JOHANNESBURG (miningweekly.com) – The high-throughput bulk X-ray technology that the TSX- and JSE-listed Rockwell Diamonds has been putting through its paces has passed with flying colours.
The pilot bulk X-ray project at the Saxendrift mine in the Northern Cape has already repaid the cost of setting it up.
The price of Rockwell shares rose more than 4% to R2.50 a share in Johannesburg on Monday.
Eighty per cent of the revenue at Rockwell’s Saxendrift operation is from stones larger than 10 mm, which are ideally suited to the bulk machines.
Rockwell CEO James Campbell said the next phase would be the rollout of the technology at Rockwell’s new Saxendrift Hill Complex mine, where the processing plant would be based on two bulk X-ray systems processing 100 000 m3 of material a month.
The capital outlay of $2-million would be funded from working capital.
“We believe this technology will become an integral component in our total diamond value management strategy. The work represents an opportunity for a step change in our approach to diamond recovery, enabling a quicker payback than any other type of recovery plant,” Campbell said.
Particularly noteworthy was that previously processed material was used and that the technology had yet to be deployed in a run-of-mine (ROM) application.
Rockwell’s projects team had demonstrated that it is able to replicate the system on other operations.
The bulk X-ray pilot project came in 7% lower than the $1.5-million budget, with revenue from the sale of the diamonds recovered totalling $4.2-million.
The technology recovered 1 596 ct from 27 609 m3 of old recovery tailings, which another operator had previously processed using older technologies.
Among the recoveries were three particularly large stones weighing 52.72 ct and 145 ct.
The recovery tailings achieved a grade of 2.97 ct/100 m3.
The deployment of the technology in ROM applications across Rockwell’s Middle Orange River projects was expected to yield additional recoveries at lower operating cost, Campbell added.