Mining Industry of South Africa - Working Conditions

Working Conditions

Conditions on most South African mines are very similar to those elsewhere except for the gold mines where the low geothermal gradient, i.e. the rate at which the temperature goes up with depth, is often as low as 9 °C per kilometre depth (compared with a world average of about 25 °C/km), and this, combined with narrow and very continuous orebodies in hard and competent rocks makes it possible to mine to depths unattainable elsewhere in the world.

Silica dust is an ever-present potential hazard so that all drilling dust and loose rock has to be wetted down at all times to prevent silicosis, a lethal disease that attacks the lungs. Unfortunately the narrowness of the inclined reefs/orebodies prevents mechanisation except in a very few cases and most work is very labour intensive. Ventilation requirements to keep working conditions tolerable are huge and a survey of the South African gold mines indicated that the average quantity of ventilating air circulated was some 6 cubic metres per second (210 cu ft/s) per 1000 ton of rock mined per month.

Another serious problem is that of heat. In the deeper mines refrigeration of the intake air is often necessary to keep conditions tolerable and this is now becoming necessary on some platinum mines which, although shallower, have a lower geothermal gradient. Refrigeration is very energy hungry and it is currently a moot point whether ESKOM, the state power company, can supply the necessary power after its recent problems, which will cut power supplies to 90% of previous levels until at least 2012, when a new powerstation is ready.

The South African mining industry is frequently criticized for its poor safety record and high number of fatalities but conditions are improving. Total fatalities were 533 in 1995 and had fallen to 199 in 2006. The overall fatality rate in 2006 was 0.43 per 1,000 per annum but this hides some important differences. The gold mining rate was 0.71, platinum mining was 0.24 and other mining was 0.35. (For comparison, the rate in the Sixties was around 1.5—see any Chamber of Mines Annual of the period). The reason for the difference is quite clear; the gold mines are much deeper and conditions are both more difficult and dangerous than on the shallower platinum mines.

Falls of ground dominated the causes at 72, machinery, transportation and mining accidents caused 70 and the remainder were classed as general. Of the falls of ground, approximately two thirds were on the deep gold mines, a reflection of the extreme pressure at depth and continual movement of to country rock. Amongst the machinery, mining and transportation fatalities were working on grizzlies without safety belts, working below loose rock in ore passes, getting crushed by that deadly combination of a loco and a ventilation door frame (the clearance between the two is only a few inches) and working on running conveyors, all direct contraventions of safety instructions. Drilling into misfires was also mentioned, a clear example of sloppy and unsafe mining.

It is difficult to see how falls of ground can be eliminated given their frequent unpredictability, which is increasing with depth, and the difficulties in providing continuous roof support as on longwall coal mines due to the violence of a face blast in the hard rock of the gold mines but clearly much can be done to improve training and to instill a sense of safe working practice in the miners, many of whom are relatively inexperienced.

Mine safety received considerable publicity in 2007, particularly after 3,200 workers were temporarily trapped underground at the Elandskraal mine after a compressed air pipe ruptured due to internal corrosion, broke lose and fell into the man-hoisting shaft. The workers were eventually rescued through the rock hoisting shaft after the blasting smoke had cleared. The incident caused South African President Thabo Mbeki to mandate full safety audits for all operating mines. This audit has caused additional facilities to shut down temporarily, including the nation's largest gold mine located at Driefontein.