Tsumeb Mine

Tsumeb Mine is notable for the huge mineralized pipe that led to its foundation. The origin of the pipe has been hotly debated. The pipe penetrates more or less vertically through the Precambrian Otavi dolomite for at least 1300 m. One possibility is that the pipe was actually a gigantic ancient cave system and that the rock filling it is sand that seeped in from above. If the pipe is volcanic, as some have suggested, then the rock filling it (the "pseudo-aplite") is peculiar in the extreme. The pipe was mined in prehistoric times but those ancient workers barely scratched the surface. Most of the ore was removed in the 20th century by cut-and-fill methods. The ore was polymetallic and from it copper, lead, silver, gold, arsenic and germanium were won. There was also a fair amount of zinc present but the recovery of this metal was always difficult for technical reasons. The pipe was famous for its richness. Many millions of tonnes of ore of spectacular grade were removed. A good percentage of the ore (called "direct smelting ore") was so rich that it was sent straight to the smelter situated near the town without first having to be processed through the mineral enrichment plant. The Tsumeb mine is also renowned amongst mineral collectors. Between 1905 and 1996, the mine produced about 30 million tons of ore yielding 1.7 Mt copper, 2.8 Mt lead 0.9 Mt zinc, as well as 80 t germanium. The average ore grade was 10% Pb, 4.3% Cu, 3.5% Zn, 100 ppm Ag, 50 ppm Ge.

It is noted for 243 valid minerals and is the type location for 56 types of mineral. Some of the germanium minerals are only found in this mine.

Gem-quality dioptase crystals from the Tsumeb mine, source of many of the world's best (and most expensive) dioptase specimens.
Tsumeb, since its founding, has been primarily a mining town. The mine was originally owned by the OMEG (Otavi Minen- und Eisenbahn-Gesellschaft) and later by TCL (Tsumeb Corporation Limited) before its closure a few years ago, when the ore at depth ran out. The main shafts became flooded by ground water over a kilometre deep and the water was collected and pumped as far as the capital, Windhoek. The mine has since been opened up again by a group of local entrepreneurs ("Ongopolo Mining"). A fair amount of oxidized ore remains to be recovered in the old upper levels of the mine. It is highly unlikely, though, that the deepest levels will ever be reopened.