Following the recovery of chrome concentrate, the miner said it was using the feed directly from the retreatment project.

The scavenger circuit, construction costs for which were less than US$150,000, can process around 40,000 tonnes of feed per month. Eastplats said it kept costs down by using its existing infrastructure that had been kept on care and maintenance.

Whole-year 2019, Eastplats produced 598,034t of chrome concentrate from the retreatment project, and December quarter production on its own was 214,828t - the best production quarter so far. Last month, the project realised 101,606t more, Eastplats' largest monthly production thus far.

"This is the first step in the company's full-scale assessment of the PGM recoverability of the tailings resource and provides further revenue opportunities for Eastplats," president and CEO Diana Hu said.

"The company will continue to move forward with its assessment of the larger PGM recoverability opportunities in relation to the tailings resource."

The miner confirmed it would be investing about US$6 million to further optimise the project by acquiring and installing additional equipment.

CRM, located 70 kilometres northwest of Johannesburg, ceased mining operations in July 2013 among a stagnant market outlook at the time.