Abstract

To optimize development of the Bingham Canyon Mine, detailed slope engineering studies have been performed. Our slope design philosophy is based on the assumption that operations can work safely around properly monitored and geotechnically defined slopes. Slope design studies have included investigation of rock structure and strength along with ground-water conditions, blasting procedures, seismic and in-situ stress conditions, and excavation methods. Oriented core holes have been drilled. Vertical wells and horizontal drain holes have been installed. An outgrowth of these studies is an increased awareness among the operating staff of the importance of slope engineering.

The ultimate slope angle analyses involve three major components: (1) bench design, which determines the steepest slope that can be mined while still maintaining adequate catch bench widths; (2) inter-ramp slope angle analysis, which provides design slope angles by computing the probability of multiple bench failure; and (3) overall slope stability analysis which examines the viability of failure of full height pit slopes.

Besides slope dewatering, practical stabilization techniques which have been employed at the Bingham Canyon Mine include surface water control, control blasting, and dozer ripping. Double benching is being used on all ultimate inter-ramp slopes exceeding 40 degrees. Slope conditions are routinely monitored to ensure safe mining conditions.