JOURNAL PAPER

Orepass best practices at South Deep

J.A. Maree

University of Pretoria

SYNOPSIS

After the South Deep complex was purchased by Goldfields in 2006 a re-feasibility study was done and the life of mine (LOM) was extended to 52 years. This also implied that the mine's infrastructure would have to be enhanced. One of the changes was the proposal of five new main orepass systems to be excavated before the mine reaches full production in 2013. Excavations started to show signs of scaling, and in some cases, whole new excavations were lost. This particular area was exposed to very high stresses and the geology was prone to body delimination rendering the relevant areas unstable. This paper investigates the conditions at the location of one of the proposed orepass systems, and the best possible orientation was suggested to ensure that the orepass system would be stable and have a practical life. It was, however, found that the fourth leg of the orepass system would require further support to be classified as stable by the chief rock engineer and the section geologist of South Deep. Several support methods and orepass system linings would then be analysed and evaluated to give calculated recommendations on how to productively and practically support an orepass system.

Keywords: Main orepass system, stresses, body delamination, impact and abrasion, rock support, concrete lining

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Paper written on project work carried out in partial fulfilment of B. Eng (Mining Engineering)