On 31 December 1966, the Congolese government, under President Joseph-Désiré Mobutu, took over the possessions and activities of the UMHK, transforming it into "Gécamines" (Société générale des Carrières et des Mines), a state-owned mining company. Mismanagement and failure to adopt modern standards of mining (rather than mining depletion), as well as outright theft by Mobutu, meant that mining production was greatly reduced, with production rate sinking as much as 70%. Those assets of UMHK not seized by Mobutu were absorbed by the Société Générale de Belgique, later becoming part of Union Minière (now Umicore).