Production Of Acid Mine Drainage Research Articles

Pengelolaan Air Asam Tambang dari Batuan Sisa di Pit Barani dan Ramba Joring serta Aplikasi Model Enkapsulasi pada Bendungan Tailing di Tambang Emas Martabe

Acid mine drainage is one of the significant negative impacts of mining activities that can result in environmental degradation. Waste rock is mine waste that is found in large quantities and can produce acid mine drainage (AMD). This study aims to identify waste rock which has the potential to generate acidity (PAF) and do not generate acidity (NAF) in the Barani and Ramba Joring pits and the application of the encapsulation model in tailings dams. The research method with the encapsulation model is a simple method designed in tailings dams to encapsulate the PAF with the NAF. Rock characterization and geochemical analysis will result in the rock being classified as PAF and NAF in both wells . The data used for this study are drilling data (cutting) data that include rock lithology and chemical quality (NAPP and NAG) data. The results identified that the PAF was dominant relative to the NAF both wells and the waste rock in the Barani pit was at a higher risk of producing acidity than the Ramba Joring pit. Measurements of oxygen diffusion and surface water quality indicated that encapsulation of waste rock in the tailings dam may prevent the formation of acidic mine drainage

Bio-oxidation behavior of pyrite, marcasite, pyrrhotite, and arsenopyrite by sulfur- and iron-oxidizing acidophiles

The oxidation of sulfide minerals is of central importance due to the acid mine drainage (AMD) production. The bio-oxidation of pyrrhotite, pyrite, marcasite, and arsenopyrite was carried out with mesophilic bacteria (Acidithiobacillus ferrooxidans, A. thiooxidans, and Leptospirillum ferrooxidans) at 34 °C for 30 days. Bio-oxidation tests showed that marcasite has a high potential in producing AMD compared to pyrrhotite. Arsenopyrite has different behavior in the presence and the absence of additives (i.e., FeSO4·7H2O and sulfur). While the absence of additives increased the nickel and zinc dissolution, their presence increased the total iron dissolution. Sulfur and jarosite were observed on the surfaces of pyrrhotite and arsenopyrite. With the formation of these passivation layers, the continuous iron extraction is effectively suppressed. This study is helpful to comparatively evaluate the AMD production of sulfide minerals in an oxidizing environment and to study the effects of passivation layers on their biooxidation in different conditions.

Temporal fluctuations in water contamination from abandoned pyrite Wieściszowice mine (Western Sudetes, Poland).

Production of acid mine drainage may occur during mining operations and may continue for many years after closure. In some cases, especially when host rock is capable of reacting with acidic drainage, metal concentrations may decrease over time and distance. Seasonal variations in water flow rate also play an important role in metals concentration both in surface and groundwater. The present study evaluates the contamination of an abandoned pyrite mining area (Wieściszowice, SW Poland) and the temporal variation of the water contamination in selected locations of 2 sampling campaigns (2000 and 2015). The mining surrounding Rudawy Janowickie Mountains range is well known for the rich mining history and is considered as one of the oldest in Europe. The Wieściszowice pyrite mine was exploited for several hundreds of years and processed Fe and Cu sulfides, and sulfur. This mine was closed in 1925 because of the high competition of pyrites from Spain. Results show clearly that water samples collected in the mining area are mainly Ca-SO4 and acid/high metal, while spring water and surface water samples, representing the local geochemical background, are Ca-HCO3 and neutral-low metal. The analysis of data shows an improvement in water quality from 2000 to 2015 as well as a decreasing of water risk assessment for human use. This improvement can be related to the fact that 2015 was a very dry year, with over 60% less flow than in 2000, leading to less water contamination.

Assessment of acid mine drainage formation using geochemical and static tests in Mutki (Bitlis, SE Turkey) mineralization area

In this study, geochemical analyses, as well as short-term contact leaching and acid-base accounting tests, were carried out to determine the occurrence of acid mine drainage (AMD) by static tests in the ore stockpile areas at the Mutki Cu-Fe-Cr deposit (Bitlis, SE Turkey). According to the short-term contact leaching tests, the high enrichment in trace element concentrations in ore-bearing samples, especially in potentially toxic metals such as Cr, Cu, Mn, and Zn, were directly related to sulphide and oxide mineralizations. The pH (3.27–4.05) values of water samples, together with the classification of the intracontinental water resources, indicated that the water quality is the fourth class. Leaching tests, paste pH (3.42–4.46) and sulphide-sulphur (3.9–13.4 wt%) values also suggested that there was AMD production potential in the mineralization area. The AMD production potential was supported by the high mobility of several elements, such as Fe, Mg, Cr, As, Cu, S, and Zn. In ore samples, net neutralization potential (NNP) and net potential ratio (NPR) values were less than –20 kg CaCO3/t and 1, respectively. The basalts forming the basement rock of the stockpile area were characterized by permeable to slightly permeable properties that potentially increase the contamination risk of the groundwater due to seepage in the stockpile area. In order to prevent seepage in the stock area, geomembrane (synthetic waterproofing covers) should be laid at the base to ensure impermeability. The improvements planned in the stock area were modeled by the finite element method and seepage discharges at a depth of 5 m were determined as 1.34 × 10–17m3/s. Thanks to these planned applications, surface and groundwater pollution can be efficiently prevented.

PREDICCIÓN DE DRENAJE ÁCIDO DE MINA, JALES DE LA MINA LA PRIETA, CHIHUAHUA, MÉXICO

The La Prieta mine, Chihuahua, Mexico, was intensively exploited (silver, lead and copper) from colonial times until its closure; consequently, large quantities of tailings produced by metallurgical processing accumulated. These tailings can produce acid mine drainage due to oxidation and hydrolysis reactions. With the objective of predicting if tailings can generate acid drainage, tailings samples were characterized and the possibility of generating acidity was investigated. The pH values found were slightly alkaline (7.8-8.4). On the other hand, sulfates and total sulfur were determined by turbidimetric and infrared methods, respectively. It is worth mentioning that total sulfur was below the limit of detection of the Leco S-144DR equipment and sulfur concentrations in the form of sulfates were very low. The mineralogical characterization showed that pyrite was found in only three samples and in low percentages. The calcite and dolomite minerals present in the skarn type deposit were involved in the neutralization of acid mine drainage and the decreased mobility of most toxic metals and metalloids.

Enhanced biotreatability of petroleum hydrocarbon-contaminated mining waste coupled with the attenuation of acid drainage production.

A biostimulation study was conducted on mining waste residue with nutrient (nitrogen and phosphorus) and/or liming agent (ash or CaCO3 ) amendment to assess petroleum hydrocarbon (PHC) biodegradation efficiency by indigenous microorganisms. Compounds accumulated and/or released by treated samples were also monitored to determine the potential for acid mine drainage production during biostimulation. The potential for natural attenuation (i.e., the biodegradation of PHC contamination) was initially low but increased significantly upon nutrient addition. The best results were obtained when nutrient addition was coupled with the addition of a liming agent, notably CaCO3 , which contributed to maintaining near-neutral pH values. In fact, during treatment without a liming agent, pH decreased due to the oxidation of sulfide minerals, resulting in acid mine drainage production with increased metals released into sample leachates. Sulfur- and iron-oxidizing bacteria were detected primarily in samples not amended with liming agents, and the predominant organisms were affiliated with Acidithiobacillus spp. and Acidiphilium spp. Overall, the results of the present study demonstrated that amendment with a liming agent when treating PHC-contaminated mining waste residue contributes to maintaining a pH close to neutrality, mitigates sulfate release, and reduces the release of metals without negatively affecting the activity of PHC degraders.

Groundwater Pollution Connected to Multiple Effect: A Case Study Kaman (Kırşehir, Turkey)

This study aim to detect the groundwater pollution connected to multiple effect such as the interaction of mineral/ore-water, mining destruction and agricultural activities in Kaman (Kırçehir). The study area has recently abondoned iron, antimony, gold and floride mine areas and so, there are a lot of mine piles. Mine waste is a rich source of hazardous trace elements to the environment. In many areas expecially abandoned sulphidic mine wastes may cause to produce acid mine drainage. Although no acid mine drainage is observed in the study area, the region needs to be reworked for this purpose in the following years. The electrical conductivity, pH and Eh values of the waters range between 126-1994 μS/cm; 7.28-8.58; 222-649 mV respectively. In the rainy season, the pH values of the waters decreased due to the effect of slight acidic precipitation and in parallel with this decrease, EC, TDS, Ca, Na, SO4, HCO3, As, Sb, U concentrations of some waters increase due to the increase of solubility of elements. As, Sb, F, U, NO3, NH4 concentrations some of water exceed the maximum limit values given in the Turkish and World Health Organization Standards. Especially As contamination is a big problem for the region, because of tens of times exceed drinking water regulations.

Analyzing variation of the water table level with three-dimensional numerical simulations to assess reclamation techniques for an acidic tailings impoundment

Tailings with sulphide minerals exposed to oxygen and water can oxidize and produce acid mine drainage (AMD). This study evaluated the impact of natural conditions and of a thin cover deposition on the water table level, with respect to selecting the reclamation technique to control AMD on the elevated portion of an abandoned tailings impoundment. The reactive tailings were partly covered with alkaline tailings transported as a pulp from a nearby mine. A three-dimensional numerical variably saturated groundwater flow model of the tailings impoundment and its surrounding area was built. The simulation results reproduced well the field observations before, during, and after the deposition of a thin layer of tailings. The calibrated model was then used to forecast the evolution of the water table position for the next 100 years under various site conditions, including a period of 5 years with dry summers. The results show that the water table levels are on average several metres below the interface between the reactive tailings and the cover, thus failing to meet the target criterion to control the production of AMD determined from previous column tests. The results are analyzed and discussed in terms of the site configuration and atmospheric recharge.

Mine tailings as a raw material in alkali activation: A review

The mining industry produces billions of tons of mine tailings annually. However, because of their lack of economic value, most of the tailings are discarded near the mining sites, typically under water. The primary environmental concerns of mine tailings are related to their heavy metal and sulfidic mineral content. Oxidation of sulfidic minerals can produce acid mine drainage that leaches heavy metals into the surrounding water. The management of tailing dams requires expensive construction and careful control, and there is the need for stable, sustainable, and economically viable management technologies. Alkali activation as a solidification/stabilization technology offers an attractive way to deal with mine tailings. Alkali activated materials are hardened, concrete-like structures that can be formed from raw materials that are rich in aluminum and silicon, which fortunately, are the main elements in mining residues. Furthermore, alkali activation can immobilize harmful heavy metals within the structure. This review describes the research on alkali activated mine tailings. The reactivity and chemistry of different minerals are discussed. Since many mine tailings are poorly reactive under alkaline conditions, different pretreatment methods and their effects on the mineralogy are reviewed. Possible applications for these materials are also discussed.

Comparative analysis of early-stage adsorption and biofilm formation of thermoacidophilic archaeon Acidianus manzaensis YN-25 on chalcopyrite and pyrite surfaces

The early-stage attachment behaviors of acidophiles on mineral surfaces and the subsequent biofilm formation play important roles in acid mine drainage production, and also can improve the leaching efficiency of metal sulfides. However, despite significant advances in correlational researches of mesophilic bacteria, studies on thermoacidophilic archaeon are still limited. In this study, the early attachment behaviors and biofilm formation of the thermoacidophilic archaeon Acidianus manzaensis YN-25 on chalcopyrite and pyrite were investigated. Experiments showed that A. manzaensis YN-25 attached quickly on chalcopyrite and pyrite within a short adsorption equilibrium time of about 20 min. After the adsorption equilibrium, the percentage of attached cells was higher on chalcopyrite than on pyrite (59 % versus 54 %). And the early-stage adsorption of Acidianus manzaensis YN-25 on chalcopyrite and pyrite surfaces was occurred through multilayer adsorption. Also, the measured adhesion forces (0.41 nN versus 0.31 nN) showed more affinity of A. manzaensis YN-25 to chalcopyrite than to pyrite. Furthermore, in the process of biofilm formation, more cells colonized on the chalcopyrite than pyrite, suggesting that the biofilm formation was positively correlated with the initial adhesion. Moreover, during the entire life cycle of A. manzaensis YN-25 biofilm, dead cells have accounted for a big proportion.

Innovative Methodology for Sulfur Release from Copper Tailings by the Oxidation Roasting Process

To effectively prevent the accumulation of copper tailings from producing acid mine drainage (AMD) and maximize the comprehensive utilization of copper tailings, the process of oxidation roasting was adopted to release sulfur in the form of SO2 to achieve the purpose of sulfur recovery later. Based on the AMD risk assessment, thermogravimetric (TG) analysis, and differential scanning calorimeter (DSC) analysis, the influences of roasting temperature, residence time, and air flow in the roasting process were investigated. The thermal stability, reaction equilibrium, mineral transformation, and residual S content were characterized by TG-DSC, HSC chemical software 6.0, X-ray diffraction (XRD), and combustion neutralization, respectively. The optimum conditions for sulfur release in the roasting process were shown with a temperature of 1200°C, a residence time of 60 min, and an air flow of 0.8 L/min. Under these conditions, the sulfur release rate was 99.82%, and the residual S content was 0.05%. Subsequently, the process of sulfur release was proposed as four steps: oxidative decomposition of pyrrhotite, formation of ferric sulfate, decomposition of ferric sulfate, and formation of hematite. All of the findings could propose a theoretical and experimental reference for the recovery of the sulfur component from tailings rich in sulfide minerals.

Differences in elemental composition of tailings, soils, and plant tissues following five decades of native plant colonization on a gold mine site in Northwestern Québec

Mining activities have significant environmental impacts, such as the production of acid mine drainage and the typical absence of vegetation on mine tailings whose absence can facilitate the migration of metals to adjacent ecosystems. We investigated the metal and metalloid composition of plants and substrates on, and near a former gold mine site to understand elemental dynamics in such environments. A mine tailings deposit rich in Mo and As in Northwestern Québec was studied following the natural colonization of the deposit by boreal plant species. The site and surrounding forest were categorized into 6 vegetation density classes (VDC) to determine if and how vegetation density, and plant elemental composition, and soil properties were linked. Macroelemental composition of plant tissues (P, K and Ca) was relatively stable, despite differences in macroelemental levels of substrates between different VDC (with lower macronutrient levels associated with less dense areas), indicating the adaptability of the three species studied (Alnus incana spp. rugosa, Betula papyrifera and Picea spp.). Results showed that across a wide range of substrate properties, it was plant species and density that explained metal and metalloid composition in plant tissues (leaves, stems, and roots), while the main environmental determinants for this were VDC, pH, Ca and Cu. Increasing vegetation density was associated with decreasing As and Mo concentrations in substrates. This study sheds light on the plasticity of alder, spruce and birch growing on mine sites, allowing us to better understand elemental dynamics on such sites, and ultimately improve their management.

Effect of Nitrate Ions on Acidithiobacillus ferrooxidans-Mediated Bio-oxidation of Ferrous Ions and Pyrite.

Exploring the effects of nitrate ions (NO3-) on the bio-oxidation of Fe2+ and pyrite will help reveal the actual mechanism of acid mine drainage (AMD) production. Long period shaking flask experiments were carried out in order to assess the effect of NO3- on the Acidithiobacillus ferrooxidans LX5 (A. ferrooxidans LX5)-mediated bio-oxidation of Fe2+ and pyrite. In Fe2+ bio-oxidation systems, A. ferrooxidans LX5 had stronger Fe2+ oxidation capabilities in a NO3--loaded solution than in a NO3--free solution after 24days, and the Fe2+ bio-oxidation capacity of A. ferrooxidans LX5 acclimatized in solutions containing low concentrations (8.2-32.9mmol/L) of NO3- was greater than when it was acclimatized in high NO3- concentration solutions (49.4-65.8mmol/L). In pyrite bio-oxidation systems, in comparison with the system without NO3-, pyrite bio-oxidation efficiency was significantly increased when the NO3- concentration in the system was 8.2-16.5mmol/L, and that the pyrite bio-oxidation efficiency in the system containing 8.2mmol/L of NO3- was greater than that for the system with 16.5mmol/L of NO3-. The pyrite bio-oxidation efficiency was inhibited when the NO3- concentration was above 32.9mmol/L. The results from this study can be used to reveal the actual control behavior of NO3- on AMD production.

NEW PARADIGMS OF TERRITORIAL PLANNING AND (POST-)MINING ECOLOGICAL RESTORATION IN THE ANDES

The paper argues for the necessity of a new paradigm of ecological restoration in the face of mining extraction in the Latin American Andes. It begins with a critical reading of the extra-territorial connections between mining sites and settlements and unfolds their ambivalent relations through chronic cycles of ecological destruction. The analysis focuses on the territorial logics embedded in four mining-settlements of the Peruvian Andes and their development from the eighteenth to the twentyfirst century. Potosí, Huancavelica, Hualgayoc, and Cajamarca form part of an extended network of landscape infrastructures and headwater resources, all of which have been (and continue to be) significantly disturbed through mining operations. The sites have inherited a relentless production of Acid Mine Drainage in addition to other hazardous post-mining ecologies. Tangible evidence of ecological misbalance demonstrates the enduring impact of past-mining activities even centuries after mineral extraction has ceased. The paper reflects on present-day practices of post-mining landscape restoration in accordance with current Peruvian legislation. It concludes with a plea for a new form of territorial planning as well as both the conception and perception of post-mining landscapes through inclusion of design strategies for Cajamarca. Such planning needs to reconcile the contradictory elements of mineral extraction, environmental engineering, and self-sustainable ecological development. Intelligent design research is a major support for such an endeavor.

Environmental Sustainability of Open-Pit Coal Mining Practices at Baganuur, Mongolia

In this paper, we studied one of the largest coal mines in Mongolia, the Baganuur Coal Mine, in terms of environmental sustainability related to mining practices, with a focus on discharged water and waste sediments. The present quality and potential for future pollution were assessed. Based on World Health Organization and Mongolian guidelines, groundwater pumped from the mining operations could be used for drinking and domestic purposes. In addition, based on the Na absorption ratio, groundwater samples from GW-2 and GW-3 could be used as agriculture water supplies with salinity reduction, or used to grow halophytes as a measure for desertification control and pasture production. All waste soil samples appeared to have a desertification potential. Dust particles smaller than 150 μm comprised more than 80% of soil samples, which had arsenic levels higher than the Mongolian soil pollution standards. In addition, soil collected between coal seams (S-5) showed high sulphur content based on X-ray fluorescence (XRF) and scanning electron microscopy–energy dispersive X-ray (SEM-EDX) spectroscopy analyses, strong potential for producing acid mine drainage in the analysis of pH of net acid generation and net acid production potential, and potential for leaching of metals, such as Co. Therefore, the Baganuur Coal Mine requires soil pollution control measures to mitigate the risks of dust and desertification. In this perspective, mine groundwater could be used to reduce environmental stresses by supporting pasture crops such as halophytes on waste disposal sites, thereby preventing dust issues and desertification. Continuous efforts, including monitoring and enacting environmental management measures, are needed from both the mining company and the government to ensure sustainable mine development.

EFECTO DEL COBRE PARA LA REMOCIÓN DE SULFATO EN UN REACTOR DE LECHO FIJO

Mining of sulfide-rich pyritic ores produce acid mine drainage (AMD), which contains high metal concentrations and have acid pH, causing major environmental problems. Over the last 20 years a variety of passive AMD treatment systems, like anaerobic wetlands, bioreactors and permeable reactive barriers, have been studied. Under controlled conditions bioreactors employ inoculants of sulfate-reducing bacteria (SRB) to treat effluents and capture commercial grade metals. The objective of this research was to evaluate the effect of Cu on the removal efficiency of sulfate in a fixed bed reactor. During 28 d the fixed bed reactor maintained a hydraulic residence time (HRT) of 12 h and an influent rate of 0.67 gCOD/gSO 4 2– . Phase I (synthetic solution with 50 mg Cu/L) lasted 7 d, allowing Cu removal of 99.59 ± 0.43 % and sulfide production of 39.29 mg S 2- /L∙d. Sulfate-reducing activity (SRA) was not affected (40.25 mg S 2- /L∙d) during Phase II (21 d without Cu). Results showed no significant alteration in sulfate and COD removal, as well as sulfur production after the addition of Cu. It is concluded that SRB can be used for AMD treatment.

Prediksi Laju Pembentukan Air Asam Tambang dengan Metode Column Leaching Test

Prediction of Acid Mine Drainage Forming using Method of Column Leaching Test. One of the environmental problems in coal mining activities is the formation of acid mine drainage. Prediction of the formation of acid mine drainage is important as an effort to control environmental impacts. Acid mine water occurs with interactions between potentially acid-forming material with oxygen, bacteria and water. Objective of study is to analyze the potential for acid mine drainage forming based on material characteristics. The research method was carried out using static and kinetic tests. The static test method classifies materials according to the ability to produce clean acids with observed parameters such as paste pH, total sulfur, Acid Neutralizing Capacity (ANC), Net Acid Generation (NAG), Maximum Potential Acid (MPA), and Net Acid Producing Potential (NAPP). The Kinetic test method predicts the rate of acid-forming of a material. The kinetic test uses the Column Leaching Test Method by using material with composition designed to represent field condition. The kinetic method parameters are pH, electrical conductivity, acidity, alkalinity, sulfate content, and dissolved metal content (Fe, Mn, and Cd). Results of the static test classified the material into NAF Non-Acid Forming (NAF), Potential Acid Forming (PAF) and Uncertain (UC) material categories. The results of the Column Leaching Method classified the material into categories of potential and no potential to form acid mine water. The columns that have the potential to form acid mine drainage occur in columns with large amounts of tonnage of PAF material or those in the upper layer so that it reacts with oxygen. The columns that have no potential to produce acid mine drainage in columns with PAF material are in the middle layer or mixed with NAF material.

Effect of iron and manganese concentration on the sulfate reducing process in acid mine drainage

Mining activities produce acid mine drainage that can be treated with microorganisms, and in this case, sulfate reducing bacteria. Iron and manganese effect on the sulfate reduction process can be investigated using anaerobic batch and continuous reactors with various iron and manganese concentrations. For batch reactors, the highest efficiency of sulfate reduction and sulfate reduction rate was obtained by 0 mg Mn/l reactor. Both efficiency and rate continued to decline with the increasing of iron and manganese concentration. The temperature for all reactors remained stable. The sediment color in 0 mg Fe/l and 0 mg Mn/l reactors were remain black, while the sediment color in the rest of the reactors changed from black to brown. The COD concentration for all the reactors decreased and the highest efficiency was 35,50% which was obtained by 0 mg Fe/l reactors. The highest efficiency of iron reduction was 99,23% and was achieved by 60 mg Fe Mn/l reactor. The effect for continuous and batch reactors are quite identical.

Silicic protective surface films for pyrite oxidation suppression to control acid mine drainage at the source

The tailings produce acid mine drainage (AMD) due to sulfide minerals, especially pyrite oxidation. AMD has caused serious pollution to the surrounding aquatic and terrestrial ecosystems because of its famous low pH value and high metal and sulfate concentration, which is an urgent environmental problem faced by the world's ore mining industry. Here, we show that silicic protective surface films can suppress the oxidation of pyrite-bearing tailings for AMD control at-source without pre-oxidation of pyrite and solution pH adjuster and buffer. We found that the silicic protective surface films formed by calcium silicate can inhibit the oxidation of pyrite-bearing tailings and reduce the production of AMD through chemical leaching tests. Fourier transform infrared (FTIR) analyses and scanning electron microscopy with energy-dispersive spectrometry (SEM/EDS) confirmed the presence of silicic protective surface films of calcium silicate on the surface of pyrite-bearing tailings.

Pyrite oxidation inhibition by hydrophobic films for acid mine drainage control at the source

Acid mine drainage (AMD), which is also known as acid rock drainage (ARD), can cause serious environmental pollution, especially for surrounding aquatic and terrestrial ecosystems due to its low pH, high metal and sulfate concentration. Acid mine drainage is an urgent environmental problem for the worldwide ore mining industry. In this paper, we demonstrated that hydrophobic films can inhibit the oxidation of pyrite-bearing tailings to achieve the control of at-source AMD. The results of chemical leaching testing showed that the hydrophobic films formed by linoleic acid can suppress the oxidation of pyrite-bearing tailings and reduce the AMD production. In addition, the presence of hydrophobic films of linoleic acid on the surface of pyrite-bearing tailings was confirmed by the results from Fourier transform infrared (FTIR) analyses and scanning electron microscopy with energy dispersive spectrometry (SEM/EDS).