Evolutionary and Revolutionary Technologies for Mining (2002) / Chapter Skim
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5 Research Opportunities in Environmental Technologies
5 Research Opportunities in Environmental Technologies
Pages 53-60
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From page 53... ...
Improved environmental technologies related to mine closures have the greatest potential for increasing overall productivity and reducing overall energy consumption because costs of long-term maintenance will be factored into the analysis. Closure procedures usually affect the quality of drainage water from the mine and thus, productive use of the land.
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From page 54... ...
Acid generation is an issue of concern for certain types of coal and hardrock mines (particularly mines that contain high concentrations of pyrite but low concentrations of pH-buffering materials)
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From page 55... ...
The most common method of treating acid drainage is lime precipitation (Kleinmann, 1997~. Lime is added to the acidic water and aerated to oxidize soluble ferrous iron to ferric iron, which then precipitates as iron oxide or oxyhydroxide.
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From page 56... ...
In areas where precipitation exceeds evaporation cover technologies must seal the surface of mine wastes to prevent the continued oxidation of sulfides and the infiltration of water. Techniques that establish and maintain chemically reducing conditions and thereby immobilize metals should also be investigated.
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From page 57... ...
Existing technologies to address the issue of pit lakes include predictive modeling, in-situ treatment by lime addition, and continued dewatering of the pit to prevent it from filling with poor-quality water. The accuracy of currently available models in estimating the quality of pit lakes is limited by the lack of data necessary to characterize the complex geology and hydrology typically encountered in mineralized regions, as well as uncertainties in predicting the acid-generation potential of sulfide materials (as discussed above with respect to acid rock drainage)
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From page 58... ...
· treatment of acidic wastewater Closure of Dump-Leaching and Heap-Leaching Operations and Tailings Impoundments · cover technologies to promote evapotranspiration, inhibit infiltration, and/or immobilize metals · in-situ destruction of cyanide · alternatives to current production and management of phosphogypsum Pit Lakes · improved predictive modeling · techniques to eliminate or reduce acid generation in pit walls and floors · treatment technologies for acidic pit water Treatment of Nonacidic Waters · removal of low concentrations of metals from large volumes of wastewater · removal of nitrate from wastewater Slurry Management · cost-effective methods of dewatering and consolidating slimes · methods to ensure the long-term stability of disposal units Methane · improved methods of methane drainage collection and recovery of diluted methane from mine ventilation exhaust Fine Particulates (PM2 5) · control of emissions of fine particulates benefit of limiting dangerous conditions in mines and the economic benefit of producing a valuable commodity.
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From page 59... ...
Although much of the recommended research involves acid rock drainage, other areas for fruitful research are improving technologies for managing nonacidic wastewaters, including effective, low-cost techniques for removing low concentrations of elements, such as selenium, from large volume flows and for removing nitrates from wastewater discharges. The dewatering of phosphate slimes and other slurried mine wastes, as well as the long-term stability of disposal units for these wastes, could also be an area for future research.
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