Petra undertakes risk assessment at Cullinan

London-listed Petra Diamonds has temporarily halted operations at its Cullinan mine, in South Africa, while it undertakes a risk assessment following the scaling of the openpit wall over the weekend. The company on Wednesday reported that a thunderstorm on October 26 had resulted in a "notable scaling of the sidewall" of the openpit over the weekend, as well as on Monday, October 28.