Lime Treatment of Mine Drainage at the Sarcheshmeh Porphyry Copper Mine,Iran

Laboratory and field treatment tests were performed to evaluate the effectiveness of lime treatment for mitigation of environmental effects of acid mine drainage (AMD) at the Sarcheshmeh porphyry copper mine. AMD associated with the rock waste dumps is contaminated with Al (>36,215 μg/L), Cd (>105 μg/L), Co (>522 μg/L), Cu (>53,250 μg/L), Mn (>42,365 μg/L), Ni (>629 μg/L), and Zn (>12,470 μg/L). The concentrations of other metals (Fe, Mo, Pb, and Se) are low or below detection limits (As, Cr, and Sb). Due to the very high Al and Mn content and the low concentration of Fe, a two-stage lime treatment method was chosen for the laboratory tests. In the first stage, the AMD was treated at four pH set points: 7.5, 8.9, 9, and 10. In the second stage, after removing the sludge at pH 9, treatment was continued at pH 10 and 11. The results indicated that a two-stage treatment method was not necessary because elements such as Al, Cu, Co, and Zn were easily treated at pH 7.5, while complete removal of Cd, Mn, and Ni only required a pH of 10. Increasing pH during the treatment process only caused a slight increase in Al. Field treatment tests support the laboratory results. Lime treatment of highly contaminated AMD from dump 11, using simple low density sludge pilot scale equipment, show that contaminant metals are treatable using this method. The mean treatment efficiency for contaminant metals was 99.4% for Al, % for Cd, 99.6% for Co, 99.7% for Cu, 98.5% for Mn, 99.7% for Ni, 99% for U, and 99.5% for Zn. The optimum pH for AMD treatment by lime was in the range of 9–10. The produced sludge in the treatment process was highly enriched in the contaminant metals, especially Cu (>7.34%), Al (>4.76%), Mn (>2.94%), and Zn (>1.25%). A correlation coefficient matrix indicates that the distribution pattern of the contaminant metals between soluble and precipitated phases is consistent with the hydrochemical behavior of the metals during the lime treatment process.     

Evaluation of Metal Attenuation from Mine Tailings in SE Spain (Sierra Almagrera): A Soil-Leaching Column Study

A laboratory study was undertaken using mine tailings and soil columns to evaluate some of the natural processes that can control the mobility of metals at Pb–Ag mine tailings impoundments. The effects of buffering, pH, and salinity were examined with tailings from the El Arteal deposit. Al, Ba, Cd, Cu, Fe, Mn, Ni, Pb, Sr, and Zn were mobilized when the tailings were leached. However, when the mine tailings were placed above alluvial soils, Al, Ba, Cd, Cu, Mn, Pb, and Zn were retained, although Fe and Sr clearly remained mobile. Most of the metal retention appears to be associated with the increase in pH caused by calcite dissolution. The sorption of some metals (Cu, Pb, and Zn) onto oxyhydroxides of Fe and Mn, sulphates, clay materials, and organic matter may also explain the removal of these metals from the leachate.     

Pollution of Water and Stream Sediments Associated with the Vale De Abrutiga Uranium Mine,Central Portugal

Abstract.   The Vale de Abrutiga uranium deposit, located in Central Portugal near the Aguieira dam reservoir, was surface mined. Low-grade ore and waste rock were deposited on permeable ground, close to the mine, and were not revegetated. A lake has formed in the open pit. Surface waters draining the mine site are acidic, have high conductivity, and high concentrations of U, SO42-, Zn, Fe, Mn, Ra, Cu, Th, and Pb. The groundwater and the water from the reservoir cannot be used for human consumption or irrigation. The sampled waters show higher contaminant concentrations in winter than in summer. Stream sediments have high geoaccumulation indices for U, Fe, Ag, Zn, Cr, Co, and Pb. In general, sediments bordering the dam reservoir have higher metal contents in winter than in summer.     

Heavy Metal Pollution Assessment in Surface Water Bodies and its Suitability for Irrigation around the Neyevli Lignite Mines and Associated Industrial Complex, Tamil Nadu, India

Opencast lignite mines, pit-head thermal power plants, and other associated industries in the Neyveli mining and industrial complex generate huge quantities of solid and liquid wastes that are contaminated with heavy metals. Some of these are toxic or carcinogenic at sufficient concentrations. Copper, Zn, Mn, Fe, Ni, Cd, Cr, Co, Pb, and Hg concentrations in surface water in the study area are from 2 to 1200 times higher than average concentrations in river water worldwide. Heavy metal contamination in the natural reservoirs (Peria, Kolakudi, Walaza, and Perumal Ponds, and the Paravannar River) is mainly due to the discharge of untreated mine water, fly-ash pond water, and effluents from associated industries. These waters have long been used for bathing, washing, animal watering, etc. Untreated mine and industrial waste water, and natural reservoir water have been used by nearby villagers for irrigation for the last four decades, which may have led to deterioration of soils, surface water, and groundwater. Heavy metal analyses of mine water, fly-ash pond and industrial effluents and the natural reservoirs reveals that Co, Cr, and Hg are above the recommended irrigation water quality standards in 17%, 75%, and 100% of the samples, respectively. Most samples were within the permissible limits for Mn, Ni, and Fe, while Pb, Zn, Cd, and Cu were within the limits in all samples. At elevated concentrations, toxic metals like Cr, Co, and Hg can accumulate in soils and enter the food chain, leading to serious health hazards and threatening the long-term sustainability of the local ecosystem.     

Influence of Past Mining on the Quality of Surface Waters at Funtana Raminosa (Sardinia)

Cu–Pb deposits at Funtana Raminosa in Central Sardinia were intensively exploited, mostly underground, from 1917 until 1983. Flotation tailings were dumped near the mine plant. A hydrogeochemical survey carried out in 2004 showed that mine drainage collected from several galleries was circumneutral, due to the availability of carbonate minerals that buffer the acidity produced by the oxidation of Fe-bearing sulphides. The mine waters contained higher concentrations of dissolved SO₄, F, Zn, Cd, Pb, Mn, and Mo than was observed in uncontaminated spring and stream waters in the area. Drainage from the oldest flotation tailings showed much lower concentrations of Zn, Cd, and Pb than those generally observed in mine waters. In contrast, drainage from the recent flotation tailings had the highest levels of dissolved SO₄, Zn, and Cd (1,600, 30, and 0.8 mg/L, respectively) when sampled in the dry season; these were two orders of magnitude lower in the rainy season under high flow condition. Pb was ≈ 5 μg/L under different flow conditions. Water in the Rio Saraxinus, a stream that drains the entire mining area, had a relatively low level of contamination (170 μg/L Zn, 7 μg/L Cd, and 0.9 μg/L Pb).     

Assessment of Metals Pollution from Tailing Sites in the North Caucuses Region,Russia

The concentrations of metals were determined in the water and bottom sediments of both the Urup and Kuban Rivers near tailings sites in the North Caucasus region of southern Russia. The average concentrations in the Urup followed the order Fe?>?Mn?>?Pb?>?Cu?>?Zn?>?Cd?>?Ni?>?Co, while in the Kuban, the order was Fe?>?Pb?>?Zn?>?Ni?>?Mn?>?Cd, with copper and cobalt not detected. The levels of Zn, Cu, Pb, Cd, and Ni were above Russia’s maximum permissible concentration in both rivers. The water pollution index (WPI) values in Urup ranged from 12.97 to 28.17, indicating that the river is extremely polluted (Class VII), while the WPI value for Kuban ranged from 2.34 to 4.33 downstream of the tailings site, which corresponds to Class IV (contaminated). Calculating the coefficient of accumulation in sediments (CAS) revealed that in Urup, the CAS values for Ni and Cu were 3046 and 11638, respectively, which indicates an emergency environmental situation, while for Co, Fe, and Mn, the situation is high level chronic pollution (CAS?>?10⁴). The Kuban CAS values of Fe and Mn were also >?10⁴, again highly and chronically polluted. Most of the metals in both rivers are bound to the sediments, with minimal mobility. The potential ecological risk is moderate to considerable in Urup, and low in the Kuban River.     

Effects of Manganese Mining on Water Quality in the Caucasus Mountains, Republic of Georgia

One of the world’s richest manganese (Mn) deposits and largest Mn mining areas lies in the foothills of the Caucasus Mountains, near the city of Chiatura in the Republic of Georgia. This study was an initial evaluation of the effects of Mn mining on water quality in the Chiatura region. Seven river and stream locations (three on the Kvirila River and four on tributaries), five untreated drinking water supplies (four springs and one groundwater well), and one untreated industrial wastewater discharge (Mn processing) were sampled and analyzed for field indicator parameters, anions, cations, and metals. Five river bed sediment sites (co-located with river water sites) were also sampled and analyzed for metals. Three of the public water supplies were contaminated by coliform bacteria, and concentrations of dissolved Mn, Fe, and Ni exceeded Georgian drinking water criteria in the groundwater supply well. The Kvirila River had very high concentrations of total Mn and Fe relative to an upstream location, especially downstream of the industrial discharges. Several tributaries also had elevated concentrations due to nonpoint source pollution from mine waste near the streams. Mn and Fe loads in the Kvirila River and tributaries were primarily in the particulate form. The river bed sediments at all five sampled river sites contained elevated metal concentrations. Mn and Ni, in particular, were very high in the Kvirila River near the discharges compared to background soil levels. Although Mn and Fe oxide solids in sediment can increase adsorption and attenuation of other metals from the water column, the contaminated sediments can also serve as a long-term residual source of metal contamination of river water, with potentially significant adverse ecological and human health effects.     

A Survey of the Geochemistry of Flooded Mine Shaft Water in Butte, Montana

Abstract.  This paper outlines general trends in the geochemistry of the more than 10,000 km of flooded underground mine workings in the Butte mining district. The waters in question range in pH from 4 to 8, are all moderately to strongly reducing, and show a huge range in concentration of dissolved metals such as Al, As, Fe, Mn, and Zn. Metal concentrations and total acidity are highest in the Kelley mine shaft, which was the main dewatering station used to pump ground water from the underground mine complex during active mining operations. In contrast, metal concentrations are much lower in the outer portions of the district where many of the mines contain hydrogen sulfide formed by sulfate-reducing bacteria. In comparison to the other heavy metals, concentrations of Pb and Cu are quite low in the flooded mine shafts. An interesting inverse correlation between pH and water temperature is noted, which may be partly caused by exothermic pyrite oxidation reactions in the central portion of the district.     

Contaminated Alluvial Ground Water in the Butte Summit Valley

Abstract.  Ground water in alluvial sediments of upper Silver Bow Creek is chronically contaminated with heavy metals, including Cd, Cu, Fe, Mn, and Zn. Most of this contamination stems from slag, mill tailings, and waste rock from the Butte mining district that had been deposited along the ancestral Silver Bow Creek floodplain. Much of this mine waste is now buried by fill, topsoil, buildings, or parking lots. Although the pH values of most wells in the region are in the 5.5 to 7.0 range, a cluster of monitoring wells near the site of a former mill and smelter contain water that is strongly acidic (pH < 4.5), with extremely high dissolved metal concentrations (Cu up to 750 mg/L; Zn up to 490 mg/L). Ground water discharging from the area is currently collected by a subsurface French drain and conveyed to a treatment facility where lime is added to precipitate metals from solution.     

煤矸石井下填充后降解残渣对地下水的影响

就煤矸石矿井填充过程中微生物作用后残渣对地下水的影响进行了研究。以平煤十二矿的焦煤、煤矸石、矿井水为研究对象,在添加接种物的情况下,以锰、铜、铅、锌、铁、钴和镍7种金属和有机质含量为研究指标,对残渣进行测定,结果表明,各种重金属随着浸泡时间的延长有不同的变化;随着浸泡时间的延长和煤矸石比例的增加,有机质含量有了大幅度的降低。     

The Chemistry of Waters Associated with Metal Mining in Macedonia

Abstract  Pollution from current and past mining is a significant problem in several parts of the former Yugoslav Republic of Macedonia. Water from six different mining areas in Macedonia was analysed to assess the effects of metalliferous mining activities. Drainage sediments at all locations show evidence of physical and chemical contamination; water compositions, however, were more variable. Low pH water associated with mining has led to the dissolution of minerals and the mobilization of metals from the ores and the host rocks. Only Sb was noted to exhibit enhanced mobility in higher pH waters. The Zletevo Pb-Zn mine discharges low pH water that has high levels of several metals, including Al, Zn, Cd, and Fe; sediment concentrations are grossly elevated for several km downstream. Toranica and Sasa Pb-Zn mines exhibit similar sediment contamination of Pb, Zn, Cd, and other ore-related metals. However, concentrations of metals in waters are far lower at both of these mines, due to less pyrite in the ore and the buffering of the acid waters by carbonate host lithologies. At the Buchim copper mine, waters are both acidic and high in dissolved solids; Cu concentrations exceed 100 mg/L. Krstov Dol and Alshar are small, disused As-Sb mines that discharge waters that exceed potable values for some contaminants (e. g. As), but this may be related to the mineralization of the bedrock rather than the mines. In general, metal concentrations decreased downstream from the source due to dilution from other rivers and coprecipitation of metals on other mineral phases (e. g. Fe-, Al- and Mn-oxides, and hydroxides).     

Drainage at Abandoned Mine Sites: Natural Attenuation of Contaminants in Different Seasons

Since 1996, hydrogeochemical surveys have been carried out in the abandoned Montevecchio Pb-Zn mining district (Sardinia, Italy), where mine drainages discharge directly into the local streams, to investigate variations in the aqueous occurrence of contaminants. Natural attenuation in dissolved contaminants occurs downstream of the abandoned mines. Iron is removed first (about 2 km downstream); lead, aluminum, and copper follow (about 4 km downstream). Other metals, such as zinc, cadmium, nickel, and rare earth elements, decrease further downstream. At high flow, natural attenuation is mainly due to dilution by rainwater. At low flow, natural attenuation processes are dominated by solid phase precipitation, efflorescent salt formation due to evaporation, and dilution by uncontaminated surface and/or groundwater inflow. Overall, concentrations of sulphate, Zn, Cd, Pb, Cu, Ni, and Co were less in 2010 than in 1996. The concentrations of dissolved sulphate and metals are lowest when the water is less acidic. However, despite ongoing natural attenuation, very high concentrations of toxic metals continue to be observed 15 years after the underground workings flooded. The amount of contaminants reaching the Marceddì lagoon increases as runoff increases following heavy rains.     

Processing of Phosphate Mine Tailings by Coagulation Flocculation to Reduce Marine Pollution in Togo: Laboratory Tests

Abstract  About 2.5 million t of sedimentary phosphorite mine tailings, highly enriched with trace metals such as Cd, Cr, Cu, Ni, and Zn, are dumped annually in the coastal waters of Togo without any pre-treatment, causing serious pollution problems in the region. We conducted laboratory jar tests of a coagulation-flocculation procedure with coagulants RM45U and AN945MPM to clarify the sludge. The efficiency of the method depends particularly on two factors: the amount of coagulant and the solid concentration of the sludge to be treated. Thus, with a mud concentration of 47.7 g/L, the average optimal amount of the two coagulants was 25 mg/L. With both coagulants, water turbidity passed from 60 x 103 NTU to approximately 3 NTU after clarification with the optimal amount of the two coagulants. RM45U reduced concentrations of Pb by 40%, Zn by 98.8%, Fe by 80.6%, and Cd by 32.8%. AN945MPM reduced Pb by 20%, Zn by 98.5%, Fe by 48%, and Cd by 32.8%.     

Removal of Metals and Acidity from Acid Mine Drainage Using Liquid and Dried Digested Sewage Sludge and Cattle Slurry

The metal removal and neutralization capacities of digested sewage sludges from municipal wastewater treatment plants, cattle slurry (liquid manure), and Biofert granules (dried granular anaerobic sludge) were compared under batch conditions using synthetic AMD (pH 2.8) containing high concentrations of Al, Cu, Fe, Mn, Pb, and Zn (100, 15, 270, 15, 2, and 30 mg/L, respectively). The effects of contact time and solids concentration were examined. Metal removal was variable for all materials. Contact time had a significant effect, with total removal often increasing over the experimental time interval (i.e. 30 min to 24 h). Removal efficiency (%) was generally highest for Cu, Pb, and Al, while Mn and Zn were the least removed. Cattle slurry was the best material for metal removal, with the following maximum removals at a solids concentration of 12.9 g/L: Cu >98 %, Al >98 %, Fe >60 %, Mn >18 %, Pb >96 %, and Zn >60 %. Metal removal using digested sewage sludge reached 88 % for Al, 98 % for Cu, 94 % for Pb, and 30 % for Zn. Neutralization was complete within 30 min after AMD was mixed with digested sludges or cattle slurry, with the pH reaching a maximum of 5.5 with the slurry. In contrast, neutralization by the Biofert granules only reached equilibrium after 300 min, and pH remained <4.0 except at high solids concentrations. It appears that recycled waste-derived organic materials can neutralize AMD and remove dissolved metals by adsorption and precipitation, creating a more treatable waste stream or one that could be discharged directly to surface water. Potential methods of safe disposal of metal-enriched organic materials are discussed.     

Passive Treatment of Circumneutral Mine Drainage from the St. Louis Mine Tunnel,Rico CO: Part 2—Vertical Biotreatment Train Pilot Study

This is the second of three papers dealing with metal-bearing circumneutral mine drainage from the inactive Rico-Argentine mine site located at an elevation of ≈ 2740 m (9000 feet) in the San Juan mountain range in southwestern Colorado. This paper evaluates two years of mine drainage treatment using a passive system that included a vertical-flow engineered biotreatment cell. The collapsed St. Louis Tunnel (SLT) discharges circumneutral mine water from several sources that contains elevated concentrations of Cd, Cu, Fe, Mn, Zn. A demonstration-scale 114 L/min (30 gpm) gravity-flow passive treatment system was installed, consisting of a settling basin (utilizing coagulant addition to improve suspended solids settling efficiency), an anaerobic sulfate-reducing bioreactor, and an aeration cascade for effluent polishing. The treatment system generally met target treatment goals for Cd, Cu, Fe, and Pb. Nanophase ZnS in system effluent decreased the frequency of meeting total Zn project treatment goals. Unexpectedly high levels of Mn removal were observed in both the anaerobic bioreactor and the aeration cascade. Large seasonal variations in influent metals concentrations and pH present the greatest challenge in managing system performance.

     

皖北煤矿区农田土壤-小麦中重金属分布特征 及健康风险评价

为了研究矿区农田土壤-小麦中重金属分布及农作物中重金属的迁移特征,以皖北恒源煤矿为研究对象,在矿区范围内采集了16个农田土壤和对应的小麦样品进行测试分析,应用内梅罗指数法评价了矿区内农田土壤重金属的污染状况,采用回归模型分析研究土壤根系、根系茎籽粒中重金属的迁移转化,并利用靶标危害系数法评价了小麦籽粒中重金属对人身健康的影响。研究结果表明:研究区农田土壤中的Cu、Zn、Mn、Pb、Hg、Cd、As、Cr和Ni等8种重金属元素含量低;小麦籽粒中重金属含量也未超出标准限量值;在小麦根、茎、籽粒等器官中,Mn、Pb、Cd、As、Cr和Ni在小麦根部含量最大,Hg较多地分布在小麦的茎中,Zn和Cu更易向上迁移至小麦的籽粒中;小麦籽粒中的Pb、Hg、Cd、As和Cr等重金属的单一重金属元素的靶标危害系数THQ和多种重金属元素的复合危害系数TTHQ均小于1。     

鞍山某铁矿区土壤重金属形态分布及生物有效性分析

研究鞍山某铁矿区周边土壤中5种重金属（Cd、Pb、Cu、Zn和Ni）的全量和形态分布,采用风险评价编码（RAC）法及次生相与原生相分布比值（RSP）法对元素生物有效性和环境风险进行评价。研究结果表明,该区土壤中Cd和Ni全量超出了国家二级标准,Pb、Cu和Zn未超限,但在土壤中富集明显;各重金属生物有效态占比的大小顺序为Cd > Pb > Ni > Zn > Cu,Cd元素生物活性最高且毒性最强;5种重金属的RAC值大小依次为Cd（40.62%）> Pb（21.60%）> Ni（16.31%）> Cu（12.16%）> Zn（9.74%）,RSP值大小依次为:Cd（1.31）> Pb（1.06）> Zn（0.94）> Ni（0.71）> Cu（0.39）。结合总量、生物有效性及形态学评价,该矿区土壤重金属Cd是生物活性最强、环境风险最高的元素,其次是Pb;Ni的生物有效性较低,但其全量已超标,因此应对该区Cd、Pb和Ni给予特别关注。      

煤矿复垦区土壤重金属含量时空分布及富集特征研究

为研究煤矿复垦区土壤重金属污染的时空变化及富集特征,以安徽淮南市潘一矿复垦区土壤为例,在2008-2010年期间对复垦区土壤中Cu,Mn,Ni,Pb,Cd,Hg,As 七种重金属元素进行了测定,并利用Surfer8.0软件对重金属的水平分布特征进行可视化表达。采用富集因子法来判断土壤中重金属人为污染情况。结果表明：煤矸石充填复垦区土壤,随着覆土年限的增加,除Mn和As元素外,Cu,Ni,Pb,Cd和Hg这5种重金属元素含量均高于淮南市土壤背景值,并出现一定程度的累积;从表层土壤重金属元素的水平空间分布看,煤矸石山的堆积、淋溶和粉煤灰贮灰场的存在对周边土壤造成了一定程度和范围的重金属污染。复垦区土壤剖面上Cu,Ni,Pb,Cd元素含量呈现表层（0~20 cm）和底层（80~100 cm）含量高,中部（20~80 cm）含量低的分布规律。分析重金属元素的富集因子,表明复垦区土壤已经受到了煤矿开采和煤矸石充填活动的影响。其中Cu,Ni,Pb,Hg和Cd元素已经出现富集,并且Cu,Ni,Pb,Hg元素达到了轻微污染水平,Cd元素达到了显著污染水平。Mn和As元素主要来源于土壤母质,没有受到污染。     

Assessment of Metal Contamination in the Mine Water of the West Bokaro Coalfield,India

This study was carried out in the West Bokaro coalfield area of the Jharkhand state of India to assess water quality for drinking and domestic purposes. Thirty mine water samples were collected from opencast and underground mines, and concentrations of Al, As, Ba, Cr, Cu, Fe, Mn, Ni, Se, and Zn were determined using ICP-MS. Spatial distribution maps were prepared using GIS software so that the quality of the mine water could be easily understood. Metal concentrations were higher in the pre-monsoon season than in the post-monsoon season, irrespective of location, but there were more significant seasonal variations in the opencast mine water than in the underground mine water. The concentrations of Al, Ba, Fe, Mn, and Ni exceeded the desirable as well as the permissible drinking water limits in both seasons. The quality of the surface water as well as the groundwater in the region may be adversely affected by the high metal concentrations in this mine water.     

Heavy Metals in Stream Sediments from the Coquimbo region (Chile): Effects of Sustained Mining and Natural Processes in a Semi-arid Andean Basin

Abstract.   Active sediments from the Elqui River in Chile were sampled 4 times at 10 sites during 2000. Concentrations of Ag, Ba, Cd, Co, Cr, Hg, Mn, Mo, Ni, Pb, Sr, Ti, V, Al, Ca, Fe, K, Mg, Na, P, and S were normal. Zinc levels were clearly high, and those of Cu (hundred to thousands ppm) and As (tens to hundreds ppm) were highly anomalous. Dissolved Cu (0.1-12.7 ppm) and Zn (0.2-2.2 ppm) levels were also very high. The anomalies of the upper tributaries are due to the El Indio–Tambo Au-Cu-As district and large hydrothermal alteration zones at altitudes between 3500–4500 m. Lower on the river, old and active tailing waste deposits and on-going mining operations in the Talcuna Cu (Pb) district are responsible. Partially eroded tailing deposits in the alluvial plain of the Elqui River and its tributaries, and especially in the El Indio-Tambo district, after mine closure in 2000, warrant special attention.