The Union Minière du Haut-Katanga (French; "Mining Union of Upper Katanga"), often abbreviated to Union Minière or UMHK, was a Belgian mining company which operated in the former Congo Free State and Belgian Congo between 1906 and 1966.
Created in 1906, under the urging of Leopold II, the company was set up by Société Générale de Belgique, Comite Special du Katanga (formed in 1900 by Compagnie du Katanga and the Congo Free State to exploit Katanga's mineral wealth), and Tanganyika Concessions Ltd. Union Miniere was granted a 7,700 square mile concession in Katanga, allowing it to mine uranium, copper, cobalt, radium, zinc, cadmium, germanium, manganese, silver, gold, and tin. By the start of WWII, Société Générale de Belgique' controlled 70% of the Congolese economy. Exercising preponderant influence over the Comité spécial, the Société Générale effectively controlled the Union Minière from its inception to 1960. Some of the remains of the UMHK form part of the present day company Umicore.
During its years of operation, the UMHK greatly contributed to the wealth of Belgium, and, to a lesser extent, Katanga—which developed more than the surrounding regions without similar mineral resources. The company could be considered harshly capitalistic, but its motto at the time, best expressing their opinion of development was "good health, good spirits, and high productivity." Possibly it was because of this approach, and in order to keep and placate the workforce, that the Union introduced an accident compensation scheme as early as 1928. Katanga's mineral wealth led to the construction of railways (including the Benguela railway) to connect it with the Angolan coast which took place in 1911, other rail lines connected Katanga to Northern Rhodesia. Thereafter, mineral production, especially of copper, took off. For instance, in 1911, the Ruashi Mine, owned by the UMHK, began operation, supplying 997 tonnes of copper on its first year. By 1919, annual production had risen to 22,000 tonnes, produced by seven furnaces. In 1935, the Union was party to the World Copper Agreement. One of its prominent figure were Belgian financier and lawyer Felicien Cattier and businessman Emile Francqui. In the 1950s, Congo was the world’s fourth largest copper-producing country.
In addition to the copper for which it is known, Katanga was also rich in other minerals. The company controlled the exports of cobalt (the UMHK was responsible for 75 percent of world production during the 1950s), tin, uranium and zinc in its mines, among the richest in the world. Henri Buttgenbach, a famous Belgian metallurgist and administrator of UMHK from 1911, described cornetite, fourmarierite, cuprosklodowskite and thoreaulite. The finding of radium deposits in Katanga at the same time eventually led to a Belgian radium-extracting industry. Johannes Franciscus Vaes, who has studied minerals coming from the UMHK, is responsible for the discovery of billietite, masuyite, renierite, richetite, schuilingite-(Nd), sengierite, tudtite and vandendriesscheite. Gaston Briart, after whom Briartite is named, was a UMHK consultant. In 1922, the UMHK built its first refinery for uranium ore, and by 1926 had a virtual monopoly of the world uranium market (holding most of the deposits known at the time), to be broken only by the German invasion of 1940. This uranium was mostly refined at Olen, Belgium. In 1939 , Frédéric Joliot-Curie, head of the French newly established Centre National de la Recherche Scientifique (CNRS), arranged for the UMHK to provide his organization with 5 tonnes of uranium oxide, technical assistance with the construction of a reactor and a million francs, in exchange for having all discoveries made by the CNRS patented by a syndicate, with profits shared between the CNRS and the UMHK. This uranium oxide was transferred to England before German troops entered Paris.
The United States of America obtained uranium for the atomic bomb from the Union Minière. At a meeting on 18 September 1942 between Edgar Sengier, head of UMHK, and United States General Kenneth Nichols of the Manhattan Project, Nichols purchased the 1500 tonnes of uranium (mostly mined at Shinkolobwe mine, near the town of Likasi) the project required. This was already in the United States, and additional ore was shipped from the Congo. The mine had a "tremendously rich lode of uranium pitchblende. Nothing like it has ever again been found"; the ore was 65% uranium and even the waste piles were 20%; "after the war the MED and the AEC considered ore containing three tenths of 1 percent as a good find". Some 1200 tonnes of uranium stored at the Olen refinery were captured by the Germans in 1940, and only recovered by US troops at the end of the war.
During its heyday, the UMHK operated schools, dispensaries, hospitals and sporting establishments, and had enjoyed virtually unlimited funds with the Banque de la Société Générale de Belgique. In 1959, Belgian profits from the Union Miniere were in excess of 3.5 billion Belgian francs, and export duties paid to the Congolese government constituted 50% of the government's revenue. There were times when the Belgian colony's tax on the UMHK accounted for up to 66% of its revenues. It is reported that in 1960, the UMHK had annual sales of $200 million USD, had produced 60 percent of the uranium in the West, 73 percent of the cobalt, and 10 percent of the copper, and had in the Congo 24 affiliates including hydroelectric plants, chemical factories and railways.
This eventually came to an end. Turbulence started in 1960, with the Congolese declaration of independence. In 1961, the UMHK supported the secession of the province of Katanga from the Congo and the murder of Patrice Lumumba, Congo's first prime minister after Belgian colonial rule, in order to preserve its holdings in a Katangan client-state. During the province's secession, the Union transferred 1.25 billion Belgian francs (35 million USD) into Moïse Tshombe's bank account, an advance on 1960 taxes which should in fact have been paid to Lumumba's government. On 31 December 1966, the Congolese government, under President Mobutu Sese Seko (then Joseph 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).
Göran Björkdahl (a Swedish aid worker) wrote in 2011 that he believed Dag Hammarskjöld's 1961 death was a murder committed in part to benefit mining companies like Union Minière, after Hammarsköld had made the UN intervene in the Katanga crisis. Björkdahl based his assertion on interviews with witnesses of the plane crash near the border of the DRC with Zambia, and on archival documents.