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Smithsonite is often found as a secondary mineral in the oxidation zone of zinc ore deposits. It can also be observed in sedimentary deposits and as a direct oxidation product of sphalerite.
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Classification of Smithsonite
5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H2O
B : Alkali-earth (and other M2+) carbonates
14 : ANHYDROUS NORMAL CARBONATES
1 : A(XO3)
11 : Carbonates
6 : Carbonates of Zn and Cd
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Occurrences of Smithsonite
Physical Properties of Smithsonite
On {1011}.
Crystallography of Smithsonite
Galena is the primary ore mineral of lead. Worked for its lead content as early as 3000 BC, it is found in ore veins with sphalerite, pyrite, chalcopyrite, tennantite-tetrahedrite, etc. and in skarns, as well as in sedimentary rocks where it may replace carbonate beds or be deposited in pore spaces. The crystals are bright when fresh but often tarnish after exposure to air.
Classification of Galena
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
C : Metal Sulfides, M: S = 1: 1 (and similar)
D : With Sn, Pb, Hg, etc.
2 : SULFIDES
8 : AmXp, with m:p = 1:1
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
6 : Sulphides etc. of Sb and Pb
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Physical Properties of Galena
{001}
Crystallography of Galena
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| Motto: Glück Auf (German mining term for Good luck!) | ||
 Satellite view | ||
  Tsumeb | ||
| Coordinates: 19°15′S 17°52′E / 19.250°S 17.867°E | ||
| Country |  Namibia | |
|---|---|---|
| Region | Oshikoto Region | |
| Elevation | 4,098 ft (1,249 m) | |
| Population (2011)[1] | ||
| • Total | 19,275 | |
| Time zone | South African Standard Time (UTC+1) | |
| Climate | Cwa | |
Tsumeb (Otjiherero name: Okavisume)[2] is a city[3] of 15,000 inhabitants and the largest town in Oshikoto region in northern Namibia. Tsumeb is the "gateway to the north" of Namibia.[4] It is the closest town to the Etosha National Park. Tsumeb used to be the regional capital of Oshikoto until 2008 when Omuthiya was proclaimed a town and the new capital.[5] The area around Tsumeb forms its own electoral constituency and has a population of 44,113.[6] The town is the site of a deep mine (the lower workings now closed), that in its heyday was known simply as "The Tsumeb Mine" but has since been renamed the Ongopolo mine.
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[hide]The town and the Tsumeb mine
The name Tsumeb is generally pronounced "SOO-meb". The name is not a derivative of German, Afrikaans, or English. It has been suggested that it comes from Nama and means either "Place of the moss" or "Place of the frog". Perhaps this old name had something to do with the huge natural hill of green, oxidized copper ore that existed there before it was mined out.
The town was founded in 1905 by the German colonial power and celebrated its 100th year of existence in 2005.
Tsumeb 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.[7] The average ore grade was 10% Pb, 4.3% Cu, 3.5% Zn, 100 ppm Ag, 50 ppm Ge.[8]
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.[9]
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.[9]
The other notable feature of the town is the metal smelter, currently owned by Namibia Custom Smelters. The Annual Copper Festival is a well-known event on the local festival calendar.
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Tsumeb Mine (Tsumcorp Mine), Tsumeb, Otjikoto Region (Oshikoto), Namibia
| Latitude & Longitude (WGS84): | 19° 15' South , 17° 42' East |
| Latitude & Longitude (decimal): | -19.25, 17.7 |
A world-famous Cu-Pb-Zn-Ag-Ge-Cd mine, renowned for a wealth of rare and unusual minerals. Discovered and initially operated in 1907 and closed in 1996 for economic reasons.
The Tsumeb Mine is currently operated by Ongopolo, the previous name of 'Tsumcorp Mine' was superseded after the collapse of Tsumeb Corporation Ltd (TCL) after whom the mine was originally named.
Mineralization is hosted in Neoproterozoic Otavi Dolomite. The ore body is a pipe. It is about 120 by 15 meters in cross section, steeply dipping and extending from surface to at least 1,000 meters in depth. Controls for ore emplacement include interrupted circular fracturing, core breccia, and an internal mass of pseudo-aplite (Tsumeb Pipe). Local rocks include mainly Late Proterozoic sedimentary terrane.
Workings include extensive underground openings to a depth of 1,000 meters.
Mineral List
313 entries listed. 286 valid minerals. 71 (TL) - type locality of valid minerals. 1 (FRL) - first recorded locality of unapproved mineral/variety/etc.
Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia