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Waring, C. L., & Taylor, J. R. (1999). (R. Fernández Rubio, Ed.). Mine, Water & Environment. Ii: International Mine Water Association.
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Mitchell, P., Rybock, J., & Wheaton, A. (1999). Treatment and prevention of ARID using silica micro encapsulation. In S. A. Bengson, & D. M. Bland (Eds.), Proceedings of the 16th annual National meeting of the American Society for Surface Mining and Reclamation; Mining and reclamation for the next millennium (pp. 657–661). 16.
Abstract: In response to the known drawbacks of liming and the ever-increasing regulatory demands on the mining industry, KEECO has developed a silica micro encapsulation (SME) process. SME is a cost-effective, high performance reagent that is utilized in conjunction with simple chemical delivery systems. By encapsulating metals in a silica matrix formation and rapidly precipitating them into a sand-like sludge, it offers all the advantages of liming without the negative drawbacks. Utilizing an injection technique via a high shear mixing device, a slurry from of the SME product called KB-1 (super TM) was applied to ARD at the Bunker Hill Mine in Idaho and to ARD pumped from collection ponds at a remote mine site in the Sierra Nevada Mountains. Flow rates at both sites ranged from 500 to 800 gallons per minute. Treated water from the Bunker Hill Mine operation achieved the site's NPDES criteria for all evaluated metals and U.S. Drinking Water quality for arsenic, cadmium, chromium, lead and zinc with a dosage rate of 1.34 grams KB-1 (super TM) per liter. Treated water from the Sierra Nevada project focused on the control of aluminum, arsenic, copper, iron and nickel. All water samples displayed a >99.5% reduction in these metals, as well as an 84%-87% reduction in the concentration of sulfate. Testing on sludge generated from both operations achieved TCLP Action Limits. The SME process is currently under evaluation as a means to coat the pyrite surfaces of newly generated mine tailings to prevent oxidation and future acid generation.
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Ayala, J., & Fernández, B. (2005). (J. Loredo, & F. Pendás, Eds.). Mine Water 2005 – Mine Closure. Oviedo: University of Oviedo.
Abstract: The objective of this study was to examine the use of flying ash to remove the copper cyanide species from gold mine effluents. In order to discharge them safely with minimum impact to the environment the effluents must be treated in such a way that the legal conditions were attained with the lowest possible cost. This paper presents the treatment of cyanide solution originating from tailing ponds at the end of detoxification by direct contact with flying ash.
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Rammlmair, D., & Grissemann, C. (2000). Natural attenuation in slag heaps versus remediation. In D. Rammlmair, J. Mederer, T. Oberthuer, R. B. Heimann, & H. J. Pentinghaus (Eds.), Applied mineralogy in research, economy, technology, ecology and culture (pp. 645–648).
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Guay, R., Cantin, P., Karam, A., Vezina, S., Paquet, A., & Ballester, R. A. and A. (1999). Effect of flooding of oxidized mine tailings on T. ferrooxidans and T. thiooxidans survival and acid mine drainage production: a 4 year restoration-environmental follow-up. In Process Metallurgy (pp. 635–643). Volume 9, Part 2: Elsevier Science B.V.
Abstract: A pilot-scale study on the effect of flooding unoxidized and oxidized Cu/Zn tailings demonstrated the technical feasability of this technology to remediate a mining site where over 3 million tons of tailings were impounded. Full-scale flooding of the tailing pond with free running water was undertaken after the construction of an impervious dam; approximately 2 million m3 of surface water at pH 7,4 completely covered the tailings after 16 months. The minimal water column over the tailings was established at 1,20 m and reached 4,5 m, depending on the site topography. Water and tailings samples were collected from 9 different locations from the surface of the man-made lake using a specially designed borer and were analyzed for pH, conductivity, iron- and sulfur-oxidizing bacteria activity and numbers as well as the sulfate reducing bacteria (SRB) population. We showed that over a four year period of flooding, the overall population of iron-oxidizers decreased considerably; their numbers drastically fell from 1x106 to 1x102 active cells per g of oxidized tailings while the SRBs increased from 101 to 105/g. The pH of the influent, the reservoir and the effluent water remained fairly constant between 6,9 up to 7,4 over the entire period. During this time, interstitial water pH increased from 2,9 to 4,3 in flooded tailings where lime could not be incorporated in the first 20 cm of tailings; elsewhere, the pH of the tailings suspensions remained fairly constant around neutral values (pH 7,0). Dissolved oxygen was measured at fixed intervals and remained also constant between 6 and 7.5 mg/L while water temperatures fluctuated below freezing point to +20C respectively in winter and summer season.
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