The post-war period
The Tsumeb mine was put up for sale in 1946 by the Custodian of Enemy Property. It was sold in January 1947, to the O’okiep Copper Company, on behalf of the Tsumeb Corporation Limited (TCL), which would operate the mine for the next half-century. TCL was a consortium of American, British, and South African companies including Newmont Mining Corporation; American Metal Company; Selection Trust; British South Africa Company; Union Corporation; South West Africa Company; and the O’okiep Copper Company. A major programme of development and expansion for both the mine and the town followed this change of ownership.
Geological investigation revealed that the ore body was widening with depth, justifying the sinking of a new shaft from surface to 30 Level. Before this could be done, however, additional power generating capacity had to be installed to cope with the need to pump increasingly large volumes of water out of the mine.
De Wet Shaft was collared in 1949 and sunk to a depth of 1006 metres, with a pump station just below 30 Level; it came into production in late 1953, initially hoisting waste rock, but switching later to ore. By 1957 the preparation of the De Wet Shaft block was complete and stopes began to break ore on 26, 28 and 30 Levels. Surprisingly this deeper ore was highly oxidized – a second oxidation zone – and associated with numerous water-bearing fissures which only added to the mine’s enormous pumping requirement, and necessitated extensive use of cementation for the development of these deeper headings.
The post-war period also saw the redesign, and new construction of an extended metallurgical concentrator, commencing in 1947 with grinding and flotation circuits introduced to replace the old gravity-separation plant. From a metallurgical perspective, the mineralogical complexity of the Tsumeb ore body was always problematic and, during the late 1940s and 1950s, much work was undertaken to optimise the recovery of metals from both sulphide and oxide ores. From 1954 a flotation circuit to recover a germanium concentrate was introduced. In 1959 and 1960 respectively, decisions were made to construct first a new copper smelter, and then a lead smelter.