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Tsukamoto, T. K., & Miller, G. C. (1999). Methanol as a Carbon Source for Microbiological Treatment of Acid Mine Drainage. Water Res., 33(6), 1365–1370.
Abstract: Sulfate reducing passive bioreactors are increasingly being used to remove metals and raise the pH of acidic waste streams from abandoned mines. These systems commonly use a variety of organic substrates (i.e. manure, wood chips) for sulfate reduction. The effectiveness of these systems decreases as easily accessible reducing equivalents are consumed in the substrate through microbial activity. Using column studies at room temperature (23-26 degrees C), we investigated the addition of lactate and methanol to a depleted manure substrate as a method to reactivate a bioreactor that had lost >95% of sulfate reduction activity. A preliminary experiment compared sulfate removal in gravity fed, flow through bioreactors in which similar masses of each substrate were added to the influent solution. Addition of 148 mg/l lactate resulted in a 69% reduction in sulfate concentration from 300 to 92 mg/l, while addition of 144 mg/l methanol resulted in an 88% reduction in sulfate concentration from 300 to 36 mg/l. Because methanol was found to be an effective sulfate reducing substrate, it was chosen for further experiments due to its inherent physical properties (cost, low freezing point and low viscosity liquid) that make it a superior substrate for remote, high elevation sites where freezing temperatures would hamper the use of aqueous solutions. In these column studies, water containing sulfate and ferrous iron was gravity-fed through the bioreactor columns, along with predetermined methanol concentrations containing reducing equivalents to remove 54% of the sulfate. Following an acclimation period for the columns, sulfate concentrations were reduced from of 900 mg/l in the influent to 454 mg/l in the effluent, that reflects a 93% efficiency of electrons from the donor to the terminal electron acceptor. Iron concentrations were reduced from 100 to 2 mg/l and the pH increased nearly 2 units. (C) 1999 Elsevier Science Ltd.
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Bolzicco, J., Carrera, J., & Ayora, C. (2004). Eficiencia de la barrera permeable reactiva de Aznalcollar (Sevilla, Espana) como remedio de aguas acidas de mina. Reactive permeable disposal barrier at Aznalcollar Mine, Seville, Spain; as remediation for acid mine drainage. Revista Latino-Americana de Hidrogeologia, 4, 27–34.
Abstract: As a result of the collapse of a mine tailing dam in april 1998 about 40 km of the Agrio and Guadiamar valleys were covered with a layer of pyrite sludge. Although most of the sludge was removed, a small amount remains in the soil of the Agrio valley and the aquifer remains polluted with acid water (ph<4) and metals (10 mg/L Zn, 5 mg/L Cu and Al). A permeable reactive barrier was build across the aquifer to increase the alcalinity and retain the metals. The barrier is made up of three sections of 30 m longX1.4 m thickX5 m deep (average) containing different proportions of limestone gravel, organic compost and zero-valent iron. The residence time of the water in the barrier is about two days. Within the barrier, the pH values increase to near neutral mainly due to calcite dissolution. Metals co-precipitate as oxyhydroxides, and they are also adsorbed on the organic matter surface. Down-stream the barrier, the total pollution removal is around 60-90% for Zn and Cu, and from 50 to 90% for Al and acidity.
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Brown, M., Barley, B., & Wood, H. (2002). Minewater treatment; technology, application and policy. London: IWA Publishing.
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Davies, G. J., Holmes, M., Wireman, M., King, K., Gertson, J. N., & Stefanic, J. M. (2001). Water tracing at scales of hours to decades as an aid to estimating hydraulic characteristics of the Leadville Mine drainage tunnel.
Abstract: The Leadville Mine Drainage Tunnel (LMDT) is a 3.3 kilometer structure that was constructed in the complicated geology of the Leadville mine district in the 1940's. Discharge from the LMDT is impacted by heavy metals and is treated at a plant built in 1992 operated by the United States Bureau of Reclamation. On the surface waste rock and other remnants of the mining operations litter the landscape and this material is exposed to precipitation. As a result of contact with this material, surface water often has pH of less than 3 and its containment and disposal is necessary before it impacts surface drainage and the nearby Arkansas River. Using a borehole drilled into the mine workings the U.S. EPA has devised a plan in which the impacted water is contained on the surface which then can be discharged into the mine workings to discharge from the LMDT and be treated. The percentage of water discharging from the mining district along the drainage tunnel is unknown, and since there is no access, information about the condition of the tunnel with regards to blockages is also relatively obscure. Application of quantitative water tracing using fluorescent dyes was used to model the flow parameters at the scale of hours in the tunnel and evaluate the likelihood of blockages. Because the tunnel has intersected several lithologies and faults, other locations such as discharging shafts, adits and surface streams that could be hydraulically connected to the LMDT were also monitored. An initial tracer experiment was done using an instantaneous injection, which was followed by additional injections of water. Another tracer injection was done when there was a continuous flow of impacted water into the workings. Analysis of the tracer concentration responses at water-filled shafts and at the portal were used to model the flow along the tunnel and estimate several hydraulic parameters. Waters in these settings are mixtures of components with different residence times, so, qualitative tritium data were used to evaluate residence times of decades. The combined injected tracer and tritium data as well as other geochemical data were used to infer the nature of flow and recharge into the tunnel.
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Berthelot, D., & Haggis, M. (1999). Application of remote monitoring and data management systems to environmental management of tailings facilities. In D. Goldsack, N. Belzile, P. Yearwood, & G. Hall (Eds.), Sudbury '99; Mining and the environment II; conference proceedings.
Abstract: The mining industry has made tremendous strides in the last 20 years in the prevention and control of acid mine drainage. However, there remain a number of circumstances where the long-term operation, care and maintenance of tailings management facilities will be required. The application of progressive environmental technologies and management systems is key to cost control and environmental liability management at these sites. Mine Waste Management Inc. currently operates Rio Algom Limited's five effluent treatment plants and seven waste management areas in the Elliot Lake, Ontario region using a Remote Plant Monitoring and Control Network (RPMCN). This system, based on Intellutions's “Fix 32” technology, enables the monitoring and control of these plants from a centralized location thus reducing labour costs while providing 24-hour surveillance. Scheduling, auditing and reporting of plant operating and environmental monitoring programs are integrated and controlled using the Envista (super TM) environmental information management system. Proper application of these technologies and management systems facilitates delivery of cost-effective environmental monitoring, and care and maintenance programs at these sites and provides tools to demonstrate compliance with all environmental performance criteria.
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