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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Li, L., Jiang, Y., & Guo, Y. (1999). Research on a comprehensive industrialization technology for the treatment of mining water containing sulfate ions. Meitian Dizhi Yu Kantan = Coal Geology & Exploration, 27(6), 51–53.
Abstract: A method using a barium reagent was developed for the purification of the higher-sulphate mine water.
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Laine, D. M. (1999). (R. Fernández Rubio, Ed.). Mine, Water & Environment. Ii: International Mine Water Association.
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Kuyucak, N., Lindvall, M., Rufo Serrano, J. A., & Oliva, A. F. (1999). (R. Fernández Rubio, Ed.). Mine, Water & Environment. Ii: International Mine Water Association.
Abstract: Lime neutralization is a frequently used method in the mining industry for the treatment of acid waters. These waters contain metal ions such as zinc, manganese, copper, cadmium, lead, etc. The conventional, straight lime neutralization technology generates a Low Density Sludge (LDS) having only 1-2% solids content. This creates sludge disposal difficulties, and results in the loss of potentially large quantities of recovered water, which in turn increases the demand for fresh water requirements for mining/milling activities. The High Density Sludge (HDS) process, on the other hand, is the state-of-the-art technology in North America. It generates a dense sludge with less volume and better particulate properties. Furthermore, the typical gelatinous nature of the sludge changes to a granulated, sand-like texture. Boliden Apirsa, S.L. investigated the feasibility of an HDS process to increase the treatment capacity of their existing plant, and resolve the issues associated with the LDS process for their Los Frailes project. The project required, given that the production of ore was going to be doubled, a significant increase in water was needed without altering the water reservoir sitting north of the concentrator. In addition, the final effluent quality was a priority issue. First, a pilot-scale study was undertaken in 1996, and parameters critical to the design and performance of the process were determined. The results showed that the HDS process could significantly improve the sludge characteristics by increasing the solids fraction from 1.5 to 12.0%, thereby decreasing the sludge volume to be disposed to the tailings ponds by a factor of 10. A full-scale, HDS lime neutralization treatment plant for an average flow rate of 1500 m3/hr was designed and was commissioned in early 1998 in collaboration with Colder Associates, Ottawa, Canada. So far, the full-scale treatment plant has been generating a sludge with more than 30% solids content, exceeding its target value of 12% solids. It produces excellent effluent quality, and scaling in the handling equipment is virtually eliminated. The sludge has dense, easily settable granular particles rather than fluffy flocs, yet has low viscosity that facilitates its unassisted gravity flow. The process has resulted in an increase in the treated water volume. The rate of lime consumption per unit volume of water treated also decreased. The process principles and the steps taken in process development will be discussed and the results obtained to date will be summarized in this communication.
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Berg, G. J., & Arthur, B. (1999). Proposed mine water treatment in Wisconsin. In D. Goldsack, N. Belzile, P. Yearwood, & G. J. Hall (Eds.), Sudbury '99; mining and the environment II; Conference proceedings. Sudbury: Sudbury Environmental.
Abstract: Water quality standards are driving wastewater effluent limits to ultra-low levels in the nanogram/L range. Standards are proposed that require discharges to match background water quality. The new ultra-low level standards require cautious sampling techniques, super clean laboratory methods and more advanced treatment technologies. This paper follows a case history through water quality standards for ultra-low metals, laboratory selection, and the design of a wastewater treatment system that can meet the water quality standards which are required to permit a proposed copper and zinc mine in Northern Wisconsin. A high degree of care must be taken when sampling for ultra-low level metals. Both surface water and treated effluent samples present new challenges. Sampling methods used must assure that there are no unwanted contaminants being introduced to the samples. The selection of a laboratory is as critical as the construction of a state of the art wastewater treatment system. Treatment methods such as lime and sulfide precipitation have had a high degree of success, but they do have limitations. Given today's ultra-low standards, it is necessary to assess the ability of reverse osmosis, deionization, and evaporation to provide the high level of treatment required.
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