Study of the stability mechanism within shallow mining operations that will impact on the sustainability of platinum mines

Abstract

Support in shallow platinum mining operations is typically provided by in-stope pillars with width-to-height ratios of 3:1. A significant percentage of ore reserves is locked up in these pillars, which reduces the life of mine. In the mid 1990s, a mine in the Rustenburg area removed in-stope pillars over an area of 500 m x 140 m on the Merensky Reef horizon without any incidence of instability. This provided a unique opportunity to study rockmass characteristics under large-span conditions. The ability to either partially or fully extract in-stope pillars has positive implications towards ensuring the sustainability of mining within the Bushveld Complex. It has been determined that, if all pillars created in a single year across the Bushveld Complex were reduced in size by 1.0 m, approximately R1.0 billion profit could be realised by the platinum mining industry annually (based on 2004 prices and costs). The work to be presented will describe the stability mechanisms, determined from data obtained via instrumentation, observations, numerical and analytical techniques