JOHANNESBURG (miningweekly.com) – Multicommodity miner Premier African Minerals expects the first commercial shipment from its flagship RHA tungsten project, in Zimbabwe, to start on July 17.

"Despite the challenges of the fast-track approach taken with RHA, I am pleased to report that initial fines concentrates from our plant are running as high as 70%. All regulatory requirements, contracts and inspections processes necessary for export have been agreed,” CEO George Roach commented.

He added that, during the optimisation process, it became clear that the downstream concentration circuits had surplus capacity in excess of the designed 16 t/h capacity on the crushing circuits.

“We have, therefore, ordered modifications that are expected to be incorporated into the process within the next 30 days that will both improve the efficiency of the crushing circuits and will allow better use of the surplus capacity on the downstream concentration circuits.

“The immediate effect of this is anticipated to be an increase in the percentage of higher-grade fines concentrate over the coarse concentrate, with a probable overall increase of total tonnage of concentrate produced. Capital cost is nominal,” Roach said.

Following production of first concentrates on June 5, the components of the process plant had steadily undergone optimisation and fine-tuning. The plant had been running on a 24-hour continuous production cycle since June 26 and first ores from areas identified in the resource model started arriving at the plant on June 30.

This, together with the developments of the past few weeks, are anticipated to result in a substantial increase in concentrates produced and the start of shipments, the Aim-listed company said in a statement.

Fines concentrates from the tables had exceeded grades of 67% tungsten trioxide (WO3) on a regular basis with as high as 70% WO3 recorded to date.

The company embarked on a drilling campaign to supplement the existing water supply from the RHA dam. To date, four holes were successfully completed which would be incorporated into the water supply infrastructure.

Further drilling was under way.