Delayed Blasting Tests to Improve Highwall Stability-A Final Report

摘要

The Bureau of Mines conducted a series of delayed blasting experiments at a Barbour County, WV, contour coal mine that resulted in smoother highwalls. The highwalls were smoother due to reduced overbreak (excessive rock breakage beyond the excavation limit) and were inherently safer due to reduced likelihood of rockfall. The experiments were directed at reducing overbreak without special drilling or significant additional cost. Reduced overbreak was accomplished by increasing the highwall hole delays, which changed the effective delay pattern geometry and the direction of burden movement.