Laser scanner shows it’s metal at world’s deepest gold mine

Anglogold Ashanti has purchased a high speed laser scanner to support mining operations at the world’s deepest and most substantial gold mine. The VZ-400, purchased from 3D Laser Mapping, will be used to determine off-line and grade mining at the Mponeng Mine in South Africa, where depths are currently over 2 kilometres below sea level. The use of high speed, high accuracy, non-contact laser data acquisition will help improve operational efficiencies and reduce the risk to personnel working in the active mine.

“We tested laser scanners from many manufacturers before selecting the RIEGL VZ-400,” commented Michael Harcombe, Senior Mine Surveyor at Anglogold Ashanti’s Mponeng Mine. “The virgin rock temperature is around 60 degrees Centigrade and working temperatures tend to be between 30 and 35 degrees. At these ambient levels, sensitive equipment, such as laser scanners, simply do not get the opportunity to disperse the heat they generate, so tend to overheat and stop operating! This is not an issue with the RIEGL VZ-400.”

By using the VZ-400, purchased from 3D Laser Mapping, to determine off-line and grade mining Anglogold Ashanti will eradicate the need for later redevelopment and therefore reworking of areas already mined. The Mponeng Mine is located between the towns of Carletonville and Fochville on the border between Gauteng and the North West Province, southwest of Johannesburg. The operation, the world‘s deepest mine, extracts the Ventersdorp Contact Reef (VCR) at depths between 2,400 metres and 3,900 metres through sequential-grid mining producing more than 500,000 ounces of gold a year.

Anglogold Ashanti are also hoping to use the laser scanner to monitor workings for signs of deformation; a common phenomenon as rocks at these depths are under enormous pressure. The company currently undertakes visual inspections. However, using the VZ-400 they would be able to capture highly accurate and repeatable measurements, at regular intervals, in order to identify any possible issues at the earliest opportunity.

The RIEGL VZ-400 is a high speed laser scanner with a wide range of view. The VZ-400 utilises unique echo digitisation and online waveform analysis to achieve superior performance and accuracies of measurement, even under adverse weather conditions. Achieving accuracies of 3 millimetres at ranges of up to 600 metres the VZ-400 can capture up to 122,000 points per second with a 100 x 360-degree field of view.