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Most Appalachian coal refuse materials contain significant amounts of pyritic sulfur and are likely to produce acid mine drainage (AMD). A column technique was designed and implemented to evaluate the effects of various AMD mitigation treatments including fly ash, topsoil, lime, and rock-P. Two types of fly ash were tested, one at four blending rates, the other at two rates. Conventional lime plus topsoil, lime without topsoil, topsoil only, topsoil with fly ash, rock-P plus topsoil, and rock-P plus fly ash were also evaluated and compared with pure refuse controls. The columns were dosed weekly with 2.5 cm of simulated acid rain, an amount equivalent to 152 cm (60 in.) rainfall per year and remained unsaturated at all times. The experiment was conducted for 40 weeks. The drainage from the unamended columns rapidly dropped to less than pH 2 with very high levels of Fe, Mn, B, S, and Al. Alkaline fly ash dramatically reduced drainage Fe concentrations as well as Mn, Al, Cu and S when compared to the untreated refuse. As expected, lime treatments also reduced the drainage Fe, Mn, Al, Cu and S concentrations. The rock-P treatments initially reduced Fe, Mn, Al and S, but eventually decreased in mitigation capability over time. Leachate B concentrations were initially high for some of the ash columns but eventually followed the same B elution trend as the untreated refuse. The combined treatments of phosphate/ash, ash/topsoil, and pure refuse with topsoil were intermediate between the pure ash treatments and unamended refuse in drainage quality. The data were analyzed to determine treatment effectiveness in reducing AMD, and to evaluate the overall replicability of the column design. All treatments varied greatly for the first 5 weeks as the initial flush of salts from the materials occurred, but most treatments stabilized by week 6 with relatively low within treatment variability. The high ash blending rates remained alkaline for extended periods of time and stabilized pyrite while neutralizing any acidity. The rock-P treatment appears to have bound free Fe and other elements released from pyrite oxidation but did not prevent acidification. Long term analysis may prove fly ash to be a viable alternative to conventional topsoiling/lime treatments to ameliorate AMD if adequate alkalinity is present in the ash/refuse mixture. If fly ash alkalinity is inadequate to balance potential acidity, accelerated leaching of ash bound metals may occur. / M.S.

The Clinch and Powell Rivers located in Southwestern Virginia contain some of the most diverse freshwater mussel assemblages found throughout North America. However, in recent decades mussel species decline has been documented by researchers. The presence of coal mining activity in the watersheds has been hypothesized to be linked to the decline of numerous species and the extirpation of others. The effects of various discharges from an active coal preparation plant facility located in Honaker, Virginia were evaluated for acute and chronic toxicity using field and laboratory tests. The results of the study suggested that the primary effluent from the coal preparation facility had acute and chronic toxicity; however, the settling pond system utilized at this plant mitigated the impacts of the plant from reaching the Clinch River. Along with active mine discharges, acid mine drainage (AMD) has been documented as another potential stressor. Ecotoxicological recovery was evaluated in two acid mine drainage impacted subwatersheds (Black Creek and Ely Creek) in the Powell River watershed following remediation. The results in Ely Creek suggested that successive alkalinity producing systems were effective in mitigating the harmful impacts of AMD as previously impacted sites had decreased water column aluminum and iron levels in conjunction with increased survival in laboratory toxicity tests conducted with Ceriodaphnia dubia and Daphnia magna. Corbicula fluminea (Asian clam) in-situ tests confirmed the results in the laboratory tests as all sites located below the remediated areas had improved survival. However, active AMD influences and loss of quality habitat seemed to be hindering the recovery of the benthic macroinvertebrate community located in Ely Creek. In Black Creek, re-mining and outlet control pond construction have not resulted in a successful remediation in the lower subwatershed. A decrease in Ecotoxicological Ratings at some of the lowest mainstem sites compared to pre-remediation data was observed. Furthermore, decreased survival in sediment associated toxicity tests with D. magna in 2007-08 was supported by 100% Asian clam mortality at the LBC-5 and LBC-6 sites in 2007, while growth impairment in 2008 was observed at the LBC-6 site. / Master of Science

Three streams (Parker Run, Little Leading Creek and Thomas Fork) in the Leading Creek watershed, Meigs County, Ohio were impacted by active coal mining, agricultural and abandoned mined land sedimentation and acid mine drainage (AMD), respectively. An ecotoxicological evaluation was performed using physical (water chemistry and sediment depth analyses), toxicological (acute water column, chronic sediment and 35-day in situ toxicity tests) and ecological (benthic macroinvertebrate community sampling) parameters. Persistent acute toxicity (mean 48-hr LC50 of 30.3% to C. dubia) due to low pH (mean of 5.4) and high concentrations of dissolved metals (ex: Al ~ 10 mg/L) were responsible for the significantly depressed benthic macroinvertebrate community sampled in Thomas Fork. Heavy sedimentation (>30 inches), with no associated toxins, significantly decreased both abundance and diversity of benthic macroinvertebrates in Little Leading Creek. High concentrations of sodium (mean of 910 mg/L), TDS (mean of 3,470 mg/L), and periodic acute water column toxicity (mean C. dubia survival of 62% in 100% sample) were most likely responsible for the depressed benthic macroinvertebrate community observed in Parker Run. In ranking the severity of impacts, AMD was first followed by non-toxic sedimentation, and active coal mining ranked last. A catastrophic coal slurry spill significantly impacted the benthic macroinvertebrate community in Parker Run in April 1997. Six sampling stations were established to monitor the recovery of the stream's benthic community and evaluate any impact the active coal mine effluent had on the recovery time of the community. The effluent, characterized by high concentrations of TDS (~4,200 mg/L), significantly hindered benthic macroinvertebrate community recovery in Parker Run. The benthic community at the initial spill site, which was above the active mine effluent, recovered to levels measured at an upstream reference within 4-9 months. Benthic communities impacted by both the slurry spill and the effluent still had not recovered 16 months after the spill. Concentrations of TDS measured in the stream were significantly correlated (r = -0.765 and -0.649 respectively) with both EPT richness and percent C. dubia survival in water column toxicity tests. Laboratory analysis of synthetic coal mine effluent, similar in composition to that of the Parker Run effluent, was performed to determine toxicity thresholds for sodium, sulfate, TDS and conductivity. Acute toxicity thresholds were found for sodium (between 900 and 1,000 mg/L), TDS (4,200 and 6,400 mg/L), and conductivity (5,000 and 6,200 µmhos/cm). It was also determined that any toxic contribution of sulfate in solution with high concentrations of sodium (~1,000 mg/L) and/or TDS (~4,200 __ 6,400 mg/L) was secondary to that of the toxic effect of sodium or TDS in that solution. / Master of Science

Acid mine drainage (AMD) forms when sulfur bearing rocks such as pyrite, are exposed to air and water. The oxidation of these minerals leads to the generation of sulfuric acid, which in turn mobilizes metals such as iron, aluminum, manganese, and others. If left untreated, AMD can cause severe harm to the surrounding ecosystem. By law, mining companies are required to treat AMD, often by oxidizing the contaminated water, raising the pH with a chemical additive, and precipitating the metals out of solution. Recent studies at West Virginia University and Virginia Tech have shown that AMD and the treatment precipitates (AMDp) are enriched in rare earth elements (REEs). Given the importance of REEs to modern technology, as well as potential supply restrictions, subsequent research has attempted to identify promising methods to extract and recovery REEs from AMD and AMDp. Prior studies have shown that the physical characteristics of AMDp can vary considerably from site to site, and a robust processes scheme must account for any site-specific disparities. To better understand the inherent variability of AMDp, a scientific study was commissioned to investigate a standard method of characterizing AMDp for the optimization of rare earth extraction processes. The tests developed in this work define the total acid dose needed to dissolve AMDp at various target pH points. Through the course of the study, over 150 unique AMDp samples were evaluated, and comparative analyses were conducted on samples from different sites as well as replicate samples from the same sites. The resultant dataset was analyzed using an empirical model, and a statistical analysis was conducted to correlate the model parameters and other AMDp physical properties. Relationships between elemental assays, moisture, and fitting parameters of the empirical models were found. These results ultimately led to a recommendation for future treatment of AMD and prospective sites. / MS / Acid mine drainage (AMD) is a longstanding environmental issue that is caused when sulfur-bearing rocks are exposed to the environment during the mining process. By law, companies are required to treat AMD prior to discharging the water back into the environment. This treatment process creates a waste byproduct, AMD precipitate, that largely consists of metal hydroxides, including iron, aluminum, manganese, and others. Historically, AMD precipitate has been considered an undesirable waste that must be carefully disposed either in old mine workings or in permanent storage cells. However, recent research has shown that AMD precipitate contains elevated concentrations of rare earth elements (REEs). REEs are a group of chemically similar elements that are well known for their use in several modern technologies, including magnets, catalysts, glasses, light-weight metal alloys, and other high-tech uses. REEs are often sparsely concentrated in nature and rarely form ore deposits of a commercial grade. As a result, several private companies and government agencies have sought alternative sources of REEs. Prior research has shown that AMD precipitate may be a suitable alternative source; however, the chemical and physical nature of AMD varies considerably between different sites. This research seeks to utilize a standard characterization test to identify the characteristics of AMD precipitate that ultimately dictate process amenability. Throughout the course of the study, over 150 unique AMD precipitate samples were analyzed, and the cumulative results show which class of sites constitute the most promising prospecting targets.

The river drainages originating in the Cumberland region of Virginia, Tennessee and Kentucky are home to some of the last surviving and most diverse assemblages of native freshwater mussels. This region of the country also has historically and continues to be a major source of coal for the United States. Numerous experiments were carried out in an attempt to determine what ecotoxicological effects these activities have had on mussels as well as what has been done to correct some of the most severe cases of environmental pollution due to historical coal mining operations. Analysis of interstitial water (IW), sediment and in situ toxicity testing and chemical analyses showed that the most likely cause for mussel declines was elevated metal concentrations (Al, Cu, Fe, Pb) found in IW. Ecotoxicological assessments of the two streams (Black and Ely Creeks) most impacted by acid mine drainage (AMD) in the state of Virginia were carried out to determine their potential for future degradation of the Powell River watershed into which they drain. The Powell River is a major system still inhabited by native mussels. Sophisticated wetland systems built at Ely Creek have significantly improved the ecological health of Ely Creek, decreasing the pollution into the Powell River. Reclamation and wetland construction at Black Creek have had a positive impact but active coal mining and un-remediated AMD are still negatively affecting this system. After the watershed has been fully reclaimed the discharge from Black Creek will likely be improved. / Master of Science

This study focuses on Acid Mine Drainage (AMD) in the three basins of the Witwatersrand’s goldfields in the Vaal River System in South Africa. AMD has become a highly contested issue. A difference in its definition exists between two groups of role-players identified in the study: government and consultants/activists/NGOs. This study unpacks the differences in the way AMD is defined, the situation of AMD in each of the three basins and the socio-economic implications caused by AMD. A crucial finding was that these definitions determine how the issue is understood and what solutions these role-players propose. The main purpose of the study was to determine whether the South African government’s policy response was appropriate given the socio-economic impacts of AMD and imperatives of sustainable development. This study concluded that, in the policy, there was no clear indication as to what the socio-economic impacts are, and limited attention was therefore given to these impacts. / Development Studies / M.A. (Development Studies)

Acid mine drainage (AMD) is a worldwide environmental problem associated with the mining wastes, generated from active and inactive mining sites from mineral processing activities. AMD is defined as the drainage that occurs as a result of oxidation of sulphide minerals/wastes/tailings when exposed to air and water in the presence of chemolithotrophs namely the Acidithiobacillus sp. AMD is characterised by low pH and increased acidity due to elevated heavy metals and sulphate concentration. The acid production potential was carried out for sulphide minerals such as pyrite and chalcopyrite and copper tailings sample in the absence and presence of bacteria namely Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. Acidity was generated in all the cases due to the oxidation of the mineral samples. The oxidation was found to occur at a higher rate in the presence of the bacteria compared to the control samples. Bioremediation experiments were conducted on acid mine water collected from the Ingaldahl Mines, Chitradurga, Karnataka, India, using organic and inorganic substrates. In the experiments with rice husk, complete removal of metal ions from the acid mine water was achieved with an attendant increase in the pH of the acid mine water from 2.3 to 5.5. About 21% of sulphate could be removed using Dsm. nigrificans from acid mine water pretreated with rice husk at pH 5.5 and this was further increased to 40% by the supplementation of organic components. The rice husk filtrate was found to serve as a good growth medium for Dsm. nigrificans. About 96 % of Fe, 75 % of Zn, 92 % of Cu and 41 % of sulphate removal was achieved from the acid mine water of pH 2.4 with a concomitant increase in the pH value by two units after interaction with the tree bark. About 56 % and 71 % of sulphate reduction could be achieved at initial pH values of 4.1 and 5.5 respectively of the acid mine water pretreated with E. tereticornis (Sm) bark, after inoculation with Dsm. nigrificans. The complete removal of Fe2+ and Fe3+, 80% of Zn, 83% of Cu and 62% of sulphate could be removed from acid mine water using fly ash as the substrate with an increase in pH of acid mine water from 2.3 to 7. About 68% of sulphate reduction at pH 6.8 could be achieved in acid mine water pretreated with fly ash in the presence of Dsm. nigrificans. With red mud as the substrate, complete removal of all the metal ions namely Fe2+, Fe3+, Zn, and Cu from acid mine water was achieved with a concomitant increase in the pH from 2.3 to 8. The sulphate reduction was increased to about 51% at pH 7.2 when the acid mine water pretreated with red mud was inoculated with Dsm. nigrificans. The adsorption experiments carried out on the acid mine water using either organic or inorganic substrates indicated that the free energy of adsorption was negative for all the chosen metal ions attesting to favorable interaction. The adsorption isotherms of the metal ions for rice husk exhibited Langmuirian behaviour, while those for the other substrates adhered to both Langmuir and Freundlich relationships. The adsorption process was found to be endothermic in nature for rice husk, fly ash and red mud. On the contrary, the adsorption onto tree bark showed exothermic behaviour. The adsorption kinetics of the metal ions onto the various substrates adhered to the first order Lagergren equation. The metal uptake processes by the organic and inorganic substrates chosen for this study involve ionic, chemical and physical forces of adsorption. The different types of functional groups present on the surface of the substrates such as carboxyl, hydroxyl and carbonyl, as revealed by FTIR spectroscopic studies, partake in metal binding. The metal ions will also be adsorbed by complexing with the negatively charged reaction sites on the substrate surfaces. Furthermore, the complex solution chemistry of the metals as a function of pH has also to be taken into consideration. The mechanism of sulphate reduction by Dsm. nigrificans in the presence of organic carbon can be illustrated as: 2CH2O + SO42- + 2H+  2CO2 + 2H2O + H2S M2 + H2S  MS  + 2H+ where, CH2O represents the organic matter and M represents the metal ion.

[Truncated abstract] As mineral deposits continue to be mined, the non economic gangue materials such as sulphides (e.g. pyrite) that are extracted as part of the ore body or overburden are deposited within the waste rock and/or milled tailings. As a result of natural weathering processes, these reactive materials represent a potential hazard to surrounding environments. A major consequence, resulting from mine-waste impoundments containing sulphidic materials, relates to the offsite movement of low pH leachates containing elevated concentrations of metal ions posing a contamination threat. The processes and mechanisms acting in the formation of acid mine drainage (AMD) are highly variable and, to a high extent, controlled by climatic conditions as the main driver of water flow and wetness of the system which in turn determines the availability of oxygen as well as water for pyrite weathering. In particular, this thesis is based on the hypothesis that in semiarid and arid climates the acid production may be water … The experiments were repeated at different water contents ranging from 0.24 to 0.33 cm3 cm-3. Breakthrough curves (BTC) of Li+, K+, Ca2+, Mg2+, Na+ and pH were measured and described with models of different complexities. This included the use of a simple linear and non-linear isotherms for Li+ alone, a binary Li+ - K+ ion exchange, and a complete multicomponent chemical equilibrium description of ion transport. The latter, by including dissolution of primary minerals which released base cations such as Mg2+, Ca2+ and K+ explained some of the elution patterns of base cations for which the Li+ - K+ exchange was the dominant process. Furthermore, under unsaturated water flow conditions, retardation of Li+ increased with decreasing water content. Thus solute mobility in mafic rock tailings appears to decrease under strongly unsaturated water flow conditions.

This study focuses on Acid Mine Drainage (AMD) in the three basins of the Witwatersrand’s goldfields in the Vaal River System in South Africa. AMD has become a highly contested issue. A difference in its definition exists between two groups of role-players identified in the study: government and consultants/activists/NGOs. This study unpacks the differences in the way AMD is defined, the situation of AMD in each of the three basins and the socio-economic implications caused by AMD. A crucial finding was that these definitions determine how the issue is understood and what solutions these role-players propose. The main purpose of the study was to determine whether the South African government’s policy response was appropriate given the socio-economic impacts of AMD and imperatives of sustainable development. This study concluded that, in the policy, there was no clear indication as to what the socio-economic impacts are, and limited attention was therefore given to these impacts. / Development Studies / M.A. (Development Studies)