Tailings Site Research Articles

Remote and in situ photogrammetric history of the Kidd Copper tailings site, Sudbury, Ontario

There is much concern regarding the genesis of acidic leachate by mine tailings and its potential impact on local water systems. Genesis of the leachate and its subsequent escape into the surrounding watershed is controlled by the primary distribution of facies within the tailings pond. Leachate generation and percolation is enhanced in high-sulphide coarse-grained sands, while percolation is restricted in fine-grained clays formed from bentonitic slimes. The Kidd Copper deposit, located on the South Range of the Sudbury Basin, was a typical offset dike nickel deposit, where mining took place between 1970 and 1990. Using a sequence of temporally separate aerial photographs dating from 1945 to 2002, it is possible to document the initial development of the mine, its closure and the subsequent degradation of the mine tailings waste that was produced during mining activity. Since the mine's closure, the resulting tailings deposit has progressively oxidized, generating acid-rich leachate. Leachate can escape from the tailings via surface run-off and subsurface flow. The spatial distribution of possible flow pathways was mapped using a combination of sub-centimetre-resolution real-time kinematic (RTK) GPS and individual, high-resolution, oriented photographs of subsurface pits. Lithologic mapping information of the Kidd Copper tailings deposit can provide an insight into the distribution of local aquifers and aquitards. Subsurface lithologic mapping was achieved using a combination of sub-centimetre-resolution RTK GPS and individual, high-resolution, oriented photographs of subsurface pits. The photograph of each pit provides lithologic information of a specific point in the tailings deposit, while the high-resolution GPS locates the individual photographs in three-dimensional (3D) geographic space. Combining these data allows us to identify continuous lithologic surfaces between pits, leading to the construction of a 3D model of the deposition of the tailings pond. Grain size and textural details extracted from the images of each lithology permit discrimination between aquifers and aquitards. The final geometric model could be used as input for estimating the hydrologic and chemical evolution of the tailings.

A mine of information: Benthic algal communities as biomonitors of metal contamination from abandoned tailings

Various biomonitoring approaches were tested in the field to assess the response of natural periphythic algal communities to chronic metal contamination downstream from an abandoned mine tailings site. The accumulation of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) as well as the production of phytochelatins, the presence of diatom taxa known to tolerate high metal concentrations, diatom diversity and the presence of teratologies were determined. We observed highly significant relationships between intracellular metal and calculated free metal ion concentrations. Such relationships are often observed in laboratory studies but have been rarely validated in field studies. These results suggest that the concentration of metal inside the field-collected periphyton, regardless of its species composition, is a good indicator of exposure and is an interesting proxy for bioavailable metal concentrations in natural waters. The presence of teratologies and metal-tolerant taxa at our contaminated sites provided a clear indication that diatom communities were responding to this metal stress. A multi-metric approach integrating various bioassessment methods could be used for the field monitoring of metal contamination and the quantification of its effects.

Response of Key Soil Parameters during Compost-Assisted Phytostabilization in Extremely Acidic Tailings: Effect of Plant Species

Phytostabilization of mine tailings acts to mitigate both eolian dispersion and water erosion events which can disseminate barren tailings over large distances. This technology uses plants to establish a vegetative cover to permanently immobilize contaminants in the rooting zone, often requiring addition of an amendment to assist plant growth. Here we report the results of a greenhouse study that evaluated the ability of six native plant species to grow in extremely acidic (pH ∼ 2.5) metalliferous (As, Pb, Zn: 2000-3000 mg kg(-1)) mine tailings from Iron King Mine Humboldt Smelter Superfund site when amended with a range of compost concentrations. Results revealed that three of the six plant species tested (buffalo grass, mesquite, and catclaw acacia) are good candidates for phytostabilization at an optimum level of 15% compost (w/w) amendment showing good growth and minimal shoot accumulation of metal(loid)s. A fourth candidate, quailbush, also met all criteria except for exceeding the domestic animal toxicity limit for shoot accumulation of zinc. A key finding of this study was that the plant species that grew most successfully on these tailings significantly influenced key tailings parameters; direct correlations between plant biomass and both increased tailings pH and neutrophilic heterotrophic bacterial counts were observed. We also observed decreased iron oxidizer counts and decreased bioavailability of metal(loid)s mainly as a result of compost amendment. Taken together, these results suggest that the phytostabilization process reduced tailings toxicity as well as the potential for metal(loid) mobilization. This study provides practical information on plant and tailings characteristics that is critically needed for successful implementation of assisted phytostabilization on acidic, metalliferous mine tailings sites.

Suitability of an organic residual cover on tailings for bioenergy crop production: A preliminary assessment

Hargreaves, J., Lock, A., Beckett, P., Spiers, G. A., Tisch, B, Lanteigne, L., Posadowski, T. and Soenens, M. 2012. Suitability of an organic residual cover on tailings for bioenergy crop production: A preliminary assessment. Can. J. Soil Sci. 92: 203–211. To test the potential for production of bioenergy crops, such as canola and corn, an organic cover was constructed over acid-producing mine tailings containing nickel and copper, belonging to Vale in Sudbury, Ontario, Canada. The 1 m deep cover was of organic residuals (biosolids) obtained from a regional paper mill. Corn and canola crops were successfully grown using agricultural techniques. Crop yields from each of 2 yr from the tailings site were greater than those obtained at an agricultural site in the region. Root, shoot and grain analyses indicated low potential for bioaccumulation of potentially hazardous metals from the organic residual cover or the underlying tailings. Over the short term, there was no evidence of metal movement into the biosolids cover or uptake by the crops from the underlying tailing deposits. Importantly, canola seeds and corn kernels, the feedstocks for biodiesel and ethanol biofuels production, did not accumulate environmentally sensitive metals. This preliminary study demonstrates that the placement of an organic residuals cover on mine tailings to support growth of bioenergy crops is a potential novel reclamation strategy for the mining and smelting industry, or for industrial brownfields in general.

Rural Cooperatives Magazine, November/December 2012

Features - Flying High; Minnesota home to largest number of ag co-ops; Iowa tops for business volume; Preserving Common Ground; The Many Faces of Cooperatives; Mine tailing sites tested for growing miscanthus grass for biofuel

Henderson Deep Underground Science and Engineering Lab: Unearthing the secrets of the Universe, underground

The Henderson Mine near Empire, Colorado is proposed to be the site to host a Deep Underground Science and Engineering Laboratory (DUSEL), which will have a rich program for forefront research in physics, biology, geosciences, and mining engineering. The mine is owned by the Climax Molybdenum Company (CMC). It is located about 50 miles west of Denver and is easily accessible via major highways. The mine is modern and has extensive infrastructure with reserve capacity well-suited to the demands of DUSEL. CMC owns all land required for DUSEL, including the tailings site. It also has all environmental and mining permits required for DUSEL excavation, core drilling, and rock disposal. The mine owners are enthusiastic supporters of this initiative. In support of the Henderson DUSEL project, the State of Colorado has pledged substantial funding for surface construction.

Modeling the effect of stratification on cemented layer formation in sulfide-bearing mine tailings

Abstract Reactive transport simulations have been applied to investigate possible effects of stratification on the potential of sulfide-bearing mine tailings to form protective cemented layers. The simulations are based on characteristic strata found at a German tailings site, including sulfide-enriched heavy mineral layers, mica-enriched silt layers, and homogeneously mixed layers. The simulated secondary phases (jarosite, gypsum, amorphous ferric arsenate, amorphous Fe hydroxide, alunite, amorphous silica, and kaolinite) are similar to those observed in the field. Using scanning electron microscope analyses of cemented layers, it has been observed that the pore area becomes disconnected if the porosity is decreased to values below 15%, which would indicate a strong decrease in permeability. Stratification was found to play a crucial role in cemented layer formation. Cemented layers are absent or insignificant in systems with a homogeneous distribution of Fe-bearing sulfides. They are extensively developed in systems with (a) an arsenopyrite-rich layer or (b) a mica-enriched layer situated immediately below an Fe-sulfide enriched layer. The modeling results have clearly demonstrated that the key processes operating in scenario (a) are very different from the key processes in scenario (b). In scenario (a), the oxidation of arsenopyrite is followed by the precipitation of amorphous ferric arsenate, which can be solely responsible for significant pore reduction. In scenario (b), the presence of a large amount of reactive aluminosilicates (e.g. biotite and Ca-bearing plagioclase) immediately below the Fe-sulfide rich layer appears to be crucial. Key processes are extensive formation of Acid Rock Drainage (ARD) followed by enhanced (pH-driven) weathering of aluminosilicates, resulting in the accumulation of secondary phases directly below the Fe-sulfide rich layer. In both scenarios, a cemented layer is formed that effectively retards the further downward movement of the oxidation front. The presented details on the role of stratification in the formation of cemented layers could be considered in the construction of mining heaps as a possible measure to stimulate natural attenuation.

광물찌꺼기에 함유된 오염물질의 안정화를 위한 표면 차폐재의 성능 평가

This study examined evaluation on stabilization of major and trace elements in tailings by various surface water-preventing materials. Six columns were filled with tailings of the Sinlim mine, then covered with tailings only, compacted soils, clay, soil-bentonite mixture, pozzolan and bentonite mat. After injection of artificial rain water, the leachate was sampled with times (3, 6, 9 and 12 pore volume) and analysed for major (Ca, Na, Mg, K) and trace elements (As, Cd, Cu, Pb, Zn) by ICP-AES. With exception to pozzolan type, the pH values of leachate from the other types became stabilized from 5.5 to 7.5, and EC (electric conductivity) of leachate from them decreased with times. For the pozzolan type, however, the pH and EC of leachate increased with time due to its alkalinity producing system. Concentrations of most major and trace elements in leachate decreased and stabilized with time. Consequently, soil-bentonite mixed cover shows the best ability of water-preventing and reducing mobility of elements in tailings site.

Ethanol Addition for Enhancing Denitrification at the Uranium Mill Tailing Site in Monument Valley, AZ

Past mining and processing of uranium ore at a former uranium mining site near Monument Valley, AZ has resulted in nitrate contamination of groundwater. The objective of this study was to investigate the potential of ethanol addition for enhancing the reduction of nitrate in groundwater. The results of two pilot-scale field tests showed that the concentration of nitrate decreased, while the concentration of nitrous oxide (a product of denitrification) increased. In addition, changes in aqueous concentrations of sulfate, iron, and manganese indicated that the ethanol amendment caused a change in prevailing redox conditions. The results of compound-specific stable isotope analysis for nitrate–nitrogen indicated that the nitrate concentration reductions were biologically mediated. Denitrification rate coefficients estimated for the pilot tests were approximately 50 times larger than resident-condition (non-enhanced) values obtained from prior characterization studies conducted at the site. The nitrate concentrations in the injection zone have remained at levels three orders of magnitude below the initial values for many months, indicating that the ethanol amendments had a long-term impact on the local subsurface environment.

Mineralogical characterization of arsenic in gold mine tailings from three sites in Nova Scotia

ABSTRACT Chronic exposure to high concentrations of arsenic (As) in windblown and vehicle-raised dust from tailings sites in Nova Scotia poses a potential health risk to recreational users of these areas and to nearby residents. The exposure may involve inhalation of dust, as well as oral ingestion of particles. It is important to understand the mineralogy and morphology of As-bearing dust particles in order to evaluate the risk posed by near-surface particulates in As-bearing tailings fields, as this will influence the stability and toxicity of As in the wastes. Optical mineralogy, scanning electron microscopy, electron microprobe, X-ray diffraction, synchrotron-based micro-X-ray diffraction (μXRD) and micro-X-ray absorption near edge structure (μXANES), and sequential leach extractions were applied to tailings samples from three sites in eastern Nova Scotia. Arsenic occurs naturally in these gold deposits mainly in arsenopyrite (FeAsS). In the near-surface material of the tailings fields, sulphide minerals have almost completely oxidized to secondary minerals such as scorodite (FeAsO 4 •2H 2 O) and Ca-Fe arsenates. Iron oxyhydroxides contain variable amounts of As 2 O 5 from trace to 30 wt.% and CaO up to 8 wt.%. The presence of multiple As-hosting solid phases, including relatively soluble Ca-Fe arsenates and Fe oxyhydroxides with adsorbed As has important implications for human health risk assessment and remediation design.

Environmental impact of mining activities in the Lousal area (Portugal): Chemical and diatom characterization of metal-contaminated stream sediments and surface water of Corona stream

Lousal mine is a typical “abandoned mine” with all sorts of problems as consequence of the cessation of the mining activity and lack of infrastructure maintenance. The mine is closed at present, but the heavy metal enriched tailings remain at the surface in oxidizing conditions. Surface water and stream sediments revealed much higher concentrations than the local geochemical background values, which the “Contaminated Sediment Standing Team” classifies as very toxic. High concentrations of Cu, Pb, Zn, As, Cd and Hg occurred within the stream sediments downstream of the tailings sites (up to: 817 mg kg −1 As, 6.7 mg kg −1 Cd, 1568 mg kg −1 Cu, 1059 mg kg −1 Pb, 82.4 mg kg −1 Sb, 4373 mg kg −1 Zn). The AMD waters showed values of pH ranging from 1.9 to 2.9 and concentrations of 9249 to 20,700 mg L −1 SO 4 −2, 959 to 4830 mg L −1 Fe and 136 to 624 mg L −1 Al. Meanwhile, the acid effluents and mixed stream waters also carried high contents of SO 4 2−, Fe, Al, Cu, Pb, Zn, Cd, and As, generally exceeding the Fresh Water Aquatic Life Acute Criteria. Negative impacts in the diatom communities growing at different sites along a strong metal pollution gradient were shown through Canonical Correspondence Analysis: in the sites influenced by Acid Mine Drainage (AMD), the dominant taxon was Achnanthidium minutissimum. However, Pinnularia acoricola was the dominant species when the environmental conditions were extremely adverse: very low pH and high metal concentrations (sites 2 and 3). Teratological forms of Achnanthidium minutissimum (Kützing) Czarnecki, Brachysira vitrea (Grunow) Ross in Hartley, Fragilaria rumpens (Kützing) G. W. F. Carlson and Nitzschia hantzschiana Rabenhorst were found. A morphometric study of B. vitrea showed that a decrease in size was evident at the most contaminated sites. These results are evidence of metal and acidic pollution.

The application of an organic amendment modifies the arbuscular mycorrhizal fungal communities colonizing native seedlings grown in a heavy-metal-polluted soil

A mesocosm experiment was conducted to investigate whether communities of arbuscular mycorrhizal (AM) fungi associated with roots of native (Piptatherum miliaceum, Retama sphaerocarpa, Psoralea bituminosa, Coronilla juncea, and Anthyllis cytisoides) and for comparison (Lolium perenne) seedlings in a heavy-metal-contaminated, semiarid soil were affected by the application of composted sugar beet waste. We also investigated whether there were relation between AMF diversity and metal concentration (Al, Cd, Cu, Fe, Mn, Pb and Zn) and total P in shoot as well as some soil parameters (total organic carbon and total N) when the SB waste was added to the soil. We analyzed a portion of approximately 795 base pairs of the small-subunit (SSU) rRNA gene by nested PCR, cloning, sequencing, and phylogenetic analyses. Twelve different AMF sequence types were distinguished: seven of these belonged to Glomus group A, one to Glomus group B, one to Diversispora, one to Archaeospora, and two to Paraglomus. The AM fungal populations colonizing roots in a heavy-metal-polluted soil were quite dependent on the host plant, the highest diversity values being obtained in authochtonous plants recognized as metallophytes, such as P. bituminosa, and in an allochtonous, invasive species (L. perenne). No significant correlation was found between AMF diversity and plant metal concentration and soil parameters. Excepting P. bituminosa, when sugar beet waste was added to soil, the populations of AM fungi in roots increased and the shoot metal concentrations decreased in all host plant species studied. Therefore, the addition of sugar beet waste can be considered a good strategy for the remediation and/or phytostabilization of mine tailing sites.

Transfer of natural radionuclides from soil to the grass around uranium mine area Žirovski vrh, Slovenia

Uranium mine Žirovski vrh in Slovenia was closed in the year 1993. In the past years a lot of work was done for restoration of the area around the mine. There are two tailing sites, Jazbec and Borst, filled with material with high specific activity of 226 Ra. Tailings are covered by different layers of clay and soil in depth of 2 m for reducing radon exhalation rate. Gras, growing on the surface of tailing sites has been used as fodder for domestic animals. We were interesting about the amount of the specific activity of natural radionuclides 238 U, 226 Ra or 210 Pb, transferred from the covering soil on the tailing to the grass on the surface area. The transfer factors of naturally occurring radionuclides have not been studied to the same extent as their artificial counterparts, but some comprehensive investigations have been done by various institutions around the world. In case of 226 Ra calculated values are two times or four times bigger than measured. For 210 Pb measured values are up to hundred times bigger than calculated. The reason for that is radon in the air, decays to the 210 Pb, deposited on the grass and not 210 Pb coming from the soil.

Influence of biosolids and fertilizer amendments on physical, chemical and microbiological properties of copper mine tailings

A 3-yr field study was conducted on two texturally different tailings sites at the Highland Valley Copper Partnership mine in south-central British Columbia to determine the effects of fertilizer and biosolids amendments on selected soil physical, chemical and microbiological properties. Soil bulk density and penetration resistance decreased in the upper 15 cm of tailings with increasing dry biosolids application rates of 50, 100, 150, 200 and 250 Mg ha-1. The addition of biosolids increased gravimetric water retention at field capacity and wilting point, but no significant changes occurred in the gravimetric water-holding capacity as both field and wilting point increased proportionally. Increasing biosolids decreased volumetric water-holding capacity on the silt loam, but had no effect at the sandy site because of decreased bulk density. Soil pH was not impacted by the treatments while electrical conductivity, soil organic matter, total carbon and cation exchange capacity increased with increasing levels of biosolids applied. Biosolids enhanced biological activity by increasing total aerobic, total anaerobic, iron reducing, sulfate reducing and denitrifying microorganisms near the surface. The fertilizer amendment did not alter soil physical or chemical properties from those of the control. The addition of biosolids was more effective at enhancing properties related to soil quality and fertility and therefore more effective for building soil organic matter on reclaimed tailings sites than the traditional use of inorganic fertilizer.

Surface Complexation Modeling of U(VI) Adsorption by Aquifer Sediments from a Former Mill Tailings Site at Rifle, Colorado

A study of U(VI) adsorption by aquifer sediment samples from a former uranium mill tailings site at Rifle, Colorado, was conducted under oxic conditions as a function of pH, U(VI), Ca, and dissolved carbonate concentration. Batch adsorption experiments were performed using <2 mm size sediment fractions, a sand-sized fraction, and artificial groundwater solutions prepared to simulate the field groundwater composition. To encompass the geochemical conditions of the alluvial aquifer at the site, the experimental conditions ranged from 6.8 x 10(-8) to 10(-5) M in [U(VI)](tot), 7.2 to 8.0 in pH, 3.0 x 10(-3) to 6.0 x 10(-3) M in [Ca(2+)], and 0.05 to 2.6% in partial pressure of carbon dioxide. Surface area normalized U(VI) adsorption K(d) values for the sand and <2 mm sediment fraction were similar, suggesting a similar reactive surface coating on both fractions. A two-site two-reaction, nonelectrostatic generalized composite surface complexation model was developed and successfully simulated the U(VI) adsorption data. The model successfully predicted U(VI) adsorption observed from a multilevel sampling well installed at the site. A comparison of the model with the one developed previously for a uranium mill tailings site at Naturita, Colorado, indicated that possible calcite nonequilibrium of dissolved calcium concentration should be evaluated. The modeling results also illustrate the importance of the range of data used in deriving the best fit model parameters.

Comparison of nitrate attenuation characterization methods at the Uranium mill tailing site in Monument Valley, Arizona

Several methods for characterizing the occurrence and rate of nitrate attenuation were tested at a field site near Monument Valley, Arizona. Spatial and temporal nitrate concentration data collected from a transect of monitoring wells located along the plume centerline were analyzed to evaluate the overall rates of natural attenuation. The occurrence and rate of denitrification was evaluated through microcosm experiments, nitrogen isotopic fractionation analysis, and solute-transport modeling. First-order denitrification-rate coefficients calculated with each method were comparable. In addition, the composite natural attenuation rate coefficient was similar to the denitrification-rate coefficients, which suggests that microbially induced decay primarily controls nitrate attenuation at the site. This research highlights the benefits associated with a multiple-method approach for the characterization of natural attenuation.

Effect of Composts, Lime and Diammonium Phosphate on the Phytoavailability of Heavy Metals in a Copper Mine Tailing Soil

Soil samples from a historic copper mine tailing site at the Parys Mountain, North Wales (UK) were amended with green waste compost (GC), GC+30% sewage sludge (GCS), lime and diammonium phosphate (DAP), to determine the effect of amendments on DTPA- and Ca(NO 3) 2-extractable metals in the mine tailing and on the phytoavailability of heavy metals by a lettuce ( Lactuca sativa L.). Both compost were added at the rate of 10% by weight, lime was added as calcium carbonate equivalent (pH = 7) and DAP at a 2 300 mg kg −1 soil level. The experiment was arranged in randomised complete design with three replicates in pots under control environment. Addition of lime resulted in the largest reduction in metal extractability with DTPA and Ca(NO 3) 2 and phytoavailability of Cu, Fe and Zn while DAP was effective in lowering Pb extractability and phytoavailability. With exception of Zn, all other metals extracted decreased with time after amendment applications. The distribution of heavy metals between and within the four procedures of potentially bioavailable sequential extraction (PBASE) varied significantly ( P < 0.001). Stronger relationships were noted between the metals extracted with PBASE SE1 and Cu, Pb ( P < 0.01) and Fe ( P < 0.001) in the lettuce. These results indicate that addition of lime is sufficient to restore the vegetative cover to a high metal mine waste while DAP is good for stabilizing Pb, but its detrimental role on plant growth and the risk associated with presence of N in DAP (through N leaching) may restrict its chances for remediation of contaminated sites.

English

In 1929, the Block P Mill and Tailings Site (Block P) near Monarch, MT was the largest lead producer in Montana. When the mill finally closed in 1943 the site left behind a legacy of barren, phytotoxic soil and an ongoing transport of hazardous trace elements into nearby streams. Problems included areas of soil acidity as low as 1.8 pH, and zones with highly elevated concentrations of arsenic, cadmium, copper, lead, zinc and manganese in both soils and tailings materials. As a result, much of Block P, which would have been fully covered with vegetation if undisturbed, was nearly devoid of plant life. In 2001, however, it was decided to clean up and restore Block P to a functional site with natural vegetation. In 2004 and 2005, waste materials were consolidated to a centralized repository. Then, soil amendments (compost, slow-release fertilizer and lime) were added to areas from which tailings were removed, leave-area soils and imported fill materials. In 2005 and 2006, the project site was replanted with native grass and forb seeds, as well as containerized woody plant species that had been propagated from local stock. In July 2008, scientists from ESG monitored the status of revegetation at Block P. Monitoring included assessments of containerized woody plant survival, herbaceous cover, and overall cover on the nine revegetation units at the site. The monitoring results show a continued trend toward successful revegetation. The average containerized woody plant survival, weighted for unit size, was 74 percent, which exceeds the 70 percent project goal. Average herbaceous canopy cover and average total canopy cover of all plants across the entire project site are respectively 46 and 49 percent. The canopy cover of native species far exceeds non-native canopy cover, the cover of weedy exotic species is minimal, and hundreds of woody volunteer plants are appearing. The improvements in vegetation, environmental, and aesthetic values of the Block P Mill and Tailings site are clear and palpable, and demonstrate the efficacy of using appropriate soil amendments and site-adapted native plant species to restore even the most challenging of disturbed sites.

Effects of phosphate and Cr3+ on the sorption and transport of uranium(VI) on a silica column

Six column experiments were performed and seven breakthrough curves (BTCs) and seven displacement (desorption) curves (DPCs) of phosphate and U(VI) were obtained, which demonstrated the effects of phosphate and Cr3+ on the sorption and transport of U(VI) on a silica column at pH 3 and uranium concentration 10−5–10−6 mol/L of the influent. It was found that in the presence of phosphate sorbed preliminarily on the silica column, the amount of U(VI) sorbed on this column is significantly increased owing to the interaction of U(VI) with phosphate sorbed as compared with that in the absence of phosphate, and the breakthrough and the mean residence time of U(VI) on this column are similar to those in the absence of phosphate. While the effect of simultaneous injection of Cr3+ on the retardation of U(VI) on the silica column, the maximum concentration of BTC and the amount of U(VI) sorbed was found to be insignificant. Transport and sorption studies of U(VI) are important, since all uranium isotopes are radioactive, there is a need to understand the potential for migration away from radioactive waste storage and mill tailing sites.

Mapping mine tailing surface mineralogy using hyperspectral remote sensing

Acid mine drainage resulting from mine tailings poses an environmental threat. An important initial step towards the reclamation of mine tailing sites is to detect the presence of acid-generating, sulphide-rich minerals and determine their spatial distribution. In this study, the potential of hyperspectral remote sensing for characterizing mine tailings is investigated. The study site is located in northern Ontario, Canada, and the data were collected with PROBE-1, an imaging spectrometer that covers the visible, near-infrared, and shortwave-infrared spectral ranges. The results indicate that using the weakly constrained linear spectral unmixing technique PROBE-1 data can provide information on mineral compositions of the tailing surface. The spatial locations and associations of acid-generating source minerals such as pyrite and pyrrhotite along with their oxidation products (e.g., copiapite, jarosite, ferrihydrite, goethite, and hematite) can provide information about the distribution of oxidation processes at the site. This remote mapping technique can be very valuable when attempting to identify abandoned mine-waste sites and the potential risk they might present where there are no a priori knowledge and field samples available.