THE MineralPET machine, developed at the University of Johannesburg (UJ) in collaboration with the University of Witwatersrand and engineering company Bateman Engineering, applies techniques used in nuclear medicine to identify rocks that contain diamonds.
PET stands for positron emission tomography and, in medicine, the PET scan is used to image the inside of the human body using gamma rays.
“We’ve been able to image diamond in rock using nuclear and particle (physics) techniques,” says Simon Connell, one of the project leaders, who is based in the UJ’s physics faculty.
Diamonds are made up of carbon — but the carbon atoms are arranged differently to coal or graphite. Using a gamma-ray process, the machine differentiates between the carbon in diamonds and the surrounding material and nondiamond carbon. A kimberlite rock-feed stream, with the rocks broken down to a diameter of about 10m are passed through the machine, which can separate rocks with diamonds from rocks without.
The project claims that benefits include “cost, environmental impact and the recovery of large diamonds”, among others. “We’ve patented it everywhere and are trying to commercialise it at the moment,” Prof Connell says.
Willem Clarke, head of UJ’s spin-off company, Resolution Circle, says one of its projects is a mining spin-off, and that “we’re negotiating with some mines”.