Hydrogeochemistry,Elemental Flux,and Quality Assessment of Mine Water in the Pootkee-Balihari Mining Area,Jharia Coalfield,India

Ninety nine mine water discharge samples were collected and analyzed for pH, electrical conductivity (EC), major cations, anions, and trace metals in the Pootkee-Balihari coal mining area of the Jharia coalfield. The mines of the area annually discharge 34.80 × 10⁶ m³ of mine water and 39,099 t of solute loads. The pH of the analyzed mine waters ranged from 6.97 to 8.62. EC values ranged from 711 μS cm⁻¹ to 1862 μS cm⁻¹, and reflect variations in lithology, geochemical processes, and hydrological regimes in the mines. The cation and anion chemistry indicate the general ionic abundance as: Mg²⁺ > Ca²⁺ > Na⁺ > K⁺ and HCO₃ ⁻ > SO₄ ²⁻ > Cl⁻ > NO₃ ⁻ > F⁻, respectively. Elevated SO₄ ²⁻ concentrations in the Gopalichuck, Kendwadih, and Kachhi-Balihari mine waters are attributed to pyrite weathering. The water quality assessment indicated that TDS, hardness, Mg²⁺, and SO₄ ²⁻ are the major parameters of concern in the study area. Except for Fe, all of the measured metals in the mine water were well within the levels recommended for drinking water. With only a few exceptions, the mine water is of good to permissible quality and suitable for irrigation.     

Pyromorphite : Bunker Hill Mine,Coeur d'Alene District,Shoshone County,Idaho

Nikischerite, ideally NaFe²⁺ ₆Al₃(SO₄)₂(OH)₁₈(H₂O)₁₂, occurs as dark yellow-green micaceous plates to 4 mm, forming radiating balls and aggregates (Huminicki et al. 2003). The mineral has a dull to greasy luster, a pale grayish streak, and a Mohs hardness of 2. It has a perfect cleavage parallel to {001}, which is also the dominant form displayed by the platy crystals. The type locality is the Huanuni tin mine, Dalence Province, Oruro Department, Bolivia, where nikischerite occurs in and on a clay matrix, associated with minor pyrite, pyrrhotite, siderite, and cronstedtite.     

ICP-AES法测定钴铬烤瓷合金中钨、钼、 铁、钌、镓、镉、铍、镍的含量

通过对样品前处理方法、分析谱线、氢氟酸用量及酸度、钴铬基体影响以及杂质元素之间的相互影响等因素进行试验,确定了最佳样品溶解方法和最佳测定条件.建立了用王水+氢氟酸、微波消解溶解样品,再用ICP-AES直接测定烤瓷合金中钨、钼、铁、钌、镓、镉、铍、镍含量的方法.试验结果表明,在选定的条件下,钴铬基体对所测元素无影响,钨、钼等8种杂质元素间也没有干扰.本方法的加标回收率在98.0%~102.0%之间,与分光光度法及原子吸收光谱法的测定结果一致.本法的相对标准偏差在1.04%~3.23%之间,能够满足快速、准确测定钴铬烤瓷合金中多种元素的需要.     

Groundwater Recharge Assessment in an Arid,Coastal, Middle Mountain Copper Mining District,Coquimbo Region,North-central Chile

Groundwater recharge processes operating in a portion of the western slope of the Chilean Coastal Cordillera (30°S) were assessed. The study takes advantage of the presence of the Cerro Brillador Mine (CBM), currently part of the Universidad de La Serena mining research center. Six factors—slope, solar exposure, drainage density, lineament density, geology and vegetation were characterized in a 12 km × 12 km area around the mine to identify the zones of greatest and least potential for groundwater recharge. The analysis indicates that approximately 66% of the total area presents favorable conditions for recharge. At a more local scale, the work focused on the CBM itself, an experimental facility where structural measurements in the interior and exterior of the mine, monitoring of the water level in the shaft, and sampling of mine water for chemical and isotopic composition were carried out. The chemical analysis highlighted the lack of acid drainage, despite the existence of pyrite (FeS₂) and copper-sulfate mineralization in the mine. The isotopic analysis showed that the groundwater has a similar signature to local precipitation. From this information, a simple conceptual model for the hydrogeology is proposed, in which precipitation rapidly recharges the mine along faults and joints with a preferential N-S strike, but is impounded by the Urrutia fault, which facilitates the storage of groundwater in the underground workings by acting as a flow barrier. A simple analysis suggests a recharge rate on the order of 5% of the average annual precipitation for the CBM area.

     

Microbiological Evidence for the Origin of Acid Mine Drainage at the Green Valley Site,Vigo County,and Friar Tuck Site,Greene County,Indiana, USA

We examine the origin of acid mine drainage (AMD) that forms within coal refuse (gob) piles at the Green Valley and Friar Tuck sites in Indiana, using microbiology, traditional geochemistry, and oxygen and hydrogen isotopes. Reducing the AMD load from these sites has been an historical priority. Our observations indicate that AMD generation at these sites in Indiana is driven by three complementary factors: elevated populations of chemolithotrophic microbes of the species Acidithiobacillus ferrooxidans; a growth substrate that provides ‘food’ (e.g. pyrite) for these microbes, and a gob pile with geometry and other properties conducive to maintaining the thermal window of 25–40°C for optimal A. ferrooxidans growth. In particular, increasing levels of Fe⁺³ and total dissolved solids (TDS), and decreasing pH for gob waters were found to be highly correlated with increasing populations of A. ferrooxidans. Furthermore, the chemosythetic bacteria population increase correlates with increasing hydrogen stable isotope shift away from the global meteoric water line for gob waters in this study, though it is unclear if this shift is the result of microbial metabolic processes or a secondary effect due to microbially-mediated pH change or electrolysis.     

Passive aerobic treatment of net-alkaline,iron-laden drainage from a flooded underground anthracite mine,Pennsylvania, USA

This report evaluates the results of a continuous 4.5-day laboratory aeration experiment and the first year of passive, aerobic treatment of abandoned mine drainage (AMD) from a typical flooded underground anthracite mine in eastern Pennsylvania, USA. During 1991–2006, the AMD source, locally known as the Otto Discharge, had flows from 20 to 270 L/s (median 92 L/s) and water quality that was consistently suboxic (median 0.9 mg/L O₂) and circumneutral (pH ≈ 6.0; net alkalinity >10) with moderate concentrations of dissolved iron and manganese and low concentrations of dissolved aluminum (medians of 11, 2.2, and <0.2 mg/L, respectively). In 2001, the laboratory aeration experiment demonstrated rapid oxidation of ferrous iron (Fe²⁺) without supplemental alkalinity; the initial Fe²⁺ concentration of 16.4 mg/L decreased to less than 0.5 mg/L within 24 h; pH values increased rapidly from 5.8 to 7.2, ultimately attaining a steady-state value of 7.5. The increased pH coincided with a rapid decrease in the partial pressure of carbon dioxide (PCO₂) from an initial value of 10^−1.1 atm to a steady-state value of 10^−3.1 atm. From these results, a staged aerobic treatment system was conceptualized consisting of a 2 m deep pond with innovative aeration and recirculation to promote rapid oxidation of Fe²⁺, two 0.3 m deep wetlands to facilitate iron solids removal, and a supplemental oxic limestone drain for dissolved manganese and trace-metal removal. The system was constructed, but without the aeration mechanism, and began operation in June 2005. During the first 12 months of operation, estimated detention times in the treatment system ranged from 9 to 38 h. However, in contrast with 80–100% removal of Fe²⁺ over similar elapsed times during the laboratory aeration experiment, the treatment system typically removed less than 35% of the influent Fe²⁺. Although concentrations of dissolved CO₂ decreased progressively within the treatment system, the PCO₂ values for treated effluent remained elevated (10^−2.4 to 10^−1.7 atm). The elevated PCO₂ maintained the pH within the system at values less than 7 and hence slowed the rate of Fe²⁺ oxidation compared to the aeration experiment. Kinetic models of Fe²⁺ oxidation that consider effects of pH and dissolved O₂ were incorporated in the geochemical computer program PHREEQC to evaluate the effects of detention time, pH, and other variables on Fe²⁺ oxidation and removal rates. These models and the laboratory aeration experiment indicate that performance of this and other aerobic wetlands for treatment of net-alkaline AMD could be improved by aggressive, continuous aeration in the initial stage to decrease PCO₂, increase pH, and accelerate Fe²⁺ oxidation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Dear Readers,Authors, and Prospective Authors

Introduction

Dear Readers, Authors, and Prospective Authors     

Physical, Hydrologic, and Aqueous Chemical Characterization of the Ore Knob Tailings Pile (Ashe County, North Carolina, USA)

Oxidation of pyrrhotite and related sulfide minerals in the vadose zone of the Ore Knob Mine tailings pile generates dissolved Fe⁺², SO₄⁻², and acidity, which are rapidly transported through the pile by infiltrating surface water. Significant spatial variations in the physical and hydraulic characteristics of the tailings cause large variations in air-filled porosity and effective oxygen diffusion into the pile. Tailings in the upstream areas are more fine-grained, with less air-filled porosity and oxygen diffusivity. The original tailings in the downstream areas are more coarse-grained, with less water retention and greater oxygen diffusivity. However, weathering processes have increased the fine-grained fraction in the oxidized zone and hardpan layer, increasing water retention and lowering oxygen diffusivity. The thickness of the downstream oxidized zone combined with increased water retention due to weathering may have significantly reduced acid generation in these areas.     

Downflow Limestone Beds for Treatment of Net-Acidic,Oxic, Iron-Laden Drainage from a Flooded Anthracite Mine,Pennsylvania, USA: 1. Field Evaluation

Passive-treatment systems that route acidic mine drainage (AMD) through crushed limestone and/or organic-rich substrates have been used to remove the acidity and metals from various AMD sources, with a wide range of effects. This study evaluates treatment of net-acidic, oxic, iron-laden AMD with limestone alone, and with organic-rich compost layered with the limestone. In the fall of 2003, a treatment system consisting of two parallel, 500-m² downflow cells followed by a 400-m² aerobic settling pond and wetland was installed to neutralize the AMD from the Bell Mine, a large source of AMD and baseflow to the Schuylkill River in the Southern Anthracite Coalfield, in east-central Pennsylvania. Each downflow cell consisted of a lower substrate layer of 1,090 metric tons (t) of dolomitic limestone (60 wt% CaCO₃) and an upper layer of 300 t of calcitic limestone (95 wt% CaCO₃); one of the downflow cells also included a 0.3 m thick layer of mushroom compost over the limestone. AMD with pH of 3.5–4.3, dissolved oxygen of 6.6–9.9 mg/L, iron of 1.9–5.4 mg/L, and aluminum of 0.8–1.9 mg/L flooded each cell to a depth 0.65 m above the treatment substrates, percolated through the substrates to underlying, perforated outflow pipes, and then flowed through the aerobic pond and wetland before discharging to the Schuylkill River. Data on the flow rates and chemistry of the effluent for the treatment system indicated substantial neutralization by the calcitic limestone but only marginal effects from the dolomitic limestone or compost. Because of its higher transmissivity, the treatment cell containing only limestone neutralized greater quantities of acidity than the cell containing compost and limestone. On average, the treatment system removed 62% of the influent acidity, 47% of the dissolved iron, 34% of the dissolved aluminum, and 8% of the dissolved manganese. Prior to treatment of the Bell Discharge, the Schuylkill River immediately below its confluence with the discharge had pH as low as 4.1 and supported few, if any, fish. However, within the first year of treatment, the pH was maintained at values of 5.0 or greater and native brook trout were documented immediately below the treatment system, though not above.     

Downflow Limestone Beds for Treatment of Net-Acidic, Oxic, Iron-Laden Drainage from a Flooded Anthracite Mine, Pennsylvania, USA: 2. Laboratory Evaluation

Acidic mine drainage (AMD) containing elevated concentrations of dissolved iron and other metals can be neutralized to varying degrees by reactions with limestone in passive treatment systems. We evaluated the chemical and mineralogical characteristics and the effectiveness of calcitic and dolomitic limestone for the neutralization of net-acidic, oxic, iron-laden AMD from a flooded anthracite mine. The calcitic limestone, with CaCO₃ and MgCO₃ contents of 99.8 and <0.1 wt%, respectively, and the dolomitic limestone, with CaCO₃ and MgCO₃ contents of 60.3 and 40.2 wt%, were used to construct a downflow treatment system in 2003 at the Bell Mine, a large source of AMD and baseflow to the Schuylkill River in the Southern Anthracite Coalfield, in east-central Pennsylvania. In the winter of 2002–2003, laboratory neutralization-rate experiments evaluated the evolution of effluent quality during 2 weeks of continuous contact between AMD from the Bell Mine and the crushed calcitic or dolomitic limestone in closed, collapsible containers (cubitainers). The cubitainer tests showed that: (1) net-alkaline effluent could be achieved with detention times greater than 3 h, (2) effluent alkalinities and associated dissolution rates were equivalent for uncoated and Fe(OH)₃-coated calcitic limestone, and (3) effluent alkalinities and associated dissolution rates for dolomitic limestone were about half those for calcitic limestone. The dissolution rate data for the cubitainer tests were used with data on the volume of effuent and surface area of limestone in the treatment system at the Bell Mine to evaluate the water-quality data for the first 1.5 years of operation of the treatment system. These rate models supported the interpretation of field results and indicated that treatment benefits were derived mainly from the dissolution of calcitic limestone, despite a greater quantity of dolomitic limestone within the treatment system. The dissolution-rate models were extrapolated on a decadal scale to indicate the expected decreases in the mass of limestone and associated alkalinities resulting from the long-term reaction of AMD with the treatment substrate. The models indicated the calcitic limestone would need to be replenished approaching the 5-year anniversary of treatment operations to maintain net-alkaline effluent quality.     

Process mineralogy studies of Corrego do Garimpo REE ore, catalao-I alkaline complex, Goias, Brazil

Corrego do Garimpo is described as a lateritic rare earths (REE) deposit related to hydrothermal alteration of dolomitic carbonatitic rocks. Although the deposit has been known since the sixties, all the previous mineral dressing attempts to concentrate the REE bearing minerals resulted in unsatisfactory outcomes. Process mineralogy studies of bulk and borehole samples were fundamental to understanding the ore's behavior and to the development of an unusual physical concentration process.The ore comprises a medium to very fine-grained soil material with large amounts of secondary (autigenous) minerals. Monazite, the essential REE bearing mineral, occurs as microcrystalline aggregates, sometimes presenting colloidal textures, which are frequently associated with iron oxide—hydroxides and quartz. Since these aggregates are extremely friable, the monazite crystallites are mainly associated with the −20 μm size fraction.These particular characteristics supported the development of an unconventional mineral processing method for monazite based on disaggregation, followed by scrubbing and hydrocyclone classification operations. Three volumetric samples and 27 borehole samples, comprising four ore types, have been studied. The attained final products, −10 μm, were further submitted to leaching tests, simulating chemical processing for the REE sulphuric extraction at low temperature.     

Geochemistry and Isotopic Composition of H2S-rich Water in Flooded Underground Mine Workings,Butte, Montana,USA

Abstract.   Groundwater being pumped from the flooded West Camp mine workings of Butte, Montana, is elevated in hydrogen sulfide (H₂S), has a circum-neutral pH, and has high arsenic but otherwise low metal concentrations. The daily flux of H₂S and As pumped from the extraction well are each estimated at roughly 0.1 kg. Isotopic analysis of coexisting aqueous sulfide and sulfate confirms that the H₂S was produced by bacterial sulfate reduction. the mine waters are close to equilibrium saturation with amorphous FeS, amorphous ZnS, siderite, rhodochrosite, calcite, and goethite, but are undersaturated with orpiment (As₂S₃). The higher solubility of orpiment relative to other mental sulfides allows concentrations of dissolved arsenic (~ 100 g/L) that are well above human health standards. The West Camp waters differ markedly from the acidic and heavy metal-rich mine waters of the nearby Berkeley pit-lake. These differences are partly attributed to geology, and partly to mining history.     

Petrographic characterization and evolution of the Karharbari coals,Talcher Coalfield,Orissa, India

In the present study an attempt has been made to carry out the detailed petrographic characterization of the Karharbari coals of Talcher coalfield and to reconstruct the paleoenvironment conditions of coal formation using macerals and microlithtotypes as a tool. For these purposes a large number of samples were collected following the pillar sampling method and were subjected to detailed petrographic study. The petrographic observation shows that these coals are vitrinite rich followed by the liptinite and inertinite group of macerals. On microlithotype scale, these coals shows the dominance of the vitrite followed by clarite, vitrinertite and inertite. The concentration of liptite, clarodurite, duroclarite and vitrinertoliptite are insignificant. The vitrinite reflectance ranks the Karharbari coal as high volatile bituminous ‘C’ to high volatile ‘B’ bituminous. Coal petrography based depositional models suggest peat accumulation in forested telmatic swamp. Moreover, during the time of their evolution, there were alternate phases of oxic and anoxic moor conditions with good tissue preservation.

     

Arsenic,Selenium, and Sulfate Removal using an Ethanol-Enhanced Sulfate-Reducing Bioreactor

A laboratory scale sulfate-reducing bioreactor column study was used to investigate removal of arsenic, selenium, and sulfate in neutral to alkaline simulated mine water. Selenium was effectively removed as insoluble elemental selenium from 200 μg/L to below the maximum contaminant level (50 μg/L). With the addition of ferrous chloride in the influent, arsenic was also effectively removed to near the maximum contaminant level (10 μg/L). Sulfate removal was apparently limited by the presence of undissociated hydrogen sulfide, which was found to limit sulfate-reducing bacterial activity in the range of 20–40 mg/L and will need to be considered for sulfate-reducing bacteria treatment system designs.     

Removal of Sulfate,Zinc, and Lead from Alkaline Mine Wastewater Using Pilot-scale Surface-Flow Wetlands at Tara Mines,Ireland

Abstract.    Passive treatment systems have primarily been used at abandoned mines to increase pH and remove metals from the drainage water. Two pilot-scale treatment wetlands were constructed and monitored at an active lead/zinc mine (Tara Mines) in Ireland to treat alkaline mine water with elevated sulfate and metal levels. Each system comprised three in-series surface-flow cells that contained spent mushroom compost substrate. Typically, aqueous concentrations of 900 mg L^-1 sulfate, 0.15 mg L^-1 lead, and 2.0 mg L^-1 zinc flowed into the treatment wetlands at c. 1.5 L min^-1. During a two-year monitoring period, removal of sulfate (mean of 10.4 g m^-2 day ^-1 (31%), range of 0-42 g m^-2 day ^-1 (0-81%)), lead (mean of 1.9 mg m^-2 day ^-1 (32%), range of 0-6.6 mg m^-2 day ^-1 (0-64%)) and zinc (mean of 18.2 mg m^-2 day ^-1 (74%), range of 0-70 mg m^-2 day ^-1 (0-99%)) were achieved. These contaminants were somewhat associated with the vegetation roots but more significantly with the substrate. Communities of colonizing macroinvertebrates, macrophytes, algae, and microorganisms contributed to the development of a diverse ecosystem, which proved to be a successful alternative treatment process. The interacting processes within the wetland ecosystems responsible for wastewater decontamination are being further elucidated and quantified using a systems dynamic model.     

Geochemistry of Perched Water in an Abandoned Underground Mine, Butte, Montana

Abstract.  The Lexington tunnel is the last accessible underground mine working in the Butte, Montana mining district. Used as recently as 1993, the tunnel and adjacent workings have been abandoned for over 10 years. Although the Lexington tunnel is over 200 m above the regional water table, perched water is present over much of its extent. Mine water near the portal is moderately acidic (pH 4 to 5), with extremely high concentrations of metals, including Cu (up to 1000 mg/L) and Zn (up to 1400 mg/L). In the middle reaches of the tunnel, the quality of the water is much better, with near-neutral pH, high bicarbonate alkalinity, and lower concentrations of heavy metals. The low acidity and metal content is attributed to a lack of pyrite and other sulfides in this portion of the mine, as well as the presence of carbonate minerals, such as rhodochrosite (MnCO₃), in exposed veins. Sulfide minerals are more widespread further back in the tunnel, and are now oxidizing rapidly, leading to pockets of severe acid drainage (pH< 3, dissolved Zn up to 5000 mg/L). Geochemical modeling suggests that the near-neutral waters—the most voluminous type encountered in the Lexington tunnel—are close to equilibrium saturation with rhodochrosite and hydrous Zn-carbonate (ZnCO₃•H₂O). The Eh of these waters is most likely controlled by redox reactions involving dissolved Mn²⁺ and secondary, Zn-rich, hydrous Mn-oxides. In contrast, the Eh of the acidic waters appears to be controlled by reactions involving Fe²⁺ and Fe³⁺. Most of the acidic waters are saturated with K-jarosite, which forms delicate, straw-like dripstones at several localities. Decaying mine timbers could be an important renewable source of organic carbon for heterotrophic microorganisms, such as iron- and sulfate-reducing bacteria, especially deeper in the mine workings where the ground is saturated with anoxic ground water.     

Assessment of Hydrogeochemical Processes and Mine Water Suitability for Domestic,Irrigation, and Industrial Purposes in East Bokaro Coalfield,India

Mine water samples collected from the East Bokaro coalfield were analysed to assess suitability for domestic, irrigation, and industrial purposes. The pH of the samples ranged from 6.78 to 8.11 in the pre-monsoon season, 5.89–8.51 during the monsoon season, and 6.95–8.48 in the post-monsoon season. The anion chemistry was dominated by HCO₃^? and SO₄^2?, with minor amounts of Cl^?, NO₃^? and F^?. The Fe concentrations exceeded the maximum permissible limit of the BIS drinking water standard in about 44% of the collected samples. Turbidity, TDS, Fe, total hardness (TH), SO₄^2?, and Mg²⁺ also sometimes exceeded drinking water limits. The TDS, TH and SO₄^2? concentrations of the mine water makes it unsuitable for domestic purposes or for industrial use; high values of %Na, SAR, RSC, and Mg-hazard at certain sites restrict its suitability for agricultural use.     

Mobility of Be,Bi, F,Ga, Ge and W in Surface Water and the Water Quality Impact on Epilithic Diatoms Downstream of the Historical Yxsjöberg Mine Site,Sweden

There is a potential risk that the geochemical cycles of several critical metals will be affected when mining of these metals increases to meet the demand of green technology. The geochemistry of Be, Bi, Ga, Ge, and W, herewith called CM5, is lacking, yet is necessary to ensure responsible mine waste and water management. Beryllium, Bi, and W are all considered immobile, but in previous studies of skarn tailings in Yxsjöberg, Sweden, all three elements were mobilized. The tailings are enriched in CM5, together with pyrrhotite, calcite, and fluorite. The mobility and environmental impact of CM5 and F in surface waters downstream of the Yxsjöberg mine site, Sweden, were studied using monthly water samples from seven locations and analysis of diatoms at five of these locations. Bismuth, Ge, and W were present at low concentrations, transported in the particulate phase, and likely settled in the sediments hundreds of meters from the tailings. Beryllium and F were present at high concentrations and dominantly transported in the dissolved phase. At these pH conditions (5.6), Be should form insoluble hydroxides; however, elevated concentrations of dissolved Be were observed more than 5 km from the mine site. Diatoms downstream of the mine site were negatively affected by the mine drainage. The release of low quality neutral mine drainage will continue for hundreds of years if remediation actions are not undertaken since only a small portion of the tailings have weathered during 50–100 years of storage.

     

Petrographic characteristics and paleomires of Mand-Raigarh coals,Mahanadi Gondwana Basin,Chhattisgarh, India

International Journal of Coal Science & Technology - Mand-Raigarh coalfield is one of the largest coalfields in the Mahanadi basin. The Geological Survey of India carried out initial study...     

江西井冈山市乌石头山滑坡形成机制及稳定性研究

采用定性和定量相结合的方式对乌石头山滑坡进行了研究。研究结果表明:乌石头山滑坡为小型牵引式土质滑坡,滑坡的产生主要与滑坡体的岩土体性质、滑坡处的地质环境条件(地形、地貌、降雨)及人工活动有关。对滑坡进行定量计算分析可知:自重工况下,坡体稳定系数1.44(>1.15),处于较为稳定状态;自重+暴雨工况下,坡体稳定系数1.03(<1.15),处于欠稳定状态,极端条件下坡体可能再次发生滑坡。