1986-12-08_GENERAL DOCUMENTS - M1977493 (2)

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I METHODS AND COSTS FOR STABILIZING FINE SIZED MINERAL WASTES 1 by I ; 'I, s q.r, K. C. Dean, Richard Havens, and M. W. Glantz2 �4I 9 is u +* ABSTRACT ` r Fine-sized mineral wastes discarded by ore milling plants require stabi- lization to prevent air and water pollution. Stabilization has been attained " by physical, chemical, vegetative, and combination procedures. Vegetative reclamation is preferred to physical and chemical stabilization but is diffi- cult to achieve because the wastes are sterile, contain deleterious inorganic 4 salts, and lack the essential nutrients and physical characteristics required " for sustaining vegetative growth. Methods now have been developed for attain ing vegetative growth on all but excessively acidic, basic , or saline tailings < ^ ! at costs ranging from $120 to $650 per acre. The cost for stabilizing tail- ings requiring more intensive treatment techniques may range upward to $1 ,750 per acre. This report summarizes procedures developed by the Bureau of Mines and industry for vegetating amenable tailings, lists costs for the various processes, and suggests procedures that may be applicable for stabilizing saline and pyrite-containing tailings. Ridged planting beds , drip irrigation, and deep-furrow planting techniques are suggested for stabilizing saline , wastes. A combination of mill tailings and sewage sludge can be used for pro- ducing synthetic soils , and layers of sewage sludge buried under a layer of tailings offer promise of inhibiting acid formation from oxidation of sulfides Il,p in mineral wastes. fa ' INTRODUCTION ilk About 1 billion tons of mineral wastes are discarded annually in the United States. Mineral waste piles currently cover over 2 million acres of land. These mineral wastes are second only to agricultural wastes in quantity I and represent over 30 percent of the total wastes produced in the United States. Approximately 40 percent of the mineral discard is fine-size material !i requiring some sort of stabilization if air and water pollution are to be min- imized. On active mill tailing ponds, air pollution is controlled by keeping the surfaces of the ponds wet either by tailings discharge or by sprinkling. On inactive ponds, more lasting stabilization is required; physical, chemical , vegetative, and combination methods for stabilizing tailings have been devel- oped and are in use. 'Metallurgist. 2Chemist. r