Although diamond is the hardest naturally occurring mineral, it is very brittle. All stages of the mining process, from transportation to comminution -or resizing of the material - can damage the valuable product. An important characteristic is the breakage function which gives a measure of how easily a diamond is damaged and has, until now, not been fully possible. With the use of a compression testing machine, high-speed video and 3D imaging technology, researchers at South African company DebTech, an R&D arm of the world's largest diamond producer De Beers, have for the first time been able to experimentally measure this function. Garry Morrison, senior research scientist at DebTech, said the ability to qharacterise the breakage function of the ore body of a material enables appropriate comminution circuits for machines such as crushers and mills to be designed so they operate as efficiently as possible. 'In the case of diamond mining, however, we must efficiently break the host ore body, while leaving the diamonds undamaged,' he said. 'It is only by understanding the breakage function that we can figure out how hard we can operate our comminution circuits without breaking diamonds, and hence losing revenue.' For their experiments the researchers used a Zwick compression machine equipped with a 30kN load cell and Zwick's testXpert software.
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