The richest known goldfields in the world were deposited more than two billion years ago along the gravel shores of an ancient inland sea, now buried in a subterranean reef from Nigel in the east through Johannesburg, Klerksdorp and Welkom.
Gold was first discovered in what is now the North West Province on the farm Rietkuil near Klerksdorp in 1887, just a year after the discovery of the Johannesburg Main Reef. The outcrop closely resembled the Witwatersrand and sparked a gold rush which drew 4000 diggers and speculators to the area. A stock exchange was opened and by 1888 more than 150 mining companies were listed on the Klerksdorp Stock Exchange. Almost all, however, were short-lived and most did not even open a mine. Mining at that time was restricted to relatively shallow ore-bodies and simple technology and the Klerksdorp reef was fragmented and its yields were unreliable. The real wealth of the region lay deep underground and remained undiscovered for another fifty years. One mine, owned by Charles Scott, managed to survive and years later his son Jack Scott benefited from his perseverance.
The Witwatersrand Main Reef was more consistent than that at Klerksdorp and the gold mining industry and the South African economy prospered through the late nineteen and early twentieth centuries.
However the known gold-bearing reef appeared to be restricted to the Witwatersrand area and by 1930 no new goldfields were evident west of Randfontein. Contrary to the opinions of most miners, Guy Carlton Jones, a young Canadian mining engineer working for the Consolidated Gold Fields mining company, calculated that the reef persisted to the west, albeit at exceptionally deep levels. Working with Dr Rudolf Krahmann, an expert in the new science of geophysics and the use of the magnetometer, he supervised the prospecting of the open dolomitic grasslands of the Gatsrand between Randfontein and Potchefstroom. Positive initial results were confirmed by boreholes and there, at depths greater than any mine at the time, they discovered the immensely rich Vaal Reef. When South Africa left the gold standard in 1933 the boost to the mining industry stimulated prospecting in the new goldfield but the Second World war delayed exploitation. In the years immediately after the war the two large Johannesburg mining houses, Anglo American and Anglo Transvaal collaborated with Jack Scott's mining activity at Stilfontein and established the super-deep mines that characterise the area today.
Development of the mines of the Klerksdorp-Orkney-Stilfontein-Hartebeestfontein (KOSH) region required world-leading technological innovation in the fields of water extraction, cooling the underground working areas and shaft sinking though hundreds of meters of dolomite, groundwater and mud. The management of labour has also been revolutionised on these mines where earlier appalling recruitment, wages and working conditions for mine labourers have been eliminated.