Optimised monolayer magnetics removal during ore preparation improves throughput to the Bourevestnik X-Ray sorters.Photo Supplied

Dineo Faku

X-RAY machines could become the gem production method of choice should the technology that was recently adopted by Rockwell Diamonds become successful in the next year, according to Peter Major, a mining analyst at Cadiz Corporate Solutions.

X-ray machines have been used in diamond mining for years, but new Russian technology in which Rockwell Diamonds invested $1.5 million (R12.4m), can handle larger volumes and is aimed at improving efficiency and security.

It was developed by Russian mining equipment and training provider Bourevestnik. Russia is a significant producer of diamonds.

“The processing plant is simpler and therefore carries lower maintenance requirements once commissioned,” Rockwell said last week.

Using the X-ray sampling machine, Rockwell recovered 316 stones totalling 1 109 carats in the first four weeks of production at its Saxendrift tailings mine in the Northern Cape in April. This included 14 stones exceeding 10 carats, with the largest weighing 52.67 carats.

Rockwell intended to introduce the bulk X-ray system at its Jasper operation as well.

Diamond producer Trans Hex said it had been using X-ray technology imported from Russia for almost a year.

Trans Hex said the X-ray technology had increased the recovery rate of diamonds and could be adjusted to suit the firm’s production profile.

“The technology allows for a higher throughput and is efficient, cost effective, secure and environmentally friendly,” said the company spokeswoman.

Major said the machines used at the Saxendrift mine were able to do the work of two other pieces of equipment, including that of a dense-media separation (DMS) plant, which was large and complex.

“Instead of processing 3 tons an hour as do current X-ray sorters in South Africa, the Russian machine is able to sort up to 100 to 150 tons an hour. They are a lot cheaper and faster for companies to process large volumes,” Major said.

The X-ray unit was ideal in situations where water scarcity makes DMS applications difficult. As these bulk sorters produced a high recovery yield, a conventional recovery plant was also needed.

Nico van Zyl, the marketing and new business development manager at De Beers subsidiary DebTech, said the firm had been supplying similar X-ray recovery machines for the past 30 years.

During the past two years DebTech sold units to producers in South Africa, Russia and Canada. Van Zyl said the machines were highly efficient and made a significant difference in the recovery of especially low luminescent diamonds.

“We are also working on new developments and have recently launched a low-cost scavenger unit,” Van Zyl said.

Rockwell shares closed unchanged at R3.40 yesterday, while Trans Hex stock closed 1.2 percent higher at R3.44.