Being proactive about dam safety

Understanding the risk that our dams could pose to our surrounding communities and receiving environments, dam safety has long been of utmost importance to Gem Diamonds.

In the wake of the tragic events in Brazil, we reiterate our commitment to investing in the safe operations of our dams.

The dam walls, for both our waste and fresh water storage facilities, undergo stringent safety procedures in the form of inspections and audits, which are conducted both internally and externally. At Letšeng, three facilities are considered: the Patiseng tailings storage facility (TSF), the old TSF, which is now dormant, and the Mothusi Dam, our fresh-water supply resource.

The Patiseng TSF undergoes stringent inspections on a daily, weekly and monthly basis, surveying various factors such as water level, beach height and overall structural stability. Quarterly structural stability inspections are carried out by an external civil engineering specialist.

The old TSF is inspected daily, weekly and monthly again with quarterly structural stability inspections supplied by an external consultant. The Mothusi Dam is also inspected on a daily, weekly and monthly basis, with inspection frequencies increasing during higher rainfall periods. Outsourced specialists conduct quarterly inspections for the Mothusi wall. All three dams are closely monitored via V-notch weirs, which determine flow rate and are connected to a flow monitoring system. Facility risk assessments, resistivity surveys and flow model studies are also regularly carried out to ensure responsible management of the facilities.

Letšeng has also put in place a system designed to manage the unlikely event of dam wall failure in an effectual and timely manner. An early warning system has been established for potentially affected communities with the provision of radio equipment and alarm systems. Communities have also undergone training and awareness programmes to ensure their emergency readiness.

Ghaghoo currently has two slimes dams. Internal inspections on the dams are carried out daily, with structural stability inspections being made on a weekly basis. An outsourced consultancy firm has been appointed for external quarterly inspections. Ghaghoo staged an emergency drill in June of 2015 to assess emergency preparedness plans. The drill was successful, and quarterly drills are being planned for the year ahead.

A risk management strategy has been put in place to negate potential threats to the safety of our dams.

We believe that ensuring our dam wall safety relies on correct management procedures. Gem Diamonds ensures that the strictest management plans are put in place to ensure complete stability and conformity to the established system.

Ghaghoo Diamond Mine, aerial view.   Letšeng Diamond Mine, aerial view of Patiseng TSF.