Union Minière du Haut Katanga The Union Minière du Haut Katanga ( UMHK ) was a Belgian mining company , once operating in Katanga , in what is now the Democratic Republic of the Congo ( formerly , Congo Free State , from 1908 , Belgian Congo , from 1972 , Zaire ) . It was created on October 28 , 1906 , as a result of a merger of a company created by Léopold II and Tanganyika Concessions Ltd ( a British company created by Robert Williams , which started prospecting for minerals in 1899 , and was granted mining concessions in 1900 ) , in order to exploit the mineral wealth of Katanga . It was owned jointly by the " Société Générale de Belgique " , Belgium ' s largest holding company ( which controlled 70 % of the Congolese economy ) and Tanganyika Concessions Ltd . Some of the remains of the UMHK form part of the present day company Umicore . Company history . Copper ' s travail . 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 . In the 1950s , Congo was the world ’ s fourth largest copper - producing country . Uranium and politics . 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 75 % of the production of which 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 , cuprosklodowskie 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 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 franc s , 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 . Lumumba and Mobutu . 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 . Upon 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 December 31 , 1966 , the Congolese government , under president Mobutu Sese Seko , 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 .