Kafubu area

Emerald mines of the Kafubu area

Kafubu area

The Kafubu area near Kitwe in the Copperbelt hosts a large number of emerald occurrences in Proterozoic metasediments and ultramafic rocks cut by pegmatites. The intrusion beryllium-rich pegmatite fluids reacting with Chromium-bearing rocks lead to the formation of emerald.

Kagem mine:
Kagem is probably the world's largest coloured gemstone mine. It is owned to 75% by Gemfields, a British gemstone mining and trading company and to 25% by the Zambian state. The open pit stretches over almost 1km and is over 100m deep. The mine is fully mechanised with large excavators and dump trucks operating, but mining of the productive contact zones around the pegmatites, where the best emeralds occur, is still done by hand only. We had the opportunity to visit the mine in 2010.

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Kagem mine, September 2010

Kagem mine:The Kafubu area near Kagem mine

Kagem mine: One of the mine gates

Kagem mine: Large pegmatites cut through the rock sequence (Cr-bearing schist)

Kagem mine: The soil profile is deeply weathered. Even the resistant pegmatites are completely weathered away near the surface

Kagem mine: Mechanised mining

Kagem mine: Mining the productive zone is done by hand and is closely watched all the time

Kagem mine: Piece of low-grade emerald

Kagem mine: Piece of contact zone with quartz and black tourmaline

Kagem mine: Because the pit wall is already more than 100m high, it becomes uneconomical to remove the overburden when mining deeper into the pit. Therefore, a trial shaft was built to check for the possibilities of underground mining.

Kagem mine: Trial mining underground

Kagem mine: Contact zone between pegmatite (pinkish white; left) and the Schist (dark grey; right). The contact zone contains quartz, black tourmaline, biotite and emerald.