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.
The scaling was along geological structures and about three-million tonnes of material fell into the openpit, which was discontinued more than 50 years ago. The Cullinan mine is now an underground operation.
"Following this incident, there has been thorough engagement with the Department of Mineral Resources and Energy, the labour unions and the local community, with a number of actions agreed upon.
"The operation is being disrupted for about one day to give management the opportunity to thoroughly inspect the underground workings for any anomalies and to complete a risk assessment before allowing operations to continue," Petra noted in a statement.
"We will take whatever steps are necessary, including the engagement of external technical specialists if required, to better understand this incident and any impact on future pit stability. The safety of our employees and surrounding communities continues to remain our key focus," CEO Richard Duffy added.
The company does not expect this incident to have a material impact on production.