Rockwell Diamonds said its pilot Bulk X-Ray project at the Saxendrift Mine, in South Africa has already repaid the cost of setting it up from processing the old recovery tailings.
The Bulk X-Ray project was initiated in November last year.
The miner said in a statement that during the six month period to date, a total of 1,596 carats had been recovered from reprocessing 27,609 m3 of old recovery tailings that had previously been processed by another operator using older technologies.
These, it said, included three particularly large stones weighing 52, 72 and 145 carats respectively.
Rockwell said in addition to a capital investment of $1.4 million, operating costs of $0.39 million were incurred, with revenue from sales of the diamonds recovered totalling $ 4.2 million over the period to October 31, 2012.
The recovery tailings achieved a grade of 2.97 carats/100 m3.
It said the recovery of diamonds from these tailings suggested that the deployment of this technology in run-of-mine applications across Rockwell’s Middle Orange River projects should yield additional recoveries beyond the stated grades and diamond values which have been identified using historical technology.
“We are delighted that our initial capital outlay was paid back and believe this technology will become an integral component in our total diamond value management strategy,” said Rockwell chief executive James Campbell.
“The work represents the opportunity for a step change in Rockwell’s approach to diamond recovery, enabling a quicker payback than any other type of recovery plant. Particularly noteworthy is the fact that we achieved this only from material that had been processed previously. We have yet to deploy the technology in a run of mine application.”
He said the next phase was to roll out the technology at the new Saxendrift Hill Complex mine where the processing plant would be based on two Bulk X-Ray systems at a monthly processing rate of 100,000 m3.
Mathew Nyaungwa, Editor in Chief of the African Bureau, Rough&Polished
