 In 1929, Loeb resigned as AMCO's president over a disagreement in AMCO's taking on debt to fund the purchase of copper mining interests in Africa (previously, AMCO had minimized its ownership in mines and instead relied on exclusive supply contracts).The board purchased Loeb's 80,000 shares for eighty-five dollars apiece which was fortuitous for Loeb as the Wall Street Crash of 1929 followed later in the year.In 1930, AMCO purchased a major interest in two of the world's largest copper mines in Africa, including the Roan Antelope Copper Mine in Luanshya (in the Copperbelt Province) and the Rhodesian Selection Trust (formed in 1928 by Irish-American mining magnate Alfred Chester Beatty).