Mitigating the risks associated with underground coal pillar extraction in South Africa

Abstract

The safe and economic extraction of underground coal pillars is of paramount significance and importance to the South African coal mining industry. Research was undertaken into local pillar extraction operations and extended to similar operations in New South Wales, Australia to assess the way forward for pillar extraction in South Africa. It was found that although little in the way of new technologies has emerged in this field in the recent past in South Africa, significant contributions can be made in the field of risk analysis to obtain a generic design methodology for pillar extraction. For example, a pillar extraction planning tool was developed (A-PEP) to assess pillar extraction potential based on certain physical, risk and economic factors. A-PEP is an intelligent tool which can be used as a preliminary output indicator before more in-depth investigations into the future use of pillar extraction are warranted. The design methodology and planning tool presented here (which has significant origins based on the New South Wales experience) are tested against a pillar extraction operation in the Witbank coalfield and it is seen that its predictive nature is consistent to the workings of the actual operation. The A-PEP tool is a positive step toward an integrated approach considering legal and operational aspects which could form the basis for legislative guidelines when considering pillar extraction in South Africa.