Numerical investigations of ore pass hang-up phenomena

Abstract

Material flow in ore pass systems is critical to the economic performance of mining operations. The design of ore passes, however, does not seem to receive the same engineering attention as other mining infrastructure. Quite often, it is only when ore pass systems fail to perform, and material flow is disrupted, that ore pass design and operation come under scrutiny. A survey of ore pass design and performance in 10 Quebec underground mines has shown that, while cohesive arching is also observed, interlocking hang-ups of coarse material are by far the most frequently observed phenomena in the surveyed mines. This paper summarizes work undertaken using the distinct element method to conduct a series of numerical experiments in order to investigate the influence of ore pass geometry, rock fragments shape and size distribution on material flow in an ore pass. The employed modelling methodology contributes to a better understanding of interlocking and provides a series of guidelines to help limit the occurrence of interlocking hang-ups in an ore pass. Better flow is achieved when using vertical ore passes with square cross sections. Particle shape is an important element as demonstrated by using spherical as well as cubical particles. It is recognised that cubical particles provide more realistic results.