Change in the pitwall stability with depth

Abstract

It is known that under certain conditions, the structural geology, seismic, design and technology factors do not inhibit increase in the inclination of the limit pitwalls in deep open pit mines. The evaluation of the limit pitwall stability is made by the pitwall stability index, considered nst = 1 in ideal case. In practice, nst = 1.2−1.3, which flattens pitwalls, expands the open pit mine limits on the surface and increases stripping. Therefore it is proposed to construct a convex pitwall with the depth-wise decreasing stability index. It is assumed that when an open pit mine reaches its design depth and depletes its design reserves, the open pit mine stability coefficient cannot exceed 1. The article shows that this approach has both economical and physical preconditions.