1987-01-08_REVISION - M1977493 - Laserfiche WebLink

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12 differing environments. Tailing ponds in areas representative of markedly varying climatic conditions and with differing mineral bases were planted using different modifications suited to the areas, Small acreages in such diverse environments as Durango, Colo., White Pine, Mich „ Flat River, Mo., and Mica, Wash., have been successfully stabilized using the chemical- vegetative procedure, Kennecott Copper Co. also has subsequently stabilized an additional 100 acres in McGill, COMPARATIVE COSTS Mining companies have tested many of the outlined procedures for stabiliz- ing and reclaiming mineral wastes, Stabilization costs using various proce- dures are shown in table 1. In general, costs for reclaiming sloping dike. areas have been about 25 percent greater than costs for flat pond areas. The costs given in table 1, updated for 1973, are estimated for a tailings accumu- lation consisting of 80 and 20 percent, respectively, of pond and dike areas, These costs, although broadly generalized, provide some comparison of differ- ent methods, TABLE 1. - Cost comparison of stabilization methodsl Type of stabilization Effectiveness Maintenance Approximate cost per acre, dollars Physical: Water sprinkling .. .............. Fair........ Continual.. - Slag (9-inch depth): By pumping ..................... Good,.,...... Moderate,,, $350- 450 By trucking ...... ...... .. ... do. .... ,do.... 950-1,050 Straw harrowing ............ ... ... Fair..,...... ...do..,. 40- 75 Bark covering .................... Good......... ....do..... 900-1,000 Country gravel and soil: 4-inch depth ................... Excellent.... Minimal,,,, 250- 600 12-inch depth ................. ....do...... ...do.... 700-1,700 Chemical: Elastomeric polymer .............. Good......... Moderate... x300- 750 Lignosulfonate ................... .....do...... ....do..... 2250- 600 Vegetative: 4-inch soil cover and vegetationa Excellent.... Minimal.... 300- 650 12-inch cover and vegetation4.... ....do...... ...do.... 750-1,750 Hydroseeding ..................... .....do...... ....do..... 200- 450 Mattinga ......................... .....do...... ....do..... 2600- 750 Chemical-ve etative.. .do.. .do... 2120- 270 `Based on average tailings, costs could be revised upwards for acidic tailing: requiring limestone or other neutralizing additives, 2Bureau-industry derived costs based upon cooperative stabilization efforts, The remaining data were obtained from industry. a Generally used on pond area rather than on dikes. Also, not as effective as 12-inch soil cover when tailings are excessively acidic or saline, °Substantiated as the optimum economic depth of soil cover when reclaiming baux• ite mined lands with soil covers ranging from 6 to 24 inches (6) although a lesser soil cover may be satisfactory on other types of waste materials. 6Based on placing 3-foot-wide matting at 3-foot intervals over the seeded area,