMed

Głuszcz, Paweł; Petera, Jerzy; Ledakowicz, Stanisław

2011-03-01

The mathematical model of the integrated process of mercury contaminated wastewater bioremediation in a fixed-bed industrial bioreactor is presented. An activated carbon packing in the bioreactor plays the role of an adsorbent for ionic mercury and at the same time of a carrier material for immobilization of mercury-reducing bacteria. The model includes three basic stages of the bioremediation process: mass transfer in the liquid phase, adsorption of mercury onto activated carbon and ionic mercury bioreduction to Hg(0) by immobilized microorganisms. Model calculations were verified using experimental data obtained during the process of industrial wastewater bioremediation in the bioreactor of 1 m³ volume. It was found that the presented model reflects the properties of the real system quite well. Numerical simulation of the bioremediation process confirmed the experimentally observed positive effect of the integration of ionic mercury adsorption and bioreduction in one apparatus.

Vulnerability of soils towards mining operations in gold-bearing sands in Chile

NASA Astrophysics Data System (ADS)

Jordán, Manuel Miguel; González, Irma; Bech, Jaume; Sanfeliu, Teófilo; Pardo, Francisco

2015-04-01

The contamination levels in handicraft mining, despite less production and processing less equipment, have high repercussions upon the environment in many cases. High-grade ore extraction, flotation, gravity concentration, acid leaching cementation and mercury amalgamation are the main metallurgical technologies employed. Gold recovery involving milling and amalgamation appears to the most contamination source of mercury. This research work is only a starting point for carrying out a risk probability mapping of pollutants of the gold bearing sands. In southern Chile, with a mild and rainy climate, high levels of pollutants have been detected in some gold placer deposits. The handicraft gold-bearing sands studied are located in X Region of "Los Lagos" in southern Chile. A great quantity of existing secondary deposits in the X Region is located in the coastal mountain range. The lithological units that are found in this range correspond with metamorphic rocks of a Paleozoic crystalline base that present an auriferous content liberated from the successive erosive processes suffered. Metasedimentary and metavolcanic rocks also make up part of this range, but their auriferous load is much smaller. The methodology used in the characterization of the associated mineralization consists of testing samples with a grain size distribution, statistical parameter analysis and mineralogical analysis using a petrographic microscope, XRD and SEM/EDX. The chemical composition was determined by means of XRF and micro-chemical analysis. The major concentrations of heavy minerals are located in areas of dynamic river energy. In the studied samples, more the 75 % of the heavy minerals were distributed among grain sizes corresponding to thin sand (0.25-0.05 mm) with good grain selection. The main minerals present in the selected analysed samples were gold, zircon, olivine, ilmenite, hornblende, hematite, garnet, choromite, augite, epidote, etc. The main heavy metals found were mercury, lead, cadmium, crome, zinc, cobalt, cooper, platinum, gold, indium, tellurium, etc., and as well some traces of cerium, praseodymium, gadolinium, neodymium, samarium and lanthanum. The recurring presence of Pb, sulphur and Hg, among others, in mineral species like galena and cinnabar reveal accumulation indices, a product of the contaminating action of human beings. This is notable since no records exist of natural deposits of these minerals that can justify their presence, and records were utilized from semi-industrial exploitations for the extaction of gold where Hg is utilized in the amalgamation processes.

Mercury mass flow in iron and steel production process and its implications for mercury emission control.

PubMed

Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Gao, Wei; Wu, Qingru; Hao, Jiming

2016-05-01

The iron and steel production process is one of the predominant anthropogenic sources of atmospheric mercury emissions worldwide. In this study, field tests were conducted to study mercury emission characteristics and mass flows at two iron and steel plants in China. It was found that low-sulfur flue gas from sintering machines could contribute up to 41% of the total atmospheric mercury emissions, and desulfurization devices could remarkably help reduce the emissions. Coal gas burning accounted for 17%-49% of the total mercury emissions, and therefore the mercury control of coal gas burning, specifically for the power plant burning coal gas to generate electricity, was significantly important. The emissions from limestone and dolomite production and electric furnaces can contribute 29.3% and 4.2% of the total mercury emissions from iron and steel production. More attention should be paid to mercury emissions from these two processes. Blast furnace dust accounted for 27%-36% of the total mercury output for the whole iron and steel production process. The recycling of blast furnace dust could greatly increase the atmospheric mercury emissions and should not be conducted. The mercury emission factors for the coke oven, sintering machine and blast furnace were 0.039-0.047gHg/ton steel, and for the electric furnace it was 0.021gHg/ton steel. The predominant emission species was oxidized mercury, accounting for 59%-73% of total mercury emissions to air. Copyright © 2016. Published by Elsevier B.V.

High precision isotope ratio measurements of mercury isotopes in cinnabar ores using multi-collector inductively coupled plasma mass spectrometry.

PubMed

Hintelmann, Holger; Lu, ShengYong

2003-06-01

Variations in Hg isotope ratios in cinnabar ores obtained from different countries were detected by high precision isotope ratio measurements using multi-collector inductively coupled mass spectrometry (MC-ICP-MS). Values of delta198/202Hg varied from 0.0-1.3 percent per thousand relative to a NIST SRM 1641d Hg solution. The typical external uncertainty of the delta values was 0.06 to 0.26 percent per thousand. Hg was introduced into the plasma as elemental Hg after reduction by sodium borohydride. A significant fractionation of lead isotopes was observed during the simultaneous generation of lead hydride, preventing normalization of the Hg isotope ratios using the measured 208/206Pb ratio. Hg ratios were instead corrected employing the simultaneously measured 205/203T1 ratio. Using a 10 ng ml(-1) Hg solution and 10 min of sampling, introducing 60 ng of Hg, the internal precision of the isotope ratio measurements was as low as 14 ppm. Absolute Hg ratios deviated from the representative IUPAC values by approximately 0.2% per u. This observation is explained by the inadequacy of the exponential law to correct for mass bias in MC-ICP-MS measurements. In the absence of a precisely characterized Hg isotope ratio standard, we were not able to determine unambiguously the absolute Hg ratios of the ore samples, highlighting the urgent need for certified standard materials.

40 CFR 440.104 - New source performance standards (NSPS).

Code of Federal Regulations, 2011 CFR

2011-07-01

..., in-situ leach or vat-leach processes to extract copper from ores or ore waste materials. The Agency... Molybdenum Ores Subcategory § 440.104 New source performance standards (NSPS). Except as provided in subpart... technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines that produce...

40 CFR 440.104 - New source performance standards (NSPS).

Code of Federal Regulations, 2010 CFR

2010-07-01

..., in-situ leach or vat-leach processes to extract copper from ores or ore waste materials. The Agency... Molybdenum Ores Subcategory § 440.104 New source performance standards (NSPS). Except as provided in subpart... technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines that produce...

Mercury in the Walker River Basin, Nevada and California--sources, distribution, and potential effects on the ecosystem

USGS Publications Warehouse

Seiler, Ralph L.; Lico, Michael S.; Wiemeyer Evers, David C.

2004-01-01

Mercury is one of the most serious contaminants of water, sediment, and biota in Nevada because of its use during 19th century mining activities to recover gold and silver from ores. In 1998, mercury problems were discovered in the Walker River Basin of California and Nevada when blood drawn from three common loons from Walker Lake was analyzed and found to have severely elevated mercury levels. From 1999 to 2001, the U.S. Geological Survey and the U.S. Fish and Wildlife Service collected water, sediment, and biological samples to determine mercury sources, distribution, and potential effects on the Walker River Basin ecosystem. Total-mercury concentrations ranged from 0.62 to 57.11 ng/L in streams from the Walker River system and ranged from 1.02 to 26.8 ng/L in lakes and reservoirs. Total-mercury concentrations in streambed sediment ranged from 1 to 13,600 ng/g, and methylmercury concentrations ranged from 0.07 to 32.1 ng/g. The sediment-effects threshold for mercury for fresh-water invertebrates is 200 ng/g, which was exceeded at nine stream sites in the Walker River Basin. The highest mercury concentrations were in streams with historic mines and milling operations in the watershed. The highest mercury concentration in sediment, 13,600 ng/g, was found in Bodie Creek near Bodie, Calif., a site of extensive gold mining and milling activities during the 19th century. Sediment cores taken from Walker Lake show total-mercury concentrations exceeding 1,000 ng/g at depths greater than 15 cm below lake bottom. The presence of 137Cs above 8 cm in one core indicates that the upper 8 cm was deposited sometime after 1963. The mercury peak at 46 cm in that core, 2,660 ng/g, likely represents the peak of mining and gold extraction in the Bodie and Aurora mining districts between 1870 and 1880. Mercury concentrations in aquatic invertebrates at all sites downstream from mining activities in the Rough Creek watershed, which drains the Bodie and Aurora mining districts, were elevated (range 0.263 to 0.863 ?g/g, dry weight). Mercury concentrations in the Walker Lake tui chub, the most abundant and likely prey for common loons, ranged from approximately 0.09 ?g/g to approximately 0.9 ?g/g (wet weight). Larger tui chub in the lake, which are most likely older, had the highest mercury concentrations. Blood samples from 94 common loons collected at Walker Lake between 1998 and 2001 contained a mean mercury concentration of 2.96 ?g/g (standard deviation 1.72 ?g/g). These levels were substantially higher than those found in more than 1,600 common loons tested across North America. Among the 1,600 common loons, the greatest blood mercury concentration, 9.46 ?g/g, was from a loon at Walker Lake. According to risk assessments for northeastern North America, blood mercury concentrations exceeding 3.0 ?g/g cause behavioral, reproductive, and physiological effects. At least 52 percent of the loons at Walker Lake are at risk for adverse effects from mercury on the basis of their blood-mercury concentrations. The larger loons staging in the spring are the most at risk group. The elevated mercury levels found in tui chub and common loons indicate that there is a potential threat to the well being and reproduction of fish and wildlife that use Walker Lake. Wildlife that use Weber Reservoir may also be at risk because it is the first reservoir downstream from mining activities in the Bodie and Aurora areas and mercury concentrations in sediment were elevated. Additional data on mercury concentrations in top level predators, such as piscivorous fish and birds, are needed to assess public health and other environmental risks.

Chemical analysis of extracting transition metal oxides from polymetallic ore by sulphate process

NASA Astrophysics Data System (ADS)

Enkh-Uyanga, Otgon-Uul; Munkhtsetseg, Baatar; Urangoo, Urtnasan; Tserendulam, Enkhtur; Agiimaa, Davaadorj

2017-06-01

In this research work we attempt to improve the purity of polymetallic ores in Mongolia whilst developing practical applications of its refinement processes and this paper presents the results of chemical research of extracting transition metal titanium oxides, ferrous oxide and rare earth oxides from polymetallic ore. Thereby, chemical and mineral analysis of polymetallic ore is carried out basis of responses to the support process at various degrees of water whereas transition metal sulphates solubility differ. As a result of sulphate and resulphurization process we have extracted anatase with 62.5 percent titanium dioxide and brookite mineral with 89.6 percent of titanium dioxide as well as mineral with 83.8 percent of ferrous oxide hematite and rare earth oxides with 57.6 percent of cerium oxide. These oxides are identified under various conditions in the thermal processing. The morphology structure and chemical content compound of the mineral has been verified as a result of the XRF, XRD, SEM-EDX analysis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, V.; Shah, H.; Bannochie, C. J.

Mercury (Hg) in the Savannah River Site Liquid Waste System (LWS) originated from decades of canyon processing where it was used as a catalyst for dissolving the aluminum cladding of reactor fuel. Approximately 60 metric tons of mercury is currently present throughout the LWS. Mercury has long been a consideration in the LWS, from both hazard and processing perspectives. In February 2015, a Mercury Program Team was established at the request of the Department of Energy to develop a comprehensive action plan for long-term management and removal of mercury. Evaluation was focused in two Phases. Phase I activities assessed themore » Liquid Waste inventory and chemical processing behavior using a system-by-system review methodology, and determined the speciation of the different mercury forms (Hg+, Hg++, elemental Hg, organomercury, and soluble versus insoluble mercury) within the LWS. Phase II activities are building on the Phase I activities, and results of the LWS flowsheet evaluations will be summarized in three reports: Mercury Behavior in the Salt Processing Flowsheet (i.e. this report); Mercury Behavior in the Defense Waste Processing Facility (DWPF) Flowsheet; and Mercury behavior in the Tank Farm Flowsheet (Evaporator Operations). The evaluation of the mercury behavior in the salt processing flowsheet indicates, inter alia, the following: (1) In the assembled Salt Batches 7, 8 and 9 in Tank 21, the total mercury is mostly soluble with methylmercury (MHg) contributing over 50% of the total mercury. Based on the analyses of samples from 2H Evaporator feed and drop tanks (Tanks 38/43), the source of MHg in Salt Batches 7, 8 and 9 can be attributed to the 2H evaporator concentrate used in assembling the salt batches. The 2H Evaporator is used to evaporate DWPF recycle water. (2) Comparison of data between Tank 21/49, Salt Solution Feed Tank (SSFT), Decontaminated Salt Solution Hold Tank (DSSHT), and Tank 50 samples suggests that the total mercury as well as speciated forms in the assembled salt batches in Tanks 21/49 pass through the Actinide Removal Process (ARP) / Modular Caustic Side Solvent Extraction Unit (MCU) process to Tank 50 with no significant change in the mercury chemistry. (3) In Tank 50, Decontaminated Salt Solution (DSS) from ARP/MCU is the major contributor to the total mercury including MHg. (4) Speciation analyses of TCLP leached solutions of the grout samples prepared from Tank 21, as well as Tank 50 samples, show the majority of the mercury released in the solution is MHg.« less

40 CFR 421.200 - Applicability: Description of the secondary mercury subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... secondary mercury subcategory. 421.200 Section 421.200 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Mercury Subcategory § 421.200 Applicability: Description of the secondary mercury... mercury from secondary mercury facilities processing recycled mercuric oxide batteries and other mercury...

40 CFR 421.200 - Applicability: Description of the secondary mercury subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... secondary mercury subcategory. 421.200 Section 421.200 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Mercury Subcategory § 421.200 Applicability: Description of the secondary mercury... mercury from secondary mercury facilities processing recycled mercuric oxide batteries and other mercury...

40 CFR 421.200 - Applicability: Description of the secondary mercury subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... secondary mercury subcategory. 421.200 Section 421.200 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Mercury Subcategory § 421.200 Applicability: Description of the secondary mercury... mercury from secondary mercury facilities processing recycled mercuric oxide batteries and other mercury...

40 CFR 421.200 - Applicability: Description of the secondary mercury subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... secondary mercury subcategory. 421.200 Section 421.200 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Mercury Subcategory § 421.200 Applicability: Description of the secondary mercury... mercury from secondary mercury facilities processing recycled mercuric oxide batteries and other mercury...

40 CFR 421.200 - Applicability: Description of the secondary mercury subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... secondary mercury subcategory. 421.200 Section 421.200 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Mercury Subcategory § 421.200 Applicability: Description of the secondary mercury... mercury from secondary mercury facilities processing recycled mercuric oxide batteries and other mercury...

Priority-pollutant trace elements in streambed sediments of the Cook Inlet basin, Alaska, 1998-2000

USGS Publications Warehouse

Frenzel, Steven A.

2002-01-01

Trace element concentrations in 48 streambed sediment samples collected at 47 sites in the Cook Inlet Basin, Alaska, were compared to concentrations from studies in the conterminous United States using identical methods and to Probable Effect Concentrations. Concentrations of arsenic, chromium, mercury, and nickel in the 0.063-mm size fraction of streambed sediments from the Cook Inlet Basin were elevated relative to reference sites in the conterminous United States. Concentrations of cadmium, lead, and zinc were highest at the most urbanized site in Anchorage and at two sites downstream from an ore body in Lake Clark National Park and Preserve. At least 35 percent of the 48 samples collected in the Cook Inlet Basin exceeded the Probable Effect Concentration for arsenic, chromium, or nickel. More than 50 percent of the samples were considered to have low potential toxicity for cadmium, lead, mercury, nickel, selenium, and zinc. A Probable Effect Concentration quotient that reflects the combined toxicity of arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc was exceeded in 44 percent of the samples from the Cook Inlet Basin. The potential toxicity was high in the Denali and Lake Clark National Parks and Preserves where organic carbon concentrations in streambed sediments were low. However, potential toxicity results should be considered in context with the very small amounts of fine-grained sediment present in the streambed sediments of the Cook Inlet Basin.

Adsorptive behaviour of mercury on algal biomass: competition with divalent cations and organic compounds.

PubMed

Carro, Leticia; Barriada, José L; Herrero, Roberto; Sastre de Vicente, Manuel E

2011-08-15

Biosorption processes constitute an effective technique for mercury elimination. Sorption properties of native and acid-treated Sargassum muticum have been studied. Effect of pH, initial mercury concentration and contact time studies provided fundamental information about the sorption process. This information was used as the reference values to analyse mercury sorption under competition conditions. Saline effect has shown little influence in sorption, when only electrostatic modifications took place upon salt addition. On the contrary, if mercury speciation dramatically changed owing to the addition of an electrolyte, such as in the case of chloride salt, very large modifications in mercury sorption were observed. Competition with other divalent cations or organic compounds has shown little or none effect on mercury, indicating that a different mechanism is taking place during the removal of these pollutants. Finally, continuous flow experiments have clearly shown that a reduction process is also taking place during mercury removal. This fact is not obvious to elucidate under batch sorption experiments. Scanning Electron Microscopy analysis of the surface of the materials show deposits of mercury(I) and metallic mercury which is indicative of the reduction process proposed. Copyright © 2011 Elsevier B.V. All rights reserved.

Process and apparatus for solvent extraction of oil from oil-containing diatomite ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karnofsky, G. B.

1980-12-16

A process for solvent extraction of oil from oil bearing diatomite ore and an apparatus for use therewith, wherein the ore is extracted by countercurrent decantation with a hydrocarbon solvent, solvent is recovered from the extract by multiple effect evaporation followed by stripping, and the spent diatomite is contacted with water to displace a major portion of the solvent therefrom, and solvent is recovered from the aqueous slurry of the spent diatomite by stripping with steam at superatmospheric pressure.

Microbial solubilization of phosphate

DOEpatents

Rogers, R.D.; Wolfram, J.H.

1993-10-26

A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorus can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution. 6 figures.

Microbial solubilization of phosphate

DOEpatents

Rogers, Robert D.; Wolfram, James H.

1993-01-01

A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorous can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution.

Effects of reduction temperature to Ni and Fe content and the morphology of agglomerate of reduced laterite limonitic nickel ore by coal-bed method

NASA Astrophysics Data System (ADS)

Abdul, Fakhreza; Pintowantoro, Sungging; Kawigraha, Adji; Nursidiq, Ahlidin

2018-04-01

As the current drop of nickel sulfide ore on earth, the attention to nickel laterite ore processing was inscreased in order to fulfill the future nickel demand needs. This research aims to optimized the process of nickel laterite ore extraction using coal bed method. This research was conducted by reducing low grade nickel laterite ore (limonitic) with nickel content of 1.25 %. The reduction process was carried out using CO gas which formed by the reaction of coal and dolomite. The Briquette of nickel ore, coal, Na2SO4 mixtures incorporated in the crucible with bed, then reduced for 6 hours at the temperature of 1200 °C. 1400 °C, and 1400 °C. The result of the research shown that the highest increase of Ni content and Ni recovery value was in the reduction temperature of 1400 °C with the increase of 3.44 %, and the recovery value of Ni equal to 86.75 %. While the highest increase of Fe content and Fe recovery value, respectively, was in the reduction temperature of 1300 °C with the increase of 22.67 % and 1200 °C with Fe recovery value of 89.41 %.

Bio-mineralization and potential biogeochemical processes in bauxite deposits: genetic and ore quality significance

NASA Astrophysics Data System (ADS)

Laskou, Magdalini; Economou-Eliopoulos, Maria

2013-08-01

The Parnassos-Ghiona bauxite deposit in Greece of karst type is the 11th largest bauxite producer in the world. The mineralogical, major and trace-element contents and δ18O, δ12C, δ34S isotopic compositions of bauxite ores from this deposit and associated limestone provide valuable evidence for their origin and biogeochemical processes resulting in the beneficiation of low grade bauxite ores. The organic matter as thin coal layers, overlying the bauxite deposits, within limestone itself (negative δ12C isotopic values) and the negative δ34S values in sulfides within bauxite ores point to the existence of the appropriate circumstances for Fe bio-leaching and bio-mineralization. Furthermore, a consortium of microorganisms of varying morphological forms (filament-like and spherical to lenticular at an average size of 2 μm), either as fossils or presently living and producing enzymes, is a powerful factor to catalyze the redox reactions, expedite the rates of metal extraction and provide alternative pathways for metal leaching processes resulting in the beneficiation of bauxite ore.

The effect of smelting time and composition of palm kernel shell charcoal reductant toward extractive Pomalaa nickel laterite ore in mini electric arc furnace

NASA Astrophysics Data System (ADS)

Sihotang, Iqbal Huda; Supriyatna, Yayat Iman; Ismail, Ika; Sulistijono

2018-04-01

Indonesia is a country that is rich in natural resources. Being a third country which has a nickel laterite ore in the world after New Caledonia and Philippines. However, the processing of nickel laterite ore to increase its levels in Indonesia is still lacking. In the processing of nickel laterite ore into metal, it can be processed by pyrometallurgy method that typically use coal as a reductant. However, coal is a non-renewable energy and have high enough levels of pollution. One potentially replace is the biomass, that is a renewable energy. Palm kernel shell are biomass that can be used as a reductant because it has a fairly high fix carbon content. This research aims to make nickel laterite ores become metal using palm kernel shell charcoal as reductant in mini electric arc furnace. The result show that the best smelting time of this research is 60 minutes with the best composition of the reductant is 2,000 gram.

Kinetic study of nickel laterite reduction roasting by palm kernel shell charcoal

NASA Astrophysics Data System (ADS)

Sugiarto, E.; Putera, A. D. P.; Petrus, H. T. B. M.

2017-05-01

Demand to process nickel-bearing laterite ore increase as continuous depletion of high-grade nickel-bearing sulfide ore takes place. Due to its common nickel association with iron, processing nickel laterite ore into nickel pig iron (NPI) has been developed by some industries. However, to achieve satisfying nickel recoveries, the process needs massive high-grade metallurgical coke consumption. Concerning on the sustainability of coke supply and positive carbon emission, reduction of nickel laterite ore using biomass-based reductor was being studied.In this study, saprolitic nickel laterite ore was being reduced by palm kernel shell charcoal at several temperatures (800-1000 °C). Variation of biomass-laterite composition was also conducted to study the reduction mechanism. X-ray diffraction and gravimetry analysis were applied to justify the phenomenon and predict kinetic model of the reduction. Results of this study provide information that palm kernel shell charcoal has similar reducing result compared with the conventional method. Reduction, however, was carried out by carbon monoxide rather than solid carbon. Regarding kinetics, Ginstling-Brouhnstein kinetic model provides satisfying results to predict the reduction phenomenon.

40 CFR 63.9621 - What test methods and other procedures must I use to demonstrate initial compliance with the...

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing Initial Compliance... section. (b) For each ore crushing and handling affected source and each finished pellet handling affected... each ore crushing and handling affected source and each finished pellet handling affected source, you...

A geochemical assessment of possible lunar ore formation

NASA Technical Reports Server (NTRS)

Haskin, Larry A.; Colson, Russell O.; Vaniman, David

1991-01-01

The Moon apparently formed without appreciable water or other relatively volatile materials. Interior concentrations of water or other volatile substances appear to be extremely low. On Earth, water is important to the genesis of nearly all types of ores. Thus, some have reasoned that only abundant elements would occur in ore concentrations. The definition and recognition of ores on the Moon challenge the imaginations and the terrestrial perceptions of ore bodies. Lunar ores included solar-wind soaked soils, which contain abundant but dilute H, C, N, and noble gases (including He-3). Oxygen must be mined; soils contain approximately 45 percent (wt). Mainstream processes of rock formation concentrated Si, Mg, Al, Fe, and Ca, and possibly Ti and Cr. The highland surface contains approximately 70 percent (wt) feldspar (mainly CaAl2Si2O8), which can be separated from some highland soils. Small fragments of dunite were collected; dunite may occur in walls and central peaks of some craters. Theoretical extensions of observations of lunar samples suggest that the Moon may have produced ores of trace elements. Some small fragments have trace-element concentrations 10(exp 4) times higher than the lunar average, indicating that effective geochemical separations occurred; processes included fractional crystallization, silicate immiscibility, vaporization and condensation, and sulfide metamorphism. Operations of these processes acting on indigenous materials and on meteoritic material in the regolith could have produced ores. Infalling carbonaceous meteorites and comets have added water and hydrocarbons that may have been cold-trapped. Vesicles in basalts, pyroclastic beads, and reported transient events suggest gag emission from the lunar interior; such gas might concentrate and transport rare elements. Large impacts may disperse ores or produce them through deposition of heat at depth and by vaporization and subsequent condensation. The main problem in assessing lunar resources is the ignorance about the largely unexplored Moon.

China's emergence as the world's leading iron-ore-consuming country

USGS Publications Warehouse

Kirk, W.S.

2004-01-01

China has become the leading iron ore consuming nation, and, based on recent steel production capacity increases and plans for more, its consumption will almost certainly to continue to grow. China's iron ore industry, however, faces a number of problems. China's iron ore is low-grade, expensive to process, and its mines are being depleted. For many Chinese steelmakers, particularly in the coastal regions, the delivered cost of domestic iron ore, is more than the delivered cost of foreign ore. Thus China's iron ore imports are expected to increase. As China's growth continues, it will almost certainly surpass Japan to become the leading iron ore importing country as well. Without China's increasing appetite for iron ore, the world iron ore market would be flat or declining. China's recent imports largely offset the slump in demand in North America and Europe. China is regarded by the iron ore industry as the growth sector for the next decade. Although Chinese imports are expected to continue their rapid increase and imports in other Asian countries are expected to continue growing, there appears to be enough greenfield and expansion projects to meet future demand for iron ore worldwide. Present suppliers of iron ore, Australia, Brazil, India, and South Africa, will probably be the chief beneficiaries of China's increasing consumption of iron ore. How long China can continue its extraordinary growth is the primary issue for the future of the iron ore industry. Based on the number and size of planned blast furnaces it appears that China's growth could continue for several more years. ?? 2004 Taylor and Francis.

Mercury speciation on three European mining districts by XANES techniques

NASA Astrophysics Data System (ADS)

Esbri, J. M.; Garcia-Noguero, E. M.; Guerrero, B.; Kocman, D.; Bernaus, A.; Gaona, X.; Higueras, P.; Alvarez, R.; Loredo, J.; Horvat, M.; Ávila, M.

2009-04-01

The mobility, bioavailability and toxicity of mercury in the environment depend on the chemical species in which is present in soil, sediments, water or air. In this work we used synchrotron radiation to determine mercury species in geological samples of three mercury mining districts: Almadén (Spain), Idria (Slovenia) and Asturias (Spain). The aim of this study was to find differences on mobility and bioavailability of mercury on three mining districts with different type of mineralization. For this porpoises we selected samples of ore, calcines, soils and stream sediments from the three sites, completely characterized by the Almadén School of Mines, Josef Stefan Institute of Ljubljana and Oviedo School of Mines. Speciation of mercury was carried out on Synchrotron Laboratories of Hamburg (HASYLAB) by XANES techniques. Spectra of pure compounds [HgCl2, HgSO4, HgO, CH3HgCl, Hg2Cl2 (calomel), HgSred (cinnabar), HgSblack (metacinnabar), Hg2NCl0.5(SO4)0.3(MoO4)0.1(CO3)0.1(H2O) (mosesite), Hg3S2Cl2 (corderoite), Hg3(SO4)O2 (schuetteite) y Hg2ClO (terlinguaite)] were obtained on transmittance mode. The number and type of the compounds required to reconstruct experimental spectra for each sample was obtained by PCA analysis and linear fitting of minimum quadratics of the pure compounds spectra. This offers a semiquantitative approach to the mineralogical constitution of each analyzed sample. The results put forward differences on the efficiency of roasting furnaces from the three studied sites, evidenced by the presence of metacinnabar on the less efficient (Almadén and Asturias) and absence on the most efficient (Idria). For the three studied sites, sulfide species (cinnabar and metacinnabar) were largely more abundant than soluble species (chlorides and sulfates). On the other hand, recent results on the mobility of both Hg and As on the target sites will be presented. These results correlate with the related chemical species found by XANES techniques.

PROCESS OF EXTRACTING URANIUM AND RADIUM FROM ORES

DOEpatents

Sawyer, C.W.; Handley, R.W.

1959-07-14

A process is presented for extracting uranium and radium values from a uranium ore which comprises leaching the ore with a ferric chloride solution at an elevated temperature of above 50 deg C and at a pH less than 4; separating the ore residue from the leaching solution by filtration; precipitating the excess ferric iron present at a pH of less than 5 by adding CaCO/sub 3/ to the filtrate; separating the precipitate by filtration; precipitating the uranium present in the filtrate at a Ph less than 6 by adding BaCO/sub 3/ to the filtrate; separating the precipitate by filtration; and precipitating the radium present in the filtrate by adding H/sub 2/SO/sub 4/ to the filtrate.

Assessment of environmental and health risks in former polymetallic ore mining and smelting area, Slovakia: Spatial distribution and accumulation of mercury in four different ecosystems.

PubMed

Árvay, Július; Demková, Lenka; Hauptvogl, Martin; Michalko, Miloslav; Bajčan, Daniel; Stanovič, Radovan; Tomáš, Ján; Hrstková, Miroslava; Trebichalský, Pavol

2017-10-01

Former long-term mining and smelting of pollymetallic ores in the Middle Spiš area caused a serious contamination problem of the environment with heavy metals and metalloids, especially mercury (Hg). Several studies have reported concentration of Hg in the area but this paper provides first detailed characterization of Hg contamination of different environmental components in agricultural, forest, grassland and urban ecosystems. The ecosystems are in different distances from emission sources - former mercury and copper smelting plants in NE Slovakia. Total Hg content was studied in soil/substrate samples (n = 234) and characteristic biological samples (Athyrium filix-femina (L.) Roth, Macrolepiota procera (Scop.) Singer, Boletus edulis Bull., Cyanoboletus pulverulentus (Opat.) Gelardi, Vizzini & Simonini, Triticum aestivum (L.), Poa pratensis (L.)) (n = 234) collected in the above-mentioned ecosystems. The level of contamination and environmental risks were assessed by contamination factor (C f ), index of geoaccumulation (I geo ) and potential environmental risk index (PER). To determine the level of transition of Hg from abiotic to biotic environment, bioconcentration factor (BCF) was used. To determine a health risk resulting from regular and long-term consumption of the locally available species, the results of the Hg content were compared with the Provisional Tolerable Weekly Intake (PTWI) for Hg defined by World Health Organization. The results suggest that almost 63% of the area belong to the very high risk category and 80% of the sampling sites shown very high contamination factor. Geoaccumulation index showed that almost 30% of the area is very strongly contaminated and only 8% is not contaminated with Hg. Spearman's correlation relationship confirmed that the values of PER, BCF, C f and I geo decreased with an increasing distance from the pollution source. The percentage of contribution to PTWI ranged between 5.76-69.0% for adults and 11.5-138% for children. Mushroom M. procera showed the highest %PTWI among the tested biological samples. Studied ecotoxicological parameters showed high level of health risk for population living in the area. Consumption of the crops grown in the area and mainly edible wild mushrooms might negatively affect the health of the consumers in the long-term. Copyright © 2017 Elsevier Inc. All rights reserved.

Rock-magnetism and ore microscopy of the magnetite-apatite ore deposit from Cerro de Mercado, Mexico

NASA Astrophysics Data System (ADS)

Alva-Valdivia, L. M.; Goguitchaichvili, A.; Urrutia-Fucugauchi, J.; Caballero-Miranda, C.; Vivallo, W.

2001-03-01

Rock-magnetic and microscopic studies of the iron ores and associated igneous rocks in the Cerro de Mercado, Mexico, were carried out to determine the magnetic mineralogy and origin of natural remanent magnetization (NRM), related to the thermo-chemical processes due to hydrothermalism. Chemical remanent magnetization (CRM) seems to be present in most of investigated ore and wall rock samples, replacing completely or partially an original thermoremanent magnetization (TRM). Magnetite (or Ti-poor titanomagnetite) and hematite are commonly found in the ores. Although hematite may carry a stable CRM, no secondary components are detected above 580°, which probably attests that oxidation occurred soon enough after the extrusion and cooling of the ore-bearing magma. NRM polarities for most of the studied units are reverse. There is some scatter in the cleaned remanence directions of the ores, which may result from physical movement of the ores during faulting or mining, or from perturbation of the ambient field during remanence acquisition by inhomogeneous internal fields within these strongly magnetic ore deposits. The microscopy study under reflected light shows that the magnetic carriers are mainly titanomagnetite, with significant amounts of ilmenite-hematite minerals, and goethite-limonite resulting from alteration processes. Magmatic titanomagnetites, which are found in igneous rocks, show trellis, sandwich, and composite textures, which are compatible with high temperature (deuteric) oxy-exsolution processes. Hydrothermal alteration in ore deposits is mainly indicated by martitization in oxide minerals. Grain sizes range from a few microns to >100 mm, and possible magnetic state from single to multidomain, in agreement with hysteresis measurements. Thermal spectra, continuous susceptibility measurements, and IRM (isothermal remanent magnetization) acquisition suggest a predominance of spinels as magnetic carriers, most probably titanomagnetites with low-Ti content. For quantitative modeling of the aeromagnetic anomalies, we used data on bulk susceptibility and natural remanent intensity for quantifying the relative contributions of induced and remanent magnetization components and allow a better control of the geometry of source bodies. The position and geometry of this magnetic source are shown as an ENE-striking tabular body, steeply inclined (75°) to the south.

Combined oxidative leaching and electrowinning process for mercury recovery from spent fluorescent lamps.

PubMed

Ozgur, Cihan; Coskun, Sezen; Akcil, Ata; Beyhan, Mehmet; Üncü, Ismail Serkan; Civelekoglu, Gokhan

2016-11-01

In this paper, oxidative leaching and electrowinnig processes were performed to recovery of mercury from spent tubular fluorescent lamps. Hypochlorite was found to be effectively used for the leaching of mercury to the solution. Mercury could be leached with an efficiency of 96% using 0.5M/0.2M NaOCl/NaCl reagents at 50°C and pH 7.5 for 2-h. Electrowinning process was conducted on the filtered leaching solutions and over the 81% of mercury was recovered at the graphite electrode using citric acid as a reducing agent. The optimal process conditions were observed as a 6A current intensity, 30g/L of reducing agent concentration, 120min. electrolysis time and pH of 7 at the room temperature. It was found that current intensity and citric acid amount had positive effect for mercury reduction. Recovery of mercury in its elemental form was confirmed by SEM/EDX. Oxidative leaching with NaOCl/NaCl reagent was followed by electrowinning process can be effectively used for the recovery of mercury from spent fluorescent lamps. Copyright © 2016 Elsevier Ltd. All rights reserved.

Concentrations of selected metals in Quaternary-age fluvial deposits along the lower Cheyenne and middle Belle Fourche Rivers, western South Dakota, 2009-10

USGS Publications Warehouse

Stamm, John F.; Hoogestraat, Galen K.

2012-01-01

The headwaters of the Cheyenne and Belle Fourche Rivers drain the Black Hills of South Dakota and Wyoming, an area that has been affected by mining and ore-milling operations since the discovery of gold in 1875. A tributary to the Belle Fourche River is Whitewood Creek, which drains the area of the Homestake Mine, a gold mine that operated from 1876 to 2001. Tailings discharged into Whitewood Creek contained arsenopyrite, an arsenic-rich variety of pyrite associated with gold ore, and mercury used as an amalgam during the gold-extraction process. Approximately 18 percent of the tailings that were discharged remain in fluvial deposits on the flood plain along Whitewood Creek, and approximately 25 percent remain in fluvial deposits on the flood plain along the Belle Fourche River, downstream from Whitewood Creek. In 1983, a 29-kilometer (18-mile) reach of Whitewood Creek and the adjacent flood plain was included in the U.S. Environmental Protection Agency's National Priority List of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, commonly referred to as a "Superfund site." Listing of this reach of Whitewood Creek was primarily in response to arsenic toxicity of fluvial deposits on the flood plain. Lands along the lower Cheyenne River were transferred to adjoining States and Tribes in response to the Water Resources Development Act (WRDA) of 1999. An amendment in 2000 to WRDA required a study of sediment contamination of the Cheyenne River. In response to the WRDA amendment, the U.S. Geological Survey completed field sampling of reference sites (not affected by mine-tailing disposal) along the lower Belle Fourche and lower Cheyenne Rivers. Reference sites were located on stream terraces that were elevated well above historical stream stages to ensure no contamination from historical mining activity. Sampling of potentially contaminated sites was performed on transects of the active flood plain and adjacent terraces that could potentially be inundated during high-flow events. Sampling began in 2009 and was completed in 2010. A total of 74 geochemical samples were collected from fluvial deposits at reference sites, and 473 samples were collected from potentially contaminated sites. Sediment samples collected were analyzed for 23 metals, including arsenic and mercury. Sequential replicate, split duplicate, and field quality-control samples were analyzed for quality assurance of data-collection methods. The metal concentrations in sediment samples and location information are presented in this report in electronic format (Microsoft Excel), along with non-parametric summary statistics of those data. Cross-sectional topography is graphed with arsenic and mercury concentrations on transects at the potentially contaminated sites. The mean arsenic concentration in reference sediment samples was 8 milligrams per kilogram (mg/kg), compared to 250, 650, and 76 mg/kg for potentially contaminated sediment samples at the surface of the middle Belle Fourche River site, the subsurface of the middle Belle Fourche River site, and the surface of the lower Cheyenne River site, respectively. The mean mercury concentration in reference sediment samples was 16 micrograms per kilogram (μg/kg), compared to 130, 370, and 71 μg/kg for potentially contaminated sediment samples at the surface of the middle Belle Fourche River site, the subsurface of the middle Belle Fourche River site, and the surface of the lower Cheyenne River site, respectively.

Plasma precipitation on Mercury's nightside and its implications for magnetospheric convection and exosphere generation.

NASA Astrophysics Data System (ADS)

Raines, J. M.; Slavin, J. A.; Tracy, P.; Gershman, D. J.; Zurbuchen, T.; Korth, H.; Anderson, B. J.; Solomon, S. C.

2015-12-01

Plasma impact onto Mercury's surface can be an important contributor to Mercury's exosphere through the process of ion sputtering. Under some circumstances, this process can produce a substantial fraction of the exosphere. When the impacting plasma originates from the magnetosphere itself, this sputtering process can conversely be considered as a sink for the plasma of the Mercury magnetosphere, providing evidence for the processes at work in that system. One such process is reconnection in Mercury's magnetotail, which can accelerate ions and electrons from the central plasma sheet toward the nightside of the planet. By analogy with processes at Earth, it is hypothesized that as these flows approach the planet, much of the plasma is diverted from impact onto the surface by the increasingly strong planetary magnetic field closer to the planet. The remainder of the plasma is expected to follow nearly dipolar field lines, impacting the nightside surface and potentially contributing to field-aligned currents. We present the first direct evidence that this process is operating at Mercury. We examine ion precipitation events on Mercury's nightside with the Fast Imaging Plasma Spectrometer (FIPS) on the MESSENGER spacecraft, which orbited Mercury from 2011 to 2015. We characterize the energy distributions of these events and their extent in latitude and local time. We use these observations to predict the precipitating proton flux from altitudes as low as 11 km. We use this information to bound the region of Mercury's surface that remains protected from plasma bombardment by the planetary dipole magnetic field, and to explore the implications of this information for magnetospheric convection and exosphere generation at Mercury.

Plasma precipitation on Mercury's nightside and its implications for magnetospheric convection and exosphere generation.

NASA Astrophysics Data System (ADS)

Raines, J. M.; Slavin, J. A.; Tracy, P.; Gershman, D. J.; Zurbuchen, T.; Dewey, R. M.; Sarantos, M.

2016-12-01

Plasma impact onto Mercury's surface can be an important contributor to Mercury's exosphere through the process of ion sputtering. Under some circumstances, this process can produce a substantial fraction of the exosphere. When the impacting plasma originates from the magnetosphere itself, this sputtering process can conversely be considered as a sink for the plasma of the Mercury magnetosphere, providing evidence for the processes at work in that system. One such process is reconnection in Mercury's magnetotail, which can accelerate ions and electrons from the central plasma sheet toward the nightside of the planet. By analogy with processes at Earth, it is hypothesized that as these flows approach the planet, much of the plasma is diverted from impact onto the surface by the increasingly strong planetary magnetic field closer to the planet. The remainder of the plasma is expected to follow nearly dipolar field lines, impacting the nightside surface and potentially contributing to field-aligned currents. We present the first direct evidence that this process is operating at Mercury. We examine ion precipitation events on Mercury's nightside with the Fast Imaging Plasma Spectrometer (FIPS) on the MESSENGER spacecraft, which orbited Mercury from 2011 to 2015. We characterize the energy distributions of these events and their extent in latitude and local time. We use these observations to predict the precipitating proton flux from altitudes as low as 11 km. We use this information to bound the region of Mercury's surface that remains protected from plasma bombardment by the planetary dipole magnetic field, and to explore the implications of this information for magnetospheric convection and exosphere generation at Mercury.

MODELING PROCESSES CONTROLLING MERCURY FATE IN WATERSHEDS RECEIVING ATMOSPHERIC DEPOSITION - COMPARISON OF FIELD SCALE GLEAMS AND WATERSHED SCALE WCS-GBMM

EPA Science Inventory

Long-term simulations of mercury fate in watersheds are needed to support regulations such as TMDLs and to predict the effectiveness of regulatory proposals, such as the Clean Air Mercury Rule (CAMR). Scientific uncertainties in mercury fate process descriptions combined with in...

BLENDING LOW ENRICHED URANIUM WITH DEPLETED URANIUM TO CREATE A SOURCE MATERIAL ORE THAT CAN BE PROCESSED FOR THE RECOVERY OF YELLOWCAKE AT A CONVENTIONAL URANIUM MILL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schutt, Stephen M.; Hochstein, Ron F.; Frydenlund, David C.

2003-02-27

Throughout the United States Department of Energy (DOE) complex, there are a number of streams of low enriched uranium (LEU) that contain various trace contaminants. These surplus nuclear materials require processing in order to meet commercial fuel cycle specifications. To date, they have not been designated as waste for disposal at the DOE's Nevada Test Site (NTS). Currently, with no commercial outlet available, the DOE is evaluating treatment and disposal as the ultimate disposition path for these materials. This paper will describe an innovative program that will provide a solution to DOE that will allow disposition of these materials atmore » a cost that will be competitive with treatment and disposal at the NTS, while at the same time recycling the material to recover a valuable energy resource (yellowcake) for reintroduction into the commercial nuclear fuel cycle. International Uranium (USA) Corporation (IUSA) and Nuclear Fuel Services, Inc. (NFS) have entered into a commercial relationship to pursue the development of this program. The program involves the design of a process and construction of a plant at NFS' site in Erwin, Tennessee, for the blending of contaminated LEU with depleted uranium (DU) to produce a uranium source material ore (USM Ore{trademark}). The USM Ore{trademark} will then be further processed at IUC's White Mesa Mill, located near Blanding, Utah, to produce conventional yellowcake, which can be delivered to conversion facilities, in the same manner as yellowcake that is produced from natural ores or other alternate feed materials. The primary source of feed for the business will be the significant sources of trace contaminated materials within the DOE complex. NFS has developed a dry blending process (DRYSM Process) to blend the surplus LEU material with DU at its Part 70 licensed facility, to produce USM Ore{trademark} with a U235 content within the range of U235 concentrations for source material. By reducing the U235 content to source material levels in this manner, the material will be suitable for processing at a conventional uranium mill under its existing Part 40 license to remove contaminants and enable the product to re-enter the commercial fuel cycle. The tailings from processing the USM Ore{trademark} at the mill will be permanently disposed of in the mill's tailings impoundment as 11e.(2) byproduct material. Blending LEU with DU to make a uranium source material ore that can be returned to the nuclear fuel cycle for processing to produce yellowcake, has never been accomplished before. This program will allow DOE to disposition its surplus LEU and DU in a cost effective manner, and at the same time provide for the recovery of valuable energy resources that would be lost through processing and disposal of the materials. This paper will discuss the nature of the surplus LEU and DU materials, the manner in which the LEU will be blended with DU to form a uranium source material ore, and the legal means by which this blending can be accomplished at a facility licensed under 10 CFR Part 70 to produce ore that can be processed at a conventional uranium mill licensed under 10 CFR Part 40.« less

Process and apparatus for solvent extraction of oil from oil-containing diatomite ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karnofsky, G.B.

1979-09-11

A process is described for solvent extraction of oil-bearing diatomite ore. An apparatus is provided for use therewith, wherein the ore is extracted by countercurrent decantation with a hydrocarbon solvent. The solvent is recovered from the extract by multiple effect evaporation followed by stripping, and the spent diatomite is contacted with water to displace a major portion of the solvent therefrom. The solvent is recovered from the aqueous slurry of the spent diatomite by stripping with steam at superatmospheric pressure. 17 claims.

DISSOLUTION AND ANALYSIS OF YELLOWCAKE COMPONENTS FOR FINGERPRINTING UOC SOURCES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hexel, Cole R; Bostick, Debra A; Kennedy, Angel K

2012-01-01

There are a number of chemical and physical parameters that might be used to help elucidate the ore body from which uranium ore concentrate (UOC) was derived. It is the variation in the concentration and isotopic composition of these components that can provide information as to the identity of the ore body from which the UOC was mined and the type of subsequent processing that has been undertaken. Oak Ridge National Laboratory (ORNL) in collaboration with Lawrence Livermore and Los Alamos National Laboratories is surveying ore characteristics of yellowcake samples from known geologic origin. The data sets are being incorporatedmore » into a national database to help in sourcing interdicted material, as well as aid in safeguards and nonproliferation activities. Geologic age and attributes from chemical processing are site-specific. Isotopic abundances of lead, neodymium, and strontium provide insight into the provenance of geologic location of ore material. Variations in lead isotopes are due to the radioactive decay of uranium in the ore. Likewise, neodymium isotopic abundances are skewed due to the radiogenic decay of samarium. Rubidium decay similarly alters the isotopic signature of strontium isotopic composition in ores. This paper will discuss the chemical processing of yellowcake performed at ORNL. Variations in lead, neodymium, and strontium isotopic abundances are being analyzed in UOC from two geologic sources. Chemical separation and instrumental protocols will be summarized. The data will be correlated with chemical signatures (such as elemental composition, uranium, carbon, and nitrogen isotopic content) to demonstrate the utility of principal component and cluster analyses to aid in the determination of UOC provenance.« less

Determination of total mercury in biological and geological samples

USGS Publications Warehouse

Crock, James G.

2005-01-01

The analytical chemist is faced with several challenges when determining mercury in biological and geological materials. These challenges include widespread mercury contamination, both in the laboratory and the environment, possible losses of mercury during sample preparation and digestion, the wide range of mercury values commonly observed, ranging from the low nanogram per gram or per liter for background areas to hundreds of milligrams per kilogram in contaminated or ore-bearing areas, great matrix diversity, and sample heterogeneity1. These factors can be naturally occurring or anthropogenic, but must be addressed to provide a precise and accurate analysis. Although there are many instrumental methods available for the successful determination of mercury, no one technique will address all problems or all samples all of the time. The approach for the determination of mercury used at the U.S. Geological Survey, Crustal Imaging and Characterization Team, Denver Laboratories, utilizes a suite of complementary instrumental methods when approaching a study requiring mercury analyses. Typically, a study could require the analysis of waters, leachates or selective digestions of solids, vegetation, and biological materials such as tissue, bone, or shell, soils, rocks, sediments, coals, sludges, and(or) ashes. No one digestion or sample preparation method will be suitable for all of these matrices. The digestions typically employed at our laboratories include: (i) a closed-vessel microwave method using nitric acid and hydrogen peroxide, followed by digestion/dilution with a nitric acid/sodium dichromate solution, (ii) a robotic open test-tube digestion with nitric acid and sodium dichromate, (iii) a sealed Teflon? vessel with nitric acid and sodium dichromate, (iv) a sealed glass bottle with nitric acid and sodium dichromate, or (v) open test tube digestion with nitric and sulfuric acids and vanadium pentoxide. The common factor in all these digestions is that they are very oxidative to ensure the conversion of all mercury forms into Hg (II). Each method of digestion has its advantages and limitations. The method of detection used in our laboratories involves a combination of an in-house, custom, classic continuous-flow cold-vapor atomic absorption spectrometry (CVAAS), a commercially available, automated, flow-injection and a continuous flow cold-vapor atomic fluorescence spectrometry (CV-AFS) systems, and a relatively new, automated and integrated approach where solid or liquid samples are thermally decomposed under an oxygen atmosphere (a nitrogen atmosphere is used for coals) and the released mercury vapor trapped onto a gold gauze and then thermally released into an AAS system. Other less frequently used instrumental methods available for the determination of mercury include inductively coupled plasma ? optical emission spectrometry (ICP-OES), inductively couple plasma ? mass spectrometry (ICP-MS) (both solution nebulization and laser ablation), and instrumental neutron activation analysis (INAA). Results from two case studies involving the determination of mercury in the challenging matrices of biological materials will be presented. These will include fillet, liver and stomach-content samples from grayling for a baseline/background study in Alaska, and samples of meat tissue and shell material from Tanner crabs from Glacier Bay, Alaska. These studies show that the method of digestion is more important than a very sensitive detection limit for mercury.

Mercury Reduction and Removal from High Level Waste at the Defense Waste Processing Facility - 12511

DOE Office of Scientific and Technical Information (OSTI.GOV)

Behrouzi, Aria; Zamecnik, Jack

2012-07-01

The Defense Waste Processing Facility processes legacy nuclear waste generated at the Savannah River Site during production of enriched uranium and plutonium required by the Cold War. The nuclear waste is first treated via a complex sequence of controlled chemical reactions and then vitrified into a borosilicate glass form and poured into stainless steel canisters. Converting the nuclear waste into borosilicate glass is a safe, effective way to reduce the volume of the waste and stabilize the radionuclides. One of the constituents in the nuclear waste is mercury, which is present because it served as a catalyst in the dissolutionmore » of uranium-aluminum alloy fuel rods. At high temperatures mercury is corrosive to off-gas equipment, this poses a major challenge to the overall vitrification process in separating mercury from the waste stream prior to feeding the high temperature melter. Mercury is currently removed during the chemical process via formic acid reduction followed by steam stripping, which allows elemental mercury to be evaporated with the water vapor generated during boiling. The vapors are then condensed and sent to a hold tank where mercury coalesces and is recovered in the tank's sump via gravity settling. Next, mercury is transferred from the tank sump to a purification cell where it is washed with water and nitric acid and removed from the facility. Throughout the chemical processing cell, compounds of mercury exist in the sludge, condensate, and off-gas; all of which present unique challenges. Mercury removal from sludge waste being fed to the DWPF melter is required to avoid exhausting it to the environment or any negative impacts to the Melter Off-Gas system. The mercury concentration must be reduced to a level of 0.8 wt% or less before being introduced to the melter. Even though this is being successfully accomplished, the material balances accounting for incoming and collected mercury are not equal. In addition, mercury has not been effectively purified and collected in the Mercury Purification Cell (MPC) since 2008. A significant cleaning campaign aims to bring the MPC back up to facility housekeeping standards. Two significant investigations are being undertaken to restore mercury collection. The SMECT mercury pump has been removed from the tank and will be functionally tested. Also, research is being conducted by the Savannah River National Laboratory to determine the effects of antifoam addition on the behavior of mercury. These path forward items will help us better understand what is occurring in the mercury collection system and ultimately lead to an improved DWPF production rate and mercury recovery rate. (authors)« less

Review of samples of water, sediment, tailings, and biota at the Little Bonanza mercury mine, San Luis Obispo County, California

USGS Publications Warehouse

Rytuba, James J.; Hothem, Roger L.; Goldstein, Daniel N.; Brussee, Brianne E.; May, Jason T.

2011-01-01

Sample Sites and Methods Samples were collected to assess the concentrations of Hg and biogeochemically relevant constituents in tailings and wasterock piles at the Little Bonanza Hg mine. Tailings are present adjacent to a three-pipe retort used to process the Hg ore. The tailings occur in the upper 15 cm of the soil adjacent to the retort and slag from the retort is present on the surface. An area of disturbed soil and rock uphill from the retort was likely formed during construction of a dam that provided water for mining activities. Wasterock in these piles was sampled. The largest amount of tailings is exposed to the west of the retort in the bank of WF Las Tablas Creek. Water, sediment, and biota were sampled from WF Las Tablas Creek, which flows through the mine area. Sample-site locations are shown in figures 10 and 11 and listed in table 1. Samples were collected when streamflow was low and no precipitation had occurred.

The impact of bacteria of circulating water on apatite-nepheline ore flotation.

PubMed

Evdokimova, G A; Gershenkop, A Sh; Fokina, N V

2012-01-01

A new phenomenon has been identified and studied-the impact of bacteria on the benefication process of non-sulphide ores using circulating water supply-a case study of apatite-nepheline ore. It is shown that bacteria deteriorate the floatability of apatite due to their interaction with active centres of calcium-containing minerals and intense flocculation, resulting in a decrease of the flotation process selectivity thus deteriorating the quality of concentrate. Based on the comparative analysis of primary sequences of 16S rRNA genes, there have been identified dominating bacteria species, recovered from the circulating water used at apatite-nepheline concentrating mills, and their phylogenetic position has been determined. All the bacteria were related to γ-Proteobacteria, including the Acinetobacter species, Pseudomonas alcaliphila, Ps. plecoglossicida, Stenotrophomonas rhizophila. A method of non-sulphide ores flotation has been developed with consideration of the bacterial factor. It consists in use of small concentrations of sodium hypochlorite, which inhibits the development of bacteria in the flotation of apatite-nepheline ores.

Recovery of magnetite from low grade banded magnetite quartzite (BMQ) ore

NASA Astrophysics Data System (ADS)

Tripathy, Alok; Bagchi, Subhankar; Rao, Danda Srinivas; Nayak, Bijaya Ketana; Rout, Prashanta Kumar; Biswal, Surendra Kumar

2018-04-01

There has been a steady increase of iron ore demand in the last few decades. This growing demand could be countered by use of low grade iron ore after beneficiation. Banded iron formations (BIF) are one of the resources of such low grade iron ores. Banded magnetite quartzite (BMQ) is one such BIF and a source of iron phase mineral in the form of magnetite. In the present study a low grade BMQ ore containing around 25.47% Fe was beneficiated for recovery of magnetite. XRD study shows that quartz, magnetite, hematite, and goethite are the major minerals phases present in the low grade BMQ sample. Unit operations such as crushing, scrubbing, grinding, and magnetic separations were used for recovering magnetite. Based on the large scale beneficiation studies the process flowsheet has been developed for enrichment of magnetite. It was found that with the help of developed process flowsheet it is possible to enrich Fe value up to 65.14% in the concentrate with a yield of 24.59%.

PROCESS OF RECOVERING URANIUM FROM ITS ORES

DOEpatents

Galvanek, P. Jr.

1959-02-24

A process is presented for recovering uranium from its ores. The crushed ore is mixed with 5 to 10% of sulfuric acid and added water to about 5 to 30% of the weight of the ore. This pugged material is cured for 2 to 3 hours at 100 to 110 deg C and then cooled. The cooled mass is nitrate-conditioned by mixing with a solution equivalent to 35 pounds of ammunium nitrate and 300 pounds of water per ton of ore. The resulting pulp containing 70% or more solids is treated by upflow percolation with a 5% solution of tributyl phosphate in kerosene at a rate equivalent to a residence time of about one hour to extract the solubilized uranium. The uranium is recovered from the pregnant organic liquid by counter-current washing with water. The organic extractant may be recycled. The uranium is removed from the water solution by treating with ammonia to precipitate ammonium diuranate. The filtrate from the last step may be recycled for the nitrate-conditioning treatment.

Hydrogen Plasma Processing of Iron Ore

NASA Astrophysics Data System (ADS)

Sabat, Kali Charan; Murphy, Anthony B.

2017-06-01

Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

The Use of Bacteria for Remediation of Mercury Contaminated Groundwater

EPA Science Inventory

Many processes of mercury transformation in the environment are bacteria mediated. Mercury properties cause some difficulties of remediation of mercury contaminated environment. Despite the significance of the problem of mercury pollution, methods of large scale bioremediation ...

Dzhida Ore District: Geology, Structural and Metallogenic Regionalization, Genetic Types of Ore Deposits, Geodynamic Conditions of Their Formation, Forecast, and Outlook for Development

NASA Astrophysics Data System (ADS)

Gordienko, I. V.; Gorokhovsky, D. V.; Smirnova, O. K.; Lantseva, V. S.; Badmatsyrenova, R. A.; Orsoev, D. A.

2018-01-01

Based on complex structural, rheological, and metallogenic studies, taking into account the results of earlier subject-specific, prospecting, mapping, and exploration works, it has been established that the geological structure of the district was caused by the ensimatic evolution of the Vendian-Early Paleozoic Dzhida island-arc system, in which oceanic and island-arc complexes served as a melanocratic basement for Late Paleozoic-Mesozoic active within-plate (riftogenic) processes, which gave rise to the formation of ore deposits and occurrences of strategic mineral commodities (Mo, W, Au, Pt, Ag, and rare elements, including REE). Mantle plumes and flows of deep-seated transmagmatic solutions (ore-forming fluids) played a critical role in these processes, the significance of which increases in upper crustal swarms of dikes and fault systems. The forecasts and development prospects of the Dzhida ore district envisage the expansion of geological prospecting and exploration, scientific research, and technological testing of ore for insight into strategic mineral commodities, as well as reanimation of mining within the areas of the Dzhida's large territorial and industrial complex (TIC) in eastern Siberia.

Microbial reduction of iron ore

DOEpatents

Hoffmann, M.R.; Arnold, R.G.; Stephanopoulos, G.

1989-11-14

A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry. 11 figs.

Microbial reduction of iron ore

DOEpatents

Hoffmann, Michael R.; Arnold, Robert G.; Stephanopoulos, Gregory

1989-01-01

A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry.

Evaluation of mercury in the liquid waste processing facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, Vijay; Shah, Hasmukh; Occhipinti, John E.

2015-08-13

This report provides a summary of Phase I activities conducted to support an Integrated Evaluation of Mercury in Liquid Waste System (LWS) Processing Facilities. Phase I activities included a review and assessment of the liquid waste inventory and chemical processing behavior of mercury using a system by system review methodology approach. Gaps in understanding mercury behavior as well as action items from the structured reviews are being tracked. 64% of the gaps and actions have been resolved.

Methods for dispensing mercury into devices

DOEpatents

Grossman, Mark W.; George, William A.

1987-04-28

A process for dispensing mercury into devices which requires mercury. Mercury is first electrolytically separated from either HgO or Hg.sub.2 Cl.sub.2 and plated onto a cathode wire. The cathode wire is then placed into a device requiring mercury.

Precipitation of lead-zinc ores in the Mississippi Valley-type deposit at Treves, Cevennes region of southern France

USGS Publications Warehouse

Leach, D.; Macquar, J.-C.; Lagneau, V.; Leventhal, J.; Emsbo, P.; Premo, W.

2006-01-01

The Trèves zinc–lead deposit is one of several Mississippi Valley-type (MVT) deposits in the Cévennes region of southern France. Fluid inclusion studies show that the ore was deposited at temperatures between approximately 80 and 150°C from a brine that derived its salinity mainly from the evaporation of seawater past halite saturation. Lead isotope studies suggest that the metals were extracted from local basement rocks. Sulfur isotope data and studies of organic matter indicate that the reduced sulfur in the ores was derived from the reduction of Mesozoic marine sulfate by thermochemical sulfate reduction or bacterially mediated processes at a different time or place from ore deposition. The large range of δ34S values determined for the minerals in the deposit (12.2–19.2‰ for barite, 3.8–13.8‰ for sphalerite and galena, and 8.7 to −21.2‰ for pyrite), are best explained by the mixing of fluids containing different sources of sulfur. Geochemical reaction path calculations, based on quantitative fluid inclusion data and constrained by field observations, were used to evaluate possible precipitation mechanisms. The most important precipitation mechanism was probably the mixing of fluids containing different metal and reduced sulfur contents. Cooling, dilution, and changes in pH of the ore fluid probably played a minor role in the precipitation of ores. The optimum results that produced the most metal sulfide deposition with the least amount of fluid was the mixing of a fluid containing low amounts of reduced sulfur with a sulfur-rich, metal poor fluid. In this scenario, large amounts of sphalerite and galena are precipitated, together with smaller quantities of pyrite precipitated and dolomite dissolved. The relative amounts of metal precipitated and dolomite dissolved in this scenario agree with field observations that show only minor dolomite dissolution during ore deposition. The modeling results demonstrate the important control of the reduced sulfur concentration on the Zn and Pb transport capacity of the ore fluid and the volumes of fluid required to form the deposit. The studies of the Trèves ores provide insights into the ore-forming processes of a typical MVT deposit in the Cévennes region. However, the extent to which these processes can be extrapolated to other MVT deposits in the Cévennes region is problematic. Nevertheless, the evidence for the extensive migration of fluids in the basement and sedimentary cover rocks in the Cévennes region suggests that the ore forming processes for the Trèves deposit must be considered equally viable possibilities for the numerous fault-controlled and mineralogically similar MVT deposits in the Cévennes region.

Identification of elemental mercury in the subsurface

DOEpatents

Jackson, Dennis G

2015-01-06

An apparatus and process is provided for detecting elemental mercury in soil. A sacrificial electrode of aluminum is inserted below ground to a desired location using direct-push/cone-penetrometer based equipment. The insertion process removes any oxides or previously found mercury from the electrode surface. Any mercury present adjacent the electrode can be detected using a voltmeter which indicates the presence or absence of mercury. Upon repositioning the electrode within the soil, a fresh surface of the aluminum electrode is created allowing additional new measurements.

Mercury's exosphere: observations during MESSENGER's First Mercury flyby.

PubMed

McClintock, William E; Bradley, E Todd; Vervack, Ronald J; Killen, Rosemary M; Sprague, Ann L; Izenberg, Noam R; Solomon, Sean C

2008-07-04

During MESSENGER's first Mercury flyby, the Mercury Atmospheric and Surface Composition Spectrometer measured Mercury's exospheric emissions, including those from the antisunward sodium tail, calcium and sodium close to the planet, and hydrogen at high altitudes on the dayside. Spatial variations indicate that multiple source and loss processes generate and maintain the exosphere. Energetic processes connected to the solar wind and magnetospheric interaction with the planet likely played an important role in determining the distributions of exospheric species during the flyby.

Evaluation of Mercury in Liquid Waste Processing Facilities - Phase I Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, V.; Occhipinti, J.; Shah, H.

2015-07-01

This report provides a summary of Phase I activities conducted to support an Integrated Evaluation of Mercury in Liquid Waste System (LWS) Processing Facilities. Phase I activities included a review and assessment of the liquid waste inventory and chemical processing behavior of mercury using a system by system review methodology approach. Gaps in understanding mercury behavior as well as action items from the structured reviews are being tracked. 64% of the gaps and actions have been resolved.

Evaluation of mercury in liquid waste processing facilities - Phase I report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, V.; Occhipinti, J. E.; Shah, H.

2015-07-01

This report provides a summary of Phase I activities conducted to support an Integrated Evaluation of Mercury in Liquid Waste System (LWS) Processing Facilities. Phase I activities included a review and assessment of the liquid waste inventory and chemical processing behavior of mercury using a system by system review methodology approach. Gaps in understanding mercury behavior as well as action items from the structured reviews are being tracked. 64% of the gaps and actions have been resolved.

Mineralogical and geochemical characteristics of the Noamundi-Koira basin iron ore deposits (India)

NASA Astrophysics Data System (ADS)

Mirza, Azimuddin; Alvi, Shabbar Habib; Ilbeyli, Nurdane

2015-04-01

India is one of the richest sources of iron ore deposits in the world; and one of them is located in the Noamundi-Koira basin, Singhbhum-Orissa craton. The geological comparative studies of banded iron formation (BIF) and associated iron ores of Noamundi-Koira iron ore deposits, belonging to the iron ore group in eastern India, focus on the study of mineralogy and major elemental compositions along with the geological evaluation of different iron ores. The basement of the Singhbhum-Orissa craton is metasedimentary rocks which can be traced in a broadly elliptical pattern of granitoids, surrounded by metasediments and metavolcanics of Greenstone Belt association. The Singhbhum granitoid is intrusive into these old rocks and to younger, mid Archaean metasediments, including iron formations, schists and metaquartzites and siliciclastics of the Precambrian Iron Ore Group (Saha et al., 1994; Sharma, 1994). The iron ore of Noamundi-Koira can be divided into seven categories (Van Schalkwyk and Beukes 1986). They are massive, hard laminated, soft laminated, martite-goethite, powdery blue dust and lateritic ore. Although it is more or less accepted that the parent rock of iron ore is banded hematite jasper (BHJ), the presence of disseminated martite in BHJ suggests that the magnetite of protore was converted to martite. In the study area, possible genesis of high-grade hematite ore could have occurred in two steps. In the first stage, shallow, meteoric fluids affect primary, unaltered BIF by simultaneously oxidizing magnetite to martite and replacing quartz with hydrous iron oxides. In the second stage of supergene processes, deep burial upgrades the hydrous iron oxides to microplaty hematite. Removal of silica from BIF and successive precipitation of iron resulted in the formation of martite- goethite ore. Soft laminated ores were formed where precipitation of iron was partial or absent. The leached out space remains with time and the interstitial space is generally filled with kaolinite and gibbsite, which make it low grade. Massive iron ores are devoid of any lamination and usually associated with BHJ and lower shale. The thickness of the massive ore layer varies with the location. The massive iron ore grades in to well-developed bedded BHJ in depth. Blue dust occurs in association with BHJ as pockets and layers. Although blue dust and friable ore are both powdery ores, and subjected to variable degree of deformation, leading to the formation of folding, faulting and joints of complex nature produce favourable channels. Percolating water play an important role in the formation of blue dust and the subterranean solution offers the necessary acidic environment for leaching of quartz from the BHJ. The dissolution of silica and other alkalis are responsible for the formation of blue dust. The friable and powdery ore on the other hand are formed by soft laminated ore. As it is formed from the soft laminated ore, its alumina content remains high similar to soft laminated ore compaired to blue dust. Mineralogy study suggests that magnetite was the principal iron oxide mineral, now a relict phase whose depositional history is preserved in BHJ, where it remains in the form of martite. The platy hematite is mainly the product of martite. The different types of iron ores are intricately related with the BHJ. Hard laminated ores, martite-goethite ore and soft laminated ore are resultant of desilicification process through the action of hydrothermal fluids. Geochemistry of banded iron-formations of the Noamundi-Koira iron ore deposits shows that they are detritus-free chemical precipitates. The mineralogical and geochemical data suggest that the hard laminated, massive, soft laminated ores and blue dust had a genetic lineage from BIF's aided with certain input from hydrothermal activity. The comparative study of major elemental composition of the basin samples and while plotting a binary diagram, it shows a relation between major oxides against iron oxides, in which iron oxides is taken as a reference oxide (Mirza, 2011). On the other hand, by plotting a binary diagram between chemical index of alteration (CIA) and other oxides while taking the samples of lower, middle and upper shales. It reflects an immobility and mobility of ions during partial and complete weathering processes (Mirza, 2011). Geochemical data indicate that BIF are in general detritus free chemical precipitates. Fe2O3 content of BHJ are varies in between 36.6% to 65.04%. In hard laminated ore, Fe2O3 content varies from 93.8% to 96.38%, Soft laminated ore varies from 83.64% to 89.5% and laterite ore varies from 53.5% to 79.11%. Fe2O3 content in Martite- Goethite ore varies from 86.38% to 89.42% and blue dust having 90.74% to 95.86% and all other oxides like SiO2, Al2O3, CaO, MgO, K2O, Na2O are decreases. Major part of the iron could have been added to the bottom sea water by hydrothermal solutions derived from hydrothermally active anoxic marine environments. The presence of intacalated tuffaceous shales pointing towards the genesis of iron, which could have leached from sea floor by volcanogenic process. Iron and silica of BIF were provided by the hydrothermal solutions emplaced at the vent sites situated at the Archean-Mid Oceanic Ridges. References: Mirza A (2011). Major element geochemistry of iron ore deposits in Noamundi-Koira basin of Singhbhum-Orissa craton (India). MSc thesis, Aligarh Muslim University, India. Saha AK (1994). Crustal evolution of Singhbhum, North Orissa, Eastern India; Geol. Soc. India Memoir 27 341. Sharma M, Basu AR and Ray SL (1994). Sm-Nd isotopic and geochemical study of the Archaean tonalite-amphibolite association from the eastern Indian craton. Contrib. Mineral Petrol. 117:45-55. Van Schalkwyk J and Beukes N J (1986). The Sishen iron ore deposit, Griqualand West; In: Mineral deposits of Southern Africa (eds) Annhaeusser C R and Maske S S, Geological Society of South Africa, Johannesburg, 931-956.

Methods for dispensing mercury into devices

DOEpatents

Grossman, M.W.; George, W.A.

1987-04-28

A process is described for dispensing mercury into devices which requires mercury. Mercury is first electrolytically separated from either HgO or Hg[sub 2]Cl[sub 2] and plated onto a cathode wire. The cathode wire is then placed into a device requiring mercury. 2 figs.

Possible lunar ores

NASA Technical Reports Server (NTRS)

Gillett, Stephen L.

1991-01-01

Despite the conventional wisdom that there are no lunar ores, geochemical considerations suggest that local concentrations of useful rare elements exist on the Moon in spite of its extreme dryness. The Moon underwent protracted igneous activity in its history, and certain magmatic processes can concentrate incompatible elements even if anhydrous. Such processes include: (1) separation of a magma into immiscible liquid phases (depending on composition, these could be silicate-silicate, silicate-oxide, silicate-sulfide, or silicate-salt); (2) cumulate deposits in layered igneous intrusions; and (3) concentrations of rare, refractory, lithophile elements (e.g., Be, Li, Zr) in highly differentiated, silica-rich magmas, as in the lunar granites. Terrestrial mining experience indicates that the single most important characteristic of a potential ore is its concentration of the desire element. The utility of a planet as a resource base is that the welter of interacting processes over geologic time can concentrate rare element automatically. This advantage is squandered if adequate exploration for ores is not first carried out.

Purification of trona ores by conditioning with an oil-in-water emulsion

DOEpatents

Miller, J. D.; Wang, Xuming; Li, Minhua

2009-04-14

The present invention is a trona concentrate and a process for floating gangue material from trona ore that comprises forming an emulsion, conditioning the trona ore at a high solids content in a saturated trona suspension, and then floating and removing the gangue material. The process for separating trona from gangue materials in trona ore can include emulsifying an oil in an aqueous solution to form an oil-in-water emulsion. A saturated trona suspension having a high solids content can also be formed having trona of a desired particle size. The undissolved trona in the saturated suspension can be conditioned by mixing the saturated suspension and the oil-in-water emulsion to form a conditioning solid suspension of trona and gangue material. A gas can be injected through the conditioning solid suspension to float the gangue material. Thus, the floated gangue material can be readily separated from the trona to form a purified trona concentrate without requirements of additional heat or other expensive processing steps.

Mercury

NASA Technical Reports Server (NTRS)

Vilas, Faith (Editor); Chapman, Clark R. (Editor); Matthews, Mildred Shapley (Editor)

1988-01-01

Papers are presented on future observations of and missions to Mercury, the photometry and polarimetry of Mercury, the surface composition of Mercury from reflectance spectrophotometry, the Goldstone radar observations of Mercury, the radar observations of Mercury, the stratigraphy and geologic history of Mercury, the geomorphology of impact craters on Mercury, and the cratering record on Mercury and the origin of impacting objects. Consideration is also given to the tectonics of Mercury, the tectonic history of Mercury, Mercury's thermal history and the generation of its magnetic field, the rotational dynamics of Mercury and the state of its core, Mercury's magnetic field and interior, the magnetosphere of Mercury, and the Mercury atmosphere. Other papers are on the present bounds on the bulk composition of Mercury and the implications for planetary formation processes, the building stones of the planets, the origin and composition of Mercury, the formation of Mercury from planetesimals, and theoretical considerations on the strange density of Mercury.

40 CFR 440.148 - Best Management Practices (BMP).

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold Placer Mine... control: The amount of new water allowed to enter the plant site for use in ore processing shall be...

40 CFR 440.148 - Best Management Practices (BMP).

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold Placer Mine... control: The amount of new water allowed to enter the plant site for use in ore processing shall be...

40 CFR 440.148 - Best Management Practices (BMP).

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold Placer Mine... control: The amount of new water allowed to enter the plant site for use in ore processing shall be...

Total mercury, methylmercury and selenium in mercury polluted areas in the province Guizhou, China.

PubMed

Horvat, Milena; Nolde, Natasa; Fajon, Vesna; Jereb, Vesna; Logar, Martina; Lojen, Sonja; Jacimovic, Radojko; Falnoga, Ingrid; Liya, Qu; Faganeli, Jadran; Drobne, Damjana

2003-03-20

The province of Guizhou in Southwestern China is currently one of the world's most important mercury production areas. Emissions of mercury from the province to the global atmosphere have been estimated to be approximately 12% of the world total anthropogenic emissions. The main objective of this study was to assess the level of contamination with Hg in two geographical areas of Guizhou province. Mercury pollution in the areas concerned originates from mercury mining and ore processing in the area of Wanshan, while in the area of Quingzhen mercury pollution originates from the chemical industry discharging Hg through wastewaters and emissions to the atmosphere due to coal burning for electricity production. The results of this study confirmed high contamination with Hg in soil, sediments and rice in the Hg mining area in Wanshan. High levels of Hg in soil and rice were also found in the vicinity of the chemical plant in Quingzhen. The concentrations of Hg decreased with distance from the main sources of pollution considerably. The general conclusion is that Hg contamination in Wanshan is geographically more widespread, due to deposition and scavenging of Hg from contaminated air and deposition on land. In Quingzhen Hg contamination of soil is very high close to the chemical plant but the levels reach background concentrations at a distance of several km. Even though the major source of Hg in both areas is inorganic Hg, it was observed that active transformation of inorganic Hg to organic Hg species (MeHg) takes place in water, sediments and soils. The concentration of Hg in rice grains can reach up to 569 microg/kg of total Hg of which 145 microg/kg was in MeHg form. The percentage of Hg as MeHg varied from 5 to 83%. The concentrations of selenium can reach up to 16 mg/kg in soil and up to 1 mg/g in rice. A correlation exists between the concentration of Se in soil and rice, indicating that a portion of Se is bioavailable to plants. No correlation between Hg and Se in rice was found. Exposure of the local population to Hg may occur due to inhalation of Hg present in air (in particular in Hg mining area) and consumption of Hg contaminated food (in particular rice and fish) and water. Comparison of intake through these different routes showed that the values of Hg considerably exceed the USA EPA Reference Concentration (RfC) for chronic Hg exposure (RfC is 0.0004 mg/m(3)) close to the emission sources. Intake of Hg through food consumption, particularly rice and fish, is also an important route of Hg exposure in study area. In general, it can be concluded that the population mostly at risk is located in the vicinity of smelting facilities, mining activities and close to the waste disposal sites in the wider area of Wanshan. In order to assess the real level of contamination in the local population, it is recommended that biomonitoring should be performed, including Hg and MeHg measurements in hair, blood and urine samples.

The Resin-in-pulp Process and Its Application to Ores from Brosses "BRS 10"; LE PROCEDE "RESIN IN PULP" ET SON APPLICATION AUX MINERAIS DES BROSSES "BRS 10"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kremer, M.

1959-03-01

The resin-in-pulp process is a technical variant of the recovery process of uranium in dilute solution by means of ion exchange resins. An anion resin, XE 123, of a welldefined grain size is placed in direct contact with the pulp produced by sulfuric acid attack on ore with a low uranium content. This process is of particular value in the treatment of pulps that cannot be filtered or decanted, such as those obtained with ore from Brosses. The preparation of the pulp, the elution of the uranium, and its fixation, as well as the various factors encountered in these operations,more » are discussed. (auth)« less

Investigation of sulphur isotope variation due to different processes applied during uranium ore concentrate production.

PubMed

Krajkó, Judit; Varga, Zsolt; Wallenius, Maria; Mayer, Klaus; Konings, Rudy

The applicability and limitations of sulphur isotope ratio as a nuclear forensic signature have been studied. The typically applied leaching methods in uranium mining processes were simulated for five uranium ore samples and the n ( 34 S)/ n ( 32 S) ratios were measured. The sulphur isotope ratio variation during uranium ore concentrate (UOC) production was also followed using two real-life sample sets obtained from industrial UOC production facilities. Once the major source of sulphur is revealed, its appropriate application for origin assessment can be established. Our results confirm the previous assumption that process reagents have a significant effect on the n ( 34 S)/ n ( 32 S) ratio, thus the sulphur isotope ratio is in most cases a process-related signature.

Special issue on mercury in Canada's North: summary and recommendations for future research.

PubMed

Chételat, John; Braune, Birgit; Stow, Jason; Tomlinson, Scott

2015-03-15

Important scientific advances have been made over the last decade in identifying the environmental fate of mercury and the processes that control its cycling in the Canadian Arctic. This special issue includes a series of six detailed reviews that summarize the main findings of a scientific assessment undertaken by the Government of Canada's Northern Contaminants Program. It was the first assessment to focus exclusively on mercury pollution in the Canadian Arctic. Key findings, as detailed in the reviews, relate to sources and long-range transport of mercury to the Canadian Arctic, its cycling within marine, freshwater, and terrestrial environments, and its bioaccumulation in, and effects on, the biota that live there. While these accomplishments are significant, the complex nature of the mercury cycle continues to provide challenges in characterizing and quantifying the relationships of mercury sources and transport processes with mercury levels in biota and biological effects of mercury exposure. Of particular concern are large uncertainties in our understanding of the processes that are contributing to increasing mercury concentrations in some Arctic fish and wildlife. Specific recommendations are provided for future research and monitoring of the environmental impacts of anthropogenic mercury emissions, influences of climate change, and the effectiveness of mitigation strategies for mercury in the Canadian Arctic. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Processing of metal and oxygen from lunar deposits

NASA Technical Reports Server (NTRS)

Acton, Constance F.

1992-01-01

On the moon, some whole rocks may be ores for abundant elements, such as oxygen, but beneficiation will be important if metallic elements are sought from raw lunar dirt. In the extraction process, a beneficiated metallic ore, such as an oxide, sulfide, carbonate, or silicate mineral, is converted to reduced metal. A variety of plausible processing technologies, which includes recovery of meteoritic iron, and processing of lunar ilmenite, are described in this report.

Effects of metal-soil contact time on the extraction of mercury from soils.

PubMed

Ma, Lan; Zhong, Huan; Wu, Yong-Gui

2015-03-01

To investigate the mercury aging process in soils, soil samples were spiked with inorganic mercury (Hg(II)) or methylated mercury (MeHg) and incubated for 2, 7, 14 or 28 days in the laboratory. Potential availability of mercury, assessed by bovine serum albumin (BSA) or calcium chloride (CaCl2) extraction, decreased by 2-19 times for Hg(II) or 2-6 times for MeHg, when the contact time increased from 2 to 28 days. Decreased Hg(II) extraction could be explained by Hg(II) geochemical fractionation, i.e., Hg(II) migrated from more mobile fractions (water soluble and stomach acid soluble fractions) to refractory ones (organo-complexed, strongly complexed and residual fractions) over time, resulting in more stable association of Hg(II) with soils. In addition, decrease of mercury extraction was more evident in soils with lower organic content in most treatments, suggesting that organic matter may potentially play an important role in mercury aging process. In view of the significant decreased Hg(II) or MeHg extraction with prolonged contact time, mercury aging process should be taken into account when assessing risk of mercury in contaminated soils.

Thermodynamic Analysis of the Selective Reduction of a Nickeliferous Limonitic Laterite Ore by Hydrogen

NASA Astrophysics Data System (ADS)

Elliott, R.; Pickles, C. A.

2017-09-01

Nickeliferous limonitic laterite ores are becoming increasingly attractive as a source of metallic nickel as the costs associated with recovering nickel from the sulphide ores increase. Unlike the sulphide ores, however, the laterite ores are not amenable to concentration by conventional mineral processing techniques such as froth flotation. One potential concentrating method would be the pyrometallurgical solid state reduction of the nickeliferous limonitic ores at relatively low temperatures, followed by beneficiation via magnetic separation. A number of reductants can be utilized in the reduction step, and in this research, a thermodynamic model has been developed to investigate the reduction of a nickeliferous limonitic laterite by hydrogen. The nickel recovery to the ferronickel phase was predicted to be greater than 95 % at temperatures of 673-873 K. Reductant additions above the stoichiometric requirement resulted in high recoveries over a wider temperature range, but the nickel grade of the ferronickel decreased.

Nonlinear metallogeny and the depths of the earth

NASA Astrophysics Data System (ADS)

Shcheglov, A. D.; Govorov, I. N.

This book is concerned with the basic relations regarding a new approach in the field of knowledge of metallogenesis, taking into account the complex character of the mutual dependence between ore deposits, the structure of the earth's crust, and depth relations. The principles of nonlinear metallogeny are examined, giving attention to the development of the metallogenic science during the past few years, the formation of the concept 'nonlinear metallogeny', the main aspects of nonlinear metallogeny, the origin of the ore deposits and the characteristics of ore formations in the mantle, the parallel manifestation of ore-forming processes in the crust, sedimentary-hydrothermal ore formations and their place in nonlinear metallogeny, and various types of rock and ore formations. The structure, composition, and metalliferous characteristics found at various depth zones of the tectonosphere are discussed along with the geochemical and metallogenic heterogeneity in the mantle. General questions of nonlinear metallogeny are also investigated.

Safeguards on uranium ore concentrate? the impact of modern mining and milling process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Francis, Stephen

2013-07-01

Increased purity in uranium ore concentrate not only raises the question as to whether Safeguards should be applied to the entirety of uranium conversion facilities, but also as to whether some degree of coverage should be moved back to uranium ore concentrate production at uranium mining and milling facilities. This paper looks at uranium ore concentrate production across the globe and explores the extent to which increased purity is evident and the underlying reasons. Potential issues this increase in purity raises for IAEA's strategy on the Starting Point of Safeguards are also discussed.

Method for removal and stabilization of mercury in mercury-containing gas streams

DOEpatents

Broderick, Thomas E.

2005-09-13

The present invention is directed to a process and apparatus for removing and stabilizing mercury from mercury-containing gas streams. A gas stream containing vapor phase elemental and/or speciated mercury is contacted with reagent, such as an oxygen-containing oxidant, in a liquid environment to form a mercury-containing precipitate. The mercury-containing precipitate is kept or placed in solution and reacts with one or more additional reagents to form a solid, stable mercury-containing compound.

Phase 2 Report--Mercury Behavior In The Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.; Fellinger, T.

2016-07-27

The purpose of this report is to provide a summary of the DWPF processing history in regards to mercury, document the mercury results obtained on the product and condensate samples, and provide further recommendations based on the data obtained.

Occurrence and transport of total mercury and methyl mercury in the Sacramento River Basin, California

USGS Publications Warehouse

Domagalski, Joseph L.

1999-01-01

Mercury poses a water-quality problem for California's Sacramento River, a large river with a mean annual discharge of over 650 m3/s. This river discharges into the San Francisco Bay, and numerous fish species of the bay and river contain mercury levels high enough to affect human health if consumed. Two possible sources of mercury are the mercury mines in the Coast Ranges and the gold mines in the Sierra Nevada. Mercury was once mined in the Coast Ranges, west of the Sacramento River, and used to process gold in the Sierra Nevada, east of the river. The mineralogy of the Coast Ranges mercury deposits is mainly cinnabar (HgS), but elemental mercury was used to process gold in the Sierra Nevada. Residual mercury from mineral processing in the Sierra Nevada is mainly in elemental form or in association with oxide particles or organic matter and is biologically available. Recent bed-sediment sampling, at sites below large reservoirs, showed elevated levels of total mercury (median concentration 0.28 ??g/g) in every large river (the Feather, Yuba, Bear, and American rivers) draining the Sierra Nevada gold region. Monthly sampling for mercury in unfiltered water shows relatively low concentrations during the nonrainy season in samples collected throughout the Sacramento River Basin, but significantly higher concentrations following storm-water runoff. Measured concentrations, following storm-water runoff, frequently exceeded the state of California standards for the protection of aquatic life. Results from the first year of a 2-year program of sampling for methyl mercury in unfiltered water showed similar median concentrations (0.1 ng/l) at all sampling locations, but with apparent high seasonal concentrations measured during autumn and winter. Methyl mercury concentrations were not significantly higher in rice field runoff water, even though rice production involves the creation of seasonal wetlands: higher rates of methylation are known to occur in stagnant wetland environments that have high dissolved carbon.Mercury poses a water-quality problem for California's Sacramento River, a large river with a mean annual discharge of over 650 m3/s. This river discharges into the San Francisco Bay, and numerous fish species of the bay and river contain mercury levels high enough to affect human health if consumed. Two possible sources of mercury are the mercury mines in the Coast Ranges and the gold mines in the Sierra Nevada. Mercury was once mined in the Coast Ranges, west of the Sacramento River, and used to process gold in the Sierra Nevada east of the river. The mineralogy of the Coast Ranges mercury deposits is mainly cinnabar (HgS), but elemental mercury was used to process gold in the Sierra Nevada. Residual mercury from mineral processing in the Sierra Nevada is mainly in elemental form or in association with oxide particles or organic matter and is biologically available. Recent bed-sediment sampling, at sites below large reservoirs, showed elevated levels of total mercury (median concentration 0.28 ??g/g) in every large river (the Feather, Yuba, Bear, and American rivers) draining the Sierra Nevada gold region. Monthly sampling for mercury in unfiltered water shows relatively low concentrations during the nonrainy season in samples collected throughout the Sacramento River Basin, but significantly higher concentrations following storm-water runoff. Measured concentrations, following storm-water runoff, frequently exceeded the state of California standards for the protection of aquatic life. Results from the first year of a 2-year program of sampling for methyl mercury in unfiltered water showed similar median concentrations (0.1 ng/l) at all sampling locations, but with apparent high seasonal concentrations measured during autumn and winter. Methyl mercury concentrations were not significantly higher in rice field runoff water, even though rice production involves the creation of seasonal wetlands: higher rates of methylation a

The action of macrosounds on graphite ore and derived products

NASA Technical Reports Server (NTRS)

Bradeteanu, C.; Dragan, O.

1974-01-01

A suspension of graphite ore, floated graphite, and the gangue left over from flotation were subjected to the action of macrosounds under determinant conditions. The following was found: (1) The graphite ore undergoes an efficient settling action. (2) The floated graphite is strongly crushed down to the dimensions of colloidal graphite. (3) The gangue left over from flotation can be further processed to recuperate graphite from its nuclei.

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

DOE PAGES

Balboni, Enrica; Jones, Nina; Spano, Tyler; ...

2016-08-31

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balboni, Enrica; Jones, Nina; Spano, Tyler

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Cyanide hazards to plants and animals from gold mining and related water issues

USGS Publications Warehouse

Eisler, R.; Wiemeyer, Stanley N.

2004-01-01

Highly toxic sodium cyanide (NaCN) is used by the international mining community to extract gold and other precious metals through milling of high-grade ores and heap leaching of low-grade ores (Korte et al. 2000). The process to concentrate gold using cyanide was developed in Scotland in 1887 and was used almost immediately in the Witwatersrand gold fields of the Republic of South Africa. Heap leaching with cyanide was proposed by the U.S. Bureau of Mines in 1969 as a means of extracting gold from low-grade ores. The gold industry adopted the technique in the 1970s, soon making heap leaching the dominant technology in gold extraction (Da Rosa and Lyon 1997). The heap leach and milling processes, which involve dewatering of gold-bearing ores, spraying of dilute cyanide solutions on extremely large heaps of ores containing low concentrations of gold, or the milling of ores with the use of cyanide and subsequent recovery of the gold-cyanide complex, have created a number of serious environmental problems affecting wildlife and water management. In this account, we review the history of cyanide use in gold mining with emphasis on heap leach gold mining, cyanide hazards to plants and animals, water management issues associated with gold mining, and proposed mitigation and research needs.

Hemimorphite Ores: A Review of Processing Technologies for Zinc Extraction

NASA Astrophysics Data System (ADS)

Chen, Ailiang; Li, Mengchun; Qian, Zhen; Ma, Yutian; Che, Jianyong; Ma, Yalin

2016-10-01

With the gradual depletion of zinc sulfide ores, exploration of zinc oxide ores is becoming more and more important. Hemimorphite is a major zinc oxide ore, attracting much attention in the field of zinc metallurgy although it is not the major zinc mineral. This paper presents a critical review of the treatment for extraction of zinc with emphasis on flotation, pyrometallurgical and hydrometallurgical methods based on the properties of hemimorphite. The three-dimensional framework structure of hemimorphite with complex linkage of its structural units lead to difficult desilicification before extracting zinc in the many metallurgical technologies. It is found that the flotation method is generally effective in enriching zinc minerals from hemimorphite ores into a high-grade concentrate for recovery of zinc. Pure zinc can be produced from hemimorphite or/and willemite with a reducing reagent, like methane or carbon. Leaching reagents, such as acid and alkali, can break the complex structure of hemimorphite to release zinc in the leached solution without generation of silica gel in the hydrometallurgical process. For optimal zinc extraction, combing flotation with pyrometallurgical or hydrometallurgical methods may be required.

TREATMENT OF HEXAVALENT CHROMIUM IN CHROMITE ORE PROCESSING SOLID WASTE USING A MIXED REDUCTANT SOLUTION OF FERROUS SULFATE AND SODIUM DITHIONITE

EPA Science Inventory

We developed a method for disseminating ferrous iron in the subsurface to enhance chemical reduction of hexavalent chromium (Cr(VI)) in a chromite ore processing solid waste derived from the production of ferrochrome alloy. The method utilizes ferrous sulfate (FeSO4) in combinati...

The Hydrothermal Chemistry of Gold, Arsenic, Antimony, Mercury and Silver

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bessinger, Brad; Apps, John A.

2003-03-23

A comprehensive thermodynamic database based on the Helgeson-Kirkham-Flowers (HKF) equation of state was developed for metal complexes in hydrothermal systems. Because this equation of state has been shown to accurately predict standard partial molal thermodynamic properties of aqueous species at elevated temperatures and pressures, this study provides the necessary foundation for future exploration into transport and depositional processes in polymetallic ore deposits. The HKF equation of state parameters for gold, arsenic, antimony, mercury, and silver sulfide and hydroxide complexes were derived from experimental equilibrium constants using nonlinear regression calculations. In order to ensure that the resulting parameters were internally consistent,more » those experiments utilizing incompatible thermodynamic data were re-speciated prior to regression. Because new experimental studies were used to revise the HKF parameters for H2S0 and HS-1, those metal complexes for which HKF parameters had been previously derived were also updated. It was found that predicted thermodynamic properties of metal complexes are consistent with linear correlations between standard partial molal thermodynamic properties. This result allowed assessment of several complexes for which experimental data necessary to perform regression calculations was limited. Oxygen fugacity-temperature diagrams were calculated to illustrate how thermodynamic data improves our understanding of depositional processes. Predicted thermodynamic properties were used to investigate metal transport in Carlin-type gold deposits. Assuming a linear relationship between temperature and pressure, metals are predicted to predominantly be transported as sulfide complexes at a total aqueous sulfur concentration of 0.05 m. Also, the presence of arsenic and antimony mineral phases in the deposits are shown to restrict mineralization within a limited range of chemical conditions. Finally, at a lesser aqueous sulfur concentration of 0.01 m, host rock sulfidation can explain the origin of arsenic and antimony minerals within the paragenetic sequence.« less

Microwave enhanced recovery of nickel-copper ore: communition and floatability aspects.

PubMed

Henda, R; Hermas, A; Gedye, R; Islam, M R

2005-01-01

A study describing the effect of microwave radiation, at a frequency of 2450 MHz, on the processes of communication and flotation of a complex sulphide nickel-copper ore is presented. Ore communication has been investigated under standard radiation-free conditions and after ore treatment in a radiated environment as a function of ore size, exposure time to radiation, and microwave power. The findings show that communication is tremendously improved by microwave radiation with values of the relative work index as low as 23% at a microwave power of 1.406 kW and after 10 s of exposure time. Communication is affected by exposure time and microwave power in a nontrivial manner. In terms of ore floatability, the experimental tests have been carried out on a sample of 75 microm in size under different exposure times. The results show that both ore concentrate recoveries and grades of nickel and copper are significantly enhanced after microwave treatment of the ore with relative increases in recovered concentrate, grade of nickel, and grade of copper of 26 wt%, 15 wt%, and 27%, respectively, at a microwave power of 1330 kW and after 30 s of exposure time.

Selective Removal of Iron from Low-Grade Ti Ore by Reacting with Calcium Chloride

NASA Astrophysics Data System (ADS)

Kang, Jungshin; Okabe, Toru H.

2017-02-01

Recently, titanium metal production by molten salt electrolysis using CaCl2 as molten salt and TiO2 or rutile (94 to 96 pct TiO2) as feedstock has been drawing attention. However, when a low-grade Ti ore (mainly FeTiO3) is used as feedstock, removal of iron (Fe) from the ore is indispensable. In this study, the influence of reaction temperature, reaction time, particle size of the ore, and source country for the ore on the removal of iron by selective chlorination using CaCl2 was assessed. Experimental results showed that the mass percent of iron in the ore decreased from 49.7 to 1.79 pct under certain conditions by selective removal of iron as FeCl2. As a result, high-grade CaTiO3 was produced when the ore particles smaller than 74 µm reacted with CaCl2 at 1240 K (967 °C) for 8 to 10 hours. Therefore, this study demonstrates that the removal of iron from the ore is feasible through the selective chlorination process using CaCl2 by optimizing the variables.

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.148 - Best Management Practices (BMP).

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold Placer Mine Subcategory § 440.148...: The amount of new water allowed to enter the plant site for use in ore processing shall be limited to...

Beneficiation of the gold bearing ore by gravity and flotation

NASA Astrophysics Data System (ADS)

Gül, Alim; Kangal, Olgaç; Sirkeci, Ayhan A.; Önal, Güven

2012-02-01

Gold concentration usually consists of gravity separation, flotation, cyanidation, or the combination of these processes. The choice among these processes depends on the mineralogical characterization and gold content of the ore. Recently, the recovery of gold using gravity methods has gained attention because of low cost and environmentally friendly operations. In this study, gold pre-concentrates were produced by the stepwise gravity separation and flotation techniques. The Knelson concentrator and conventional flotation were employed for the recovery of gold. Gold bearing ore samples were taken from Gümüşhane Region, northern east part of Turkey. As a result of stepwise Knelson concentration experiments, a gold concentrate assaying around 620 g/t is produced with 41.4wt% recovery. On the other hand, a gold concentrate about 82 g/t is obtained with 89.9wt% recovery from a gold ore assaying 6 g/t Au by direct flotation.

Biomining-biotechnologies for extracting and recovering metals from ores and waste materials.

PubMed

Johnson, D Barrie

2014-12-01

The abilities of acidophilic chemolithotrophic bacteria and archaea to accelerate the oxidative dissolution of sulfide minerals have been harnessed in the development and application of a biotechnology for extracting metals from sulfidic ores and concentrates. Biomining is currently used primarily to leach copper sulfides and as an oxidative pretreatment for refractory gold ores, though it is also used to recover other base metals, such as cobalt, nickel and zinc. Recent developments have included using acidophiles to process electronic wastes, to extract metals from oxidized ores, and to selectively recover metals from process waters and waste streams. This review describes the microorganisms and mechanisms involved in commercial biomining operations, how the technology has developed over the past 50 years, and discusses the challenges and opportunities for mineral biotechnologies in the 21st century. Copyright © 2014 Elsevier Ltd. All rights reserved.

Thermodynamics of ultra-sonic cavitation bubbles in flotation ore processes

NASA Astrophysics Data System (ADS)

Royer, J. J.; Monnin, N.; Pailot-Bonnetat, N.; Filippov, L. O.; Filippova, I. V.; Lyubimova, T.

2017-07-01

Ultra-sonic enhanced flotation ore process is a more efficient technique for ore recovery than classical flotation method. A classical simplified analytical Navier-Stokes model is used to predict the effect of the ultrasonic waves on the cavitations bubble behaviour. Then, a thermodynamics approach estimates the temperature and pressure inside a bubble, and investigates the energy exchanges between flotation liquid and gas bubbles. Several gas models (including ideal gas, Soave-Redlich-Kwong, and Peng-Robinson) assuming polytropic transformations (from isothermal to adiabatic) are used to predict the evolution of the internal pressure and temperature inside the bubble during the ultrasonic treatment, together with the energy and heat exchanges between the gas and the surrounding fluid. Numerical simulation illustrates the suggest theory. If the theory is verified experimentally, it predicts an increase of the temperature and pressure inside the bubbles. Preliminary ultrasonic flotation results performed on a potash ore seem to confirm the theory.

Resource potential for commodities in addition to Uranium in sandstone-hosted deposits: Chapter 13

USGS Publications Warehouse

Breit, George N.

2016-01-01

Sandstone-hosted deposits mined primarily for their uranium content also have been a source of vanadium and modest amounts of copper. Processing of these ores has also recovered small amounts of molybdenum, rhenium, rare earth elements, scandium, and selenium. These deposits share a generally common origin, but variations in the source of metals, composition of ore-forming solutions, and geologic history result in complex variability in deposit composition. This heterogeneity is evident regionally within the same host rock, as well as within districts. Future recovery of elements associated with uranium in these deposits will be strongly dependent on mining and ore-processing methods.

Mercury in tropical and subtropical coastal environments

PubMed Central

Costa, Monica F.; Landing, William M.; Kehrig, Helena A.; Barletta, Mário; Holmes, Christopher D.; Barrocas, Paulo R. G.; Evers, David C.; Buck, David G.; Vasconcellos, Ana Claudia; Hacon, Sandra S.; Moreira, Josino C.; Malm, Olaf

2012-01-01

Anthropogenic activities influence the biogeochemical cycles of mercury, both qualitatively and quantitatively, on a global scale from sources to sinks. Anthropogenic processes that alter the temporal and spatial patterns of sources and cycling processes are changing the impacts of mercury contamination on aquatic biota and humans. Human exposure to mercury is dominated by the consumption of fish and products from aquaculture operations. The risk to society and to ecosystems from mercury contamination is growing, and it is important to monitor these expanding risks. However, the extent and manner to which anthropogenic activities will alter mercury sources and biogeochemical cycling in tropical and sub-tropical coastal environments is poorly understood. Factors as (1) lack of reliable local/regional data; (2) rapidly changing environmental conditions; (3) governmental priorities and; (4) technical actions from supra-national institutions, are some of the obstacles to overcome in mercury cycling research and policy formulation. In the tropics and sub-tropics, research on mercury in the environment is moving from an exploratory “inventory” phase towards more process-oriented studies. Addressing biodiversity conservation and human health issues related to mercury contamination of river basins and tropical coastal environments are an integral part of paragraph 221 paragraph of the United Nations document “The Future We Want” issued in Rio de Janeiro in June 2012. PMID:22901765

Individual Differences in Holistic Processing Predict the Own-Race Advantage in Recognition Memory

PubMed Central

DeGutis, Joseph; Mercado, Rogelio J.; Wilmer, Jeremy; Rosenblatt, Andrew

2013-01-01

Individuals are consistently better at recognizing own-race faces compared to other-race faces (other-race effect, ORE). One popular hypothesis is that this recognition memory ORE is caused by differential own- and other-race holistic processing, the simultaneous integration of part and configural face information into a coherent whole. Holistic processing may create a more rich, detailed memory representation of own-race faces compared to other-race faces. Despite several studies showing that own-race faces are processed more holistically than other-race faces, studies have yet to link the holistic processing ORE and the recognition memory ORE. In the current study, we sought to use a more valid method of analyzing individual differences in holistic processing by using regression to statistically remove the influence of the control condition (part trials in the part-whole task) from the condition of interest (whole trials in the part-whole task). We also employed regression to separately examine the two components of the ORE: own-race advantage (regressing other-race from own-race performance) and other-race decrement (regressing own-race from other-race performance). First, we demonstrated that own-race faces were processed more holistically than other-race faces, particularly the eye region. Notably, using regression, we showed a significant association between the own-race advantage in recognition memory and the own-race advantage in holistic processing and that these associations were weaker when examining the other-race decrement. We also demonstrated that performance on own- and other-race faces across all of our tasks was highly correlated, suggesting that the differences we found between own- and other-race faces are quantitative rather than qualitative. Together, this suggests that own- and other-race faces recruit largely similar mechanisms, that own-race faces more thoroughly engage holistic processing, and that this greater engagement of holistic processing is significantly associated with the own-race advantage in recognition memory. PMID:23593119

Individual differences in holistic processing predict the own-race advantage in recognition memory.

PubMed

Degutis, Joseph; Mercado, Rogelio J; Wilmer, Jeremy; Rosenblatt, Andrew

2013-01-01

Individuals are consistently better at recognizing own-race faces compared to other-race faces (other-race effect, ORE). One popular hypothesis is that this recognition memory ORE is caused by differential own- and other-race holistic processing, the simultaneous integration of part and configural face information into a coherent whole. Holistic processing may create a more rich, detailed memory representation of own-race faces compared to other-race faces. Despite several studies showing that own-race faces are processed more holistically than other-race faces, studies have yet to link the holistic processing ORE and the recognition memory ORE. In the current study, we sought to use a more valid method of analyzing individual differences in holistic processing by using regression to statistically remove the influence of the control condition (part trials in the part-whole task) from the condition of interest (whole trials in the part-whole task). We also employed regression to separately examine the two components of the ORE: own-race advantage (regressing other-race from own-race performance) and other-race decrement (regressing own-race from other-race performance). First, we demonstrated that own-race faces were processed more holistically than other-race faces, particularly the eye region. Notably, using regression, we showed a significant association between the own-race advantage in recognition memory and the own-race advantage in holistic processing and that these associations were weaker when examining the other-race decrement. We also demonstrated that performance on own- and other-race faces across all of our tasks was highly correlated, suggesting that the differences we found between own- and other-race faces are quantitative rather than qualitative. Together, this suggests that own- and other-race faces recruit largely similar mechanisms, that own-race faces more thoroughly engage holistic processing, and that this greater engagement of holistic processing is significantly associated with the own-race advantage in recognition memory.

Application of indigenous sulfur-oxidizing bacteria from municipal wastewater to selectively bioleach phosphorus from high-phosphorus iron ore: effect of particle size.

PubMed

Shen, Shaobo; Rao, Ruirui; Wang, Jincao

2013-01-01

The effects of ore particle size on selectively bioleaching phosphorus (P) from high-phosphorus iron ore were studied. The average contents of P and Fe in the iron ore were 1.06 and 47.90% (w/w), respectively. The particle sizes of the ores used ranged from 58 to 3350 microm. It was found that the indigenous sulfur-oxidizing bacteria from municipal wastewater could grow well in the slurries of solid high-phosphorus iron ore and municipal wastewater. The minimum bioleaching pH reached for the current work was 0.33. The P content in bioleached iron ore reduced slightly with decreasing particle size, while the removal percentage of Fe decreased appreciably with decreasing particle size. The optimal particle size fraction was 58-75 microm, because the P content in bioleached iron ore reached a minimum of 0.16% (w/w), the removal percentage of P attained a maximum of 86.7%, while the removal percentage of Fe dropped to a minimum of 1.3% and the Fe content in bioleached iron ore was a maximum of 56.4% (w/w) in this case. The iron ores thus obtained were suitable to be used in the iron-making process. The removal percentage of ore solid decreased with decreasing particle size at particle size range of 106-3350 microm. The possible reasons resulting in above phenomena were explored in the current work. It was inferred that the particle sizes of the iron ore used in this work have no significant effect on the viability of the sulfur-oxidizing bacteria.

Sedimentary exhalative nickel-molybdenum ores in south China

USGS Publications Warehouse

Lott, D.A.; Coveney, R.M.; Murowchick, J.B.; Grauch, R.I.

1999-01-01

Unique bedded Ni-Mo ores hosted by black shales were discovered in localized paleobasins along the Yangzte platform of southern China in 1971. Textural evidence and radiometric dates imply ore formation during sedimentation of black shales that grade into readily combustible beds, termed stone coals, which contain 10 to 15 percent organic carbon. Studies of 427 fluid inclusions indicate extreme variation in hydrothermal brine salinities that were contained by Proterozoic dolostones underlying the ore zone in Hunan and Guizhou. Variations of fluid inclusion salinities, which range from 0.1 to 21.6 wt percent NaCl equiv, are attributed to differences in the compositions of brines in strata underlying the ore bed, complicated by the presence of seawater and dilute fluids that represent condensates of vapors generated by boiling of mineralizing fluids or Cambrian meteoric water. The complex processes of ore deposition led to scattered homogenization temperatures ranging from 100??to 187??C within the Hunan ore zone and from 65??to 183??C within the Guizhou ore zone. While living organisms probably did not directly accumulate metals in situ in sufficient amounts to explain the unusually high grades of the deposits, sulfur isotope ratios indicate that bacteria, now preserved as abundant microfossils, provided sufficient sulfide for the ores by reduction of seawater sulfate. Such microbiota may have depended on vent fluids and transported organic matter for key nutrients and are consistent with a sedex origin for the ores. Vent fluids interacted with organic remains, including rounded fragments of microbial mats that were likely transported to the site of ore deposition by the action of waves and bottom currents prior to replacement by ore minerals.

An investigation of mercury sources in the Puyango-Tumbes River: Using stable Hg isotopes to characterize transboundary Hg pollution.

PubMed

Schudel, Gary; Miserendino, Rebecca Adler; Veiga, Marcello M; Velasquez-López, P Colon; Lees, Peter S J; Winland-Gaetz, Sean; Davée Guimarães, Jean Remy; Bergquist, Bridget A

2018-07-01

Mercury (Hg) concentrations and stable isotopes along with other trace metals were examined in environmental samples from Ecuador and Peru's shared Puyango-Tumbes River in order to determine the extent to which artisanal- and small-scale gold mining (ASGM) in Portovelo-Zaruma, Ecuador contributes to Hg pollution in the downstream aquatic ecosystem. Prior studies investigated the relationship between ASGM activities and downstream Hg pollution relying primarily on Hg concentration data. In this study, Hg isotopes revealed an isotopically heavy Hg signature with negligible mass independent fractionation (MIF) in downstream sediments, which was consistent with the signature observed in the ASGM source endmember. This signature was traced as far as ∼120 km downstream of Portovelo-Zaruma, demonstrating that Hg stable isotopes can be used as a tool to fingerprint and trace sources of Hg over vast distances in freshwater environments. The success of Hg isotopes as a source tracer in fresh waters is largely due to the particle-reactive nature of Hg. Furthermore, the magnitude and extent of downstream Hg, lead, copper and zinc contamination coupled with the Hg isotopes suggest that it is unlikely that the smaller artisanal-scale activities, which do not use cyanidation, are responsible for the pollution. More likely it is the scale of ores processed and the cyanide leaching, which can release other metals and enhance Hg transport, used during small-scale gold mining that is responsible. Thus, although artisanal- and small-scale gold mining occur in tandem in Portovelo-Zaruma, a distinction should be made between these two activities. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sources of mercury to San Francisco Bay surface sediment as revealed by mercury stable isotopes

USGS Publications Warehouse

Gehrke, Gretchen E.; Blum, Joel D.; Marvin-DePasquale, Mark

2011-01-01

Mercury (Hg) concentrations and isotopic compositions were examined in shallow-water surface sediment (0–2 cm) from San Francisco (SF) Bay to determine the extent to which historic Hg mining contributes to current Hg contamination in SF Bay, and to assess the use of Hg isotopes to trace sources of contamination in estuaries. Inter-tidal and wetland sediment had total Hg (HgT) concentrations ranging from 161 to 1529 ng/g with no simple gradients of spatial variation. In contrast, inter-tidal and wetland sediment displayed a geographic gradient of δ202Hg values, ranging from -0.30% in the southern-most part of SF Bay (draining the New Almaden Hg District) to -0.99% in the northern-most part of SF Bay near the Sacramento–San Joaquin River Delta. Similar to SF Bay inter-tidal sediment, surface sediment from the Alviso Slough channel draining into South SF Bay had a δ202Hg value of -0.29%, while surface sediment from the Cosumnes River and Sacramento–San Joaquin River Delta draining into north SF Bay had lower average δ202Hg values of -0.90% and -0.75%, respectively. This isotopic trend suggests that Hg-contaminated sediment from the New Almaden Hg District mixes with Hg-contaminated sediment from a low δ202Hg source north of SF Bay. Tailings and thermally decomposed ore (calcine) from the New Idria Hg mine in the California Coast Range had average δ202Hg values of -0.37 and +0.03%, respectively, showing that Hg calcination fractionates Hg isotopes resulting in Hg contamination from Hg(II) mine waste products with higher δ202Hg values than metallic Hg(0) produced from Hg mines. Thus, there is evidence for at least two distinct isotopic signals for Hg contamination in SF Bay: Hg associated with calcine waste materials at Hg mines in the Coast Range, such as New Almaden and New Idria; and Hg(0) produced from these mines and used in placer gold mines and/or in other industrial processes in the Sierra Nevada region and SF Bay area.

Manganese and Mercury Levels in Water, Sediments, and Children Living Near Gold-Mining Areas of the Nangaritza River Basin, Ecuadorian Amazon.

PubMed

González-Merizalde, Max V; Menezes-Filho, José A; Cruz-Erazo, Claudia Teresa; Bermeo-Flores, Santos Amable; Sánchez-Castillo, María Obdulia; Hernández-Bonilla, David; Mora, Abrahan

2016-08-01

Artisanal and small-scale gold-mining activities performed in mountain areas of the Southern Ecuadorian Amazon have incorporated several heavy metals into the aquatic systems, thus increasing the risk of exposure in populations living in adjacent zones. Therefore, the objective of this study was to evaluate the contamination levels of mercury (Hg) and manganese (Mn) in several rivers of the Nangaritza River basin and assess the exposure in school-aged children residing near the gold-mining zones. River water and sediment samples were collected from a highly contaminated (HEx) and a moderately contaminated (MEx) zones. Hair Mn (MnH) and urinary Hg (HgU) levels were determined in school-aged children living in both zones. High concentrations of dissolved Mn were found in river waters of the HEx zone (between 2660 and 3990 µg l(-1)); however, Hg levels, in general, were lower than the detection limit (DL; <1.0 µg l(-1)). Similarly, Mn levels in sediments were also increased (3090 to 4086 µg g(-1)). Median values of MnH in children of the HEx and MEx zones were 5.5 and 3.4 µg g(-1), respectively, whereas the median values of HgU concentrations in children living in the HEx and MEx zones were 4.4 and 0.62 µg g-creat(-1), respectively. Statistically significant differences were observed between both biomarkers in children from the HEx and MEx zones. In addition, boys presented significantly greater MnH levels in both zones. The greater MnH values were found in children living in alluvial areas, whereas children living in the high mountain areas, where some ore-processing plants are located close to or inside houses and schools, had the greater HgU concentrations. In summary, the data reported in this paper highlights that artisanal and small-scale gold-mining activities can not only produce mercurial contamination, that can also release other heavy metals (such as Mn) that may pose a risk to human health.

Geophysical investigation of Red Devil mine using direct-current resistivity and electromagnetic induction, Red Devil, Alaska, August 2010

USGS Publications Warehouse

Burton, Bethany L.; Ball, Lyndsay B.

2011-01-01

Red Devil Mine, located in southwestern Alaska near the Village of Red Devil, was the state's largest producer of mercury and operated from 1933 to 1971. Throughout the lifespan of the mine, various generations of mills and retort buildings existed on both sides of Red Devil Creek, and the tailings and waste rock were deposited across the site. The mine was located on public Bureau of Land Management property, and the Bureau has begun site remediation by addressing mercury, arsenic, and antimony contamination caused by the minerals associated with the ore deposit (cinnabar, stibnite, realgar, and orpiment). In August 2010, the U.S. Geological Survey completed a geophysical survey at the site using direct-current resistivity and electromagnetic induction surface methods. Eight two-dimensional profiles and one three-dimensional grid of direct-current resistivity data as well as about 5.7 kilometers of electromagnetic induction profile data were acquired across the site. On the basis of the geophysical data and few available soil borings, there is not sufficient electrical or electromagnetic contrast to confidently distinguish between tailings, waste rock, and weathered bedrock. A water table is interpreted along the two-dimensional direct-current resistivity profiles based on correlation with monitoring well water levels and a relatively consistent decrease in resistivity typically at 2-6 meters depth. Three settling ponds used in the last few years of mine operation to capture silt and sand from a flotation ore processing technique possessed conductive values above the interpreted water level but more resistive values below the water level. The cause of the increased resistivity below the water table is unknown, but the increased resistivity may indicate that a secondary mechanism is affecting the resistivity structure under these ponds if the depth of the ponds is expected to extend below the water level. The electromagnetic induction data clearly identified the three monofills and indicate, in conjunction with the three-dimensional resistivity data, additional possible landfill features on the north side of Red Devil Creek. No obvious shallow feature was identified as a possible source for a spring that is feeding into Red Devil Creek from the north bank. However, a discrete, nearly vertical conductive feature observed on the direct-current resistivity line that passes within 5 meters of the spring may be worth investigating. Additional deep soil borings that better differentiate between tailings, waste rock, and weathered bedrock may be very useful in more confidently identifying these rock types in the direct-current resistivity data.

A COMPUTATIONAL AND EXPERIMENTAL STUDY OF MERCURY SPECIATION AS FACILITATED BY THE DEACON PROCESS

EPA Science Inventory

The paper gives results of a computational and experimental study of mercury (Hg) speciation as facilitated by the Deacon process. Fly ashes that contain trace cupric or ferric oxide are effective catalysts for elemental mercury (Hg) conversion to mercuric chloride in the presenc...

GEOCHEMICAL FACTORS GOVERNING METHYL MERCURY PRODUCTION IN MERCURY CONTAMINATED SEDIMENTS

EPA Science Inventory

Bench scale experiments were conducted to improve our understanding of aquatic mercury transformation processes (biotic and abiotic), specifically those factors which govern the production of methyl mercury (MeHg) in sedimentary environments. The greatest cause for concern regar...

A MIXED CHEMICAL REDUCTANT FOR TREATING HEXAVALENT CHROMIUM IN A CHROMITE ORE PROCESSING SOLID WASTE

EPA Science Inventory

We evaluated a method for delivering ferrous iron into the subsurface to enhance chemical reduction of Cr(VI) in a chromite ore processing solid waste (COPSW). The COPSW is characterized by high pH (8.5 -11.5), high Cr(VI) concentrations in the solid phase (up to 550 mg kg-1) and...

Biotechnology for the extractive metals industries

NASA Astrophysics Data System (ADS)

Brierley, James A.

1990-01-01

Biotechnology is an alternative process for the extraction of metals, the beneficiation of ores, and the recovery of metals from aqueous systems. Currently, microbial-based processes are used for leaching copper and uranium, enhancing the recovery of gold from refractory ores, and treating industrial wastewater to recover metal values. Future developments, emanating from fundamental and applied research and advances through genetic engineering, are expected to increase the use and efficiency of these biotechnological processes.

Numerical Study of the Reduction Process in an Oxygen Blast Furnace

NASA Astrophysics Data System (ADS)

Zhang, Zongliang; Meng, Jiale; Guo, Lei; Guo, Zhancheng

2016-02-01

Based on computational fluid dynamics, chemical reaction kinetics, principles of transfer in metallurgy, and other principles, a multi-fluid model for a traditional blast furnace was established. The furnace conditions were simulated with this multi-fluid mathematical model, and the model was verified with the comparison of calculation and measurement. Then a multi-fluid model for an oxygen blast furnace in the gasifier-full oxygen blast furnace process was established based on this traditional blast furnace model. With the established multi-fluid model for an oxygen blast furnace, the basic characteristics of iron ore reduction process in the oxygen blast furnace were summarized, including the changing process of the iron ore reduction degree and the compositions of the burden, etc. The study found that compared to the traditional blast furnace, the magnetite reserve zone in the furnace shaft under oxygen blast furnace condition was significantly reduced, which is conducive to the efficient operation of blast furnace. In order to optimize the oxygen blast furnace design and operating parameters, the iron ore reduction process in the oxygen blast furnace was researched under different shaft tuyere positions, different recycling gas temperatures, and different allocation ratios of recycling gas between the hearth tuyere and the shaft tuyere. The results indicate that these three factors all have a substantial impact on the ore reduction process in the oxygen blast furnace. Moderate shaft tuyere position, high recycling gas temperature, and high recycling gas allocation ratio between hearth and shaft could significantly promote the reduction of iron ore, reduce the scope of the magnetite reserve zone, and improve the performance of oxygen blast furnace. Based on the above findings, the recommendations for improvement of the oxygen blast furnace design and operation were proposed.

Water leaching of titanium from ore flotation residue.

PubMed

Jaworska, Malgorzata M; Guibal, Eric

2003-01-01

Copper ore tailings were tested for the stability of titanium submitted to water leaching in three different reactor systems (agitated vessel, bioreactor and percolated fixed-bed column). For each of these systems, titanium extraction did not exceed 1% of the available metal. Biomass removed from ore residue adsorbed a small part of the titanium with sorption capacities below 20-30 mg g(-1), but most of this biomass was sequestered in the ore residue. Oxygen and carbon dioxide concentrations were monitored and changes in concentration correlated with bacteria development at the initial stage of the process and to fungal development in the latter stages.

Towards Mechanistic Understanding of Mercury Availability and Toxicity to Aquatic Primary Producers.

PubMed

Dranguet, Perrine; Flück, Rebecca; Regier, Nicole; Cosio, Claudia; Le Faucheur, Séverine; Slaveykova, Vera I

2014-11-01

The present article reviews current knowledge and recent progress on the bioavailability and toxicity of mercury to aquatic primary producers. Mercury is a ubiquitous toxic trace element of global concern. At the base of the food web, primary producers are central for mercury incorporation into the food web. Here, the emphasis is on key, but still poorly understood, processes governing the interactions between mercury species and phytoplankton, and macrophytes, two representatives of primary producers. Mass transfer to biota surface, adsorption to cell wall, internalization and release from cells, as well as underlying toxicity mechanisms of both inorganic mercury and methylmercury are discussed critically. In addition, the intracellular distribution and transformation processes, their importance for mercury toxicity, species-sensitivity differences and trophic transfer are presented. The mini-review is illustrated with examples of our own research.

ECONOMIC AND ENVIRONMENTAL ANALYSIS OF TECHNOLOGIES TO TREAT MERCURY AND DISPOSE IN A WASTE CONTAINMENT FACILITY

EPA Science Inventory

The use of mercury in products and processes is decreasing. It is likely that in the future, the supply of mercury will far exceed the demand for mercury. In addition, the Department of Defense (DOD) has stockpiled more than 4,800 tons of mercury that are no longer needed, and th...

Process for removing mercury from aqueous solutions

DOEpatents

Googin, J.M.; Napier, J.M.; Makarewicz, M.A.; Meredith, P.F.

1985-03-04

A process for removing mercury from water to a level not greater than two parts per billion wherein an anion exchange material that is insoluble in water is contacted first with a sulfide containing compound and second with a compound containing a bivalent metal ion forming an insoluble metal sulfide. To this treated exchange material is contacted water containing mercury. The water containing not more than two parts per billion of mercury is separated from the exchange material.

Process for removing mercury from aqueous solutions

DOEpatents

Googin, John M.; Napier, John M.; Makarewicz, Mark A.; Meredith, Paul F.

1986-01-01

A process for removing mercury from water to a level not greater than two parts per billion wherein an anion exchange material that is insoluble in water is contacted first with a sulfide containing compound and second with a compound containing a bivalent metal ion forming an insoluble metal sulfide. To this treated exchange material is contacted water containing mercury. The water containing not more than two parts per billion of mercury is separated from the exchange material.

Multi-trophic level response to extreme metal contamination from gold mining in a subarctic lake.

PubMed

Thienpont, Joshua R; Korosi, Jennifer B; Hargan, Kathryn E; Williams, Trisha; Eickmeyer, David C; Kimpe, Linda E; Palmer, Michael J; Smol, John P; Blais, Jules M

2016-08-17

Giant Mine, located in the city of Yellowknife (Northwest Territories, Canada), is a dramatic example of subarctic legacy contamination from mining activities, with remediation costs projected to exceed $1 billion. Operational between 1948 and 2004, gold extraction at Giant Mine released large quantities of arsenic and metals from the roasting of arsenopyrite ore. We examined the long-term ecological effects of roaster emissions on Pocket Lake, a small lake at the edge of the Giant Mine lease boundary, using a spectrum of palaeoenvironmental approaches. A dated sedimentary profile tracked striking increases (approx. 1700%) in arsenic concentrations coeval with the initiation of Giant Mine operations. Large increases in mercury, antimony and lead also occurred. Synchronous changes in biological indicator assemblages from multiple aquatic trophic levels, in both benthic and pelagic habitats, indicate dramatic ecological responses to extreme metal(loid) contamination. At the peak of contamination, all Cladocera, a keystone group of primary consumers, as well as all planktonic diatoms, were functionally lost from the sediment record. No biological recovery has been inferred, despite the fact that the bulk of metal(loid) emissions occurred more than 50 years ago, and the cessation of all ore-roasting activities in Yellowknife in 1999. © 2016 The Author(s).

Multi-trophic level response to extreme metal contamination from gold mining in a subarctic lake

PubMed Central

Korosi, Jennifer B.; Hargan, Kathryn E.; Williams, Trisha; Eickmeyer, David C.; Kimpe, Linda E.; Palmer, Michael J.; Smol, John P.; Blais, Jules M.

2016-01-01

Giant Mine, located in the city of Yellowknife (Northwest Territories, Canada), is a dramatic example of subarctic legacy contamination from mining activities, with remediation costs projected to exceed $1 billion. Operational between 1948 and 2004, gold extraction at Giant Mine released large quantities of arsenic and metals from the roasting of arsenopyrite ore. We examined the long-term ecological effects of roaster emissions on Pocket Lake, a small lake at the edge of the Giant Mine lease boundary, using a spectrum of palaeoenvironmental approaches. A dated sedimentary profile tracked striking increases (approx. 1700%) in arsenic concentrations coeval with the initiation of Giant Mine operations. Large increases in mercury, antimony and lead also occurred. Synchronous changes in biological indicator assemblages from multiple aquatic trophic levels, in both benthic and pelagic habitats, indicate dramatic ecological responses to extreme metal(loid) contamination. At the peak of contamination, all Cladocera, a keystone group of primary consumers, as well as all planktonic diatoms, were functionally lost from the sediment record. No biological recovery has been inferred, despite the fact that the bulk of metal(loid) emissions occurred more than 50 years ago, and the cessation of all ore-roasting activities in Yellowknife in 1999. PMID:27534958

Mercury in the Carson and Truckee River basins of Nevada

USGS Publications Warehouse

Van Denburgh, A.S.

1973-01-01

Upstream from major pre-1900 ore milling in the Carson and Truckee River basins, "background" concentrations of total mercury in the upper 1 to 3 inches of sand- to clay-sized stream-bottom sediment are less than 0.1 ug/g (microgram per gram). Downstream, measured concentrations were as much as 200 times the background level. Greatest concentrations were encountered in the Carson River basin within and immediately upstream from Lahontan Reservoir. Data from for the Carson River near Fort Churchill suggest that most of the mercury in the sampled bottom sediment may be present as mercuric sulfide or as a component of one of more non-methyl organic compounds or complexes, rather than existing in the metallic state. Regardless of state, this reservoir of mercury is of concern because of its possible availability to the aquatic food chain and, ultimately, to man. Among 48 samples of surface water from 29 sites in the two basins, the maximum measured total-mercury concentration was 6.3 ug/1 (micrograms per liter), for a sample from the Carson River near Fort Churchill. Except downstream from Lahontan Reservoir, most other measured values were less than 1 ug/1. (The U.S> Environmental Protection Agency interim limit for drinking water is 5 ug/1.) The total-mercury content of stream water is related to the mercury content of bottom sediments and the rate of streamflow, because the latter affects the suspended-sediment transporting capability of the stream,. Near Fort Churchill, total-mercury concentrations that might be expected at streamflows greater than those of 1971-72 are: as much as 10-15 ug/1 or more at 2,000 cfs (cubic feet per second), and as much as 10-20 ug/1 or more at 3,000 cfs. Elsewhere, expectable concentrations are much less because the bottom sediment contains much less mercury. The mercury contents of water samples from 36 wells in the Carson and Truckee basins were all less than 1 ug/1, indicating that mercury is not a problem in ground water, even adjacent to areas where stream-bottom sediment is enriched in mercury. Limited data indicate that the Carson River above Lahontan Reservoir and the reservoir itself contain only trace amounts of dissolved arsenic, cyanide, selenium, and silver. Among 17 additional trace metals analysed for on four unfiltered samples from the river above the reservoir, only six of the metals were consistently present in concentrations exceeding detection limits. Maximum measured concentrations for the six metals were: aluminum, >670 ug/1; iron, 2,500 ug/1; manganese, 1,100 ug/1; molybdenum, 15 ug/1; titanium, 110 ug/1; and vanadium, 15 ug/1. Presumably, the detected metals were associated largely or almost entirely with the suspended-sediment phase of the water samples. Selenium and silver concentrations in sampled well waters from the Carson and Truckee basins were uniformly low, with one exception--as elenium concentration of 18 ug/1 for the water of a shallow well southwest of Fallon (Public Health Service limit, 10 ug/1). The arsenic content of 15 sampled well waters ranged from 0 to 1,500 ug/1 (0 to 1.5 ppm), with seven of the values greater than 50 ug/1 (the Public Health Service limit).

Recovering and recycling Hg from chlor-alkali plant wastewater sludge

NASA Astrophysics Data System (ADS)

Twidwell, L. G.; Thompson, R. J.

2001-01-01

Montana Tech of the University of Montana and Universal Dynamics of British Columbia have developed a hydrometallurgical process for recovering and recycling mercury from chlorine plant wastewater sludge materials (U.S. Environmental Protection Agency [EPA]hazardous-waste classification K106). The hydrometallurgical process is also applicable for the treatment of mercury-contaminated soils (EPA hazardous waste classification D009) and other mercury-bearing waste materials. The process, which is capable of lowering the mercury content in the K106 solids from 10% to <50 mg/kg Hg, has been commercialized and utilized at three U.S. plants. This paper describes the fundamental chemistry of the process, the flowsheet being used, and operating plant case histories.

WORKSHOP ON MERCURY IN PRODUCTS, PROCESSES, WASTE AND THE ENVIRONMENT: ELIMINATING, REDUCING AND MANAGING RISKS FROM NON-COMBUSTION SOURCES (PROGRAM FLYER)

EPA Science Inventory

The Workshop is designed to achieve three goals:
1. Convey public and private sector perspectives on the management of mercury in products, processes, and wastes;
2. Present ongoing efforts that address mercury prevention, elimination, noncombustion treatment and disposal; ...

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, Mark W.; George, William A.

1991-01-01

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, Mark W.; George, William A.

1988-01-01

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, Mark W.; George, William A.

1989-01-01

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

Review of Manganese Processing for Production of TRIP/TWIP Steels, Part 2: Reduction Studies

NASA Astrophysics Data System (ADS)

Elliott, R.; Coley, K.; Mostaghel, S.; Barati, M.

2018-02-01

Production of ultrahigh-manganese steels is expected to result in significant increase in demand for low-carbon (LC) ferromanganese (FeMn) and silicomanganese (SiMn). Current manganese processing techniques are energy intensive and typically yield a high-carbon product. The present work therefore reviews available literature regarding carbothermic reduction of Mn oxides and ores, with the objective of identifying opportunities for future process development to mitigate the cost of LC FeMn and SiMn. In general, there is consensus that carbothermic reduction of Mn oxides and ores is limited by gasification of carbon. Conditions which enhance or bypass this step (e.g., by application of CH4) show higher rates of reduction at lower temperatures. This phenomenon has potential application in solid-state reduction of Mn ore. Other avenues for process development include optimization of the prereduction step in conventional FeMn production and metallothermic reduction as a secondary reduction step.

Mining and beneficiation of lunar ores

NASA Technical Reports Server (NTRS)

Bunch, T. E.; Williams, R. J.; Mckay, D. S.; Giles, D.

1979-01-01

The beneficiation of lunar plagioclase and ilmenite ores to feedstock grade permits a rapid growth of the space manufacturing economy by maximizing the production rate of metals and oxygen. A beneficiation scheme based on electrostatic and magnetic separation is preferred over conventional schemes, but such a scheme cannot be completely modeled because beneficiation processes are empirical and because some properties of lunar minerals have not been measured. To meet anticipated shipping and processing needs, the peak lunar mining rate will exceed 1000 tons/hr by the fifth year of operation. Such capabilities will be best obtained by automated mining vehicles and conveyor systems rather than trucks. It may be possible to extract about 40 kg of volatiles (60 percent H2O) by thermally processing the less than 20 micron ilmenite concentrate extracted from 130 tons of ilmenite ore. A thermodynamic analysis of an extraction process is presented.

Investigation of the environmental impacts of naturally occurring radionuclides in the processing of sulfide ores for gold using gamma spectrometry.

PubMed

Gbadago, J K; Faanhof, A; Darko, E O; Schandorf, C

2011-09-01

The possible environmental impacts of naturally occurring radionuclides on workers and a critical community, as a result of milling and processing sulfide ores for gold by a mining company at Bogoso in the western region of Ghana, have been investigated using gamma spectroscopy. Indicative doses for the workers during sulfide ore processing were calculated from the activity concentrations measured at both physical and chemical processing stages. The dose rate, annual effective dose equivalent, radium equivalent activity, external and internal hazard indices, and radioactivity level index for tailings, for the de-silted sediments of run-off from the vicinity of the tailings dam through the critical community, and for the soils of the critical community's basic schools were calculated and found to be lower than their respective permissible limits. The environmental impact of the radionuclides is therefore expected to be low in this mining environment.

Simultaneous determination of mercury and organic carbon using a direct mercury analyzer: Mercury profiles in sediment cores from oxbow lakes in the Mississippi Delta

USDA-ARS?s Scientific Manuscript database

Sediment cores from seasonal wetland and open water areas from six oxbow lakes in the Mississippi River alluvial flood plain were analyzed for total-mercury (Hg) using a direct mercury analyzer (DMA). In the process we evaluated the feasibility of simultaneously determining organic matter content by...

Time-Variant Reliability Analysis for Rubber O-Ring Seal Considering Both Material Degradation and Random Load

PubMed Central

Liao, Baopeng; Yan, Meichen; Zhang, Weifang; Zhou, Kun

2017-01-01

Due to the increase in working hours, the reliability of rubber O-ring seals used in hydraulic systems of transfer machines will change. While traditional methods can only analyze one of the material properties or seal properties, the failure of the O-ring is caused by these two factors together. In this paper, two factors are mainly analyzed: the degradation of material properties and load randomization by processing technology. Firstly, the two factors are defined in terms of material failure and seal failure, before the experimental methods of rubber materials are studied. Following this, the time-variant material properties through experiments and load distribution by monitoring the processing can be obtained. Thirdly, compressive stress and contact stress have been calculated, which was combined with the reliability model to acquire the time-variant reliability for the O-ring. Finally, the life prediction and effect of oil pressure were discussed, then compared with the actual situation. The results show a lifetime of 12 months for the O-ring calculated in this paper, and compared with the replacement records from the maintenance workshop, the result is credible. PMID:29053597

Mercury exposure and health impacts among individuals in the artisanal and small-scale gold mining community: a comprehensive review.

PubMed

Gibb, Herman; O'Leary, Keri Grace

2014-07-01

Mercury (Hg) is used in gold mining to extract gold from ore by forming "amalgam"-a mixture composed of approximately equal parts mercury and gold. Approximately 15 million people, including approximately 3 million women and children, participate in artisanal small-scale gold mining (ASGM) in developing countries. Thirty-seven percent of global air emissions of Hg are produced by ASGM. The recently adopted Minamata Convention calls for nations to gather health data, train health-care workers, and raise awareness in regard to ASGM activity. The purpose of our review was to evaluate the current literature regarding the health effects of Hg among those working and/or living in or near ASGM communities. We searched PubMed, ScienceDirect, and Google Scholar for studies relating to health effects and biomarkers of Hg exposure in ASGM communities. Articles published from 1990 through December 2012 were evaluated for relevance. Studies reporting health assessments, kidney dysfunction, neurological disorders and symptoms, and immunotoxicity/autoimmune dysfunction in individuals living in or near an ASGM community were identified. More than 60 studies that measured biomarkers of Hg exposure in individuals living in or near ASGM communities were also identified. These studies, conducted in 19 different countries in South America, Asia, and Africa, demonstrated that hair and urine concentrations are well above World Health Organization health guidance values in ASGM communities. ASGM workers and their families are exposed to Hg vapor, and workers, workers' families, and residents of nearby and downstream communities are consuming fish heavily contaminated with methylmercury.

EXTRACTION OF URANIUM

DOEpatents

Kesler, R.D.; Rabb, D.D.

1959-07-28

An improved process is presented for recovering uranium from a carnotite ore. In the improved process U/sub 2/O/sub 5/ is added to the comminuted ore along with the usual amount of NaCl prior to roasting. The amount of U/sub 2/O/ sub 5/ is dependent on the amount of free calcium oxide and the uranium in the ore. Specifically, the desirable amount of U/sub 2/O/sub 5/ is 3.2% for each 1% of CaO, and 5 to 6% for each 1% of uranium. The mixture is roasted at about 1560 deg C for about 30 min and then leached with a 3 to 9% aqueous solution of sodium carbonate.

Process for removal of hazardous air pollutants from coal

DOEpatents

Akers, David J.; Ekechukwu, Kenneth N.; Aluko, Mobolaji E.; Lebowitz, Howard E.

2000-01-01

An improved process for removing mercury and other trace elements from coal containing pyrite by forming a slurry of finely divided coal in a liquid solvent capable of forming ions or radicals having a tendency to react with constituents of pyrite or to attack the bond between pyrite and coal and/or to react with mercury to form mercury vapors, and heating the slurry in a closed container to a temperature of at least about 50.degree. C. to produce vapors of the solvent and withdrawing vapors including solvent and mercury-containing vapors from the closed container, then separating mercury from the vapors withdrawn.

Manual for the Construction of a Mercury Capture System for Use in Gold Shops

EPA Pesticide Factsheets

Download a manual for the construction of a mercury capture system for use in gold shops with detailed information for constructing a device to capture mercury aerosol particles emitted from gold shops that process gold dore’, a gold-mercury amalgam.

[Spatial distribution and ecological significance of heavy metals in soils from Chatian mercury mining deposit, western Hunan province].

PubMed

Sun, Hong-Fei; Li, Yong-Hu; Ji, Yan-Fang; Yang, Lin-Sheng; Wang, Wu-Yi

2009-04-15

Ores, waste tailings and slag, together with three typical soil profiles (natural soil profiles far from mine entrance and near mine entrance, soil profile under slag) in Chatian mercury mining deposit (CMD), western Hunan province were sampled and their concentrations of mercury (Hg), arsenic (As), lead (Pb), cadmium (Cd), zinc (Zn) were determined by HG-ICP-AES and ICP-MS. Enrichment factor and correlation analysis were taken to investigate the origins, distribution and migration of Hg, as well as other heavy metals in the CMD. The results show that Hg is enriched in the bottom of the soil profile far from mine entrance but accumulated in the surface of soil profiles near mine entrance and under slag. The soil profiles near mine entrance and under slag are both contaminated by Hg, while the latter is contaminated more heavily. In the soil profile under slag, Hg concentration in the surface soil, Hg average concentration in the total profile, and the leaching depth of soil Hg are 640 microg x g(-1), (76.74 +/- 171.71) microg x g(-1), and more than 100 cm, respectively; while 6.5 microg x g(-1), (2.74 +/- 1.90) microg x g(-1), and 40 cm, respectively, are found in the soil profile near mine entrance. Soil in the mercury mine area is also polluted by Cd, As, Pb, Zn besides metallogenic element Hg, among which Cd pollution is relatively heavier than others. The mobility of the studied heavy metals in soil follows the order as Hg > Cd > As > Zn approximately equal to Pb. The leaching depth of the heavy metals is influenced by total concentration in the surface soil and soil physico-chemical parameters. The origins, distribution and migration of heavy metals in soil profile in the mining area are related to primary geological environment, and strongly influenced by human mining activities.

Developmental Origins of the Other-Race Effect

PubMed Central

Anzures, Gizelle; Quinn, Paul C.; Pascalis, Olivier; Slater, Alan M.; Tanaka, James W.; Lee, Kang

2013-01-01

The other-race effect (ORE) in face recognition refers to better recognition memory for faces of one’s own race than faces of another race—a common phenomenon among individuals living in primarily mono-racial societies. In this article, we review findings suggesting that early visual and sociocultural experiences shape one’s processing of familiar and unfamiliar race classes and give rise to the ORE within the 1st year of life. However, despite its early development, the ORE can be prevented, attenuated, and even reversed given experience with a novel race class. Social implications of the ORE are discussed in relation to development of race-based preferences for social partners and racial prejudices. PMID:24049246

EVALUATING REGIONAL PREDICTIVE CAPACITY OF A PROCESS-BASED MERCURY EXPOSURE MODEL, REGIONAL-MERCURY CYCLING MODEL (R-MCM), APPLIED TO 91 VERMONT AND NEW HAMPSHIRE LAKES AND PONDS, USA

EPA Science Inventory

Regulatory agencies must develop fish consumption advisories for many lakes and rivers with limited resources. Process-based mathematical models are potentially valuable tools for developing regional fish advisories. The Regional Mercury Cycling model (R-MCM) was specifically d...

Retention of atmospheric Cu, Ni, Cd and Zn in an ombrotrophic peat profile near the Outokumpu Cu-Ni mine, SE-Finland

NASA Astrophysics Data System (ADS)

Rausch, N.; Nieminen, T. M.; Ukonmaanaho, L.; Cheburkin, A.; Krachler, M.; Shotyk, W.

2003-05-01

Peat cores taken from ombrotrophic bogs are widely used to reconstruct historical records of atmospheric lead and mercury déposition[1, 2]. In this study, the retention of copper, nickel, cadmium and zinc in peat bogs are studied by comparing high resolution, age dated concentration profiles with emissions from the main local source, the Outokumpu copper-nickel mine. An ombrotrophic peat core was taken from the vicinity of Outokumpu, E Finland. Copper and zinc concentrations of dry peat were measured by XRF, cadmium and nickel by GF-AAS, and sample ages by 210Pb. Only copper and nickel show enhanced concentrations in layers covering the mining period, indicating a retention of these elements. However, the more detailed comparison of ore production rates and concentrations in age-dated samples show clearly that only copper is likely to be permanently fixed, while nickel doesn't reflect the mining activity. Even though copper is retained in the upper part of the profile, a possible redeposition of this element by secondary processes (e.g., water table fluctuations) can not be excluded. This question will be resolved by further investigations, e.g. by pore water profiles.

Mercury-impacted scrap metal: Source and nature of the mercury.

PubMed

Finster, Molly E; Raymond, Michelle R; Scofield, Marcienne A; Smith, Karen P

2015-09-15

The reuse and recycling of industrial solid wastes such as scrap metal is supported and encouraged both internationally and domestically, especially when such wastes can be used as substitutes for raw material. However, scrap metal processing facilities, such as mini-mills, have been identified as a source of mercury (Hg) emissions in the United States. This research aims to better define some of the key issues related to the source and nature of mercury in the scrap metal waste stream. Overall, it is difficult to pinpoint the key mercury sources feeding into scrap metal recycling facilities, quantify their associated mercury concentrations, or determine which chemical forms are most significant. Potential sources of mercury in scrap metal include mercury switches from discarded vehicles, electronic-based scrap from household appliances and related industrial systems, and Hg-impacted scrap metal from the oil and gas industry. The form of mercury associated with scrap metal varies and depends on the source type. The specific amount of mercury that can be adsorbed and retained by steel appears to be a function of both metallurgical and environmental factors. In general, the longer the steel is in contact with a fluid or condensate that contains measurable concentrations of elemental mercury, the greater the potential for mercury accumulation in that steel. Most mercury compounds are thermally unstable at elevated temperatures (i.e., above 350 °C). As such, the mercury associated with impacted scrap is expected to be volatilized out of the metal when it is heated during processing (e.g., shredding or torch cutting) or melted in a furnace. This release of fugitive gas (Hg vapor) and particulates, as well as Hg-impacted bag-house dust and control filters, could potentially pose an occupational exposure risk to workers at a scrap metal processing facility. Thus, identifying and characterizing the key sources of Hg-impacted scrap, and understanding the nature and extent of associated releases, represent a practical research need that is essential for improving the environmental management of Hg-impacted scrap and assessing measures to protect workers from potential health and safety hazards that might be posed by mercury and Hg-impacted scrap. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mercury Thermometer Replacements in Chemistry Laboratories

ERIC Educational Resources Information Center

Foster, Barbara L.

2005-01-01

The consequences of broken mercury-in-glass thermometers in academic laboratories results in various health and environmental hazards, which needs to be replaced, by long-stem digital thermometers and non-mercury glass thermometers. The factors that should be considered during the mercury replacement process are types of applications in the…

DEVELOPMENT AND CHARACTERIZATION OF AN ANNULAR DENUDER METHODOLOGY FOR THE MEASUREMENT OF DIVALENT INORGANIC REACTIVE GASEOUS MERCURY IN AMBIENT AIR

EPA Science Inventory

Atmospheric mercury is predominantly present in the gaseous elemental form (Hg0). However, anthropogenic emissions (e.g. incineration, fossil fuel combustion) emit and natural processes create particulate-phase mercury (Hg(p)) and divalent reactive gas-phase mercury (RGM). RG...

Distribution and assessment of residual mercury from gold mining in Changbai Mountain Range Northeastern China

NASA Astrophysics Data System (ADS)

Meng, D.; Wang, N.; Ai, J. C.; Zhang, G.; Liu, X. J.

2016-08-01

Gold mining was first initiated in Jiapigou area, Huadian city of Northeastern China about 200 years ago. Before 2006, the mercury amalgamation technique was used in the gold mining process, which led to severe mercury contamination. The aim of this paper is to explore the influences of residual mercury on the environment media after eliminating the amalgamation process to extract gold. The mercury concentrations of the atmosphere and the soil were determined in autumn of 2011 and spring of 2012. The soil environmental quality was assessed by the index of geoaccumulation. The results indicated that the maximum value of gaseous mercury was 25ng•m-3 in autumn and 19.5ng•m-3 in spring; the maximum value of mercury in the soil was 2.06mg•kg-1 in autumn and 2.51mg•kg-1in spring. It can be seen that the peak concentrations of the gaseous mercury happened at the gold mine area and tailings, while the peak mercury concentrations in the soil were located at the places near the mining sites and the residential area in the valley. Furthermore, the regression analysis of the total mercury contents between the atmosphere and the soil showed a significant correlation, which indicated that there was certain circulation of the mercury between the regional atmosphere and soil. In general, after the elimination of the amalgamation technique in gold extraction, the distance to the mercury source, the special conditions of hilly weather and landforms and the mercury exchange flux are the main factors of mercury contamination.

Application of ecosystem-scale fate and bioaccumulation models to predict fish mercury response times to changes in atmospheric deposition.

PubMed

Knightes, Christopher D; Sunderland, Elsie M; Craig Barber, M; Johnston, John M; Ambrose, Robert B

2009-04-01

Management strategies for controlling anthropogenic mercury emissions require understanding how ecosystems will respond to changes in atmospheric mercury deposition. Process-based mathematical models are valuable tools for informing such decisions, because measurement data often are sparse and cannot be extrapolated to investigate the environmental impacts of different policy options. Here, we bring together previously developed and evaluated modeling frameworks for watersheds, water bodies, and food web bioaccumulation of mercury. We use these models to investigate the timescales required for mercury levels in predatory fish to change in response to altered mercury inputs. We model declines in water, sediment, and fish mercury concentrations across five ecosystems spanning a range of physical and biological conditions, including a farm pond, a seepage lake, a stratified lake, a drainage lake, and a coastal plain river. Results illustrate that temporal lags are longest for watershed-dominated systems (like the coastal plain river) and shortest for shallow water bodies (like the seepage lake) that receive most of their mercury from deposition directly to the water surface. All ecosystems showed responses in two phases: A relatively rapid initial decline in mercury concentrations (20-60% of steady-state values) over one to three decades, followed by a slower descent lasting for decades to centuries. Response times are variable across ecosystem types and are highly affected by sediment burial rates and active layer depths in systems not dominated by watershed inputs. Additional research concerning watershed processes driving mercury dynamics and empirical data regarding sediment dynamics in freshwater bodies are critical for improving the predictive capability of process-based mercury models used to inform regulatory decisions.

Ballistic Mercury orbiter mission via Venus and Mercury gravity assists

NASA Astrophysics Data System (ADS)

Yen, Chen-Wan Liu

1989-09-01

This paper shows that it is possible to deliver a payload of 600 to 2000 kg to a 300-km circular orbit at Mercury, using the presently available NASA STS and a single-stage bipropellant chemical rocket. This superior payload performance is attained by swingbys of Venus, plus more importantly, the use of the reverse Delta-V/EGA process. In contrast to the familiar Delta-V/EGA process used to boost the launch energy by returning to earth for a gravity assist, the reverse process reduces the Mercury approach energy each time a spacecraft makes a near-resonant return to Mercury for a gravity assist and reduces the orbit-capture Delta-V requirement. The mission sequences for such high-performance missions are described, and example mission opportunities for the years 1990 to 2010 are presented.

Static Thermochemical Model of COREX Melter Gasifier

NASA Astrophysics Data System (ADS)

Srishilan, C.; Shukla, Ajay Kumar

2018-02-01

COREX is one of the commercial smelting reduction processes. It uses the finer size ore and semi-soft coal instead of metallurgical coke to produce hot metal from iron ore. The use of top gas with high calorific value as a by-product export gas makes the process economical and green. The predictive thermochemical model of the COREX process presented here enables rapid computation of process parameters such as (1) required amount of ore, coal, and flux; (2) amount of slag and gas generated; and (3) gas compositions (based on the raw material and desired hot metal quality). The model helps in predicting the variations in process parameters with respect to the (1) degree of metallization and (2) post-combustion ratio for given raw material conditions. In general reduction in coal, flux, and oxygen, the requirement is concomitant with an increase in the degree of metallization and post-combustion ratio. The model reported here has been benchmarked using industrial data obtained from the JSW Steel Plant, India.

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, M.W.; George, W.A.

1991-06-18

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg[sub 2]Cl[sub 2] employing as the electrolyte solution a mixture of HCl and H[sub 2]O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H[sub 2]O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds. 3 figures.

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, M.W.; George, W.A.

1989-11-07

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg[sub 2]Cl[sub 2] employing as the electrolyte solution a mixture of HCl and H[sub 2]O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H[sub 2]O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds. 3 figs.

A Comparison of the Greenhouse Impacts of Magnesium Produced By Electrolytic and Pidgeon Processes

NASA Astrophysics Data System (ADS)

Ramakrishnan, Subramania; Koltun, Paul

With a focus on the global warming impact, this paper deals with the cradle-to-gate life cycle study of the following two practical production systems for producing magnesium ingots: (i) Magnesite ore is processed using the Australian Magnesium process to produce anhydrous magnesium chloride, which is then electrolysed to produce magnesium; and (ii) Dolomite ore is calcined to produce magnesium oxide, which is then thermally reduced with ferrosilicon using the Pidgeon process, based on the current practice used in China for magnesium production

Recovery of Manganese Ore Tailings by High-Gradient Magnetic Separation and Hydrometallurgical Method

NASA Astrophysics Data System (ADS)

Zhang, Xiufeng; Tan, Xiumin; Yi, Yuejun; Liu, Weizao; Li, Chun

2017-11-01

With the depletion of high-grade manganese ores, Mn ore tailings are considered valuable secondary resources. In this study, a process combining high-gradient magnetic separation (HGMS) with hydrometallurgical methods is proposed to recycle fine-grained Mn tailings. The Mn tailings were treated by HGMS at 12,500 G to obtain a Mn concentrate of 30% Mn with the recovery efficiency of 64%. The Mn concentrate could be used in the ferromanganese industry. To recover Mn further, the nonmagnetic fraction was leached by SO2 in an H2SO4 solution. Hydrogen peroxide was added to the leachate to oxidize Fe2+ to Fe3+, and the solution pH was adjusted to 5.0-5.5 with ammonia to remove Al, Fe, and Si impurities. The purified solution was reacted with NH4HCO3, and a saleable product of MnCO3 with 97.9% purity was obtained. The combined process can be applied to Mn recovery from finely dispersed weakly magnetic Mn ores or tailings.

ALKALINE CARBONATE LEACHING PROCESS FOR URANIUM EXTRACTION

DOEpatents

Thunaes, A.; Brown, E.A.; Rabbitts, A.T.

1957-11-12

A process for the leaching of uranium from high carbonate ores is presented. According to the process, the ore is leached at a temperature of about 200 deg C and a pressure of about 200 p.s.i.g. with a solution containing alkali carbonate, alkali permanganate, and bicarbonate ion, the bicarbonate ion functionlng to prevent premature formation of alkali hydroxide and consequent precipitation of a diuranate. After the leaching is complete, the uranium present is recovered by precipitation with NaOH.

Getty Oil Company Diatomite project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuber, I.L.

1984-09-01

The feasibility of using Diatomite as a synthetic fuels feedstock is discussed. The asphaltic outcropping near McKittrick, California are evidence of oil bearing deposits. Two different processes have been taken to the pilot plant stage to evaluate the viability of recovering oil from the Diatomite ore. One approach was the retorting process which was developed by Lurgi. The other process is based on a totally different concept of solvent extracting the oil from the ore. The operation and performance of the pilot plants are described.

SOLVENT EXTRACTION PROCESS FOR URANIUM RECOVERY

DOEpatents

Clark, H.M.; Duffey, D.

1958-06-17

A process is described for extracting uranium from uranium ore, wherein the uranium is substantially free from molybdenum contamination. In a solvent extraction process for recovering uranium, uranium and molybdenum ions are extracted from the ore with ether under high acidity conditions. The ether phase is then stripped with water at a lower controiled acidity, resaturated with salting materials such as sodium nitrate, and reextracted with the separation of the molybdenum from the uranium without interference from other metals that have been previously extracted.

Possibilities of magnetotelluric methods in geophysical exploration for ore minerals

NASA Astrophysics Data System (ADS)

Varentsov M., Iv.; Kulikov, V. A.; Yakovlev, A. G.; Yakovlev, D. V.

2013-05-01

In the past decade, the applications of magnetotelluric method in the electric prospecting for ore bodies have been rapidly progressing. In the present work, we summarize the first results on this way. We discuss the specificity of the geoelectrical models in the problems of mining prospecting for ore bodies. The state-of-the-art capabilities of the method, which rely on the synchronous observation systems and the procedure of joint inversion of magnetotelluric and magnetovariational responses, are considered in the context of ore mineral exploration. The results of modeling a typical mining audio-magnetotelluric survey for ore minerals are presented. On the basis of these simulations and the data provided by in-situ soundings, the efficient approaches to the processing, analysis, and inversion of these data are discussed and illustrated. The future trends in magnetotellurics as applied to the mining prospecting are analyzed.

[Biooxidation of gold-bearing sulfide ore and subsequent biological treatment of cyanidation residues].

PubMed

Kanaev, A T; Bulaev, A G; Semenchenko, G V; Kanaeva, Z K; Shilmanova, A A

2016-01-01

The percolation biooxidation parameters of ore from the Bakyrchik deposit were studied. An investigation of the technological parameters (such as the concentration of leaching agents, irrigation intensity, and pauses at various stages of the leaching) revealed the optimal mode for precious metal extraction. The stages of the ore processing were biooxidation, gold extraction by cyanidation or thiosulfate leaching, and biological destruction of cyanide. The gold and silver recovery rates by cyanidation were 64.0 and 57.3%, respectively. The gold and silver recovery rates by thiosulfate leaching were 64.0 and 57.3%, respectively. Gold and silver recovery rates from unoxidized ore (control experiment) by cyanidation were 20.9 and 26.8%, respectively. Thiosulfate leaching of unoxidized ore allowed the extraction of 38.8 and 24.2% of the gold and silver, respectively. Cyanidation residues were treated with bacteria of the genus Alcaligenes in order to destruct cyanide.

Mercury species and other selected constituent concentrations in water, sediment, and biota of Sinclair Inlet, Kitsap County, Washington, 2007-10

USGS Publications Warehouse

Huffman, R.L.; Wagner, R.J.; Toft, J.; Cordell, J.; DeWild, J.F.; Dinicola, R.S.; Aiken, G.R.; Krabbenhoft, D.P.; Marvin-DiPasquale, M.; Stewart, A.R.; Moran, P.W.; Paulson, A.J.

2012-01-01

The Methylation and Bioaccumulation Project included a comprehensive field study of mercury biogeochemistry in marine sediment, water, and zooplankton in Sinclair Inlet. Mercury, iron, and sulfur species in sediment porewater from six sites within and three sites outside of Sinclair Inlet were measured to provide insight into the processes that produce methylmercury in the sediments. Total mercury, methylmercury, dissolved organic carbon, and redox-sensitive species were measured in porewaters in the top 2 centimeters of sediment, and these data were paired with sedimentary flux measurements from core incubation experiments to connect sedimentary processes to the water column. A broad-scale study of mercury methylation potential and mercury species at 20-plus stations in Sinclair Inlet was conducted in February 2009 and 2010, June 2009, and August 2009. Sedimentary flux measurements and analysis of mercury and biogeochemicals in sediment porewater and bottom water were made at six of the broad-scale stations. Bioaccumulation processes in the water column in the context of the sedimentary flux of methylmercury were examined using monthly survey data collected between August 2008 and August 2009. The survey data included concentrations of methylmercury and isotope ratios of carbon and nitrogen in bulk zooplankton measured at four stations in Sinclair Inlet in the context of the population of bulk zooplankton ascertained by taxonomical identification. The analysis of filtered total mercury, total particulate mercury, filtered methylmercury, particulate methylmercury, chlorophyll a, isotopes of carbon and nitrogen in suspended matter, and other biogeochemical data will facilitate the examination of the biogeochemistry of mercury in Sinclair Inlet.

Mössbauer analysis of BIOX treatment of ores at Wiluna gold mine, Western Australia

NASA Astrophysics Data System (ADS)

Gagliardi, F. M.; Cashion, J. D.

2013-04-01

Mössbauer phase analysis of samples taken from nine stages of the bacterial oxidation processing of gold ore at the Wiluna Gold Mine followed the transformation of the arsenopyrite/pyrite minerals. The principal end-stage phases were szomolnokite, ferric oxyhydroxides, ferric arsenates, jarosite and incompletely transformed pyrite, with higher hydrates of ferrous sulphate being created and then dehydrating to szomolnokite during the processing.

Gold ores related to shear zones, West Santa Comba-Fervenza Area (Galicia, NW Spain): A mineralogical study

NASA Astrophysics Data System (ADS)

Castroviejo, R.

1990-12-01

Recent research has discovered high-grade Au ores in NNE-SSW trending shear zones in metamorphic proterozoic and palaeozoic terranes, some 40 km NW of Santiago de Compostela (NW Spain). The orebodies are bound to late-stage Hercynian structures, mainly due to brittle deformation, which are superimposed on earlier ductile shear zones, cutting through various catazonal lithologies, including ortho- and paragneisses, amphibolites, eclogites, and granites. Ore mineralogy, alteration, and ore textures define a frame whose main features are common to all prospects in the area. Main minerals are arsenopyrite and pyrite — accompanied by quartz, adularia, sericite, ± (tourmaline, chlorite, carbonates, graphite), as main gangue minerals -with subordinate amounts of boulangerite, bismuthinite, kobellite, jamesonite, chalcopyrite, marcasite, galena, sphalerite, rutile, titanite, scheelite, beryl, fluorite, and minor native gold, electrum, native bismuth, fahlore, pyrrhotite, mackinawite, etc., defining a meso-catathermal paragenesis. Detailed microscopic study allows the author to propose a general descriptive scheme of textural classification for this type of ore. Most of the ores fill open spaces or veins, seal cracks or cement breccias; disseminated ores with replacement features related to alteration (mainly silicification, sericitization, and adularization) are also observed. Intensive and repeated cataclasis is a common feature of many ores, suggesting successive events of brittle deformation, hydrothermal flow, and ore precipitation. Gold may be transported and accumulated in any of these events, but tends to be concentrated in later ones. The origin of the gold ores is explained in terms of hydrothermal discharge, associated with mainly brittle deformation and possibly related to granitic magmas, in the global tectonic frame of crustal evolution of West Galicia. The mineralogical and textural study suggests some criteria which will be of practical value for exploration and for ore processing. Ore grades can be improved by flotation of arsenopyrite. Non-conventional methods, such as pressure or bacterial leaching, may subsequently obtain a residue enriched in gold.

Water requirements of the iron and steel industry

USGS Publications Warehouse

Walling, Faulkner B.; Otts, Louis Ethelbert

1967-01-01

Twenty-nine steel plants surveyed during 1957 and 1958 withdrew from various sources about 1,400 billion gallons of water annually and produced 40.8 million tons of ingot steel. This is equivalent to about 34,000 gallons of water per ton of steel. Fifteen iron ore mines and fifteen ore concentration plants together withdrew annually about 89,000 million gallons to produce 15 million tons of iron ore concentrate, or 5,900 gallons per ton of concentrate. About 97 percent of the water used in the steel plants came from surface sources, 2.2 percent was reclaimed sewage, and 1.2 percent was ground water. Steel plants supplied about 96 percent of their own water requirements, although only three plants used self-supplied water exclusively. Water used by the iron ore mines and concentration plants was also predominantly self supplied from surface source. Water use in the iron and steel industry varied widely and depended on the availability of water, age and condition of plants and equipment, kinds of processes, and plant operating procedures. Gross water use in integrated steel plants ranged from 11,200 to 110,000 gallons per ton of steel ingots, and in steel processing plants it ranged from 4,180 to 26,700 gallons per ton. Water reuse also varied widely from 0 to 18 times in integrated steel plants and from 0 to 44 times in steel processing plants. Availability of water seemed to be the principal factor in determining the rate of reuse. Of the units within steel plants, a typical (median) blast furnace required 20,500 gallons of water per ton of pig iron. At the 1956-60 average rate of pig iron consumption, this amounts to about 13,000 gallons per ton of steel ingots or about 40 percent of that required by a typical integrated steel plant 33,200 gallons per ton. Different processes of iron ore concentration are devised specifically for the various kinds of ore. These processes result in a wide range of water use from 124 to 11,300 gallons of water per ton of iron ore concentrate. Water use in concentration plants is related to the physical state of the ore. The data in this report indicate that grain size of the ore is the most important factor; the very fine grained taconite and jasper required the greatest amount of water. Reuse was not widely practiced in the iron ore industry.Consumption of water by integrated steel plants ranged from 0 to 2,010 gallons per ton of ingot steel and by steel processing plants from 120 to 3,420 gallons per ton. Consumption by a typical integrated steel plant was 681 gallons per ton of ingot steel, about 1.8 percent of the intake and about 1 percent of the gross water use. Consumption by a typical steel processing plant was 646 gallons per ton, 18 percent of the intake, and 3.2 percent of the gross water use. The quality of available water was found not to be a critical factor in choosing the location of steel plants, although changes in equipment and in operating procedures are necessary when poor-quality water is used. The use of saline water having a concentration of dissolved solids as much as 10,400 ppm (parts per million) was reported. This very saline water was used for cooling furnaces and for quenching slag. In operations such as rolling steel in which the water comes into contact with the steel being processed, better quality water is used, although water containing as much as 3,410 ppm dissolved solids has been used for this purpose. Treatment of water for use in the iron and steel industry was not widely practiced. Disinfection and treatment for scale and corrosion control were the most frequently used treatment methods.

The role of metasomatism in the balance of halogens in ore-forming process at porphyry Cu-Mo deposits

NASA Astrophysics Data System (ADS)

Berzina, A. N.

2009-04-01

Volatile components play an important role in the evolution of ore-magmatic systems and their ore potential. Of special interest are fluorine and chlorine compounds that principally control the transportation of ore elements by the fluid in a magmatic process and under high-temperature hydrothermal conditions. Study of the evolution of fluorine-chlorine activity in the ore-forming process and their source is usually based on analysis of their magmatic history, whereas the additional source of fluorine and chlorine released during metasomatic alteration of rocks hosting mineralization is poorly discussed in the existing literature. Based on microprobe data on Cl and F abundances in halogen-containing minerals (biotite, amphibole, apatite, titanite) in intrusive rocks and their hydrothermally altered varieties, the role of metasomatic processes in the balance of volatiles in the ore-forming system is discussed by the example of porphyry Cu-Mo deposits of Siberia (Russia) and Mongolia. Two groups of the deposits are considered: copper-molybdenum (Erdenetiin Ovoo, Mongolia and Aksug, Russia) with prevailing propylitic and phyllic alteration and molybdenum-copper (Sora, Russia), with predominant potassic alteration. All types of hydrothermal alterations have led to drastic decrease in Cl contents in metasomatic minerals as compared with halogen-containing magmatic minerals. All studied deposits (particularly those where propylitic and phyllic alteration were developed) show a nearly complete chlorine removal from altered halogen-containing rock-forming minerals (biotite and amphibole). The Cl content in amphibole decreases several times at the stage of replacement with actinolite in the process of propylitization. In the later chlorites (ripidolite and brunsvigite) that replace amphibole, actinolite, and biotite, chlorine is not detected by microprobe (detection limit 0.01-0.02% Cl). Chlorine was also not detected in white micas (muscovite-phengite series) in quartz-sericite alteration zones. No Cl-bearing minerals were revealed in ore-metasomatic assemblages with the exception of extremely low Cl contents in secondary biotite and very rare low-Cl apatite in the early potassic alteration zone. In contrast, fluorine concentrates in chlorites and white micas; however, the F content in them is commonly lower than in dark minerals, especially in biotite from altered rocks. The highest F contents are typical of biotites related to potassic alteration (K-feldspar + biotite + quartz assemblage). For example, the F content at the Sora deposit ranges from 2.5-2.7 wt.% in the metasomatic biotite to 0.44-1.63 wt.% in the rock-forming biotite of host granitoids. At this deposit, fluorite is a major mineral of the ore-metasomatic assemblage. The Mo-rich Sora deposit drastically differs from the Cu-rich Erdenetiin Ovoo and Aksug deposits by extremely low (0.02-0.08 wt.%) Cl contents in dark minerals from all of the host rocks. The considerable quantity of chlorine released as a result of large-scale propylitic and phyllic alteration from halogen-bearing dark minerals at Cu-rich deposits considerably affected the general Cl budget in the ore-metasomatic system. This could significantly promote the generation of Cl-rich (up to 50-70 wt.% NaCl-equiv.) ore-forming solutions at such deposits. At the Sora deposit characterized by less concentrated ore-bearing solutions (12-20 wt.% NaCl-equiv.), the metasomatic alteration of host rocks was not accompanied by an appreciable removal of Cl. At the studied deposits, huge volumes of enclosing rocks were involved in metasomatism. The large amounts of halogens released during the metasomatic alteration of host rocks might have significantly influenced the balance of volatiles in the ore forming system, including the increase in the salinity of hydrothermal solutions.

Fluid inclusion gas chemistry as a potential minerals exploration tool: Case studies from Creede, CO, Jerritt Canyon, NV, Coeur d'Alene district, ID and MT, southern Alaska mesothermal veins, and mid-continent MVT's

USGS Publications Warehouse

Landis, G.P.; Hofstra, A.H.

1991-01-01

Recent advances in instrumentation now permit quantitative analysis of gas species from individual fluid inclusions. Fluid inclusion gas data can be applied to minerals exploration empirically to establish chemical (gas composition) signatures of the ore fluids, and conceptually through the development of genetic models of ore formation from a framework of integrated geologic, geochemical, and isotopic investigations. Case studies of fluid inclusion gas chemistry from ore deposits representing a spectrum of ore-forming processes and environments are presented to illustrate both the empirical and conceptual approaches. We consider epithermal silver-gold deposits of Creede, Colorado, Carlin-type sediment-hosted disseminated gold deposits of Jerritt Canyon, Nevada, metamorphic silver-base-metal veins of the Coeur d'Alene district, Idaho and Montana, gold-quartz veins in accreted terranes of southern Alaska, and the mid-continent base-metal sulfide deposits of Mississippi Valley-Type (MVT's). Variations in gas chemistry determine the redox state of the ore fluids, provide compositional input for gas geothermometers, characterize ore fluid chemistry (e.g., CH4CO2, H2SSO2, CO2/H2S, organic-rich fluids, gas-rich and gas-poor fluids), identify magmatic, meteoric, metamorphic, shallow and deep basin fluids in ore systems, locate upwelling plumes of magmatic-derived volatiles, zones of boiling and volatile separation, interfaces between contrasting fluids, and important zones of fluid mixing. Present techniques are immediately applicable to exploration programsas empirical studies that monitor fluid inclusion gas threshold concentration levels, presence or absence of certain gases, or changes in gas ratios. We suggest that the greater contribution of fluid inclusion gas analysis is in the integrated and comprehensive chemical dimension that gas data impart to genetic models, and in the exploration concepts based on processes and environments of ore formation derived from these genetic models. ?? 1991.

Discrimination of iron ore deposits of granulite terrain of Southern Peninsular India using ASTER data

NASA Astrophysics Data System (ADS)

Rajendran, Sankaran; Thirunavukkarasu, A.; Balamurugan, G.; Shankar, K.

2011-04-01

This work describes a new image processing technique for discriminating iron ores (magnetite quartzite deposits) and associated lithology in high-grade granulite region of Salem, Southern Peninsular India using visible, near-infrared and short wave infrared reflectance data of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Image spectra show that the magnetite quartzite and associated lithology of garnetiferrous pyroxene granulite, hornblende biotite gneiss, amphibolite, dunite, and pegmatite have absorption features around spectral bands 1, 3, 5, and 7. ASTER band ratios ((1 + 3)/2, (3 + 5)/4, (5 + 7)/6) in RGB are constructed by summing the bands representing the shoulders of absorption features as a numerator, and the band located nearest the absorption feature as a denominator to map iron ores and band ratios ((2 + 4)/3, (5 + 7)/6, (7 + 9)/8) in RGB for associated lithology. The results show that ASTER band ratios ((1 + 3)/2, (3 + 5)/4, (5 + 7)/6) in a Red-Green-Blue (RGB) color combination identifies the iron ores much better than previously published ASTER band ratios analysis. A Principal Component Analysis (PCA) is applied to reduce redundant information in highly correlated bands. PCA (3, 2, and 1 for iron ores and 5, 4, 2 for granulite rock) in RGB enabled the discrimination between the iron ores and garnetiferrous pyroxene granulite rock. Thus, this image processing technique is very much suitable for discriminating the different types of rocks of granulite region. As outcome of the present work, the geology map of Salem region is provided based on the interpretation of ASTER image results and field verification work. It is recommended that the proposed methods have great potential for mapping of iron ores and associated lithology of granulite region with similar rock units of granulite regions of Southern Peninsular India. This work also demonstrates the ability of ASTER's to provide information on iron ores, which is valuable for mineral prospecting and exploration activities.

Blast from the Past: Pervasive Impact and Landscape-Scale Modification from Historical Mining Over 1000 Years in Central Sweden

NASA Astrophysics Data System (ADS)

Hansson, S.; Bindler, R.

2011-12-01

In the public consciousness Sweden is often viewed as a largely natural landscape. However, many parts of the landscape have undergone substantial changes. For example, in the historically and culturally important Bergslagen region in central Sweden, which played an important role in the economic development of Sweden since the medieval period, agriculture and mining have greatly transformed the landscape over the past 1000 years. Bergslagen is an ore-rich region characterized as a granite-porphyr belt formed 1900 Ma ago, with thousands of mines and mine pits, hundreds of furnaces, smelters and forges distributed throughout the area. Drawing on data from selected lake sediment records from different historical mining districts in Central Sweden (e.g. Norberg mining district - iron ores and Falun mining district - copper ores) the aim of this presentation is to show how small-scale but pervasively widespread mining and metallurgy, along with associated settlement, have transformed the surrounding landscape. These anthropogenic activities led to changes in sedimentation and erosion rates, forest structure, and also causing large-scale metal pollution and ecological changes in recipient watercourses and lakes. This historical pollution was oftentimes on a scale we associate with modern mining pollution. Our research is based on analyses of lake sediment records, which include multi-element analyses of minor and trace elements using XRF, mercury, carbon, and in some lakes also pollen and diatoms. In two lakes in Norberg, recent catastrophic failure (1991) of a sand magazine below a now closed mine led to significant contamination of the two downstream lakes, with Cu and Hg concentrations up to 1800 ppm and 1400 ppb, respectively. These concentrations are 50 and 20 times greater than natural background values. However, such elevated concentrations are also frequently found in sediments dated to the 16th-18th centuries. For example, in one lake in the Norberg iron mining district, Hg concentrations were as high as 1100 ppb in sediments from the 16th century - about 40 times greater than background level. Although the total concentrations of metals in the lake sediments in these areas have decreased since the peak in the 16th-17th centuries, due to declines in mining and metallurgy, and the complete cessation of activities since the mid-20th century, metal concentrations have remained elevated for more than 500 years. Already 500 years ago land use and mining in some cases led to cultural alkalization of lakes, but ultimately acidification of soils and lakes in areas where sulfide ores were mined and processed. Land use and mining pollution also altered biogeochemical conditions in downstream lakes, which have not returned to natural baseline levels although mining and metallurgy have ceased over the last two centuries. Seeing that these results are symptomatic of changes that potentially affected thousands of lakes in this large region of Sweden, we believe that this has important implications for other environmental and also archaeological studies in the area, particularly those aimed at establishing reference conditions for potential future exploitation of ores.

FGD Additives to Segregate and Sequester Mercury in Solid Byproducts - Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Searcy, K; Bltyhe, G M; Steen, W A

2012-02-28

Many mercury control strategies for U.S. coal-fired power generating plants involve co-benefit capture of oxidized mercury from flue gases treated by wet flue gas desulfurization (FGD) systems. For these processes to be effective at overall mercury control, the captured mercury must not be re-emitted to the atmosphere or into surface or ground water. The project sought to identify scrubber additives and FGD operating conditions under which mercury re-emissions would decrease and mercury would remain in the liquor and be blown down from the system in the chloride purge stream. After exiting the FGD system, mercury would react with precipitating agentsmore » to form stable solid byproducts and would be removed in a dewatering step. The FGD gypsum solids, free of most of the mercury, could then be disposed or processed for reuse as wallboard or in other beneficial reuse. The project comprised extensive bench-scale FGD scrubber tests in Phases I and II. During Phase II, the approaches developed at the bench scale were tested at the pilot scale. Laboratory wastewater treatment tests measured the performance of precipitating agents in removing mercury from the chloride purge stream. Finally, the economic viability of the approaches tested was evaluated.« less

Effect of abiotic factors on the mercury reduction process by humic acids in aqueous systems

USDA-ARS?s Scientific Manuscript database

Mercury (Hg) in the environment can have serious toxic effects on a variety of living organisms, and is a pollutant of concern worldwide. The reduction of mercury from the toxic Hg2+ form to Hg0 is especially important. One pathway for this reduction to occur is through an abiotic process with humic...

Fluid inclusion characteristics and geological significance of the Dajinshan W-Sn polymetallic deposit in Yunfu, Guangdong Province

NASA Astrophysics Data System (ADS)

Yu, Zhangfa; Chen, Maohong; Zhao, Haijie

2015-05-01

The Dajinshan tungsten-tin polymetallic deposit is a quartz-vein-type ore deposit located in Western Guangdong Province. The ore bodies show a fairly simple shape and mainly occur as tungsten-tin polymetallic-bearing sulfide quartz veins, including quartz vein, quartz-greisens, and sulfide quartz veins, and their distribution is spatially related to Dajinshan granitoids. The formation of the deposit experienced three stages: a wolframite-molybdenite-quartz stage, a wolframite-cassiterite-sulfide-quartz stage, and a fluorite-calcite-carbonate stage. Based on detailed petrographic observations, we conducted microthermometric and Raman microspectroscopic studies of fluid inclusions formed at different ore-forming stages in the Dajinshan tungsten-tin polymetallic deposit, identifying four dominant types of fluid inclusions: aqueous two-phase inclusions, CO2-bearing inclusions, solid or daughter mineral-bearing inclusions, and gas-rich inclusions. The gas compositions of ore-forming fluids in the Dajinshan tungsten-tin polymetallic deposit are mostly CO2, CH4, and H2O. The hydrogen, oxygen, and sulfur isotopic data imply that the ore-forming fluids in the Dajinshan tungsten-tin polymetallic deposit were mainly derived from magmatic fluids, mixed with meteoric water in the ore-formation process. These results indicate that the fluid mixing and boiling led to the decomposition of the metal complex in ore-forming fluids and ore deposition.

Extraction of reduced alteration information based on Aster data: a case study of the Bashibulake uranium ore district

NASA Astrophysics Data System (ADS)

Ye, Fa-wang; Liu, De-chang

2008-12-01

Practices of sandstone-type uranium exploration in recent years in China indicate that the uranium mineralization alteration information is of great importance for selecting a new uranium target or prospecting in outer area of the known uranium ore district. Taking a case study of BASHIBULAKE uranium ore district, this paper mainly presents the technical minds and methods of extracting the reduced alteration information by oil and gas in BASHIBULAKE ore district using ASTER data. First, the regional geological setting and study status in BASHIBULAKE uranium ore district are introduced in brief. Then, the spectral characteristics of altered sandstone and un-altered sandstone in BASHIBULAKE ore district are analyzed deeply. Based on the spectral analysis, two technical minds to extract the remote sensing reduced alteration information are proposed, and the un-mixing method is introduced to process ASTER data to extract the reduced alteration information in BASHIBULAKE ore district. From the enhanced images, three remote sensing anomaly zones are discovered, and their geological and prospecting significances are further made sure by taking the advantages of multi-bands in SWIR of ASTER data. Finally, the distribution and intensity of the reduced alteration information in Cretaceous system and its relationship with the genesis of uranium deposit are discussed, the specific suggestions for uranium prospecting orientation in outer of BASHIBULAKE ore district are also proposed.

Culturable microorganisms associated with Sishen iron ore and their potential roles in biobeneficiation.

PubMed

Adeleke, Rasheed; Cloete, T E; Khasa, D P

2012-03-01

With one of the largest iron ore deposits in the world, South Africa is recognised to be among the top ten biggest exporters of iron ore. Increasing demand and consumption of this mineral triggered search for processing technologies, which can be utilised to "purify" the low-grade iron ore minerals that contain high levels of unwanted potassium (K) and phosphorus (P). This study investigated a potential biological method that can be further developed for the full biobeneficiation of low-grade iron ore minerals. Twenty-three bacterial strains that belong to Proteobacteria, Firmicutes, Bacteroidetes and Actinobateria were isolated from the iron ore minerals and identified with sequence homology and phylogenetic methods. The abilities of these isolates to lower the pH of the growth medium and solubilisation of tricalcium phosphate were used to screen them as potential mineral solubilisers. Eight isolates were successfully screened with this method and utilised in shake flask experiments using iron ore minerals as sources of K and P. The shake flask experiments revealed that all eight isolates have potentials to produce organic acids that aided the solubilisation of the iron ore minerals. In addition, all eight isolates produced high concentrations of gluconic acid followed by relatively lower concentrations of acetic, citric and propanoic acid. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analyses also indicated extracellular polymeric substances could play a role in mineral solubilisation.

Mercury Distribution in the Processing of Jatiroto Gold Mine Wonogiri Central Java Indonesia

NASA Astrophysics Data System (ADS)

Fitri Yudiantoro, Dwi; Nurcholis, Muhammad; Sri Sayudi, Dewi; Abdurrachman, Mirzam; Paramita Haty, Intan; Pambudi, Wiryan; Subroborini, Arum

2017-06-01

The research area is one of the Wonogiri gold producer. In this region there are nearly 30 gold processing locations. This area has a steep morphology which is part of Mt. Mas. The work of the gold processing is a part time job besides for the local farmer population. To get the gold bearing rocks, are by digging holes manually around Mt. Mas, while gold processing is carried out in their homes. As a result of these activities, then identified the distribution of mercury in the surrounding settlements. Analytical methods used in this study is the measurement mercury content using Hg meter on altered rocks, soil and using XRF (X-Ray Fluorescence) for plant samples. This results of research shows that there are conducted on mercury contents in the altered rocks, soil and plants showed significant mercury contents in altered rocks, soil and plants. This proves that mercury has polluted the environment surrounding residents, both of people living in the hill down on the lower plain areas. The results of this study are expected to be used as reference to help overcome the pollution of the area.

SORPTION OF MERCURY SPECIES BY ACTIVATED CARBONS AND CALCIUM-BASES SORBENTS: EFFECT OF TEMPERATURE, MERCURY CONCENTRATION AND ACID GASES

EPA Science Inventory

Bench-scale studies of mercury/sorbent reactions were conducted to understand mechanistic limitations of field-scale attempts to reduce emissions of mercury from combustion processes. The effects of temperature (60 - 140 degrees C), sulfur dioxide (SO2, 1000 ppm ), hydrogen chlor...

RECENT GEOCHEMICAL SAMPLING AND MERCURY SOURCES AT SULPHUR BANK MERCURY MINE, LAKE COUNTY, CA

EPA Science Inventory

The Sulphur Bank Mercury Mine (SBMM), located on the shore of Clear Lake in Lake County, California, has been identified as a significant source of mercury to the lake. Sulphur Bank was actively minded from the 1880's to the 1950's. Mining and processing operations at the Sulph...

Recovery of manganese from manganese oxide ores in the EDTA solution

NASA Astrophysics Data System (ADS)

Zhang, Chao; Wang, Shuai; Cao, Zhan-fang; Zhong, Hong

2018-04-01

A new process has been experimentally and theoretically established for the recovery of manganese from manganese oxide ores, mainly including the reductive leaching of manganese by ethylenediaminetetraacetic acid (EDTA), EDTA recovery, and manganese electrolysis. The experimental conditions for this process were investigated. Moderate leaching environment by EDTA with the pH in the range of 5-6 is of benefit to leach manganese from some manganese oxide ores with high-content impurities, such as iron and aluminum. Most of EDTA can be recovered by acidification. A small amount of the residual EDTA in the electrolyte can prevent the generation of anode mud. In addition, trimanganese tetroxide (Mn3O4) can be obtained by the roasting of the EDTA-Mn crystallized product.

An integrated systems-based approach to mercury research and technology development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, Mark J; Brooks, Scott C; Mathews, Teresa J

A 3-year strategic planning process was undertaken in Oak Ridge, Tennessee, to develop a research and technology development approach that can help guide mercury remediation in East Fork Poplar Creek (EFPC). Mercury remediation is a high priority for the US Department of Energy s (DOE s) Oak Ridge Office of Environmental Management because of large historical losses of mercury to the environment at the Y-12 National Security Complex (Y-12). Because of the extent of mercury losses and the complexities of mercury transport and fate in the stream environment, the success of conventional options for mercury remediation in the downstream sectionsmore » of EFPC is uncertain. The overall Oak Ridge mercury remediation strategy focuses on mercury treatment actions at Y-12 in the short-term and research and technology development to evaluate longer-term solutions in the downstream environment. The technology development strategy is consistent with a phased, adaptive management paradigm and DOE s Technology Readiness Level guidelines. That is, early evaluation includes literature review, site characterization, and small-scale studies of a broad number of potential technologies. As more information is gathered, technologies that may have the most promise and potential remediation benefit will be chosen for more extensive and larger-scale pilot testing before being considered for remedial implementation. Field and laboratory research in EFPC is providing an improved level of understanding of mercury transport and fate processes in EFPC that will inform the development of site-specific remedial technologies. Technology development has centered on developing strategies that can mitigate the primary factors affecting mercury risks in the stream: (1) the amount of inorganic mercury available to the stream system, (2) the conversion of inorganic mercury to methylmercury, and (3) the bioaccumulation of methylmercury through the food web. Given the downstream complexities and interdependencies between sources and processes in EFPC, no one task or approach is likely to solve the mercury problem in the creek, thus highlighting the importance of using an integrated, systems-based approach to develop remedial solutions.« less

Sodium cyanide hazards to fish and other wildlife from gold mining operations

USGS Publications Warehouse

Eisler, R.; Clark, D.R.; Wiemeyer, Stanley N.; Henny, C.J.; Azcue, Jose M.

1999-01-01

Highly toxic sodium cyanide (NaCN) is used increasingly by the international mining community to extract gold and other precious metals through milling of high grade ores and heap leaching of low grade ores. Of the 98 million kg cyanide (CN) consumed in North America in 1989, about 80% was used in gold mining (Knudson 1990). In Canada, more than 90% of the mined gold is extracted from ores with the cyanidation process. This process consists of leaching gold from the ore as a gold-cyanide complex, and gold being recovered by precipitation (Simovic and Snodgrass 1985). Milling and heap leaching require cycling of millions of liters of alkaline water containing high concentrations of potentially toxic NaCN, free cyanide, and metal cyanide complexes that are frequently accessible to wildlife. Some milling operations result in tailings ponds of 150 ha and larger. Heap leach operations that spray or drip cyanide solution onto the flattened top of the ore heap require solution processing ponds of about 1 ha in surface area. Although not intentional or desired, puddles of various sizes may occur on the top of heaps where the highest concentrations of NaCN are found. Exposed solution recovery channels are usually constructed at the base of leach heaps. All of these cyanidecontaining water bodies are hazardous to wildlife if not properly managed (Henny et al. 1994). In this account we emphasize hazards of cyanide from mining operations to fish and wildlife species and proposed mitigation to protect them.

A mineralogical perspective on the recovery of platinum group elements from Merensky Reef and UG2 at the Two Rivers mine on the Eastern limb of the Bushveld Complex in South Africa

NASA Astrophysics Data System (ADS)

Rose, Derek H.; Viljoen, K. S.; Mulaba-Bafubiandi, Antoine

2018-06-01

Published studies dealing with the process mineralogy of Pt mines on the Bushveld Complex is generally limited to the Western Bushveld. The recognition by mine management that another resource, in addition to the Upper Group 2 (UG2) reef currently being mined at the Two Rivers platinum mine (TRP), is urgently required in order to extend the life of mine, presented an opportunity to conduct such a study on the Eastern Limb of the Bushveld Complex. A process mineralogical investigation was undertaken on ore from the Merensky Reef (MR) and the UG2 at TRP. This was conducted on a suite of geological samples (channel samples) collected from the underground workings, as well as metallurgical samples obtained from the rougher circuits at the concentrator plant during the processing of MR and UG2 ore. The geological and metallurgical samples were analysed for bulk composition and quantitative mineralogy, while the geological samples were also subjected to laboratory-scale milling and flotation tests. This study shows that, although mineralogically distinct, the MR and UG2 behave similarly in terms of metallurgical performance. This holds promise for the proposed blending of MR and UG2 ores at TRP. An evaluation of the bulk rock (ore) Pt/Pd ratio as a possible indicator of the level of hydrothermal alteration of the ore, demonstrates that this may be of use in predicting recovery plant performance.

Microbiological stimulation of phytoremediation process using Salvinia natans to mercury contamined water

NASA Astrophysics Data System (ADS)

Filyarovskaya, Viktoriya; Sitarska, Magdalena; Traczewska, Teodora; Wolf, Mirela

2017-11-01

An alternative to traditional cleaning methods of heavy metals in the water environment is phytoremediation. They efficiency depends on used technological process conditions as well as plant species. One of the most dangerous metallic elements mercury plays a particular role, which is a trace element and a physiologically foreign in living organisms. Mercury has a high degree of toxicity with strong affinity to thiol groups. This may cause an adverse effect on the enzymatic processes and consequently inhibiting the physiological functions. Because of high risk for human health, water environment treatment from mercury is essential proecological action. Mercury removal studies were conducted using Salvinia natans pleustofit, sampled from its natural water environment. In the first step, epiphytic bacteria, which was resistant to high concentrations of mercury (0,6 mgHg/l), was isolated from the plant and than selected by the tiles gradient mthod. In the next step, the identification using molecular biology methods was made. In the following step plant Salvinia natans was exposure to high levels of mercury in the presence of the three isolated Pseudomonas strains with exceptional resistance characteristics to environmental factors. Has been found a positive bacteria effect on the plant condition because the selected strains belong to Pseudomonas species producing materials supporting plant growth. The use of microbial stimulation to phytoremediation by hyperaccumulator Salvinia natans can multiply the effectiveness of the process.

[Spectral characteristics and implications of quartz from Heliao lead-zinc polymetallic ore district in the south of Qinzhou-Hangzhou joint belt].

PubMed

Lü, Wen-Chao; Yang, Zhi-Jun; Zhou, Yong-Zhang; Li, Hong-Zhong; Zeng, Xiang-Qing; Chen, Qing; Liang, Jin; Zeng, Chang-Yu

2013-05-01

The XRD, FTIR and Raman spectrum were employed to study the characters of quartz from three types of rock samples, which are mineralized rock sample, near ore body rock sample and far away from ore body rock sample in Heliao lead-zinc polymetallic ore district. The research shows that the quartz in the mineralized rock and far away from ore body rock is pure, while the quartz in near ore body rock contains a small amount of impurities. But such small amounts of impurities did not cause apparent change in the quartz lattice parameters. From far away from ore body rock-->near ore body rock-->mineralized rock, the crystallinity and order degree of quartz are higher and higher. And the quartz in the mineralized rock has a trend to change into low symmetry quartz. It's a unique to mineralized rock that the quartz's absorption peak at 1 050 cm(-1) was split into two strongest ones. It can be used as the signs of whether exists mineralization. The cause for the quartz microstructure changes may be related to the activities of late mineralized hydrothermal fluids. Late hydrothermal influence was very weak to the quartz far away from ore body rock. And through the impact of the multi-stage hydrothermal effect, the quartz in mineralized rock may be purified by recrystallization and structural adjustment. However the quartz in near ore body rock didn't have enough hydrothermal influence, so it's not pure. Genealogy research technology is a useful technique for in-depth exploration of study area mineralization process and metallogenic regularity.

Total mercury in infant food, occurrence and exposure assessment in Portugal.

PubMed

Martins, Carla; Vasco, Elsa; Paixão, Eleonora; Alvito, Paula

2013-01-01

Commercial infant food labelled as from organic and conventional origin (n = 87) was analysed for total mercury content using a direct mercury analyser (DMA). Median contents of mercury were 0.50, 0.50 and 0.40 μg kg⁻¹ for processed cereal-based food, infant formulae and baby foods, respectively, with a maximum value of 19.56 μg kg⁻¹ in a baby food containing fish. Processed cereal-based food samples showed statistically significant differences for mercury content between organic and conventional analysed products. Consumption of commercial infant food analysed did not pose a risk to infants when the provisionally tolerable weekly intake (PTWI) for food other than fish and shellfish was considered. By the contrary, a risk to some infants could not be excluded when using the PTWI for fish and shellfish. This is the first study reporting contents of total mercury in commercial infant food from both farming systems and the first on exposure assessment of children to mercury in Portugal.

Integrate metalogenic database with GIS geological project (deposite Au-Ag Far East Russia). WEB-GIS approach.

NASA Astrophysics Data System (ADS)

Kucharenko, Evgeniy; Asavin, Alex

2015-04-01

Resource depletion has forced us to search for new ore deposit and reanalyze old mineral deposits. This is the main aim of metallogenic studies. Synthesis information about features resources work out deposit and emerging fields will play a key role in future. Development of metallogeny databases is one of the most difficult tasks for Earth sciences. Database needs to enter a large number of parameters describing the object of study - mine or ore occurrence. Majority of these parameters belong to different areas of geological knowledge. It can be ore mineralogy, geochemistry, lithology of host rocks, tectonic characteristics ore-controlling structures, geochemical parameters of ore processes, geochronological data on age of geological formations and processes of ore formation and some others. However, the cartographic materials of various scales apart from diverse documentation and numerical information are of a great importance. The adopted framework for the analysis of large-scale metallogeny has several levels: 1. The ore body (usually 1: 50000, 1: 100000) 2. The ore field, the field (1: 200000) 3. The ore cluster (1: 500000) Researchers can vary scheme and scale values, but fundamentally three levels of scale describing the location and geological structures controlling the placement of ore are included at least. Attention should be pay to the system of description the ore deposit. It is necessary to create the universal scheme for development of metallogeny information systems and set up the universal algorithm of ore deposit description. There is its own order of importance of used features and a form of description for each type of deposits and ore and genetic group and ore element. Lack of definition in the classification of a particular metallogenic object makes the choice of algorithm description justified quite weakly. It is quite notable that available features which used for description of different deposit (even of the same genetic group) are not of the same type or detailed enough. Waste deposit usually takes as a reference object with the most complete description in opposite to the recently discovered deposit not enough studied and with quite limited list of information indicators. There are following most actual tasks for information metallogeny system: 1. Search summarizing the characteristics of different objects 2. Select the most informative group of features 3. Show the links of groups of signs and analyze it as far as genesis of deposits. The actual task's list could be continued but it is enough to start. Essentially mentioned problems put us in a situation when deposit's metallogenic database is not available. There is only limited number of typical databases (for certain types of minerals) characterized nothing more than name of the fields and basic indicators of its economic importance (stocks, component content, ore types). The additional information: the age of host rock or ores or geochemistry features of some geological objects uses quite rarely. There is no systematic data for all objects in the database. Database of carbonatite deposits is the most well-developed. It should be also mentioned some works [Woolley & Kjarsgaard 2009; Bagdasarov et al.,2001; Burmistrov et al., 2008]. Unfortunately, such important characteristics as geological maps are not included there as

Modeling study of natural emissions, source apportionment, and emission control of atmospheric mercury

NASA Astrophysics Data System (ADS)

Shetty, Suraj K.

Mercury (Hg) is a toxic pollutant and is important to understand its cycling in the environment. In this dissertation, a number of modeling investigations were conducted to better understand the emission from natural surfaces, the source-receptor relationship of the emissions, and emission reduction of atmospheric mercury. The first part of this work estimates mercury emissions from vegetation, soil and water surfaces using a number of natural emission processors and detailed (LAI) Leaf Area Index data from GIS (Geographic Information System) satellite products. East Asian domain was chosen as it contributes nearly 50% of the global anthropogenic mercury emissions into the atmosphere. The estimated annual natural mercury emissions (gaseous elemental mercury) in the domain are 834 Mg yr-1 with 462 Mg yr-1 contributing from China. Compared to anthropogenic sources, natural sources show greater seasonal variability (highest in simmer). The emissions are significant, sometimes dominant, contributors to total mercury emission in the regions. The estimates provide possible explanation for the gaps between the anthropogenic emission estimates based on activity data and the emission inferred from field observations in the regions. To understand the contribution of domestic emissions to mercury deposition in the United States, the second part of the work applies the mercury model of Community Multi-scale Air Quality Modeling system (CMAQ-Hg v4.6) to apportion the various emission sources attributing to the mercury wet and dry deposition in the 6 United States receptor regions. Contributions to mercury deposition from electric generating units (EGU), iron and steel industry (IRST), industrial point sources excluding EGU and IRST (OIPM), the remaining anthropogenic sources (RA), natural processes (NAT), and out-of-boundary transport (BC) in domain was estimated. The model results for 2005 compared reasonably well to field observations made by MDN (Mercury Deposition Network) and CAMNet (Canadian Atmospheric Mercury Measurement Network). The model estimated a total deposition of 474 Mg yr-1 to the CONUS (Contiguous United States) domain, with two-thirds being dry deposited. Reactive gaseous mercury contributed the most to 60% of deposition. Emission speciation distribution is a key factor for local deposition as contribution from large point sources can be as high as 75% near (< 100 km) the emission sources, indicating that emission reduction may result in direct deposition decrease near the source locations. Among the sources, BC contributes to about 68% to 91% of total deposition. Excluding the BC's contribution, EGU contributes to nearly 50% of deposition caused by CONUS emissions in the Northeast, Southeast and East Central regions, while emissions from natural processes are more important in the Pacific and West Central regions (contributing up to 40% of deposition). The modeling results implies that implementation of the new emission standards proposed by USEPA (United States Environmental Protection Agency) would significantly benefit regions that have larger contributions from EGU sources. Control of mercury emissions from coal combustion processes has attracted great attention due to its toxicity and the emission-control regulations and has lead to advancement in state-of-the-art control technologies that alleviate the impact of mercury on ecosystem and human health. This part of the work applies a sorption model to simulate adsorption of mercury in flue gases, onto a confined-bed of activated carbon. The model's performances were studied at various flue gas flow rates, inlet mercury concentrations and adsorption bed temperatures. The process simulated a flue gas, with inlet mercury concentration of 300 ppb, entering at a velocity of 0.3 m s-1 from the bottom into a fixed bed (inside bed diameter of 1 m and 3 m bed height; bed temperature of 25 °C) of activated carbon (particle size of 0.004 m with density of 0.5 g cm-3 and surface area of 90.25 cm2 g -1). The model result demonstrated that a batch of activated carbon bed was capable of controlling mercury emission for approximately 275 days after which further mercury uptake starts to decrease till it reaches about 500 days when additional control ceases. An increase in bed temperature significantly reduces mercury sorption capacity of the activated carbon. Increase in flue gas flow rate may result in faster consumption of sorption capacity initially but at a later stage, the sorption rate decreases due to reduced sorption capacity. Thus, overall sorption rate remains unaffected. The activated carbon's effective life (time to reach saturation) is not affected by inlet mercury concentration, implying that the designing and operation of a mercury sorption process can be done independently. The results provide quantitative indication for designing efficient confined-bed process to remove mercury from flue gases.

A summary of laboratory testing performed to characterize and select an elastomeric O-ring material to be used in the redesigned solid rocket motors of the space transportation system

NASA Technical Reports Server (NTRS)

Turner, J. E.

1993-01-01

An elastomeric O-ring material is used in the joints of the redesigned solid motors (RSRM's) of the National Space Transportation System (NSTS). The selection of the O-ring material used in the RSRM's was a very thorough process that included efforts by NASA's Marshall Space Flight Center and the Langley Research Center, and the Thiokol Corporation. One of the efforts performed at MSFC was an extensive in-house laboratory test regime to screen potential O-ring materials and ultimately to characterize the elastomeric material that was chosen to be used in the RSRM's. The laboratory tests performed at MSFC are summarized.

Stratiform chromite deposit model: Chapter E in Mineral deposit models for resource assessment

USGS Publications Warehouse

Schulte, Ruth F.; Taylor, Ryan D.; Piatak, Nadine M.; Seal, Robert R.

2012-01-01

Most environmental concerns associated with the mining and processing of chromite ore focus on the solubility of chromium and its oxidation state. Although trivalent chromium (Cr3+) is an essential micronutrient for humans, hexavalent chromium (Cr6+) is highly toxic. Chromium-bearing solid phases that occur in the chromite ore-processing residue, for example, can effect the geochemical behavior and oxidation state of chromium in the environment.

Development of a Chemical Process for Production of Cesium Chloride from a Canadian Pollucite Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsons, H. W.; Vezina, J. A.; Simard, R.

1963-01-01

A chemical process was developed for the production of a high-purity cesium chioride from a pollucite (cesium aluminum silicate) ore from the Manitoba deposit of Chemalloy Minerais Ltd. The history of the deposit, and the present and possible future uses of cesium are briefly reviewed. Laboratory and piiot plant investigations on this ore have shown that a cyclic sulphuric acid leach followed by fractional crystallization will produce a rubidiumfree cesium alum, which can be converted to cesium chloride by thermal decomposition and ion exchange. On the basis of these findings it is concluded that the process is applicable to themore » tonnage production of cesium chloride. Reagent consumption was found to be 3.3 sulphuric acid and 0.3 lb hydrochloric acid per pound of cesium extracted. Overall extraction of cesium was 95 to 96%. (auth)« less

Manganese biomining: A review.

PubMed

Das, A P; Sukla, L B; Pradhan, N; Nayak, S

2011-08-01

Biomining comprises of processing and extraction of metal from their ores and concentrates using microbial techniques. Currently this is used by the mining industry to extract copper, uranium and gold from low grade ores but not for low grade manganese ore in industrial scale. The study of microbial genomes, metabolites and regulatory pathways provide novel insights to the metabolism of bioleaching microorganisms and their synergistic action during bioleaching operations. This will promote understanding of the universal regulatory responses that the biomining microbial community uses to adapt to their changing environment leading to high metal recovery. Possibility exists of findings ways to imitate the entire process during industrial manganese biomining endeavor. This paper reviews the current status of manganese biomining research operations around the world, identifies factors that drive the selection of biomining as a processing technology, describes challenges in exploiting these innovations, and concludes with a discussion of Mn biomining's future. Copyright © 2011 Elsevier Ltd. All rights reserved.

Loparite, a rare-earth ore (Ce, Na, Sr, Ca)(Ti, Nb, Ta, Fe+3)O3

USGS Publications Warehouse

Hedrick, James B.; Sinha, Shyama P.; Kosynkin, Valery D.

1997-01-01

The mineral loparite (Ce, NA, Sr, Ca)(Ti, Nb, Ta, Fe+3)O3 is the principal ore of the light-group rare-earth elements (LREE) in Russia. The complex oxide has a perovskite (ABO3) structure with coupled substitutions, polymorphism, defect chemistry and a tendency to become metamict. The A site generally contains weakly bonded, easily exchanged cations of the LREE, Na and Ca. The B site generally contains smaller, highly charged cations of Ti, Nb or Fe+3. Mine production is from Russia's Kola Peninsula. Ore is beneficiated to produce a 95% loparite concentrate containing 30% rare-earth oxides. Loparite concentrate is refined by either a chlorination process or acid decomposition process to recover rare-earths, titanium, niobium and tantalum. Rare-earths are separated by solvent extraction and selective precipitation/dissolution. The concentrate is processed at plants in Russia, Estonia and Kazakstan.

Investigations regarding the wet decontamination of fluorescent lamp waste using iodine in potassium iodide solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tunsu, Cristian, E-mail: tunsu@chalmers.se; Ekberg, Christian; Foreman, Mark

Highlights: • A wet-based decontamination process for fluorescent lamp waste is proposed. • Mercury can be leached using iodine in potassium iodide solution. • The efficiency of the process increases with an increase in leachant concentration. • Selective leaching of mercury from rare earth elements is achieved. • Mercury is furthered recovered using ion exchange, reduction or solvent extraction. - Abstract: With the rising popularity of fluorescent lighting, simple and efficient methods for the decontamination of discarded lamps are needed. Due to their mercury content end-of-life fluorescent lamps are classified as hazardous waste, requiring special treatment for disposal. A simplemore » wet-based decontamination process is required, especially for streams where thermal desorption, a commonly used but energy demanding method, cannot be applied. In this study the potential of a wet-based process using iodine in potassium iodide solution was studied for the recovery of mercury from fluorescent lamp waste. The influence of the leaching agent’s concentration and solid/liquid ratio on the decontamination efficiency was investigated. The leaching behaviour of mercury was studied over time, as well as its recovery from the obtained leachates by means of anion exchange, reduction, and solvent extraction. Dissolution of more than 90% of the contained mercury was achieved using 0.025/0.05 M I{sub 2}/KI solution at 21 °C for two hours. The efficiency of the process increased with an increase in leachant concentration. 97.3 ± 0.6% of the mercury contained was dissolved at 21 °C, in two hours, using a 0.25/0.5 M I{sub 2}/KI solution and a solid to liquid ratio of 10% w/v. Iodine and mercury can be efficiently removed from the leachates using Dowex 1X8 anion exchange resin or reducing agents such as sodium hydrosulphite, allowing the disposal of the obtained solution as non-hazardous industrial wastewater. The extractant CyMe{sub 4}BTBP showed good removal of mercury, with an extraction efficiency of 97.5 ± 0.7% being achieved in a single stage. Better removal of mercury was achieved in a single stage using the extractants Cyanex 302 and Cyanex 923 in kerosene, respectively.« less

Digital processing of the Mariner 10 images of Venus and Mercury

NASA Technical Reports Server (NTRS)

Soha, J. M.; Lynn, D. J.; Mosher, J. A.; Elliot, D. A.

1977-01-01

An extensive effort was devoted to the digital processing of the Mariner 10 images of Venus and Mercury at the Image Processing Laboratory of the Jet Propulsion Laboratory. This effort was designed to optimize the display of the considerable quantity of information contained in the images. Several image restoration, enhancement, and transformation procedures were applied; examples of these techniques are included. A particular task was the construction of large mosaics which characterize the surface of Mercury and the atmospheric structure of Venus.

BEHAVIOR OF MERCURY DURING DWPF CHEMICAL PROCESS CELL PROCESSING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamecnik, J.; Koopman, D.

2012-04-09

The Defense Waste Processing Facility has experienced significant issues with the stripping and recovery of mercury in the Chemical Processing Cell (CPC). The stripping rate has been inconsistent, often resulting in extended processing times to remove mercury to the required endpoint concentration. The recovery of mercury in the Mercury Water Wash Tank has never been high, and has decreased significantly since the Mercury Water Wash Tank was replaced after the seventh batch of Sludge Batch 5. Since this time, essentially no recovery of mercury has been seen. Pertinent literature was reviewed, previous lab-scale data on mercury stripping and recovery wasmore » examined, and new lab-scale CPC Sludge Receipt and Adjustment Tank (SRAT) runs were conducted. For previous lab-scale data, many of the runs with sufficient mercury recovery data were examined to determine what factors affect the stripping and recovery of mercury and to improve closure of the mercury material balance. Ten new lab-scale SRAT runs (HG runs) were performed to examine the effects of acid stoichiometry, sludge solids concentration, antifoam concentration, form of mercury added to simulant, presence of a SRAT heel, operation of the SRAT condenser at higher than prototypic temperature, varying noble metals from none to very high concentrations, and higher agitation rate. Data from simulant runs from SB6, SB7a, glycolic/formic, and the HG tests showed that a significant amount of Hg metal was found on the vessel bottom at the end of tests. Material balance closure improved from 12-71% to 48-93% when this segregated Hg was considered. The amount of Hg segregated as elemental Hg on the vessel bottom was 4-77% of the amount added. The highest recovery of mercury in the offgas system generally correlated with the highest retention of Hg in the slurry. Low retention in the slurry (high segregation on the vessel bottom) resulted in low recovery in the offgas system. High agitation rates appear to result in lower retention of mercury in the slurry. Both recovery of mercury in the offgas system and removal (segregation + recovery) from the slurry correlate with slurry consistency. Higher slurry consistency results in better retention of Hg in the slurry (less segregation) and better recovery in the offgas system, but the relationships of recovery and retention with consistency are sludge dependent. Some correlation with slurry yield stress and acid stoichiometry was also found. Better retention of mercury in the slurry results in better recovery in the offgas system because the mercury in the slurry is stripped more easily than the segregated mercury at the bottom of the vessel. Although better retention gives better recovery, the time to reach a particular slurry mercury content (wt%) is longer than if the retention is poorer because the segregation is faster. The segregation of mercury is generally a faster process than stripping. The stripping factor (mass of water evaporated per mass of mercury stripped) of mercury at the start of boiling were found to be less than 1000 compared to the assumed design basis value of 750 (the theoretical factor is 250). However, within two hours, this value increased to at least 2000 lb water per lb Hg. For runs with higher mercury recovery in the offgas system, the stripping factor remained around 2000, but runs with low recovery had stripping factors of 4000 to 40,000. DWPF data shows similar trends with the stripping factor value increasing during boiling. These high values correspond to high segregation and low retention of mercury in the sludge. The stripping factor for a pure Hg metal bead in water was found to be about 10,000 lb/lb. About 10-36% of the total Hg evaporated in a SRAT cycle was refluxed back to the SRAT during formic acid addition and boiling. Mercury is dissolved as a result of nitric acid formation from absorption of NO{sub x}. The actual solubility of dissolved mercury in the acidic condensate is about 100 times higher than the actual concentrations measured. Mercury metal present in the MWWT from previous batches could be dissolved by this acidic condensate. The test of the effect of higher SRAT condenser temperature on recovery of mercury in the MWWT and offgas system was inconclusive. The recovery at higher temperature was lower than several low temperature runs, but about the same as other runs. Factors other than temperature appear to affect the mercury recovery. The presence of chloride and iodide in simulants resulted in the formation of mercurous chloride and mercurous iodide, respectively, in the offgas system. Actual waste data shows that the chloride content is much less than the simulant concentrations. Future simulant tests should minimize the addition of chloride. Similarly, iodine addition should be eliminated unless actual waste analyses show it to be present; currently, total iodine is not measured on actual waste samples.« less

Vapor phase elemental sulfur amendment for sequestering mercury in contaminated soil

DOEpatents

Looney, Brian B.; Denham, Miles E.; Jackson, Dennis G.

2014-07-08

The process of treating elemental mercury within the soil is provided by introducing into the soil a heated vapor phase of elemental sulfur. As the vapor phase of elemental sulfur cools, sulfur is precipitated within the soil and then reacts with any elemental mercury thereby producing a reaction product that is less hazardous than elemental mercury.

Influence of the forest canopy on total and methyl mercury deposition in the boreal forest

Treesearch

E.L. Witt; R.K. Kolka; E.A. Nater; T.R. Wickman

2009-01-01

Atmospheric mercury deposition by wet and dry processes contributes mercury to terrestrial and aquatic systems. Factors influencing the amount of mercury deposited to boreal forests were identified in this study. Throughfall and open canopy precipitation samples were collected in 2005 and 2006 using passive precipitation collectors from pristine sites located across...

Description and Initial Simulation of a Dynamic Bidirectional Air-Surface Exchange Model for Mercury in Community Multiscale Air Quality Model

EPA Science Inventory

Emissions of elemental mercury (Hg⁰) from natural processes are believed to be as large as anthropogenic mercury emissions and are a critical source required to model the transport and fate of mercury. Recent ecosystem scale measurements indicate that a fraction of rec...

Electrostatic beneficiation of ores on the moon surface

NASA Technical Reports Server (NTRS)

Inculet, I. I.; Criswell, D. R.

1979-01-01

The feasibility of the electrostatic beneficiation of lunar ores is studied. It is shown that the lunar environment with its sustained high vacuum, low temperature, and low acceleration of gravity, is suitable for the use of the electrostatic technique with magnetic as well as nonmagnetic ores. Only an initial coarse screening will be required prior to processing, as the lunar soil is already in fine particulate form. The low temperature and the absence of water suggest the use of tribo-electrification for the electric charging of lunar soils.

Effect of temperature in the selective reduction process of limonite nickel ore

NASA Astrophysics Data System (ADS)

Mayangsari, W.; Febriana, Eni; Prasetyo, A. B.

2018-05-01

Temperature is the main factor for the reduction process that influence to reduction degree, phase and morphology transformation. In order to determine these effects which is caused by reduction temperature, this study was conducted. Limoniticnickel ore was prepared by drying and size reduction. A part of prepared limonitewas characterized with XRF to determine the chemical composition. The other part was mixed with reducing agent and CaSO4 to produce pellet. A series of selective reduction processes were conducted to the pellet by using graphite crucible in the muffle furnace carbolite at 800° - 1100°C for 60 minutes. Reduced ore characterized by using XRD and SEM analysis. Based on the result study, weight loss and reduction degree increase as temperature raised along with CaSO4 addition. Moreover, it caused decomposition and transformation to the metallic phase of kamacite and iron up to 7.51% and 41.44% respectively in the reduction process at 1100°C for 60 minutes. Furthermore, particle size growth as metallic phase content increased.

Estimation of mercury emission from different sources to atmosphere in Chongqing, China.

PubMed

Wang, Dingyong; He, Lei; Wei, Shiqiang; Feng, Xinbin

2006-08-01

This investigation presents a first assessment of the contribution to the regional mercury budget from anthropogenic and natural sources in Chongqing, an important industrial region in southwest China. The emissions of mercury to atmosphere from anthropogenic sources in the region were estimated through indirect approaches, i.e. using commonly acceptable emission factors method, which based on annual process throughputs or consumption for these sources. The natural mercury emissions were estimated from selected natural sources by the dynamic flux chamber technique. The results indicated that the anthropogenic mercury emissions totaled approximately 8.85 tons (t), more than 50% of this total originated in coal combustion and 23.7% of this total emission in the industrial process (include cement production, metal smelting and chemical industry). The natural emissions represented approximately 17% of total emissions (1.78 t yr(-1)). The total mercury emission to atmosphere in Chongqing in 2001 was 10.63 t.

Mercury's Exosphere During MESSENGER's Second Flyby: Detection of Magnesium and Distinct Distributions of Neutral Species

NASA Technical Reports Server (NTRS)

McClintock, William E.; Vervack, Ronald J., Jr.; Bradley, E. Todd; Killen, Rosemary M.; Mouawad, Nelly; Sprague, Ann L.; Burger, Matthew H.; Solomon, Sean C.; Izenberg, Noam R.

2009-01-01

During MESSENGER's second Mercury flyby, the Mercury Atmospheric and Surface Composition Spectrometer observed emission from Mercury's neutral exosphere. These observations include the first detection of emission from magnesium. Differing spatial distributions for sodium, calcium, and magnesium were revealed by observations beginning in Mercury's tail region, approximately 8 Mercury radii anti-sunward of the planet, continuing past the nightside, and ending near the dawn terminator. Analysis of these observations, supplemented by observations during the first Mercury flyby as well as those by other MESSENGER instruments, suggests that the distinct spatial distributions arise from a combination of differences in source, transfer, and loss processes.

The extractive metallurgy of gold

NASA Astrophysics Data System (ADS)

Kongolo, K.; Mwema, M. D.

1998-12-01

Mössbauer spectroscopy has been successfully used in investigation of the gold compounds present in ores and the gold species which occur during the process metallurgy of this metal. This paper is a survey of the basic recovery methods and techniques used in extractive metallurgy of gold. Process fundamentals on mineral processing, ore leaching, zinc dust cementation, adsorption on activated carbon, electrowinning and refining are examined. The recovery of gold as a by-product of the copper industry is also described. Alternative processing methods are indicated in order to shed light on new interesting research topics where Mössbauer spectroscopy could be applied.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Finster, Molly E; Raymond, Michelle R.; Scofield, Marcienne A.

The reuse and recycling of industrial solid wastes such as scrap metal is supported and encouraged both internationally and domestically, especially when such wastes can be used as substitutes for raw material. However, scrap metal processing facilities, such as mini-mills, have been identified as a source of mercury (Hg) emissions in the United States. This research aims to better define some of the key issues related to the source and nature of mercury in the scrap metal waste stream. Overall, it is difficult to pinpoint the key mercury sources feeding into scrap metal recycling facilities, quantify their associated mercury concentrations,more » or determine which chemical forms are most significant. Potential sources of mercury in scrap metal include mercury switches from discarded vehicles, electronic-based scrap from household appliances and related industrial systems, and Hg-impacted scrap metal from the oil and gas industry. The form of mercury associated with scrap metal varies and depends on the source type. The specific amount of mercury that can be adsorbed and retained by steel appears to be a function of both metallurgical and environmental factors. In general, the longer the steel is in contact with a fluid or condensate that contains measurable concentrations of elemental mercury, the greater the potential for mercury accumulation in that steel. Most mercury compounds are thermally unstable at elevated temperatures (i.e., above 350°C). As such, the mercury associated with impacted scrap is expected to be volatilized out of the metal when it is heated during processing (e.g., shredding or torch cutting) or melted in a furnace. This release of fugitive gas (Hg vapor) and particulates, as well as Hg-impacted bag-house dust and control filters, could potentially pose an occupational exposure risk to workers at a scrap metal processing facility. Thus, identifying and characterizing the key sources of Hg-impacted scrap, and understanding the nature and extent of associated releases, represent a practical research need that is essential for improving the environmental management of Hg-impacted scrap and assessing measures to protect workers from potential health and safety hazards that might be posed by mercury and Hg-impacted scrap.« less

Assessment of mobility and bioavailability of mercury compounds in sewage sludge and composts.

PubMed

Janowska, Beata; Szymański, Kazimierz; Sidełko, Robert; Siebielska, Izabela; Walendzik, Bartosz

2017-07-01

Content of heavy metals, including mercury, determines the method of management and disposal of sewage sludge. Excessive concentration of mercury in composts used as organic fertilizer may lead to accumulation of this element in soil and plant material. Fractionation of mercury in sewage sludge and composts provides a better understanding of the extent of mobility and bioavailability of the different mercury species and helps in more informed decision making on the application of sludge for agricultural purposes. The experimental setup comprises the composing process of the sewage sludge containing 13.1mgkg -1 of the total mercury, performed in static reactors with forced aeration. In order to evaluate the bioavailability of mercury, its fractionation was performed in sewage sludge and composts during the process. An analytical procedure based on four-stage sequential extraction was applied to determine the mercury content in the ion exchange (water soluble and exchangeable Hg), base soluble (Hg bound to humic and fulvic acid), acid soluble (Hg bound to Fe/Mn oxides and carbonates) and oxidizable (Hg bound to organic matter and sulphide) fractions. The results showed that from 50.09% to 64.55% of the total mercury was strongly bound to organo-sulphur and inorganic sulphide; that during composting, increase of concentrations of mercury compounds strongly bound with organic matter and sulphides; and that mercury content in the base soluble and oxidizable fractions was strongly correlated with concentration of dissolved organic carbon in those fractions. Copyright © 2017 Elsevier Inc. All rights reserved.

Complexometric determination of some toxic mixtures of ions using bromo-cresol orange with visual endpoint indication.

PubMed

Hafez, M A; Khalifa, M E

1997-05-01

A rapid and simple general complexometric method was presented for the determination of lead, cadmium and thallium or mercury or arsenic(V) in laboratory synthesized mixtures similar to those of some ores, minerals and alloys of such metals. The precision and accuracy attainable in successive titrations of Pb(2+), Cd(2+) and Tl(3+) or Hg(2+) or AsO(3-)(4) (As(5+)) with 0.05 and/or 0.01 mol 1(-1) solutions of disodium ethylenediaminetetraacetate (Na(2)EDTA) and standard Pb(NO(3))(2) of the same concentration using Bromo-Cresol Orange (BCO) as a new metallochromic indicator with visual endpoint indication were studied. For the analysis of a three component mixtures of the aforementioned ions, Tl(3+) was at first directly titrated with Na(2)EDTA at pH 0.5-1 (HNO(3)) using BCO as indicator. At the thallium endpoint an excess of Na(2)EDTA was added and the pH was adjusted at pH approximately 4.8 using hexamine-HNO(3) buffer (solution A). The excess EDTA was back-titrated with standard solution of Pb(NO(3))(2). 1,10-Phenanthroline (1,10-phen) was added to release the EDTA combined with Cd(2+), while thiosemicarbazide (TSC) was used to liberate the EDTA from the mercury-EDTA chelate. To determine AsO(3-)(4) ion in such type of mixtures the pH of (solution A) was raised to a value of 10 using ammonia buffer. Excess standard Mg(2+) solution was added and the formed precipitate of MgNH(4)AsO(4) was separated, dissolved and its magnesium content equivalent to AsO(3-)(4) was determined complexometrically using Eriochrome Black-T (EBT) indicator. The interference caused by different anions, cations and organic acids was investigated. A comparison of the indicators BCO and Xylenol Orange (XO) for successive titration of the studied metal ions was carried out. The proposed successive titration method was applied successfully to some real samples of ores, minerals and alloys of the studied metal ions and the results were satisfactory and agreed with those obtained by AAS.

Mercury capture within coal-fired power plant electrostatic precipitators: model evaluation.

PubMed

Clack, Herek L

2009-03-01

Efforts to reduce anthropogenic mercury emissions worldwide have recently focused on a variety of sources, including mercury emitted during coal combustion. Toward that end, much research has been ongoing seeking to develop new processes for reducing coal combustion mercury emissions. Among air pollution control processes that can be applied to coal-fired boilers, electrostatic precipitators (ESPs) are by far the most common, both on a global scale and among the principal countries of India, China, and the U.S. that burn coal for electric power generation. A previously reported theoretical model of in-flight mercury capture within ESPs is herein evaluated against data from a number of full-scale tests of activated carbon injection for mercury emissions control. By using the established particle size distribution of the activated carbon and actual or estimated values of its equilibrium mercury adsorption capacity, the incremental reduction in mercury concentration across each ESP can be predicted and compared to experimental results. Because the model does not incorporate kinetics associated with gas-phase mercury transformation or surface adsorption, the model predictions representthe mass-transfer-limited performance. Comparing field data to model results reveals many facilities performing at or near the predicted mass-transfer-limited maximum, particularly at low rates of sorbent injection. Where agreement is poor between field data and model predictions, additional chemical or physical phenomena may be responsible for reducing mercury removal efficiencies.

Determination and assessment of total mercury levels in local, frozen and canned fish in Lebanon.

PubMed

Obeid, Pierre J; El-Khoury, Bilal; Burger, Joanne; Aouad, Samer; Younis, Mira; Aoun, Amal; El-Nakat, John Hanna

2011-01-01

Fish is an important constituent of the Lebanese diet. However, very little attention in our area is given to bring awareness regarding the effect of the toxicity of mercury (Hg) mainly through fish consumption. This study aimed to report analytical data on total mercury levels in several fish species for the first time in thirty years and to also made individuals aware of the presence and danger from exposure to mercury through fish consumption. Fish samples were selected from local Lebanese markets and fisheries and included 94 samples of which were fresh, frozen, processed, and canned fish. All values were reported as microgram of mercury per gram of fish based on wet weight. The level of mercury ranged from 0.0190 to 0.5700 microg/g in fresh samples, 0.0059 to 0.0665 microg/g in frozen samples, and 0.0305 to 0.1190 microg/g in canned samples. The data clearly showed that higher levels of mercury were detected in local fresh fish as opposed to other types thus placing consumers at higher risk from mercury exposure. Moreover, the data revealed that Mallifa (yellowstripe barracuda/Sphyraena chrysotaenia), Sargous (white seabream/Diplodus sargus), Ghobbos (bogue/Boops boops), and shrimp (Penaeus sp.) were among the types containing the highest amounts of mercury. On the other hand, processed fish such as fish fillet, fish burger, small shrimp and crab are found to contain lower levels of mercury and are associated with lower exposure risks to mercury. Lebanese population should therefore, be aware to consume limited amounts of fresh local fish to minimize exposure to mercury.

Mercury Production and Use in Colonial Andean Silver Production: Emissions and Health Implications

PubMed Central

Hagan, Nicole A.

2012-01-01

Background: Colonial cinnabar mining and refining began in Huancavelica, Peru, in 1564. With a local source of mercury, the amalgamation process was adopted to refine silver in Potosí, Bolivia, in the early 1570s. As a result, large quantities of mercury were released into the environment. Objectives: We used archival, primary, and secondary sources to develop the first estimate of mercury emissions from cinnabar refining in Huancavelica and to revise previous estimates of emissions from silver refining in Potosí during the colonial period (1564–1810). Discussion: Although other estimates of historical mercury emissions have recognized Potosí as a significant source, Huancavelica has been overlooked. In addition, previous estimates of mercury emissions from silver refining under-estimated emissions because of unrecorded (contra-band) production and volatilization of mercury during processing and recovery. Archival descriptions document behavioral and health issues during the colonial period that are consistent with known effects of mercury intoxication. Conclusions: According to our calculations, between 1564 and 1810, an estimated 17,000 metric tons of mercury vapor were emitted from cinnabar smelting in Huancavelica, and an estimated 39,000 metric tons were released as vapor during silver refining operations in Potosí. Huancavelica and Potosí combined contributed > 25% of the 196,000 metric tons of mercury vapor emissions in all of Latin America between 1500 and 1800. The historical record is laden with evidence of mercury intoxication consistent with effects recognized today. Our estimates serve as the foundation of investigations of present-day contamination in Huancavelica and Potosí resulting from historical emissions of mercury. PMID:22334094

URANIUM RECOVERY PROCESS

DOEpatents

Yeager, J.H.

1958-08-12

In the prior art processing of uranium ores, the ore is flrst digested with nitric acid and filtered, and the uranium values are then extracted tom the filtrate by contacting with an organic solvent. The insoluble residue has been processed separately in order to recover any uranium which it might contain. The improvement consists in contacting a slurry, composed of both solution and residue, with the organic solvent prior to filtration. Tbe result is that uranium values contained in the residue are extracted along with the uranium values contained th the solution in one step.

Simulating Runoff from a Grid Based Mercury Model: Flow Comparisons

EPA Science Inventory

Several mercury cycling models, including general mass balance approaches, mixed-batch reactors in streams or lakes, or regional process-based models, exist to assess the ecological exposure risks associated with anthropogenically increased atmospheric mercury (Hg) deposition, so...

Magmatic Ascent and Eruption Processes on Mercury

NASA Astrophysics Data System (ADS)

Head, J. W.; Wilson, L.

2018-05-01

MESSENGER volcanic landform data and information on crustal composition allow us to model the generation, ascent, and eruption of magma; Mercury explosive and effusive eruption processes differ significantly from other terrestrial planetary bodies.

Mercury contamination from historical gold mining in California

USGS Publications Warehouse

Alpers, Charles N.; Hunerlach, Michael P.; May, Jason T.; Hothem, Roger L.

2005-01-01

Mercury contamination from historical gold mines represents a potential risk to human health and the environment. This fact sheet provides background information on the use of mercury in historical gold mining and processing operations in California, with emphasis on historical hydraulic mining areas. It also describes results of recent USGS projects that address the potential risks associated with mercury contamination. Miners used mercury (quicksilver) to recover gold throughout the western United States. Gold deposits were either hardrock (lode, gold-quartz veins) or placer (alluvial, unconsolidated gravels). Underground methods (adits and shafts) were used to mine hardrock gold deposits. Hydraulic, drift, or dredging methods were used to mine the placer gold deposits. Mercury was used to enhance gold recovery in all the various types of mining operations; historical records indicate that more mercury was used and lost at hydraulic mines than at other types of mines. On the basis of USGS studies and other recent work, a better understanding is emerging of mercury distribution, ongoing transport, transformation processes, and the extent of biological uptake in areas affected by historical gold mining. This information has been used extensively by federal, state, and local agencies responsible for resource management and public health in California.

Composition and origin of Early Cambrian Tiantaishan phosphorite-Mn carbonate ores, Shaanxi Province, China

USGS Publications Warehouse

Hein, J.R.; Fan, D.; Ye, J.; Liu, T.; Yeh, H.-W.

1999-01-01

The Tiantaishan phosphorite-Mn carbonate ores occur in the Early Cambrian Tananpo Formation in complexly folded and faulted rocks located in southern Shaanxi Province. About 65 x 106 tonnes of 17% P2O5 ore reserves exist and Mn-ore reserves are about 8.3 x 106 tonnes of +18% Mn. The stratigraphic sequence in ascending order consists of black phyllite, black to gray phosphorite ore, black phyllite, rhodochrostone ore, Mn mixed-carbonates, and dolostone. Data are presented from microprobe mineral chemistry, whole-rock chemistry, stable isotopes of carbonates, X-ray mineralogy, petrographic and SEM observations, and statistical analysis of chemical data. The dominant ore-forming minerals are hydroxy- and carbonate fluorapatite and Ca rhodochrosite, with Mg kutnahorite and dolomite comprising the Mn mixed-carbonate section. Pyrite occurs in all rock types and alabandite (MnS) occurs throughout the rhodochrostone section. The mean P2O5 content of phosphorite is 31% and argillaceous phosphorite is 16%, while the mean MnO content of rhodochrostone ore is 37%. Phosphorite ores are massive, spheroidal, laminated, and banded, while rhodochrostone ores have oolitic, spheroidal, and granular fabrics. The most distinguishing characteristics of the ores are high total organic carbon (TOC) contents (mean 8.4%) in the phosphorite and high P2O5 contents (mean 2.7%) in the rhodochrostone ore. The atypically high TOC contents in the Tiantaishan phosphorite probably result from very strong productivity leading to high sedimentation rates accompanied by weak reworking of sediments; poor utilization of the organic matter by bacteria; and/or partial replacement of bacterial or algal mats by the apatite. The depositional setting of the ores was the margin of an epicontinental seaway created as a direct consequence of global processes that included break-up of a supercontinent, formation of narrow seaways, creation of extensive continental shelves, overturn of stagnant, metal-rich deep-ocean waters, and marine transgression. Water depth increased from deposition of the black phyllite sequence through deposition of the Mn mixed-carbonate sequence, then shallowed again during deposition of the overlying dolostone sequence. Bottom waters were mostly dysoxic to suboxic, but fluctuated from oxic to anoxic. Productivity was high during deposition of the black phyllite sequence, increased during precipitation of phosphorite, and then decreased to moderate levels during precipitation of rhodochrostone ores. Biosilica contributions occur in each lithology, but are greatest in rhodochrostone. Changes in sedimentation were determined by changes in water depth, productivity, upwelling, sea-level change, and ventilation of the depositional basin. The source of the phosphorus was organic matter produced in great quantities during deposition of the black phyllite and phosphorite sequences in a zone of coastal upwelling. Organic matter accumulation was rapid. Globally, Mn was supplied by overturn of stagnant, metal-rich deep-ocean waters, which were redistributed to areas of coastal upwelling and seaways; that process may have been initiated by latest Proterozoic glaciations which would have promoted density stratification and accumulation and storage of metals. Regionally, Mn was supplied by terrigenous input into the shallow seaway and hydrothermal input into the deeper water parts of that seaway. Locally, Mn sources included leaching and transport of metals from the sediment column. Manganese was stored locally in low-oxygen (not anoxic) seawater prior to Mn-ore formation. The source of the carbon in the Mn carbonates and dolostones was predominantly seawater bicarbonate and secondarily CO2 derived from the oxidation of organic matter in the bacterially mediated diagenetic zone of sulfate reduction.

Improving the engineering-and-economical performance of ore-thermal electric furnaces in the smelting of silicomanganese

NASA Astrophysics Data System (ADS)

Kondrashov, V. P.; Pogrebisskiy, M. Ya; Lykov, A. G.; Rabinovich, V. L.; Bulgakov, A. S.

2018-02-01

Ways of increase of ore-heating electric furnaces, used for production of silicomanganese, engineering-and-economical performance are analyzed. Questions of data of the electric, thermal and technological modes of the furnace functioning collecting and processing for use in operation of an advanced control system of the furnace providing increase in technical and economic efficiency of technological process and an adaptability to quality of burden stock are considered.

Scandium recovery from slags after oxidized nickel ore processing

NASA Astrophysics Data System (ADS)

Smyshlyaev, Denis; Botalov, Maxim; Bunkov, Grigory; Rychkov, Vladimir; Kirillov, Evgeny; Kirillov, Sergey; Semenishchev, Vladimir

2017-09-01

One of the possible sources of scandium production - waste (slags) from processing of oxidized nickel ores, has been considered in present research work. The hydrometallurgical method has been selected as the primary for scandium extraction. Different reagents for leaching of scandium, such as sulfuric acid, various carbonate salts and fluorides, have been tested. Sulfuric acid has been recognized as an optimal leaching reagent. Sulfuric acid concentration of 100 g L-1 allowed recovering up to 97 % of scandium.

Stream-Sediment Geochemistry in Mining-Impacted Drainages of the Yankee Fork of the Salmon River, Custer County, Idaho

USGS Publications Warehouse

Frost, Thomas P.; Box, Stephen E.

2009-01-01

This reconnaissance study was undertaken at the request of the USDA Forest Service, Region 4, to assess the geochemistry, in particular the mercury and selenium contents, of mining-impacted sediments in the Yankee Fork of the Salmon River in Custer County Idaho. The Yankee Fork has been the site of hard-rock and placer mining, primarily for gold and silver, starting in the 1880s. Major dredge placer mining from the 1930s to 1950s in the Yankee Fork disturbed about a 10-kilometer reach. Mercury was commonly used in early hard-rock mining and placer operations for amalgamation and recovery of gold. During the late 1970s, feasibility studies were done on cyanide-heap leach recovery of gold from low-grade ores of the Sunbeam and related deposits. In the mid-1990s a major open-pit bulk-vat leach operation was started at the Grouse Creek Mine. This operation shut down when gold values proved to be lower than expected. Mercury in stream sediments in the Yankee Fork ranges from below 0.02 ppm to 7 ppm, with the highest values associated with old mill locations and lode and placer mines. Selenium ranges from below the detection limit for this study of 0.2 ppm to 4 ppm in Yankee Fork sediment samples. The generally elevated selenium content in the sediment samples reflect the generally high selenium contents in the volcanic rocks that underlie the Yankee Fork and the presence of gold and silver selenides in some of the veins that were exploited in the early phases of mining.

Sources of Minor and Rare-Earth Elements in Hydrothermal Edifices of Near-Continental Rifts with Sedimentary Cover: Evidence from the Guaymas Basin, Southern Trough

NASA Astrophysics Data System (ADS)

Lein, A. Yu.; Dara, O. M.; Bogdanova, O. Yu.; Novikov, G. V.; Ulyanova, N. V.; Lisitsyn, A. P.

2018-03-01

The mineralogy and geochemistry of a fragment of an active hydrothermal edifice from the Hydrothermal Hill of the Southern Trough valley of the Guaymas Basin in the Gulf of California were studied. The sample was collected from a depth of 1995 m by the Pisces manned submersible on cruise 12 of the R/V Akademik Mstislav Keldysh, Institute of Oceanology, Russian Academy of Sciences. The fragment and the edifice itself consists of two accrete pipes: ore (pyrrhotite) and barren (carbonate) combined in a single edifice by an outer barite-opal zone. The ore edifice is located in the rift zone of the Guaymas Basin with a thick sedimentary cover and is depleted in metals in comparison with ores from rift zones of the open ocean, which are not blocked by sedimentary deposits. This is explained by loss of metals at the boundary between hot sills and sedimentary rocks and by the processes of interaction of hydrothermal solutions with sedimentary deposits. The sedimentary series faciitates long-term preservation of endogenous heat and the ore formation process. Ore edifices of the Guaymas Basin are mostly composed of pyrrhotite, have a specific set of major elements, microelements and REEs, and contain naphthenic hydrocarbons. They may be search signs of hidden polymetallic deposits, considered to be the roots of ore occurrences localized under the surface of the bottom in young active rifts with high spreading and sedimentation rates, i.e., in near-continental areas of rifts of the humid zone with avalanche sedimentation.

A multimodal microcharacterisation of trace-element zonation and crystallographic orientation in natural cassiterite by combining cathodoluminescence, EBSD, EPMA and contribution of confocal Raman-in-SEM imaging.

PubMed

Wille, G; Lerouge, C; Schmidt, U

2018-01-16

In cassiterite, tin is associated with metals (titanium, niobium, tantalum, indium, tungsten, iron, manganese, mercury). Knowledge of mineral chemistry and trace-element distribution is essential for: the understanding of ore formation, the exploration phase, the feasibility of ore treatment, and disposal/treatment of tailings after the exploitation phase. However, the availability of analytical methods make these characterisations difficult. We present a multitechnical approach to chemical and structural data that includes scanning electron microscopy (SEM)-based imaging and microanalysis techniques such as: secondary and backscattered electrons, cathodoluminescence (CL), electron probe microanalyser (EPMA), electron backscattered diffraction (EBSD) and confocal Raman-imaging integrated in a SEM (RISE). The presented results show the complementarity of the used analytical techniques. SEM, CL, EBSD, EPMA provide information from the interaction of an electron beam with minerals, leading to atomistic information about their composition, whereas RISE, Raman spectroscopy and imaging completes the studies with information about molecular vibrations, which are sensitive to structural modifications of the minerals. The correlation of Raman bands with the presence/absence of Nb, Ta, Fe (heterovalent substitution) and Ti (homovalent substitution) is established at a submicrometric scale. Combination of the different techniques makes it possible to establish a direct link between chemical and crystallographic data of cassiterite. © 2018 The Authors Journal of Microscopy © 2018 Royal Microscopical Society.

CATALYZED OXIDATION OF URANIUM IN CARBONATE SOLUTIONS

DOEpatents

Clifford, W.E.

1962-05-29

A process is given wherein carbonate solutions are employed to leach uranium from ores and the like containing lower valent uranium species by utilizing catalytic amounts of copper in the presence of ammonia therein and simultaneously supplying an oxidizing agent thereto. The catalysis accelerates rate of dissolution and increases recovery of uranium from the ore. (AEC)

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... underground, that produce uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent... leach process for the extraction of uranium or from mines and mills using in situ leach methods. The... Vanadium Ores Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L...

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... underground, that produce uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent... leach process for the extraction of uranium or from mines and mills using in situ leach methods. The... Vanadium Ores Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L...

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2014 CFR

2014-07-01

... underground, that produce uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent... leach process for the extraction of uranium or from mines and mills using in situ leach methods. The... Vanadium Ores Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L...

40 CFR 440.104 - New source performance standards (NSPS).

Code of Federal Regulations, 2014 CFR

2014-07-01

..., in-situ leach or vat-leach processes to extract copper from ores or ore waste materials. The Agency... provided in subpart L of this part any new source subject to this subsection must achieve the following... demonstrated technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines that...

40 CFR 440.104 - New source performance standards (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

..., in-situ leach or vat-leach processes to extract copper from ores or ore waste materials. The Agency... provided in subpart L of this part any new source subject to this subsection must achieve the following... demonstrated technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines that...

Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits

NASA Astrophysics Data System (ADS)

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly D.; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan; Borch, Thomas

2017-06-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (~58-89%) of U is bound as U(IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U(VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotope signatures, consistent with largely biotic reduction of U(VI) to U(IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U(IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.

Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits

PubMed Central

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly D.; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan; Borch, Thomas

2017-01-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (∼58-89%) of U is bound as U(IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U(VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotope signatures, consistent with largely biotic reduction of U(VI) to U(IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U(IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment. PMID:28569759

Biogenic non-crystalline U (IV) revealed as major component in uranium ore deposits

DOE PAGES

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly D.; ...

2017-06-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U (VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U (IV) generated through biologically mediated U (VI) reduction is the predominant U (IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (~58-89%) of U is bound as U (IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U (VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotopemore » signatures, consistent with largely biotic reduction of U (VI) to U (IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U (IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.« less

Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits.

PubMed

Bhattacharyya, Amrita; Campbell, Kate M; Kelly, Shelly D; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan; Borch, Thomas

2017-06-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U (VI) ) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U (IV)  generated through biologically mediated U (VI)  reduction is the predominant U (IV)  species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (∼58-89%) of U is bound as U (IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U (VI) represent only minor components. The uranium deposit exhibited mostly 238 U-enriched isotope signatures, consistent with largely biotic reduction of U (VI) to U (IV) . This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U (IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.

Biogenic non-crystalline U (IV) revealed as major component in uranium ore deposits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly D.

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U (VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U (IV) generated through biologically mediated U (VI) reduction is the predominant U (IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (~58-89%) of U is bound as U (IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U (VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotopemore » signatures, consistent with largely biotic reduction of U (VI) to U (IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U (IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.« less

Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits

USGS Publications Warehouse

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan; Borch, Thomas

2017-01-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (∼58-89%) of U is bound as U(IV)to C-containing organic functional groups or inorganic carbonate, while uraninite and U(VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotope signatures, consistent with largely biotic reduction of U(VI) to U(IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U(IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.

A study of bauxite tailing quality improvement by reverse flotation

NASA Astrophysics Data System (ADS)

Wulandari, W.; Purwasasmita, M.; Sanwani, E.; Malatsih, W.; Fadilla, F.

2018-01-01

The pre-treatment of bauxite ore from Tayan, West Kalimantan includes washing and screening fine bauxite particles (-2mm) prior as the feed to the Bayer process for producing alumina. These fine particles are believed to have high content of silica which is detrimental to the process. This washed bauxite tailing still has a significant amount of alumina content. Previous research has indicated that bauxite ore can be upgraded by applying reverse flotation method to reduce its silica content in the ore. Therefore, this study is aimed to utilize reverse flotation method to recover alumina content from washed bauxite tailing. The reverse flotation experiments were carried out at pH of 6 and 8; while the particle sizes were varied at - 140+270 mesh and -270 mesh, using a batch and circuit configuration. The result of this study shows that the batch reverse flotation can recover alumina in the tailing up to 81.4%, however the silica content is still significant. The complexity of silica-alumina minerals in the tailing prevents a complete separation of the ores by only using reverse flotation.

Porphyry-copper ore shells form at stable pressure-temperature fronts within dynamic fluid plumes.

PubMed

Weis, P; Driesner, T; Heinrich, C A

2012-12-21

Porphyry-type ore deposits are major resources of copper and gold, precipitated from fluids expelled by crustal magma chambers. The metals are typically concentrated in confined ore shells within vertically extensive vein networks, formed through hydraulic fracturing of rock by ascending fluids. Numerical modeling shows that dynamic permeability responses to magmatic fluid expulsion can stabilize a front of metal precipitation at the boundary between lithostatically pressured up-flow of hot magmatic fluids and hydrostatically pressured convection of cooler meteoric fluids. The balance between focused heat advection and lateral cooling controls the most important economic characteristics, including size, shape, and ore grade. This self-sustaining process may extend to epithermal gold deposits, venting at active volcanoes, and regions with the potential for geothermal energy production.

Porphyry-Copper Ore Shells Form at Stable Pressure-Temperature Fronts Within Dynamic Fluid Plumes

NASA Astrophysics Data System (ADS)

Weis, P.; Driesner, T.; Heinrich, C. A.

2012-12-01

Porphyry-type ore deposits are major resources of copper and gold, precipitated from fluids expelled by crustal magma chambers. The metals are typically concentrated in confined ore shells within vertically extensive vein networks, formed through hydraulic fracturing of rock by ascending fluids. Numerical modeling shows that dynamic permeability responses to magmatic fluid expulsion can stabilize a front of metal precipitation at the boundary between lithostatically pressured up-flow of hot magmatic fluids and hydrostatically pressured convection of cooler meteoric fluids. The balance between focused heat advection and lateral cooling controls the most important economic characteristics, including size, shape, and ore grade. This self-sustaining process may extend to epithermal gold deposits, venting at active volcanoes, and regions with the potential for geothermal energy production.

Environmental and human exposure assessment monitoring of communities near an abandoned mercury mine in the Philippines: a toxic legacy.

PubMed

Maramba, Nelia P C; Reyes, Jose Paciano; Francisco-Rivera, Ana Trinidad; Panganiban, Lynn Crisanta R; Dioquino, Carissa; Dando, Nerissa; Timbang, Rene; Akagi, Hirokatsu; Castillo, Ma Teresa; Quitoriano, Carmela; Afuang, Maredith; Matsuyama, Akito; Eguchi, Tomomi; Fuchigami, Youko

2006-10-01

Abandoned mines are an important global concern and continue to pose real or potential threats to human safety and health including environmental damage/s. Very few countries had government mine regulation and reclamation policies until the latter part of the century where legal, financial and technical procedures were required for existing mining operations. Major reasons for mine closure may be mainly due to poor economies of the commodity making mining unprofitable, technical difficulties and national security. If the mine is abandoned, more often than not it is the government that shoulders the burden of clean-up, monitoring and remediation. The topic of abandoned mines is complex because of the associated financial and legal liability implications. Abandoned mercury mines have been identified as one of the major concerns because of their significant long-term environmental problems. Primary mercury production is still ongoing in Spain, Kyrgzystan, China, Algeria, Russia and Slovakia while world production declined substantially in the late 1980s. In the Philippines, the mercury mine located southeast of Manila was in operation from 1955 to 1976, before ceasing operation because of the decline in world market price for the commodity. During this time, annual production of mercury was estimated to be about 140,000 kg of mercury yearly. Approximately 2,000,000 t of mine-waste calcines (retorted ore) were produced during mining and roughly 1,000,000 t of these calcines were dumped into nearby Honda Bay to construct a jetty to facilitate mine operations where about 2000 people reside in the nearby three barangays. In October, 1994 the Department of Health received a request from the Provincial Health Office for technical assistance relative to the investigation of increasing complaints of unusual symptoms (e.g. miscarriages, tooth loss, muscle weakness, paralysis, anemia, tremors, etc.) among residents of three barangays. Initial health reports revealed significant elevation of blood mercury levels exceeding the then recommended exposure level of 20ppb in 12 out of the 43 (27.9%) residents examined. The majority of the volunteers were former mine workers. In this study the abnormal findings included gingivitis, mercury lines, gum bleeding and pterydium. The most common neurologic complaints were numbness, weakness, tremors and incoordination. Anemia and elevated liver function tests were also seen in a majority of those examined. The assessment also revealed a probable association between blood mercury level and eosinophilia. The same association was also seen between high mercury levels and the presence of tremors and working in the mercury mine. To date, there are very limited environmental and health studies on the impact of both total and methylmercury that have been undertaken in the Philippines. Thus, this area of study was selected primarily because of its importance as an emerging issue in the country, especially regarding the combined effects of total and methylmercury low-dose and continuous uptake from environmental sources. At present the effects of total mercury exposure combined with MeHg consumption remain an important issue, especially those of low-dose and continuous uptake. Results of the study showed that four (4) species of fish, namely ibis, tabas, lapu-lapu and torsillo, had exceeded the recommended total mercury and methylmercury levels in fish (NV>0.5 microg/gf.w., NV>0.3 microg/gf.w., respectively). Saging and kanuping also exceeded the permissible levels for methylmercury. Total and methylmercury in canned fish, and total mercury in rice, ambient air and drinking water were within the recommended levels, however, additional mercury load from these sources may contribute to the over-all body burden of mercury among residents in the area. Surface water quality at the mining area, Honda Bay and during some monitoring periods at Palawan Bay exceeded total mercury standards (NV>0.002 ng/mL). Soil samples in two sites, namely Tagburos and Honda Bay, exceeded the EPA Region 9 Primary Remediation Goal recommended values for total mercury for residential purposes (NV>23 mg/kg). The hand to mouth activity among infants and children is another significant route for mercury exposure. Statistically significant results were obtained for infants when comparing the results after one year of monitoring for methylmercury levels in hair for both exposed and control sub-groups. Likewise, comparing the initial and final hair methylmercury levels among pregnant women/mothers in the exposed group showed statistically significant (p<0.05) results. Comparing the exposed and control sub-groups' mercury hair levels per sub-group showed statistically significant results among the following: (a) initial and final total mercury hair levels among children, (b) initial and final methylmercury hair levels among children, (c) final total mercury hair levels among pregnant women, (d) initial and final total mercury hair levels among mothers, and (e) initial and final methyl hair levels among mothers.

Process for treating alkaline wastes for vitrification

DOEpatents

Hsu, Chia-lin W.

1994-01-01

According to its major aspects and broadly stated, the present invention is a process for treating alkaline waste materials, including high level radioactive wastes, for vitrification. The process involves adjusting the pH of the wastes with nitric acid, adding formic acid (or a process stream containing formic acid) to reduce mercury compounds to elemental mercury and MnO{sub 2} to the Mn(II) ion, and mixing with class formers to produce a melter feed. The process minimizes production of hydrogen due to noble metal-catalyzed formic acid decomposition during, treatment, while producing a redox-balanced feed for effective melter operation and a quality glass product. An important feature of the present invention is the use of different acidifying and reducing, agents to treat the wastes. The nitric acid acidifies the wastes to improve yield stress and supplies acid for various reactions; then the formic acid reduces mercury compounds to elemental mercury and MnO{sub 2}) to the Mn(II) ion. When the pH of the waste is lower, reduction of mercury compounds and MnO{sub 2}) is faster and less formic acid is needed, and the production of hydrogen caused by catalytically-active noble metals is decreased.

Ore genesis dating: implication of Sm-Nd method using sulfide minerals for mafic-ultramafic layered intrusions of Fennoscandian Shield

NASA Astrophysics Data System (ADS)

Serov, Pavel; Bayanova, Tamara; Steshenko, Ekaterina; Ekimova, Nadezhda

2015-04-01

The main method of dating the ore process was the Re-Os method of sulfides (Luck, Allegre, 1983; Walker et. al., 1991). However, studies of Re-Os systematics of sulfide minerals do not always give the correct ages and showing the disturbances of the Re-Os systematics. At the same time, Sm-Nd age of sulfides in good agreement with the U-Pb dating on zircon and baddeleyite and suggests that the Sm-Nd system of sulfides is more resistant to secondary alteration processes. Our studies have shown that along with rock-forming, ore minerals (sulfides) can be used to determine the ore genesis time of industrially important geological sites, since exactly with the sulfides the industry Pt-Pd mineralization is closely connected. In to Sm-Nd measurements steadily introduce new minerals-geochronometers (i.e. titanite, burbancite, eudialite etc.). Of these, sulfides of PGE-bearing layered intrusions are quite important in terms of dating the process of ore origin. Studying the REE distribution in the sulfides of MOR hydrothermal sources has shown possible REE presence in the sulfide lattice (Rimskaya-Korsakova et. al., 2003). These are difficult to carry out because the concentrations of Sm and Nd isotopes in sulfides are much lower than those in chondrites (Rimskaya-Korsakova et. al., 2003). In (Kong et. al., 2000) sulfides from two metamorphosed chondrites were studied by instrumental neutron activation analysis (INAA) and ion probe. As shown, the level of REE in the sulfide phase determined by the ion probe is quite similar to that obtained by INAA. Although the concentrations of REE in the enstatite and the Fe, Si, Cr-rich inclusions are comparable to those in sulfide, estimates based on mass balance calculations show that the silicate inclusions would not noticeably contribute to the REE budget in sulfides (Kong et. al., 2000). For the first time in Russian geochemistry laboratories using sulfide and rock-forming minerals and WR in Sm-Nd method have been dated impregnated and brecciform ores of the following objects - Pilguyarvi Cu-Ni deposits, Pechenga (1965±87 Ma); impregnated (2433±83 Ma) and redeposited (1903±24 Ma) ores of Ahmavaara intrusion (Finland); Kolvitsa massif metagabbro (1990±92 Ma, which reflect the age of Sm-Nd system closure in sulfide minerals); olivine orthopyroxenites of Sopcha 'Ore bed' (2442±59 Ma); ore gabbronorites of Penikat PGE-bearing layered intrusion (2426±38 Ma (Ekimova et.al., 2011); Pt-Pd gabbro-pegmatite ores (2476± 41 Ma, which agrees well with the U-Pb zircon age - 2470±9 Ma (Bayanova, 2004) and gabbronorites (2483±86 Ma) of PGE Kievey deposit and Fedorova Tundra metagabbroids (2494±54 Ma); Monchetundra gabbronorites - 2489±49 Ma. All investigations are devoted to memory of academician RAS, professor F. Mitrofanov (Russia), he was a leader of scientific school for geology, geochemistry and metallogenesis of ore deposits. The studies were supported by the RFBR 13-05-00493, OFI-M 13-05-12055, Department of Earth Sciences RAS (programs 2 and 4), IGCP-599.

Evidence of mercury trapping in biofilm-EPS and mer operon-based volatilization of inorganic mercury in a marine bacterium Bacillus cereus BW-201B.

PubMed

Dash, Hirak R; Basu, Subham; Das, Surajit

2017-04-01

Biofilm-forming mercury-resistant marine bacterium Bacillus cereus BW-201B has been explored to evident that the bacterial biofilm-EPS (exopolymers) trap inorganic mercury but subsequently release EPS-bound mercury for induction of mer operon-mediated volatilization of inorganic mercury. The isolate was able to tolerate 50 ppm of mercury and forms biofilm in presence of mercury. mer operon-mediated volatilization was confirmed, and -SH was found to be the key functional group of bacterial EPS responsible for mercury binding. Biofilm-EPS-bound mercury was found to be internalized to the bacterial system as confirmed by reversible conformational change of -SH group and increased expression level of merA gene in a timescale experiment. Biofilm-EPS trapped Hg after 24 h of incubation, and by 96 h, the volatilization process reaches to its optimum confirming the internalization of EPS-bound mercury to the bacterial cells. Biofilm disintegration at the same time corroborates the results.

Environmental Mercury and Its Toxic Effects

PubMed Central

Rice, Kevin M.; Walker, Ernest M.; Wu, Miaozong; Gillette, Chris

2014-01-01

Mercury exists naturally and as a man-made contaminant. The release of processed mercury can lead to a progressive increase in the amount of atmospheric mercury, which enters the atmospheric-soil-water distribution cycles where it can remain in circulation for years. Mercury poisoning is the result of exposure to mercury or mercury compounds resulting in various toxic effects depend on its chemical form and route of exposure. The major route of human exposure to methylmercury (MeHg) is largely through eating contaminated fish, seafood, and wildlife which have been exposed to mercury through ingestion of contaminated lower organisms. MeHg toxicity is associated with nervous system damage in adults and impaired neurological development in infants and children. Ingested mercury may undergo bioaccumulation leading to progressive increases in body burdens. This review addresses the systemic pathophysiology of individual organ systems associated with mercury poisoning. Mercury has profound cellular, cardiovascular, hematological, pulmonary, renal, immunological, neurological, endocrine, reproductive, and embryonic toxicological effects. PMID:24744824

New understanding on separation of Mn and Fe from ferruginous manganese ores by the magnetic reduction roasting process

NASA Astrophysics Data System (ADS)

Liu, Bingbing; Zhang, Yuanbo; Wang, Juan; Wang, Jia; Su, Zijian; Li, Guanghui; Jiang, Tao

2018-06-01

Magnetic reduction roasting followed by magnetic separation process is reported as a simple route to realize separation of Mn and Fe from ferruginous manganese ores (Fe-Mn ores). However, the separation and recovery of Mn and Fe oxides are not very effective. This work clarified the underlying reason for the poor separation and also proposed some suggestions for the magnetic reduction process. In this work, the effect of temperature on the magnetic reduction roasting - magnetic separation of Fe-Mn ore was investigated firstly. Then the reduction behaviors of MnO2-Fe2O3 system and MnO2-Fe2O3-10 wt.%SiO2 system under 10 vol.% CO-90 vol.% CO2 at 600-1000 °C were investigated by XRD, XPS, SEM-EDS, VSM, DSC and thermodynamics analyses. Reduction and separation tests showed that higher reduction temperature was beneficial to the recovery of iron while it's not in favor of the recovery of manganese when the temperature was over 800 °C. The formation of composite oxide MnxFe3-xO4 with strong magnetism between the interface of the MnO2 and Fe2O3 particles leaded to the poor separation of iron and manganese. In addition, the formation mechanism of MnxFe3-xO4 from MnO2 and Fe2O3 as well as the interface reaction reduced under 10 vol.% CO was discussed in this study. Finally, some suggestions were recommended for the magnetic reduction roasting for utilizing the Fe-Mn ores effectively.

Reducing acid leaching of manganiferous ore: effect of the iron removal operation on solid waste disposal.

PubMed

De Michelis, Ida; Ferella, Francesco; Beolchini, Francesca; Vegliò, Francesco

2009-01-01

The process of reducing acid leaching of manganiferous ore is aimed at the extraction of manganese from low grade manganese ores. This work is focused on the iron removal operation. The following items have been considered in order to investigate the effect of the main operating conditions on solid waste disposal and on the process costs: (i) type and quantity of the base agent used for iron precipitation, (ii) effective need of leaching waste separation prior to the iron removal operation, (iii) presence of a second leaching stage with the roasted ore, which might also act as a preliminary iron removal step, and (iv) effect of tailings washing on the solid waste classification. Different base compounds have been tested, including CaO, CaCO3, NaOH, and Na2CO3. The latter gave the best results concerning both the precipitation process kinetics and the reagent consumption. The filtration of the liquor leach prior to iron removal was not necessary, implying significant savings in capital costs. A reduction of chemical consumption and an increase of manganese concentration in the solution were obtained by introducing secondary leaching tests with the previously roasted ore; this additional step was introduced without a significant decrease of global manganese extraction yield. Finally, toxicity characteristic leaching procedure (TCLP) tests carried out on the leaching solid waste showed: (i) a reduction of arsenic mobility in the presence of iron precipitates, and (ii) the need for a washing step in order to produce a waste that is classifiable as not dangerous, taking into consideration the existing Environmental National Laws.

Mercury's Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroidal Space Weathering Studies

NASA Technical Reports Server (NTRS)

Domingue, Deborah L.; Chapman, Clark. R.; Killen, Rosemary M.; Zurbuchen, Thomas H.; Gilbert, Jason A.; Sarantos, Menelaos; Benna, Mehdi; Slavin, James A.; Schriver, David; Travnicek, Pavel M.;

A fluidized bed desorption system for recycling mercury from contaminated soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harriss, C.; Baum, D.L. Jr.; Read, W.L.

1995-12-31

The land disposal restrictions effective for wastes containing mercury have created a need for technologies that can meet the best demonstrated available technologies (BDAT) treatment standards. In the past, technologies for mercury were in short supply. In addition to the already existing short supply, the natural gas industry has begun to remediate the numerous metering sites that have been contaminated with mercury from manometers installed along their pipelines. To meet the need for a mercury technology, Philip Environmental Services Corporation (Philip) evaluated and tested two different technologies capable of recovering mercury from contaminated soil. Philip initially performed some tests usingmore » gravitational methods followed by pilot-scale testing using a fluidized bed desorber. As a result of the testing, Philip constructed a full-scale fluidized bed system which can recover mercury from contaminated soil and debris. The name of Philip`s technology is the Solvating Vapor Pressure Process (SVPP). The main purpose of this paper is to discuss the results of the SVPP pilot testing and describe the process.« less

Stabilization process of metallic mercury by sulphur

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vaudey, Claire-Emilie; Bardy, Maud; Huc, Christelle

2013-07-01

The technical field of this subject can be described as the treatment of mercury based wastes in order to stock or eliminate them. Toxic mercury vapours prevent from directly stocking or incinerating the wastes. Therefore, some processes have already been implemented to reduce the mercury mobility. Those immobilization processes are created to avoid mercury release in the atmosphere by volatilization or in the soil by leaching. Among the 3 current processes: encapsulation, amalgamation and stabilization, we took an interest on the last one. Stabilization can be defined as an immobilization due to a combination between a molecule and motionless particlesmore » to reduce the release of dangerous elements in the atmosphere or the biosphere. The most common technique of metallic mercury stabilization found in readings is the sulphur amalgamation technique. It consists in the chemical reaction: Hg + S → HgS. A mercury sulphide is then produced and is very insoluble in the water. A 386 deg. C heating transforms it in red sulphide. The obtained mixture can be easily and safely stored in a waste storage. In this context, solid sulphur is added in wide excess compared to the liquid mercury to cause the reaction: Hg(l) + S(s) → HgS(s) with a molar ratio between 1/6.5 and 1/19. The main drawback of this technique is the generation of an important waste quantity: a mixture of HgS and sulphur. Moreover there's no guarantee about the absence of mercury vapours. Therefore there's a real need to improve the ratio and the safety of the reaction, which is the purpose of this study. The volume of the created product is greatly reduced in this case and authorizes significant savings on storage costs. The other experimental parameters discussed in this study are temperature, volume, flask type and mixing speed. (authors)« less

Implementation of flowsheet change to minimize hydrogen and ammonia generation during chemical processing of high level waste in the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, Dan P.; Woodham, Wesley H.; Williams, Matthew S.

Testing was completed to develop a chemical processing flowsheet for the Defense Waste Processing Facility (DWPF), designed to vitrify and stabilize high level radioactive waste. DWPF processing uses a reducing acid (formic acid) and an oxidizing acid (nitric acid) to rheologically thin the slurry and complete the necessary acid base and reduction reactions (primarily mercury and manganese). Formic acid reduces mercuric oxide to elemental mercury, allowing the mercury to be removed during the boiling phase of processing through steam stripping. In runs with active catalysts, formic acid can decompose to hydrogen and nitrate can be reduced to ammonia, both flammablemore » gases, due to rhodium and ruthenium catalysis. Replacement of formic acid with glycolic acid eliminates the generation of rhodium- and ruthenium-catalyzed hydrogen and ammonia. In addition, mercury reduction is still effective with glycolic acid. Hydrogen, ammonia and mercury are discussed in the body of the report. Ten abbreviated tests were completed to develop the operating window for implementation of the flowsheet and determine the impact of changes in acid stoichiometry and the blend of nitric and glycolic acid as it impacts various processing variables over a wide processing region. Three full-length 4-L lab-scale simulations demonstrated the viability of the flowsheet under planned operating conditions. The flowsheet is planned for implementation in early 2017.« less

Mechanism of sodium chloride in promoting reduction of high-magnesium low-nickel oxide ore

PubMed Central

Zhou, Shiwei; Wei, Yonggang; Li, Bo; Wang, Hua; Ma, Baozhong; Wang, Chengyan

2016-01-01

Sodium chloride has been proved that it is an effective promoter for the reduction of high-magnesium, low-nickel oxide ore. The aim of current work is to clarify the promotion behavior of sodium chloride in the roasting reduction process. The influence of moisture on the reduction of ore in the presence of sodium chloride is studied to get clear comprehension of promotion process. In the presence of moisture, the HCl is produced by pyrohydrolysis of sodium chloride for chlorinating nickel and iron oxides, moreover, interactions between metallic oxides and sodium chloride are also a way for chlorination at high temperature (>802 °C); subsequently, the metal chloride would be reduced by reductant. In the absence of moisture, the magnetic separation results show that the recoveries of iron and nickel have a significant increase; moreover, olivine structure would be destroyed gradually with the increase of roasting temperature in the action of sodium chloride, and the sodium chloride existed in high-magnesium, low-nickel oxide ore could make the NiO isolate from NiO-bearing minerals. The NiO reacts with Fe2O3 at high temperature to form NiFe2O4, which is conductive to the formation of Ni-Fe alloy during the reduction process. PMID:27374991

Mechanism of sodium chloride in promoting reduction of high-magnesium low-nickel oxide ore.

PubMed

Zhou, Shiwei; Wei, Yonggang; Li, Bo; Wang, Hua; Ma, Baozhong; Wang, Chengyan

2016-07-04

Sodium chloride has been proved that it is an effective promoter for the reduction of high-magnesium, low-nickel oxide ore. The aim of current work is to clarify the promotion behavior of sodium chloride in the roasting reduction process. The influence of moisture on the reduction of ore in the presence of sodium chloride is studied to get clear comprehension of promotion process. In the presence of moisture, the HCl is produced by pyrohydrolysis of sodium chloride for chlorinating nickel and iron oxides, moreover, interactions between metallic oxides and sodium chloride are also a way for chlorination at high temperature (>802 °C); subsequently, the metal chloride would be reduced by reductant. In the absence of moisture, the magnetic separation results show that the recoveries of iron and nickel have a significant increase; moreover, olivine structure would be destroyed gradually with the increase of roasting temperature in the action of sodium chloride, and the sodium chloride existed in high-magnesium, low-nickel oxide ore could make the NiO isolate from NiO-bearing minerals. The NiO reacts with Fe2O3 at high temperature to form NiFe2O4, which is conductive to the formation of Ni-Fe alloy during the reduction process.

Internal structures and dating of non-sulphide Zn deposits using rock magnetism: insights from the Moroccan High Atlas

NASA Astrophysics Data System (ADS)

Charles, Nicolas; Choulet, Flavien; Sizaret, Stanislas; Chen, Yan; Barbanson, Luc; Ennaciri, Aomar; Badra, Lakhlifi; Branquet, Yannick

2016-01-01

The renewal of interest in Zn-Pb non-sulphide ores has been induced by mineral processing improvement and leads to new exploration and mining projects in the world. Although the mineralogy is often precisely known, and despite several studies linking ore deposition to regional tectonics, absolute dating of non-sulphide stages is rare and structure of ore bodies was largely disregarded. Geochronological data from non-sulphide ores are essential to timely constrain alteration episodes and to insert supergene ore genesis in the climate and tectonic evolution of the metallogenic province. The access to internal organization of ore could reveal post-mineralization episodes related to supergene evolution. Thus, a rock magnetism study combining anisotropy of magnetic susceptibility (AMS) and palaeomagnetism was performed on four non-sulphide deposits from the Moroccan High Atlas. AMS generally shows similar horizontal magnetic fabrics for ores and the clayey and carbonaceous internal sediments filling karstic cavities. The palaeomagnetic directions of ores and internal sediments are compatible, and the calculated poles are consistent with the last 30 Ma of the Africa apparent polar wander path, with an upper age at 0.78 Ma. The proposed three-step scenario is placed within the evolution of the Moroccan High Atlas belt. Deposition of primary sulphides is contemporaneous with opening of the Tethyan and Atlantic oceans. During the Tertiary, intracontinental deformation gave rise to the High Atlas fold-and-thrust belt and to regional uplift. Finally, Zn-Pb sulphides hosted in carbonates experienced oxidation under an arid climate to form karst-related Zn-Pb non-sulphide ores. These promising results pave the way for an efficient method to constrain the internal fabrics and age of Zn supergene deposits.

Restructuring the Uranium Mining Industry in Romania: Actual Situation and Prospects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Georgescu, P.D.; Petrescu, S.T.; Iuhas, T.F.

2002-07-01

Uranium prospecting in Romania has started some 50 years ago, when a bilateral agreement between Romania and the former Soviet Union had been concluded and a joint Romanian-Soviet enterprise was created. The production started in 1952 by the opening of some deposits from western Transylvania (Bihor and Ciudanovita). From 1962 the production has continued only with Romanian participation on the ore deposit Avram Iancu and from 1985 on the deposits from Eastern Carpathians (Crucea and Botusana). Starting with 1978 the extracted ores have been completely processed in the Uranium Ore Processing Plant from Feldioara, Brasov. Complying with the initial stipulationsmore » of the Nuclear National Program launched at the beginning of the 1980's, the construction of a nuclear power station in Cernavoda has started in Romania, using natural uranium and heavy water (CANDU type), having five units of 650 MW installed capacity. After 1989 this initial Nuclear National Program was revised and the construction of the first unit (number 1) was finalized and put in operation in 1996. In 2001 the works at the unit number 2 were resumed, having the year 2005 as the scheduled activating date. The future of the other 3 units, being in different construction phases, hasn't been clearly decided. Taking into consideration the exhaustion degree of some ore deposits and from the prospect of exploiting other ore deposits, the uranium industry will be subject of an ample restructuring process. This process includes workings of modernization of the mines in operation and of the processing plant, increasing the profitableness, lowering of the production costs by closing out and ecological rehabilitation of some areas affected by mining works and even new openings of some uraniferous exploitations. This paper presents the actual situation and the prospects of uranium mining industry on the base of some new technical and economical strategic concepts in accordance with the actual Romanian Program for Nuclear Energetics. (authors)« less

Application of Odor Sensors to Ore Sorting and Mill Feed Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael G. Nelson

2005-08-01

Control of the feed provided to mineral processing facilities is a continuing challenge. Much effort is currently being devoted to overcoming these problems. These projects are usually described under the general headings of Mine-to-Mill Integration or Mine-Mill Optimization. It should be possible to combine the knowledge of ore type, mineralogy, and other characteristics (located in the mine modeling system), with the advanced capabilities of state-of-the-art mill control systems, to achieve an improved level of control in mineral processing that will allow optimization of the mill processes on an almost real-time basis. This is not happening because mill feed it ismore » often treated as a uniform material, when in reality it varies in composition and characteristics. An investigation was conducted to assess the suitability of odor sensors for maintaining traceability in ore production and processing. Commercially available sensors are now used in food processing, environmental monitoring, and other applications and can detect the presence of very small amounts (0.1-500 ppm) of some molecules. An assortment of such molecules could be used to ''tag'' blocks of ore as they are mined, according to their respective characteristics. Then, as the ore came into the mill, an array of ''electronic noses'' could be used to assess its characteristics in real time. It was found that the Cyranose 320{trademark}, a commercially available odor sensor, can easily distinguish among samples of rock marked with almond, cinnamon, citronella, lemon, and orange oils. Further, the sensor could detect mixtures of rocks marked with various combinations of these oils. Treatment of mixtures of galena and silica with odorant compounds showed no detrimental effects on flotation response in laboratory tests. Additional work is recommended to determine how this concept can be extended to the marking of large volumes of materials.« less

Copper Deposits in Sedimentary and Volcanogenic Rocks

USGS Publications Warehouse

Tourtelot, Elizabeth B.; Vine, James David

1976-01-01

Copper deposits occur in sedimentary and volcanogenic rocks within a wide variety of geologic environments where there may be little or no evidence of hydrothermal alteration. Some deposits may be hypogene and have a deep-seated source for the ore fluids, but because of rapid cooling and dilution during syngenetic deposition on the ocean floor, the resulting deposits are not associated with hydrothermal alteration. Many of these deposits are formed at or near major tectonic features on the Earth's crust, including plate boundaries, rift valleys, and island arcs. The resulting ore bodies may be stratabound and either massive or disseminated. Other deposits form in rocks deposited in shallow-marine, deltaic, and nonmarine environments by the movement and reaction of interstratal brines whose metal content is derived from buried sedimentary and volcanic rocks. Some of the world's largest copper deposits were probably formed in this manner. This process we regard as diagenetic, but some would regard it as syngenetic, if the ore metals are derived from disseminated metal in the host-rock sequence, and others would regard the process as epigenetic, if there is demonstrable evidence of ore cutting across bedding. Because the oxidation associated with diagenetic red beds releases copper to ground-water solutions, red rocks and copper deposits are commonly associated. However, the ultimate size, shape, and mineral zoning of a deposit result from local conditions at the site of deposition - a logjam in fluvial channel sandstone may result in an irregular tabular body of limited size; a petroleum-water interface in an oil pool may result in a copper deposit limited by the size and shape of the petroleum reservoir; a persistent thin bed of black shale may result in a copper deposit the size and shape of that single bed. The process of supergene enrichment has been largely overlooked in descriptions of copper deposits in sedimentary rocks. However, supergene processes may be involved during erosion of any primary ore body and its ultimate displacement and redeposition as a secondary deposit. Bleached sandstone at the surface may indicate significant ore deposits near the water table.

40 CFR 421.206 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Mercury Subcategory... wastewater pollutants in secondary mercury process wastewater introduced into a POTW shall not exceed the following values: (a) Spent battery electrolyte. PSNS for the Secondary Mercury Subcategory Pollutant or...

40 CFR 421.206 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Mercury Subcategory... wastewater pollutants in secondary mercury process wastewater introduced into a POTW shall not exceed the following values: (a) Spent battery electrolyte. PSNS for the Secondary Mercury Subcategory Pollutant or...

40 CFR 421.206 - Pretreatment standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Mercury Subcategory... wastewater pollutants in secondary mercury process wastewater introduced into a POTW shall not exceed the following values: (a) Spent battery electrolyte. PSNS for the Secondary Mercury Subcategory Pollutant or...

40 CFR 421.206 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Secondary Mercury Subcategory... wastewater pollutants in secondary mercury process wastewater introduced into a POTW shall not exceed the following values: (a) Spent battery electrolyte. PSNS for the Secondary Mercury Subcategory Pollutant or...

CLEAR SKIES INITIATIVE: RGM DRY DEPOSITION RESEARCH

EPA Science Inventory

Excessive levels of mercury in the nations waters are the most widespread cause of water quality impairment in the US. Atmospheric emissions and deposition processes drive mercury accumulation in soils and sediments, and are now recognized as the major route of mercury contamina...

New data on the substantial composition of Kalba rare metal deposits

NASA Astrophysics Data System (ADS)

Oitseva, T. A.; Dyachkov, B. A.; Vladimirov, A. G.; Kuzmina, O. N.; Ageeva, O. V.

2017-12-01

Geotectonic position, features of the geological structure and rare metal specialization of the Kalba-Narym granitoid belt formed in the Hercynian cycle in the postcollision (orogenic) geodynamic situation are considered. A geological-genetic model for the formation of the leading type of rare-metal pegmatite deposits (Ta, Nb, Be, Li, etc.) is presented. They are spatially and genetically related mainly to the granitoids of the 1st phase of the Kalba complex, P1 (Bakennoye, Jubilee, Belaya Gora, etc.). The rhythmically pulsating orientation of the process of pegmatite formation with the introduction of ore-bearing fluids (H2O, F, B, Cl, Ta, Nb, Be, etc.) is emphasized from the intracamera focus of a semi-closed magmatic system. The preferred location of ore pegmatite veins in granitoids of moderate basicity occupying an intermediate position in the petrochemical composition between normal granites and granodiorites geochemically specialized in Li, Rb, Cs, Sn, Nb, Ta. The leading ore-controlling role of the latitudinal deep faults of the ancient site in the distribution of rare-metal ore fields and deposits (Ognevsk-Bakennoye, Asubulak, Belogorsk, etc.) is determined. There is a zonal structure of pegmatite veins, a gradual development of mineral complexes from the graphic and oligoclase-microcline (non-ore) to microcline-albite and color albite-spodumene (ore). The mineralization of pegmatite veins is determined by the degree of intensity of the manifestation in them of metasomatic processes (microclinization, alibitization, greisenization, spodumenization, tourmalinization, etc.) and the identification of the main ore minerals (tantalite-columbite, cassiterite, spodumene and beryl). The diversity of the material composition of rare-metal pegmatites containing many unique minerals (cleavelandite, lepidolite, ambligonite, color tourmaline, spodumene, pollucite, etc.) is reflected, which brings them closer to the pegmatite deposits of foreign countries (Koktogai, Bernik Lake, etc.). New results of the investigation of the material composition of ore-bearing granites, pegmatites and typomorphic minerals using electron microscopy reflecting the distribution of rare-earth, rare-metal, chalcophile and other elements in them are presented. Indicators of rare metal ore formation are rock-forming minerals of granites (quartz, microcline, biotite, muscovite), ore and associated minerals (cleavelandite, lepidolite, cassiterite, etc.). The most informative minerals include mica (muscovite, giltbertite, lepidolite), colored tourmalines and beryls of different composition and color. Identified typomorphic minerals and geochemical elements-indicators of rare metal pegmatite formation are considered as a leading search criterion in assessing the prospects of the territory of East Kazakhstan.

Mercury distribution in ancient and modern sediment of northeastern Bering Sea

USGS Publications Warehouse

Nelson, C.H.; Pierce, D.E.; Leong, K.W.; Wang, F.F.H.

1975-01-01

Reconnaissance sampling of surface and subsurface sediment to a maximum depth of 80 m below the sea floor shows that typical values of 0.03 p.p.m. and anomalies of 0.2-1.3 p.p.m. mercury have been present in northeastern Bering Sea since Early Pliocene time. Values are highest in modern beach (maximum 1.3 and mean 0.22 p.p.m. Hg) and nearshore subsurface gravels (maximum 0.6 and mean 0.06 p.p.m. Hg) along the highly mineralized Seward Peninsula and in clayey silt rich in organic matter (maximum 0.16 and mean 0.10 p.p.m. Hg) throughout the region. Although gold mining may be partly responsible for high mercury levels in the modern beach near Nome, Alaska (maximum 0.45 p.p.m.), equally high or greater concentrations of mercury occur in buried Pleistocene sediments immediately offshore (maximum 0.6 p.p.m.) and in modern unpolluted beach sediments at Bluff (maximum 1.3 p.p.m.); this suggests that the contamination effects of mining may be no greater than natural concentration processes in the Seward Peninsula region. The mercury content of offshore surface sediment, even adjacent to mercury-rich beaches, corresponds to that of unpolluted marine and fresh-water sediment elsewhere. The normal values that prevail offshore may be attributable to entrapment of mercury-bearing heavy minerals on beaches near sources and/or dilution effects of offshore sedimentation. The few minor anomalies offshore occur in glacial drift derived from mercury source regions of Chukotka (Siberia) and Seward Peninsula; Pleistocene shoreline processes have reworked the drift to concentrate the heavy metals. The distribution pattern of mercury indicates that particulate mercury-bearing minerals have not been widely dispersed from onland deposits in quantities sufficient to increase mercury levels above normal in offshore sediments of Bering Sea; however, it shows that natural sedimentary processes can concentrate this mercury in beaches of the coastal zone where there already is concern because of potential pollution from man's activities.

Progress and Future Plans for Mercury Remediation at the Y-12 National Security Complex, Oak Ridge, Tennessee - 13059

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilkerson, Laura O.; DePaoli, Susan M.; Turner, Ralph

2013-07-01

The U.S. Department of Energy (DOE), along with the Tennessee Department of Environment and Conservation (TDEC) and the U.S. Environmental Protection Agency (EPA), has identified mercury contamination at the Y-12 National Security Complex (Y-12) as the highest priority cleanup risk on the Oak Ridge Reservation (ORR). The historic loss of mercury to the environment dwarfs any other contaminant release on the ORR. Efforts over the last 20 years to reduce mercury levels leaving the site in the surface waters of Upper East Fork Poplar Creek (UEFPC) have not resulted in a corresponding decrease in mercury concentrations in fish. Further reductionsmore » in mercury surface water concentrations are needed. Recent stimulus funding through the American Recovery and Reinvestment Act of 2009 (ARRA) has supported several major efforts involving mercury cleanup at Y-12. Near-term implementation activities are being pursued with remaining funds and include design of a centrally located mercury treatment facility for waterborne mercury, treatability studies on mercury-contaminated soils, and free mercury removal from storm drains. Out-year source removal will entail demolition/disposal of several massive uranium processing facilities along with removal and disposal of underlying contaminated soil. As a National Priorities List (NPL) site, cleanup is implemented under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and directed by the Federal Facility Agreement (FFA) between DOE, EPA, and TDEC. The CERCLA process is followed to plan, reach approval, implement, and monitor the cleanup. (authors)« less

ECHMERIT: A new on-line global mercury-chemistry model

NASA Astrophysics Data System (ADS)

Jung, G.; Hedgecock, I. M.; Pirrone, N.

2009-04-01

Mercury is a volatile metal, that is of concern because when deposited and transformed to methylmercury accumulates within the food-web. Due to the long lifetime of elemental mercury, which is the dominant fraction of mercury species in the atmosphere, mercury is prone to long-range transport and therefore distributed over the globe, transported and hence deposited even in regions far from anthropogenic emission sources. Mercury is released to the atmosphere from a variety of natural and anthropogenic sources, in elementary and oxidised forms, and as particulate mercury. It is then transported, but also transformed chemically in the gaseous phase, as well as in aqueous phase within cloud and rain droplets. Mercury (particularly its oxidised forms) is removed from the atmosphere though wet and dry deposition processes, a large fraction of deposited mercury is, after chemical or biological reduction, re-emitted to the atmosphere as elementary mercury. To investigate mercury chemistry and transport processes on the global scale, the new, global model ECHMERIT has been developed. ECHMERIT simulates meteorology, transport, deposition, photolysis and chemistry on-line. The general circulation model on which ECHMERIT is based is ECHAM5. Sophisticated chemical modules have been implemented, including gas phase chemistry based on the CBM-Z chemistry mechanism, as well as aqueous phase chemistry, both of which have been adapted to include Hg chemistry and Hg species gas-droplet mass transfer. ECHMERIT uses the fast-J photolysis routine. State-of-the-art procedures simulating wet and dry deposition and emissions were adapted and included in the model as well. An overview of the model structure, development, validation and sensitivity studies is presented.

Mercury Contamination - Amalgamate (contract with NFS and ADA). Demonstration of DeHg SM Process. Mixed Waste Focus Area. OST Reference Number 1675

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

1999-09-01

Through efforts led by the Mixed Waste Focus Area (MWFA) and its Mercury Working Group (HgWG), the inventory of bulk elemental mercury contaminated with radionuclides stored at various U.S. Department of Energy (DOE) sites is thought to be approximately 16 m3 (Conley et al. 1998). At least 19 different DOE sites have this type of mixed low-level waste in their storage facilities. The U.S. Environmental Protection Agency (EPA) specifies amalgamation as the treatment method for radioactively contaminated elemental mercury. Although the chemistry of amalgamation is well known, the practical engineering of a sizable amalgamation process has not been tested (Tysonmore » 1993). To eliminate the existing DOE inventory in a reasonable timeframe, scalable equipment is needed that can produce waste forms that meet the EPA definition of amalgamation, produce waste forms that pass the EPA Toxicity Characteristic Leaching Procedure (TCLP) limit of 0.20 mg/L, limit mercury vapor concentrations during processing to below the Occupational Safety and Health Administration’s (OSHA) 8-h worker exposure limit (50 mg/m3) for mercury, and perform the above economically.« less

Adsorption of elemental mercury vapors from synthetic exhaust combustion gas onto HGR carbon.

PubMed

Musmarra, D; Karatza, D; Lancia, A; Prisciandaro, M; Mazziotti di Celso, G

2016-07-01

An activated carbon commercially available named HGR, produced by Calgon-Carbon Group, was used to adsorbe metallic mercury. The work is part of a wider research activity by the same group focused on the removal of metallic and divalent mercury from combustion flue gas. With respect to previously published papers, this one is aimed at studying in depth thermodynamic equilibria of metallic mercury adsorption onto a commercial activated carbon. The innovativeness lies in the wider operative conditions explored (temperature and mercury concentrations) and in the evaluation of kinetic and thermodynamic data for a commercially available adsorbing material. In detail, experimental runs were carried out on a laboratory-scale plant, in which Hg° vapors were supplied in a nitrogen gas stream at different temperature and mercury concentration. The gas phase was flowed through a fixed bed of adsorbent material. Adsorbate loading curves for different Hg° concentrations together with adsorption isotherms were achieved as a function of temperature (120, 150, 200°C) and Hg° concentrations (1.0-7.0 mg/m(3)). Experimental runs demonstrated satisfying results of the adsorption process, while Langmuir parameters were evaluated with gas-solid equilibrium data. Especially, they confirmed that adsorption capacity is a favored process in case of lower temperature and they showed that the adsorption heat was -20 kJ/mol. Furthermore, a numerical integration of differential equations that model the adsorption process was proposed. Scanning electron microscopy (SEM) investigation was an useful tool to investigate about fresh and saturated carbon areas. The comparison between them allowed identification of surface sites where mercury is adsorbed; these spots correspond to carbon areas where sulfur concentration is greater. Mercury compounds can cause severe harm to human health and to the ecosystem. There are a lot of sources that emit mercury species to the atmosphere; the main ones are exhaust gases from coal combustion and municipal solid waste incineration. Furthermore, certain CO2 capture processes, particularly oxyfuel combustion in a pulverized fuel coal-fired power station, produce a raw CO2 product containing several contaminants, mainly water vapor, oxygen, and nitrogen but also mercury, that have to be almost completely removed; otherwise these would represent a strong drawback to the success of the process.

Physicochemical characteristics of aerosol particles generated during the milling of beryllium silicate ores: implications for risk assessment.

PubMed

Stefaniak, Aleksandr B; Chipera, Steve J; Day, Gregory A; Sabey, Phil; Dickerson, Robert M; Sbarra, Deborah C; Duling, Mathew G; Lawrence, Robert B; Stanton, Marcia L; Scripsick, Ronald C

2008-01-01

Inhalation of beryllium dusts generated during milling of ores and cutting of beryl-containing gemstones is associated with development of beryllium sensitization and low prevalence of chronic beryllium disease (CBD). Inhalation of beryllium aerosols generated during primary beryllium production and machining of the metal, alloys, and ceramics are associated with sensitization and high rates of CBD, despite similar airborne beryllium mass concentrations among these industries. Understanding the physicochemical properties of exposure aerosols may help to understand the differential immunopathologic mechanisms of sensitization and CBD and lead to more biologically relevant exposure standards. Properties of aerosols generated during the industrial milling of bertrandite and beryl ores were evaluated. Airborne beryllium mass concentrations among work areas ranged from 0.001 microg/m(3) (beryl ore grinding) to 2.1 microg/m(3) (beryl ore crushing). Respirable mass fractions of airborne beryllium-containing particles were < 20% in low-energy input operation areas (ore crushing, hydroxide product drumming) and > 80% in high-energy input areas (beryl melting, beryl grinding). Particle specific surface area decreased with processing from feedstock ores to drumming final product beryllium hydroxide. Among work areas, beryllium was identified in three crystalline forms: beryl, poorly crystalline beryllium oxide, and beryllium hydroxide. In comparison to aerosols generated by high-CBD risk primary production processes, aerosol particles encountered during milling had similar mass concentrations, generally lower number concentrations and surface area, and contained no identifiable highly crystalline beryllium oxide. One possible explanation for the apparent low prevalence of CBD among workers exposed to beryllium mineral dusts may be that characteristics of the exposure material do not contribute to the development of lung burdens sufficient for progression from sensitization to CBD. In comparison to high-CBD risk exposures where the chemical nature of aerosol particles may confer higher bioavailability, respirable ore dusts likely confer considerably less. While finished product beryllium hydroxide particles may confer bioavailability similar to that of high-CBD risk aerosols, physical exposure factors (i.e., large particle sizes) may limit development of alveolar lung burdens.

Technological pretreatment of the synchysite non-oxidized ore

NASA Astrophysics Data System (ADS)

Munkhtsetseg, B.; Burmaa, G.

2013-06-01

Mongolia has rich deposits of rare, precious, and poly-metallic ores. Nowadays, it is important to research separation of rare earth elements oxides concentrates from the ores, analyze their unique physical chemical characteristics, and purified it. Our investigation on raw materials focuses on rare earth non-oxidized ores. Main mineral in this rock sample is Synchysite (LnCa(CO3)2F. We did technological and thermal pretreatment: direct sulphurization (H2SO4), sulphurization with subsequent roasting (800°C+H2SO4), sulphurization prior to roasting (H2SO4+650°C). Sulphurization method based on dissolution of rare earth mineral into sulfuric acid (93%) according to the reaction. The amount of rare earth element oxides is almost 10 times greater (29.16%) after direct sulphurization process, almost 8 times greater (21.14%) after sulphurization with subsequent roasting, and almost 20 times greater (44.62%) after sulphurization prior to roasting process. After those technological pretreatment raw material's micro elements Thorium and Uranium contents are reduced as follows: H2SO4>800°C+H2SO4>H2SO4+650°C. These results show that cerium group rare earth elements have very good solubility in water at +2°C temperature and decreasing micro elements content uranium and thorium good pretreatment condition is prior to roasting (H2SO4+650°C) of synchysite non-oxidized ore.

Ore-forming fluid system of bauxite in WZD area of northern Guizhou province, China

NASA Astrophysics Data System (ADS)

Cui, Tao

2017-12-01

The ore-forming fluid system of bauxite in Wuchuan-Zheng,an-Daozhen (short for WZD) Area of northern Guizhou Province was studied from the perspective of deposit formation mechanism. It was discovered that ore-forming fluids were mainly effective for transporting and leaching during the formation of bauxite. The means of transport mainly included colloidal transport, suspended transport and gravity flow transport. In the course of their leaching, fluids had a range of chemical reactions, as a result of which elements such as silicon and iron migrated downwards. In this process, properties of fluids changed as well.

The role of magmas in the formation of hydrothermal ore deposits

USGS Publications Warehouse

Hedenquist, Jeffrey W.; Lowenstern, Jacob B.

1994-01-01

Magmatic fluids, both vapour and hypersaline liquid, are a primary source of many components in hydrothermal ore deposits formed in volcanic arcs. These components, including metals and their ligands, become concentrated in magmas in various ways from various sources, including subducted oceanic crust. Leaching of rocks also contributes components to the hydrothermal fluid—a process enhanced where acid magmatic vapours are absorbed by deeply circulating meteoric waters. Advances in understanding the hydrothermal systems that formed these ore deposits have come from the study of their active equivalents, represented at the surface by hot springs and volcanic fumaroles.

Sulfide minerals as new Sm-Nd geochronometers for ore genesis dating of mafic-ultramafic layered intrusions

NASA Astrophysics Data System (ADS)

Serov, Pavel; Ekimova, Nadezhda; Bayanova, Tamara

2014-05-01

The main method of dating the ore process was the Re-Os method of sulfides (Luck, Allegre, 1983; Walker et. al., 1991). However, studies of Re-Os systematics of sulfide minerals do not always give the correct ages and showing the disturbances of the Re-Os systematics. At the same time, Sm-Nd age of sulfides in good agreement with the U-Pb dating on zircon and baddeleyite and suggests that the Sm-Nd system of sulfides is more resistant to secondary alteration processes. Our studies have shown that along with rock-forming, ore minerals (sulfides) can be used to determine the ore genesis time of industrially important geological sites, since exactly with the sulfides the industry Pt-Pd mineralization is closely connected. The Sm-Nd investigations steadily employ new minerals-geochronometers. Of these, sulfides of PGE-bearing layered intrusions are quite important in terms of dating the process of ore origin. Studying the REE distribution in the sulfides of MOR hydrothermal sources has shown possible REE presence in the sulfide lattice (Rimskaya-Korsakova et. al., 2003). These are difficult to carry out because the concentrations of Sm and Nd isotopes in sulfides are much lower than chondrites (Rimskaya-Korsakova et. al., 2003). For the first time in Russia with sulfide and rock-forming minerals and WR in Sm-Nd method have been dated impregnated and brecciform ores of the following objects: Pilguyarvi Cu-Ni deposits, Pechenga (1965±87 Ma); impregnated (2433±83 Ma) and redeposited (1903±24 Ma) ores of Ahmavaara intrusion (Finland); ore gabbronorites of Penikat PGE-bearing layered intrusion (2426±38 Ma (Ekimova et.al., 2011); Pt-Pd gabbro-pegmatite ores (2476± 41 Ma, which agrees with the U-Pb zircon age - 2470±9 Ma (Bayanova, 2004) and gabbronorites (2483±86 Ma) of PGE Kievei deposit and Fedorova Tundra metagabbroids (2494±54 Ma); Monchetundra gabbronorites - 2489±49 Ma. In (Kong et. al., 2000) sulfides from two metamorphosed chondrites studied by instrumental neutron activation analysis (INAA) and ion probe. As shown, the level of REE in the sulfide phase determined by the ion probe is quite similar to that obtained by INAA. Although the concentrations of REE in the enstatite and the Fe, Si, Cr-rich inclusions are comparable to those in sulfide, estimates based on mass balance calculations show that the silicate inclusions would not noticeably contribute to the REE budget in sulfides (Kong et. al., 2000). These studies were supported by the RFBR 13-05-00493, OFI-M 13-05-12055, State Earth Division Program #4 and IGCP-599.