Petra Diamonds operates four producing diamond mines in South Africa. These are all underground kimberlite pipe mines (Cullinan, Finsch, Koffiefontein and Kimberley Underground). The company also had three smaller Fissure Mines (Helam, Sedibeng and Star), but Sedibeng and Star have recently closed and Helam is being run down for closure. Petra Diamonds has a record of turning De Beers' unprofitable South African mines into financial successes. According to Nicky Oppenheimer, Chairman of De Beers, the reason for this was "De Beers was operating the mines with too large a cost structure, something Petra doesn't have."[5] The underground kimberlite mines were purchased from De Beers Consolidated Mines