Merensky Reef
The Merensky Reef is a 1 to 3 meter thick layer of igneous rock, a plagioclase - pyroxenite, in the Bushveld Complex in the Transvaal. Together with another, underlying 20-330 meters horizon, 15 to 250 cm thick UG2 chromitite layer ( UG2 = Upper Group 2 ) and the degraded at Potgietersrus Platreef here are the largest known reserves of platinum group metals ( PGMs ), such as platinum, palladium, rhodium, iridium and osmium. The content of PGM varies from 4.0 to 10.6 g / t in the rock.
The Merensky Reef, the composition throughout the Bushveld complex is relatively constant, is rich in bronzite and chromite. However, it lacks the gold, copper and nickel by-products of the Merensky Reef, whereas its PGM reserves are expected to be as high, almost twice. Rare minerals of these metals, such as Braggit, Laurit, Sperrylite, Stibiopalladinit and cooperite occur there.
The Chromititbänke often arise in large, traversed by Mafitschichten intrusions. A common theory is that Chromitite are a consequence of the introduction and the mixing process of simple magma with differentiated magma. It comes to a supersaturation of chromite in the mixture and subsequently lead to the emergence of a nearly monomineralic layer on the bottom of the magma chamber.
Platinum Executive horizons in the Bushveld complex was discovered in 1924 by Hans Merensky in the district of Lydenburg, which she pursued until 1930, a few hundred kilometers in his research. An extensive mining on the Reef was not operated until the 1950s, a sudden increase in the demand for platinum group metals arose, which are used in the catalytic emission control. This commercial mining was economically. Only after significant metallurgical advances in the 1970s it was possible to smelt the UG2 Chromitite economically.
On the extraction of platinum metals, several companies are involved. They include the Anglo American Platinum Corporation Ltd.. (formerly Rustenburg Platinum Holdings Ltd. ), Impala Platinum, Lonmin Platinum ( including Western Platinum) and Northam Platinum.