LESSONS OF STEEP-SLOPE REVEGETATION FROM THE GOLDEN SUNLIGHT MINE, MONTANA

Effective revegetation on 50% slopes is possible in a semiarid climate.Placer Dome's Golden Sunlight Mine in southwest Montana was a pioneer in 2H:1V slope revegetation.Elements of satisfactory revegetation include nearly two-foot-thick coversoils that combine 30% to 50% rock content for erosion resistance with good texture for plant growth, short-term erosion-control measures such as benches and properly aligned dozer basins, a seed mix that balances strong-establishing species with persisting ones, and seeding equipment that churns and harrows the ground surface following broadcasting.Nitrogen-fixing symbioses also can be important both to increase cover to limit erosion and by increasing productivity and transpiration -important considerations when acidproducing mine waste rock underlies the coversoil.Since steep slopes must be worked almost normal to contours, remedial measures to improve unsatisfactory revegetation are limited when compared to slopes of 3H:1V or less.This makes steep-slope revegetation very dependent on initial revegetation establishment, where weather plays an important role.Since weather during the establishment phase is beyond control, steep-slope revegetation cannot be assured.However, the practices and materials discussed here have proven themselves at the Golden Sunlight Mine.