Global investment company Kazera Global has reported that its subsidiary Deep Blue Minerals (DBM) has completed the first full-scale test run of its new diamond recovery plant in Alexander Bay, in the Northern Cape, South Africa, with results showing the facility is performing to expectations.

Simultaneously, DBM has been awarded a new mining block in the area that is regarded locally as one of the richest diamond-yielding blocks.

The company said on September 25 that the plant demonstrated processing capacity of up to 20 t an hour of gravel during the trial, confirming its potential to handle around 160 t a day at full scale.

DBM has now processed 150 t of screened gravel, producing 133 diamonds weighing 68 ct in total, including a single 6.13 ct diamond.

The ratio of carats recovered per tonne during the test was higher than the company’s long-term model, leading DBM to project recoveries of about 200 ct a month once operations reach steady production from its current coastal block.

“Able to process up to 160 t a day of diamond gravel, the final recovery plant has delivered exactly the performance we expected and gives us a clear pathway to recover around 200 ct a month at full operational capacity, based on gravels from the current coastal mining block,” Kazera CEO Dennis Edmonds said.

Alongside the plant results, DBM has secured a new block from State-owned entity Alexkor, which controls the diamond rights in Alexander Bay. The block, previously mined by another operator, is recognised as containing some of the highest carats per 100 t in the area but is classified as an operation of “high difficulty” owing to the technical challenges of extraction.

DBM’s fleet and processing systems are, however, considered well suited to the deposit, and because of the difficulty rating, the company will receive a more favourable revenue split under its agreement with Alexkor.

“Equally significant is obtaining a new high-yielding block, which ranks among the top blocks in the Alexander Bay area and is ideally suited to DBM’s equipment and processing technology. Because of its higher mining difficulty, DBM will benefit from a more favourable revenue split under its Alexkor agreement, which enhances the economics of this block,” Edmonds said.

The new block could contain thousands of carats based on historic production data, according to the company. DBM said it is undertaking further assessments and will provide updates as more information becomes available.

The September diamond production cycle has now closed, with the 133 recovered diamonds to be auctioned by Alexkor in the coming weeks. Under its agreement with Alexkor, DBM receives a share of the revenue from sales rather than direct ownership of the diamonds. The company expects to report the results of the auction within three weeks.