共查询到20条相似文献,搜索用时 15 毫秒
1.
Abstract Closure of Pb-Zn mines in the Iglesias district (SW Sardinia, Italy) caused the cessation of pumping in 1997, and the consequent flooding of underground workings. Deep saline water mixed with the shallow groundwater as the water table rose, increasing salinity. Stratification caused the saline water at depth to settle over a period of three years. At the beginning of rebound, an increase in dissolved Zn, Cd, Pb, and Hg was observed under near-neutral pH conditions. Following peak concentrations, a marked decrease of Zn, Cd, and Hg, and to a lesser extend Pb, occurred. After 7 years of rebound, the concentrations of these metals are relatively low at most mine sites, although the levels are generally still higher than in unmined areas. Nowadays, the highest release of metals to the aquatic system occurs from the weathering of tailings and mine wastes. 相似文献
2.
M. El Adnani B. Plante M. Benzaazoua R. Hakkou H. Bouzahzah 《Mine Water and the Environment》2016,35(4):508-524
The abandoned Zgounder Mine (Morocco) was exploited for Ag from 1982 to 1990 and generated nearly 490,000 t of mill tailings before it was closed without being reclaimed. The tailings contain low concentrations of sulfide (mainly as pyrite, sphalerite, and galena) and carbonates (mainly dolomite). Silicates (muscovite, albite, chlorite, labradorite, actinolite, and orthoclase) occur in high concentrations. The most abundant trace elements are As, Ti, Fe, Mn, Zn, and Pb. We studied the geochemical behavior of the mine wastes to identify the main factors controlling drainage water chemistry. Particular emphasis was put on sorption phenomena to explain the low As concentrations in the leachates despite significant As levels in the tailings. Weathering cell tests carried out on various tailings produced two types of contaminated drainage: acidic and neutral. The kinetic test leachates contained high concentrations of some contaminants, including As (0.8 mg L?1), Co (11 mg L?1), Cu (34 mg L?1), Fe (70 mg L?1), Mn (126 mg L?1), and Zn (314 mg L?1). Acidity and contaminants in the leachates were controlled by dissolution of soluble salts and Fe hydrolysis rather than sulfide oxidation. Batch sorption tests quantified the significance of As sorption, and sequential extraction showed that most of the As sorption was associated with the reducible fractions (Fe and Mn oxides and oxyhydroxides). 相似文献
3.
Christopher H. Gammons 《Mine Water and the Environment》2006,25(2):114-123
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. 相似文献
4.
B. M. Patterson B. S. Robertson R. J. Woodbury B. Talbot G. B. Davis 《Mine Water and the Environment》2006,25(3):137-145
Abstract. A high density polypropylene (HDPE) and bentonite composite cover, used to reduce oxygen ingress into a sulfidic tailings
facility, was evaluated over a 7 year post-installation period between 1998 and 2005, and found to be a reliable long-term
barrier to oxygen ingress and rainfall infiltration. The evaluation was based on multiple lines of evidence and included (i)
changes in metal and inorganic concentrations in the regional ground water immediately underlying the tailings residue; (ii)
oxygen concentrations from probes installed below the composite cover; (iii) changes in pore water levels within the tailings
residue, and; (iv) changes in temperature of the vadose zone below the composite cover.
While no systematic reduction in metal and inorganic concentrations were observed, oxygen concentrations from most probes
installed below the composite cover showed no measurable oxygen (< 0.01%) and indicated that oxygen ingress through the composite
cover was slow, compared to oxygen consumption in the tailings residue. The decline and stabilization in pore water levels
over time within the tailings residue provided evidence that the cover effectively reduced infiltration of rainfall-recharge
through the tailings residue. Temperatures below the composite cover were offset and attenuated with depth, and showed a decrease
in temperature (especially at the deepest location just above the tailings residue), suggesting that the exothermic sulfide
oxidation reaction process was not maintained after the cover was installed. 相似文献
5.
Removal of Sulfate,Zinc, and Lead from Alkaline Mine Wastewater Using Pilot-scale Surface-Flow Wetlands at Tara Mines,Ireland 总被引:1,自引:0,他引:1
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. 相似文献
6.
Abstract Batch incubation and flow-through column experiments were conducted to evaluate the use of emulsified soybean oil for in situ
treatment of acid mine drainage. Addition of soybean oil, soluble substrates, and a microbial inoculum to the batch incubations
resulted in complete depletion of SO4, 50% reduction in Fe, and an increase in pH to >6. A one time injection of emulsified soybean oil, lactate, yeast extract,
and a microbial inoculum stimulated SO4 and metal ion reduction for ≈300 days in laboratory columns packed with mine tailings receiving influent solutions with
a pH≈3 and≈5. In all emulsion treated columns, SO4 and Fe were reduced, pH increased to >6, and Al, Cu and Zn removal efficiency was 99% or greater. Cu, Fe, Mn and Zn were
removed as metal sulfides and/or carbonates with removal efficiency decreasing with increasing metal sulfide solubility. The
low pH and high heavy metals concentrations did not significantly inhibit biological activity. However, SO4 removal with associated precipitation of metal sulfides may have been limited by the short hydraulic retention time (6-7
days) of the columns. There was a significant hydraulic conductivity loss in one of the four treated columns, indicating that
hydraulic conductivity loss may be an issue under certain conditions. 相似文献
7.
Abstract. The basic chemical properties of Tertiary (T) and Quaternary (Q) aquifers near the Piaseczno opencast sulphur mine and the
water in the open pit, along with the stratigraphy and hydrogeology of the area, were characterized to assess the feasibility
of inundating the mine with ground water. Ground water quality varied markedly in the opencast area. A distinct stratification
was noted in the pit water; total dissolved solids, calcium, chloride, hardness, and hydrogen sulphide increased from the
top water level to the bottom of the pit lake. The concentrations of SO42- and Cl- in the opencast water were very high, especially in the hypolimnion zone. Based on our preliminary analysis, it appears that
an artificial lake formed in the Piaseczno open pit could be used in the future as a fish and wildlife habitat as well as
for recreational purposes. 相似文献
8.
K. Gnandi G. Tchangbedji K. Killi G. Baba A. I. Ouro Salim 《Mine Water and the Environment》2005,24(4):215-221
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%. 相似文献
9.
Kaisa Turunen Soile Backnäs Raisa Neitola Antti Pasanen 《Mine Water and the Environment》2016,35(4):407-420
The behaviour of arsenic (As) derived from tailings was investigated at the Yara Siilinjärvi apatite mine and industrial site in eastern Finland. The study assessed factors influencing the migration and fate of As and compared the anthropogenic As load to the natural geogenic background. Environmental risks related to As were assessed by examining the As concentrations in humus, glacial till, aquatic sediments, groundwater, and surface water. The occurrence and fractionation of As and the presence of secondary precipitates and geochemical transformations in the tailings and in the ambient soil and sediment were evaluated by selective extraction. The water-derived emissions were evaluated by field measurements, hydrogeochemical analysis, and modelling. Results indicate elevated environmental risks due to dust and seepage emissions from the tailings since the concentrations and mobility of As and other potentially harmful elements (PHEs) such as Co, Ni, and Zn were elevated relative to the geogenic background. These elements were mainly associated with Fe (oxy)hydroxides in the soil and their mobility was closely linked to Fe biogeochemistry. Additionally, although the concentrations of As and PHEs were high in the tailings pond and seepage water, they decreased in ambient groundwater and surface water, indicating Fe (oxy)hydroxide stability. This was supported by hydrogeochemical modelling, which indicated precipitation of Fe oxides and hydroxides. According to speciation modelling, As was present mainly as toxic trivalent arsenious acid (H3AsO3) in groundwater and as the less toxic pentavalent As acid (H2AsO4 ? and HAsO4 2?) in surface water. 相似文献
10.
Radhia Souissi Fouad Souissi Hédi Karim Chakroun Jean Luc Bouchardon 《Mine Water and the Environment》2013,32(1):16-27
Millions of tonnes of Pb–Zn ore flotation tailings and waste rock have been discharged at sites in northern Tunisia without concern for environmental issues. The tailings are dominantly fine grained (<125 μm), with high porosity and permeability. The tailings were characterized to assess base metal (Pb, Zn, and Cd) mobility. The relatively low percentage of iron sulphide and the dominance of carbonates in the matrices of the tailings indicated that only neutral mine drainage is likely. Batch sequential testing showed that the calcium and sulphate, which are the major ionic species in solution, are derived mainly from the dissolution of gypsum and not from neutralization of acidity generated by pyrite oxidation. Yet, despite the carbonate setting, the resultant neutral to slightly alkaline pH, and prolonged weathering, the studied flotation tailings maintain their capacity to release contaminants, notably Zn and Cd, into the environment. The amount of Zn that dissolves (2,400 μg L?1, on average), though significant, is below the background concentrations in the Mejerda River and the environmental norms established for surface waters. Pb concentrations come close to the standards, but only Cd (18 μg L?1, on average) sometimes exceeds current river water concentrations and environmental standards. 相似文献
11.
《Minerals Engineering》2007,20(2):173-178
In the present study, heavy-metal tolerance and precipitation by a mixed culture of sulfate-reducing bacteria (SRB) were evaluated. These bacteria have been enriched during a previous study from a sewage sludge using phosphogypsum as sulfate source. Taking into account that both sulfate and zinc are naturally occurring in phosphogypsum, zinc tolerance of SRB was tested in synthetic media containing 20 mM sulfate and zinc chloride at concentrations ranging from 0 to 200 mg L−1. Zinc tolerance was determined by bacterial growth susceptibility and zinc removal monitoring. Bacterial growth and sulfate reduction were possible between 10 and 150 mg L−1 of initial zinc concentration. Zinc concentrations more than 150 mg L−1 were lethal to SRB. Zinc was removed effectively by SRB to less than 5% from medium containing 150 mg L−1 initial zinc concentrations or less. Energy-dispersive X-ray analysis showed that precipitation of zinc occurred in the form of sulfide. The results presented in this paper have shown that this mixed culture might be of use for bioremediation of sulfate and heavy-metals containing wastewaters. 相似文献
12.
Abstract.
This paper describes pilot scale tests of a novel process for the neutralisation of acidic mine water. Leachate from a waste coal dump was neutralised with limestone, and iron, aluminium, and sulphate were removed. Specific aspects studied were: the process configuration; the rates of iron oxidation, limestone neutralisation, and gypsum crystallisation; the chemical composition of the effluents before and after treatment; the efficiency of limestone utilisation; and the sludge solids content. The acidity was decreased from 12,000 to 300 mg/L (as CaCO3), sulphate from 15,000 to 2,600 mg/L, iron from 5,000 to 10 mg/L, aluminium from 100 to 5 mg/L, while the pH increased from 2.2 to 7.0. Reaction times of 2.0 and 4.5 h were required under continuous and batch operations respectively for the removal of 4 g/L Fe (II). The iron oxidation rate was found to be a function of the Fe (II), hydroxide, oxygen, and suspended solids (SS) concentrations. The optimum SS concentration for iron oxidation in a fluidised-bed reactor was 190 g/L. Up-flow velocity had no influence on the rate of iron oxidation in the range 5 to 45 m/h. Sludge with a high solids content of 55% (m/v) was produced. This is high compared to the typical 20% achieved with the high density sludge process using lime. It was determined that neutralisation costs could be reduced significantly with an integrated iron oxidation and limestone neutralisation process because limestone is less expensive than lime, and a high-solids-content sludge is produced. Full scale implementation followed this study. 相似文献
13.
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. 相似文献
14.
The Impact of Phosphate Mine Tailings on the Bioaccumulation of Heavy Metals in Marine Fish and Crustaceans from the Coastal Zone of Togo 总被引:1,自引:0,他引:1
Abstract About 2.5 million t of sedimentary phosphorite mine tailings, highly enriched with Cd, Cr, Cu, Ni, Fe, F, and Zn, are dumped
annually in the coastal waters of Togo without any pre-treatment, causing serious pollution problems in the region. We conducted
bioaccumulation investigations on fish and crustaceans sampled from the polluted coastal zone. The highest concentrations
of metals in fish and crustacean were found close to the tailings outfall and the values decreased further away from the source
of pollution. Compared to the international reference norms for seafood given by the WHO, Cd is enriched 10 to 168 fold, Pb
20 to 107 fold, Cu up to 5 fold, Fe up to 15 fold, and F up to 3 fold. 相似文献
15.
《Minerals Engineering》2003,16(3):229-236
Along with chemicals deliberately added in the process, the process water quality is affected by species dissolved from the minerals and the air. In the case of the separation of calcite and apatite by flotation, Ca2+, CO32− and HCO3− are such species, and the variations of their aqueous concentrations can be expected to influence the process performance. In this study, both the long-term and short-term variations of pH, as well as the above-mentioned concentrations in two process water streams at the Siilinjärvi apatite concentrating plant, were monitored on-line. Obvious seasonal and diurnal variations in these concentrations were observed in the recirculated water reclaimed from the tailings ponds. Such variations are probably due to changes in the biological activity in the ponds. Further, the commercial process titrator OMT 20 DX delivered by Murtac GmbH, and sampling using laboratory-scale CERAMEC filters delivered by Outokumpu Mintec, proved to be a reliable concept in the demanding conditions of a concentrating plant. 相似文献
16.
Laboratory Evaluation of the Use of Alkaline Phosphate Wastes for the Control of Acidic Mine Drainage 总被引:1,自引:1,他引:0
Pyrrhotite tailings at the abandoned Kettara mine site in Morocco are producing acid mine drainage (AMD). We investigated
the use of alkaline phosphate waste (APW) rock from a nearby operating open-pit phosphate mine to control the AMD. The neutralizing
potential of the APW, using the Paktunc method, was estimated between 500 and 680 kg CaCO3/t. In laboratory column tests, the addition of 15 wt% APW to the coarse Kettara tailings produced leachates with significantly
lower acidities and metal concentrations than unamended controls. The high calcium concentration in the flushed solutions
indicates that calcite was responsible for the neutralization. Dolomite dissolution seems to be negligible and fluorapatite
was stable under the testing conditions. It was also observed that when the treated solution comes in contact with unweathered
Kettara coarse tailings, the pH becomes acidic, although the metal concentrations remain low. 相似文献
17.
Abstract Closure of Pb-Zn mines in the Iglesiente district (SW Sardinia, Italy) caused the cessation of pumping in 1997 at Monteponi,
and in 1998 at San Giovanni. Consequent flooding of underground workings occurred in the district and also involved Campo
Pisano. In June 1998, as the water table rose from 160 to 20 m below sea level, the deep saline water mixed with the shallow
ground water at Monteponi and nearby mines. In the same period, an increase in dissolved metals (especially Zn, Cd, and Pb)
was observed under near-neutral pH conditions. Following peak concentrations, a marked decrease of Zn, Cd, and Hg occurred.
Dissolved Pb showed fluctuating concentrations over the monitoring period (1996-2005). In January 2000, when the water table
rose to 20 m above sea level, the salinity of ground water decreased significantly at all of the mines. Stratification caused
the more saline water at depth to settle three years after rebound started. Depth profiles carried out in 2005 at Monteponi,
San Giovanni, and Campo Pisano showed an increase in conductivity and dissolved metals in ground water at deeper levels, especially
at depths below sea level.After eight years of rebound, a marine component was still present at depth in ground water at San
Giovanni (about 2%), and to a lesser extent at Monteponi (about 0.4%). 相似文献
18.
Abstract.
The integrated barium sulphide process consists of: preliminary treatment with lime, sulphate precipitation as barium sulphate, H2S-stripping, crystallization of CaCO3, and recovery of barium sulphide. Our tests showed that during lime pre-treatment, sulphate was lowered from 2 800 mg/L to 1 250 mg/L by gypsum crystallization; metals were precipitated as hydroxides. The BaS treatment then lowered sulphate to less than 200 mg/L. Sulphide was lowered from 333 to less than 10 mg/L (as S) in the stripping stage, using CO2 gas for stripping. The stripped H2S-gas was contacted with Fe (III)-solution and converted quantitatively to elemental sulphur. The alkalinity of the calcium bicarbonate-rich water was reduced from 1 000 to 110 mg/L (as CaCO3) after CO2-stripping with air due to CaCO3 precipitation. Fe (II), after sulphur production, was re-oxidized to Fe (III) using an electrolytic step. The running cost of the BaS process is R2.12/m3 (US$1 = SAR6.5) for the removal of 2 g/L of sulphate. 相似文献
19.
Abstract. Preliminary results indicate that polarimetric synthetic aperture radar (SAR) data can be useful in characterizing remote
tailings sites in Indonesia. Recent launches of polarimetric radar satellites offer new opportunities to use such data. Wishart
polarimetric radar classification was used to map tailings conditions and vegetative stress. We assessed the accuracy of our
analysis and found that almost all scatterers could be discriminated properly, and that the technique was particularly useful
in distinguishing saturated versus relatively dry tailings. Since tropical regions are subject to severe atmospheric disturbances,
tailings stability is a major issue; there is thus high potential value in using radar remote sensing to aid revegetation
and tailings stabilization. 相似文献
20.
Abstract. High-resolution airborne thermal infrared (TIR) imagery
data were collected over 90.6 km2 (35
mi2) of remote and rugged terrain in
the Kettle Creek and Cooks Run Basins, tributaries of the West
Branch of the Susquehanna River in north-central Pennsylvania.
The purpose of this investigation was to evaluate the
effectiveness of TIR for identifying sources of acid mine
drainage (AMD) associated with abandoned coal mines. Coal mining
from the late 1800s resulted in many AMD sources from abandoned
mines in the area. However, very little detailed mine
information was available, particularly on the source locations
of AMD sites. Potential AMD sources were extracted from airborne
TIR data employing custom image processing algorithms and GIS
data analysis. Based on field reconnaissance of 103 TIR
anomalies, 53 sites (51%) were classified as AMD. The AMD
sources had low pH (<4) and elevated concentrations of iron
and aluminum. Of the 53 sites, approximately 26 sites could be
correlated with sites previously documented as AMD. The other 27
mine discharges identified in the TIR data were previously
undocumented. This paper presents a summary of the procedures
used to process the TIR data and extract potential mine drainage
sites, methods used for field reconnaissance and verification of
TIR data, and a brief summary of water-quality data. 相似文献