Des qualified as a geologist and joined the Assore group in 1968. He was appointed to the Assore board in 1974 and, on the retirement of his father, Guido, in 1992, was appointed Chairman and Managing Director. In that year he was also appointed Deputy Chairman of Assmang Limited and in 1999 he became Chairman of Assmang. He is a fellow of the Institute of Directors (IoD) and of the Geological Society of South Africa (GSSA).