Crushed rock pad capability under mining equipment operation

Abstract

Operating mine equipment frequently causes adverse loading on the ground beneath the equipment. Poor ground conditions often result in equipment structural damage due to poor bearing capacity and resulting stability issues. An improved understanding of ground material behaviour under cyclic loading from operating equipment may indicate improvement considerations in operating plans and corresponding mine designs, and lead to reduced machine maintenance. The applicability of crushed limestone as a cap for multi-layer constructed operating surfaces over a weak in situ base was investigated via revisiting the applicability of the California Bearing Ratio (CBR) test. This research improved the test by considering the behaviour of an operating surface while under repetitive cyclic loading due to a mining shovel track system, modelled as a scaled cyclic plate load test. The results suggest a relationship between ground pressure stiffness and track footprint shape. A stress-deformation correlation also suggested a linear correlation proportional to pressure stiffness; common to the outcome of the more conventional CBR test. The resulting proposed relationship was shown to be a function of both the total deformation experienced by the operating surface and the number of cycles imposed.

Keywords:

• Haul road
• Haul truck
• Mining shovel track
• California Bearing Ratio (CBR) test
• Cyclic plate load test