Miningtek says it has made considerable progress in laboratory-testing facilities to enable a number of potential alternative 'rock-breaking methods' during platinum group metals (pgm) mining.

According to mining systems research area manager Gokhan Guler a prototype 'activated rock cutting machine' has already been commissioned and tested underground at Anglo Platinum's Townlands mine with some success, while other projects are also in development.

Mr Guler told Mining Weekly that a number of innovations such as the mini-disc cutter have proved effective.

Several full-scale laboratory test programs have been completed using the mini-disc cutter as well as a series of underground trials on a platinum-mine using a full size test rig.

Another development under investigation at the platinum industry's collaborative research program, Platmine, is the plasma hole-maker (PHM).

Members behind the collaboration, namely Anglo Platinum, Impala Platinum, Northam and Lonmin, have also far expressed interest in the PHM.

In contrast to the normal method of operation employed by percussive rotary drills, the PHM employs intense shockwaves generated in water by electric plasma-pulsed discharges through a special directional electrode that is continually flushed with water.

The shockwaves generated by the plasma are focused in a forward axial direction to fracture the rock in the direction of drilling, but with little breakage in the radial direction.

The consequent rapid deposition of energy generates compressive and then tensile stresses that collapse the rock along the grain boundaries.

Mr Guler says the developments could prove hugely significant for the industry particularly because of the ability to mine smaller holes.