Doornkop is situated on the northwestern margin of the Witwatersrand Basin of South Africa, one of the most prominent gold provinces in the world. While there are several gold-bearing conglomerate reefs present within the mining right area, only the Kimberley Reef and South Reef are considered to have prospects for economic extraction at this stage. In the West Rand Goldfield, the Kimberley Reefs include a number of different gold-bearing conglomerate horizons. At Doornkop, it is the Kimberley K9 Reef horizon which comprises the Mineral Resources along with the South Reef. The K9 Reef rests on an unconformity and is a multi-pulse conglomerate which is divided into four cycles, each consisting of an upper conglomerate and a lower quartzite. The South Reef comprises a basal conglomerate unit and a cycle of trough cross-bedded sediments. The South Reef is dominated by silicate phases such as quartz, carbon (seam and specks), as well as sulphide phases such as pyrite, pyrrhotite and chalcopyrite. While the upper cycles may carry some gold values, up to 95% of the gold present is located in the lower cycle. Both the Kimberley Reef and the South Reef have been subjected to faulting and are intruded by a series of dykes and sills of various ages that cut across the reefs. The gold mineralisation is interpreted to have succeeded a period of deep burial, fracturing, and alteration. The gold and other elements are believed to have precipitated through the reaction of hydrothermal flu ........

Doornkop is a deep-level single-shaft operation. The operation focuses on narrow-reef conventional mining of the South Reef gold-bearing conglomerate reef. Mining is undertaken to a depth of 2 219m below surface.

Doornkop is a single-shaft operation currently exploiting the South Reef to some 2000m below surface. The narrow South Reef is exploited by means of conventional stoping. Mining of the Kimberley Reef was suspended during FY14 to focus on the build-up of production from the South Reef and to prevent losses as a result of the lower gold price. Mining of the Kimberley Reef may resume should economic circumstances improve sufficiently.

The mining method used is longwall mining with stability pillars on major geological structures. The flat dip, which results in the development of long cross cuts, presents challenges in terms of ore handling, especially for the bottom part of the raises, ventilation and in the long lead times between the start of cross cut development to completion of stoping per raise line.

The mining method used at Doornkop is conventional breast mining, in a sequential grid, also known as sequential grid mining (“SGM”).

Doornkop does not use backfill for the support of stopes. The SGM method makes use of dip pillars and reduced mining spans with pre-developed tunnels, aimed at controlling geotechnical stress. The mining sequence at Doornkop is typically a V-shaped configuration, colloquially referred to as th ........

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