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2.
The Freiberg area in the Saxon Erzgebirge (Ore Mountains) represents one of the oldest mining districts in Germany. Argentiferous ore mineralizations with lead, zinc and copper are dominating in this region. Various waste products of mining can be found around Freiberg. In particular, the slags from ore smelting were and are regarded as unusable waste products. However, they preserve information on the smelting and weathering behaviour of slag, which makes them very useful sources of information for our purposes. To reconstruct the chemical processes during ore smelting, historical slag represents a most valuable archive. Therefore, the historical slag dump in Halsbach (Germany) was examined exemplarily for the Freiberg deposit. The slag was dumped approx. 400 years ago and is rich in lead. An interrelation between the slag and the metallurgical process applied can be made on the basis of chemical composition, appearance and microscopic results. The slags of the heap in Halsbach contain high concentrations of heavy metals (average contents in mg kg−1: Zn 40,000; Pb 10,000; Cu 1500; U 1000). Enrichments of heavy metals in the organic-rich soil horizons within the range of the dump foot (maximum contents in the A-horizon in mg kg−1: Zn 3719; Pb 9198; As 3017; Cu 963) imply a faint discharge of metals from the dump.  相似文献   

3.
The environmental impact and potential-risk assessment of an abandoned sulphide-mining site in a semiarid climate is presented here, by the study case of Sierra de Cartagena–La Unión (SE Spain), a 2,500-year-old mining district extending over an area of 100 km2. The regional map illustrates the existence of 12 open-pits, 1,902 mining wells, 2,351 waste deposits, including 89 tailing dams and waste rock derived from mining processes. Mine wastes occupy an area of 9 km2 and have an approximate volume of 200 Mm3. Mineralogical, physical and chemical data distinguish nine different types of mine and metallurgical waste. According to the concentration of sulphate and heavy metals in sediment, soil, rainwater, surface water and groundwater samples, it is possible to conclude that the impact of mine activities occurs not only in the immediate mining area (100 km2), but also in the surrounding areas (an affected area of 1,000 km2 approximately). The hydrochemical data show that groundwater, runoff water and some rainwater samples exceed Spanish and European water quality guideline values for water supply. The main geochemical process recognised is sulphide-mineral oxidation and later-generated sulphate dissolution by groundwater and runoff. Runoff and wind are the major mechanisms of metals and sulphate transport in the study area and adjacent zones.  相似文献   

4.
 The focus of this research was to determine the impact of abandoned mines on surface water and groundwater in the historical mining districts of the Cerbat Mountains, Arizona. The surface water in the mining areas was found to be contaminated by various combinations and concentrations of heavy metals. Elevated arsenic, cadmium, and iron concentrations were detected in most surface-water samples, while lead, copper, and zinc contamination differed from region to region, depending on the ore mined. The groundwater was seriously polluted by arsenic, cadmium, lead, zinc, iron, and manganese in the immediate vicinity of mines that processed ore on the site, such as the Tennessee Mine near Chloride. Chloride's groundwater, however, showed no evidence of contamination. Three possible explanations are discussed: immobilization of the heavy metals in the soil by chemical reactions and adsorption, dilution effects due to the rainy season in spring, or the existence of different groundwater systems. Received: 17 September 1996 · Accepted: 14 May 1997  相似文献   

5.
Phosphate mining in southeastern Idaho has historically resulted in the release of dissolved metals and inorganics to groundwater and surface water, primarily due to leachate from waste rock in backfilled pits and overburden storage piles. Selenium (Se) is of particular concern due to its high concentration in leachate and its limited attenuation downgradient of source zones under oxic conditions. Assessments of potential groundwater/surface water impacts from waste rock typically involve laboratory characterization using saturated and unsaturated flow columns packed with waste rock. In this study, we compare the results of saturated and unsaturated column tests with groundwater quality data from the Mountain Fuel, Champ, South and Central Rasmussen Ridge Area (SCRRA), Smoky Canyon, Ballard, Henry, and Enoch Valley Mines, to understand the release and attenuation of Se in different geochemical environments. Column studies and field results demonstrate that the ratio of aqueous Se to aqueous sulfate (Se:SO4 ratio) is a useful metric for understanding Se release and attenuation, where the extent of sulfate reduction is much less than Se reduction. Comparison of dissolved Se and sulfate results suggests that the net leachability of Se from unsaturated waste rock is variable. Overall, Se concentrations in groundwater directly beneath waste rock dumps is not as high as would be predicted from unsaturated columns. Lower Se:SO4 ratios are observed immediately beneath waste rock dumps and backfilled pits relative to areas receiving shallow waste rock runoff. It is hypothesized that Se released in the oxic upper portions of the waste rock is subsequently attenuated via reductive precipitation at depth in unsaturated, low-oxygen portions of the waste rock. This highlights an important mechanism by which Se may be naturally attenuated within waste rock piles prior to discharge to groundwater and surface water. These results have important implications for mining practices in the region. A better understanding of Se dynamics can help drive waste rock management during active mining and capping/water management options during post-mining reclamation.  相似文献   

6.
煤矿开采势必破坏天然水化学环境,然而矿区多类含水层地下水系统水化学研究尚未从时空角度分析采动影响下水化学演化的本质。以临涣矿区为研究示范,基于历年常规水化学数据开展主成分分析,揭示采动影响下水化学演化过程中的水-岩作用机制。其中,第1主成分代表碳酸盐、硫酸盐溶解及黄铁矿氧化作用,第2主成分代表阳离子交替吸附及脱硫酸作用。采动影响下矿区主要突水含水层地下水碳酸盐、硫酸盐溶解及黄铁矿氧化作用均逐渐减弱,减弱区域不尽相同;然而,阳离子交替吸附及脱硫酸作用的变化规律不明显。研究成果为矿井突水水源识别和水资源保护与利用提供理论依据。  相似文献   

7.
黑河中游绿洲典型灌区地下水资源总均衡估算   总被引：6，自引：0，他引：6  
根据对研究区多年的水文地质观测资料的分析和研究,建立了黑河中游典型灌区地下水水资源总均衡模型,选取了黑河干流具有代表性的平川、板桥、鸭暖和蓼泉灌区,对地下水均衡模型中的补给项及排泄项的主要变量分别进行了估算,结果表明:各灌区均衡期内地下水动态资料计算的均衡期始末地下水储存量变化与模型计算的均衡差基本相近,其相对误差为-17.6%,说明均衡模型对于估算内陆绿洲灌区地下水资源均衡是比较准确的。  相似文献   

8.
The oxidation of sulfide minerals generates acidic waters containing high levels of SO4 and Fe. The study area has active Pb?CZn?CCu mining. It is thought that the surface/subsurface/underground sulfide minerals in the region generally contribute to the acidification of groundwater. Low pH values are also responsible for dissolved metals (Al, Fe, Mn, SO4, Pb, Zn) in the groundwater and river. Furthermore, current mining wastes have affected concentrations of trace elements in the water. High Fe and Mn concentrations are generally found in the spring which has acidic and low Eh values, while Al, Fe and Mn concentrations in the acidic waters show notable increases with the maximum values reaching 8,829, 19,084 and 1,708?ppb, respectively. These values exceed the Turkish drinking water standard of 200, 200 and 50?ppb, respectively.  相似文献   

9.
《Applied Geochemistry》2001,16(14):1631-1640
Oxidation of sulfide present in mining residues can generate contaminating acid effluent known as acid rock drainage. Prediction and control of acid rock drainage are critically important to the mining industry because of the environmental impact resulting from the sulfide oxidation. Due to its particular reaction kinetics, once acid drainage has begun, it is very difficult to control without a substantial economic investment. For this reason, efficient prediction and prevention programs, which monitor mining waste reactivity, are required to limit the oxidation of sulfide-bearing residues before damage to the environment occurs. In this work, the authors evaluated mining waste reactivity under oxidizing conditions as a function of its voltammetric behavior before and during alteration under simulated natural conditions produced in the laboratory. This method is supported by conventional mineralogical characterization of the mineral samples and chemical quality of the effluents produced during the simulated alteration process kinetics.  相似文献   

10.
The reconstruction of the hydrogeochemical composition of the dumps in the active Lusatian lignite mining region is necessary to forecast the acid mine drainage into the residual lakes and the natural groundwater systems. Therefore, a three-dimensional geochemical model of the Jänschwalde dump was developed. By analysing the geological situation and the mining technology, it is possible to calculate the pyrite oxidation in different parts of the mine (groundwater lowering in front of the mine, natural and dump slopes, marginal pits and the dump surface).Only 4% of the total pyrite content is oxidised during the mining process within its time of operation (43 years). The major fraction (about 60%) is oxidised on the surface of the dumps, whereas the other zones contribute less to the production of acidity (groundwater lowering 5.4%, short term exposed slopes (1.2% natural slopes; 7.4% dump slopes) and 22.4% inclusion of O2 during the tipping). It may be concluded that the technology of conveyor belt bridges, combined with the selective tipping of loamy sediments on the surface is very favourable to minimise the oxidation of pyrite. It is also shown that in the open cast mine of Jänschwalde the buffer capacity of the carbonate dominates over the produced acid.  相似文献   

11.
Acidification of Earth: An assessment across mechanisms and scales   总被引：1，自引：0，他引：1  
In this review article, anthropogenic activities that cause acidification of Earth’s air, waters, and soils are examined. Although there are many mechanisms of acidification, the focus is on the major ones, including emissions from combustion of fossil fuels and smelting of ores, mining of coal and metal ores, and application of nitrogen fertilizer to soils, by elucidating the underlying biogeochemical reactions as well as assessing the magnitude of the effects. These widespread activities have resulted in (1) increased CO2 concentration in the atmosphere that acidifies the oceans; (2) acidic atmospheric deposition that acidifies soils and bodies of freshwater; (3) acid mine drainage that acidifies bodies of freshwater and groundwaters; and (4) nitrification that acidifies soils. Although natural geochemical reactions of mineral weathering and ion exchange work to buffer acidification, the slow reaction rates or the limited abundance of reactant phases are overwhelmed by the onslaught of anthropogenic acid loading. Relatively recent modifications of resource extraction and usage in some regions of the world have begun to ameliorate local acidification, but expanding use of resources in other regions is causing environmental acidification in previously unnoticed places. World maps of coal consumption, Cu mining and smelting, and N fertilizer application are presented to demonstrate the complex spatial heterogeneity of resource consumption as well as the overlap in acidifying potential derived from distinctly different phenomena. Projected population increase by country over the next four decades indicates areas with the highest potential for acidification, so enabling anticipation and planning to offset or mitigate the deleterious environmental effects associated with these global shifts in the consumption of energy, mineral, and food resources.  相似文献   

12.
A total of 31 topsoil samples were systematically collected from the Panzhihuaminingarea including steel smelting,coal mining ,urban and rural districts.A normalization procedure was adopted to establish the environmental geochemical baseline models for this area.By using the above baseline models,the regional geochemical baseline values of As,Cr,Cu,Ni,Pb and Zn were determined.On the basis of the baselines,the enrichment factors were used to analyze the mechanism of trace metal pollution in topsoil from anthropogenic sources,and the results showed that the serious trace metal pollution is caused by human activities in coal mine,iron mine,smelting factory,tailing dam and other industrial districts in the Panzhihua area.  相似文献   

13.
The aim of this research is to determine the effective factors on the hydrogeochemistry and assessment of heavy metals pollution indices in the groundwater of Ardestan copper exploration area, Iran. In this study, in total, 111 groundwater samples from one well and several qanats and springs were collected. Piper and Stiff diagrams and statistical methods and quality indices were applied to hydrochemical data. Afterward, the water samples were classified into four groups, namely CaHCO3, CaCl, NaCl, and NaHCO3. According to evaluation indices, considering the fact that only a few points are in the high risk level, the groundwater of the study area has a low level of pollution. On the other hand, the pH of the groundwater of the region was mostly neutral and acid mine drainage was not found. Since the condition of the area is in pre-mining process, two factors are possibly influential: (1) rocks or minerals having sulfides are not exposed to an atmosphere (normally below groundwater) and H+ release does not occur and (2) the existence of minerals containing silicate and carbonate that can rapidly reduce acidification of water. Finally, it seems that during mining and in post-mining conditions, acid rock drainage which results from the oxidation of sulfides will probably influence the quality of water resources in Ardestan city. This is because the groundwater flow direction is from the mine toward Ardestan plain.  相似文献   

14.
 The San Antonio-El Triunfo mining district, located at a mountainous region 45 km south-east of La Paz, Baja California, has been worked since the late 1700s. Mine waste material produced during 200 years of mineral extraction area poses a risk of local groundwater pollution and eventually, regional pollution to the Carrizal (west basin) and the Los Planes (east basin) aquifers. There are different types of deposits in the mining area. These are dominated by epithermal veins, in which arsenopyrite is an important component. Carrillo and Drever (1998a) concluded that, even though the amount of mine waste is relatively small in comparison to the large scale area, significant As in groundwater derived from the mine waste piles is found locally in the groundwater. This paper shows the results of geochemical analyses of groundwater samples from the San Antonio-El Triunfo area and the Carrizal and Los Planes aquifers during several years of monitoring (1993–1997). The highest values of total dissolved solids (TDS) and As are in the mineralized area where the mining operations occurred (∼1500 ppm TDS and 0.41 ppm As). The lowest concentrations of TDS and As are, in general, away from the mineralized area (∼500 ppm TDS and 0.01 ppm As). Sulfate and bicarbonate (alkalinity) are, in general, high near the mineralized area and low away from it. The arsenic concentrations vary seasonally, especially after the heavy summer thunderstorms. Geochemical modeling (MINTEQA2 and NETPATH) and analysis of the regional geochemical evolution of the groundwater from the mining area towards the aquifer of Los Planes shows that the most likely hydrochemical processes include: dilution, precipitation of calcite, and adsorption of As onto surfaces of iron oxyhydroxides (ferrihydrite). These processes act as natural controls to the extent and amount of As pollution in the Carrizal and Los Planes aquifers. Received: 4 May 1999 · Accepted: 22 February 2000  相似文献   

15.
São Domingos is one of the most emblematic Portuguese mining districts in the Iberian Pyrite Belt (IPB). The beginning of mining exploitation in the area has been dated back to pre-Roman times, remaining in activity until 1966 when it was definitely halted. The intense mining labours are reflected in the presence of a huge amount of sulphide-mining wastes and downstream production of acid mine drainage (AMD). The mining wastes in the area are highly heterogeneous, and numerous different types may be recognized, including slags, iron oxides, smelting ashes, brittle and blocks of pyrite, leaching tank refuses, industrial landfill and other residues coming from ore extraction (gossan wastes and country rocks). The chemical speciation of potentially toxic elements (As, Cd, Cr, Cu, Fe, Mn, Pb, S, Sb and Zn) in all mine wastes from São Domingos was determined by modified BCR-sequential extraction procedure (European Community Bureau of Reference) and combined with the mass/volume proportions of each waste to quantify the potential risk of this mining district at regional scale. Analytical recoveries by sequential extraction, with respect to a pseudo-total metal content digestion, were generally acceptable (100 ± 17%). The oxidizable fraction corresponds with metals bound to sulphides and released easily under oxidizing conditions in AMD production processes. This is the most polluting fraction for the environment in this type of residues. Part of this fraction is retained by precipitation of soluble secondary minerals in warm periods, moving to the bio-available fraction that is dissolved in rainy periods. Just considering the bio-available fraction, all mine wastes from São Domingos may leach up to 172514 ton of Fe, 10564 ton of S, 6644 ton of Pb, 2610 ton of Zn, 1126 ton of Mn, 1032 ton of Cu, 183 ton of Cr, 109 ton of As, 34 ton of Sb and 0.9 ton of Cd. The process of precipitation and re-dissolution of efflorescent salts formed directly by oxidation of the oxidizable fraction is seasonally repeated, which causes an annual self-feeding and releasing of the bio-available fraction. Thus, the present study shows the pollutant potential of this IPB mining district and explains the spoiled state of the fluvial courses in the region.  相似文献   

16.
金属硫化物矿山的废石堆场受降水淋滤影响而发生硫化物氧化,产生硫酸并释放重金属,因此采矿工程产生的废石是水污染不可忽视的来源。前人关于金属硫化矿物氧化的机理研究大多集中在单一矿物的室内实验,与野外情况匹配度较低。本研究从岩样(矿石和废石)、水样(河水、地下水、废弃尾矿库渗滤液)的水化学、微量元素和锶同位素等方面,分析某铅锌矿废石堆场对水环境的影响,并讨论其产生的化学组分在野外环境中的变化规律及机理。研究结果显示,金属硫化物氧化造成了河水酸化,pH低至2.38,SO42-高达9421 mg·L-1,同时微量元素中Zn、Pb、Ni、Mn、Cd质量浓度远超饮用水限值,如Zn达到了582 mg·L-1(饮用水限值为1 mg·L-1),且浓度与pH负相关。河水酸化的主因是黄铁矿、磁黄铁矿的氧化作用,并贡献了河水中大部分的SO42-。闪锌矿等矿物在贡献了河水中少部分SO42-的同时,也是重金属元素的主要来源。地下水离子浓度较河水低,pH在中性左右。虽然主要是受到侧向山体地下水补给稀释,但碳酸盐和硅酸盐对酸起到的中和作用对酸性水的治理有很大启示价值。以上机理的认识对于废石对水土环境污染的防治具有重要意义。  相似文献   

17.
《Applied Geochemistry》2004,19(3):261-271
The distribution of Rare Earth Elements (REE) was investigated in the acidic waters (lake and groundwater) of a lignite mining district (Germany). The Fe- and SO4-rich lake water (pH 2.7) displays high REE contents (e.g. La∼70 μg/l, Ce∼160 μg/l) and an enrichment of light REE (LREE) in the NASC normalised pattern. Considering the hydrodynamic model and geochemical data, the lake water composition may be calculated as a mixture of inflowing Quaternary and mining dump groundwaters. The groundwater of the dump aquifer is LREE enriched. Nevertheless, the leachates of dump sediments generally have low REE contents and display flat NASC normalised patterns. However, geochemical differences and REE pattern in undisturbed lignite (LREE enriched pattern and low water soluble REE contents) and the weathered lignite of the dumps (flat REE pattern and high water soluble REE contents) suggest that lignite is probably the main REE source rock for the lake water.  相似文献   

18.
Groundwater recharge rates calculated with the GROWA model have been applied as the recharge boundary condition for the regional groundwater model Rurscholle. This model simulates groundwater dynamics in the Pleistocene aquifers of the Lower Rhine lignite mining area (Germany). GROWA uses an area-differentiated approach to calculate recharge rates depending on runoff-relevant site characteristics, which are represented by a set of baseflow indices. The regional accuracy of the coupled groundwater and GROWA models has been checked using groundwater hydrographs as validation criteria. The results suggest that the current (unadjusted) version of GROWA underestimates the regional groundwater recharge rate by 10–20 mm/yr. The comparative analysis identified areas where recharge calculations could be improved by adjusting the baseflow indices for areas where runoff is dominated by slope, low water-logging and a low degree of sealing. Using the adjusted set of baseflow indices, the mean groundwater recharge rate of the Rurscholle region was modelled as approx. 170 mm/yr. This study highlights the benefit of using a coupled approach and being able to independently calibrate and validate groundwater recharge boundary conditions in regional groundwater models.  相似文献   

19.
The Shoalhaven region of NSW experiences environmental acidification due to acid sulphate soils (ASS). In order to trial an environmental engineering solution to groundwater remediation involving a permeable reactive barrier (PRB), comprehensive site characterisation and laboratory-based batch and column tests of reactive materials were conducted. The PRB is designed to perform in situ remediation of the acidic groundwater (pH 3) that is generated in ASS. Twenty-five alkaline reactive materials have been tested for suitability for the barrier, with an emphasis on waste materials, including waste concrete, limestone, calcite-bearing zeolitic breccia, blast furnace slag and oyster shells. Following three phases of batch tests, two waste materials (waste concrete and oyster shells) were chosen for column tests that simulate flow conditions through the barrier and using acidic water from the field site (pH 3). Both waste materials successfully treated with the acidic water, for example, after 300 pore volumes, the oyster shells still neutralised the water (pH 7).  相似文献   

20.
Mining/smelting wastes and reservoir sediment cores from the Lot River watershed were studied using mineralogical (XRD, SEM–EDS, EMPA) and geochemical (redox dynamics, selective extractions) approaches to characterize the main carrier phases of trace metals. These two approaches permitted determining the role of post-depositional redistribution processes in sediments and their effects on the fate and mobility of trace metals. The mining/smelting wastes showed heterogeneous mineral compositions with highly variable contents of trace metals. The main trace metal-bearing phases include spinels affected by secondary processes, silicates and sulfates. The results indicate a clear change in the chemical partitioning of trace metals between the reservoir sediments upstream and downstream of the mining/smelting activities, with the downstream sediments showing a 2-fold to 5-fold greater contribution of the oxidizable fraction. This increase was ascribed to stronger post-depositional redistribution of trace metals related to intense early diagenetic processes, including dissolution of trace metal-bearing phases and precipitation of authigenic sulfide phases through organic matter (OM) mineralization. This redistribution is due to high inputs (derived from mining/smelting waste weathering) at the water–sediment interface of (i) dissolved SO4 promoting more efficient OM mineralization, and (ii) highly reactive trace metal-bearing particles. As a result, the main trace metal-bearing phases in the downstream sediments are represented by Zn- and Fe-sulfides, with minor occurrence of detrital zincian spinels, sulfates and Fe-oxyhydroxides. Sequestration of trace metals in sulfides at depth in reservoir sediments does not represent long term sequestration owing to possible resuspension of anoxic sediments by natural (floods) and/or anthropogenic (dredging, dam flush) events that might promote trace metal mobilization through sulfide oxidation. It is estimated that, during a major flood event, about 870 t of Zn, 18 t of Cd, 25 t of Pb and 17 t of Cu could be mobilized from the downstream reservoir sediments along the Lot River by resuspension-induced oxidation of sulfide phases. These amounts are equivalent to 13-fold (Cd), ∼6-fold (Zn), 4-fold (Pb) the mean annual inputs of the respective dissolved trace metals into the Gironde estuary.  相似文献   

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