A Bright Idea For Diamond Miners

(via Gemmology Queensland, Vol.8, Issue 3, March 2007)

A Queensland company is putting more sparkle into the world’s diamond industry with a new device which helps miners recover more the precious stones. Miners normally sift through many tones of ore in order to find small number of diamonds.

Brisbane’s Partition Enterprises is developing a new generation of density and fluorescent tracers which makes finding the stones in the ore much easier. Dr Chris Wood, founder and chief executive of Partition Enterprises, explains than an enormous amount of waste ore has to be processes in the search for diamonds. The processing plants are adjusted to do this by controlling the density and precision of the separation, and that’s what density tracers are used for.

Density tracers, usually small cubes, have carefully controlled densities to mimic the composition of the valuable material the miner wants to recover, as well as waste. Diamonds, for instance, are of much higher density than the waste in which they are found. Density tracers are added to the ore that’s fed into the separator and, after checking which densities reported to diamond concentrate and which to waste, the separation characteristics can be calculated.

If need be, the machinery can then be adjusted to achieve optimal performance. “The alternative is to assess performance by taking large samples from the plant and subjecting them to exhaustive laboratory analyses using toxic liquids,” Dr Wood says.

“Typically these procedures take weeks to generate data. And those data are less reliable than a density tracer test, which can be completed in an hour.” But even after subjecting diamond-bearing material to density separation, the concentration of diamonds is still very low. So fluorescent tracers, which make use of the fact that diamonds glow blue when irradiated with X-rays, are used.

Partition Enterprises’ new tracers glow in the same way and they help calibrate X-ray diamond sorters to minimize any loss of the precious stones. Dr Wood believe his company, which he and colleagues at the Julius Kruttschnitt Mineral Research Center in Brisbane began to supply density tracers for the coal industry in 1980, is the world’s major supplier of these devices.

Source: http://www.smartstate.qld.gov.au/