The sixties and seventies
The construction of the smelters in the early 1960s led to further expansion of the town, with many new homes and the provision of sewers, water, power lines, and telephone cables for all of the new buildings. By the mid-1960s mining had reached 34 Level, but drilling had proven continuation of the ore body to a depth of 1326 metres (40 Level).
A new production record of 733,000 tonnes of ore was achieved in 1965 but, thereafter, production was slowed because of rock stability problems. In 1967 several pillar stopes collapsed and by 1974, geotechnical issues had reduced annual ore production to 420,000 tonnes. A new process for back-filling stopes was introduced, as well as increased mechanisation, allowing production to rise again to 480,000 tonnes in 1979 (Anon. 1979). By this time the deepest workings were on 38 Level, some 1274 metres below the surface.
It is worth recording, at this point, that the 1970s were the heyday for the production of specimen quality dioptase from the Tsumeb Mine. This is significant because, according to Key (1996) dioptase specimens “…exceed(s) in value all of the other minerals found at Tsumeb, with fine azurite a distant second.” The discoveries of abundant dioptase in the second oxidation zone between 29 Level and 35 Level, in the late 1960s, 1970s, and early 1980s, enormously enhanced Tsumeb’s reputation as an extraordinary mineral locality.