A graphite pilot plant in China has helped Renascor Resources (ASX: RNU) prove the viability of its Siviour graphite project in South Australia, by producing a maiden quantity of high-grade graphite concentrates from a batch of the project’s sample ore.
With a maximum throughput of 200 kilograms per hour, the pilot plant used mineral processing parameters adopted in Siviour’s pre-feasibility study (PFS) completed in March to achieve grades of 95% total graphite content (TGC) with related improvements in estimated PFS recoveries, from 18 tonnes of sample ore with an average grade of 8.5% TGC.
The ore was collected from reverse circulation drilling chips within the Siviour indicated resource and exported to China.
The produced concentrate will be used for metallurgical tests in support of the project’s definitive feasibility study (DFS), as well as in downstream testing and marketing efforts during Renascor’s ongoing offtake negotiations.
The undisclosed Chinese pilot plant, located within an operating graphite mine, completed an initial trial of eight production runs using approximately nine tonnes of Siviour sample ore blended to simulate typical composite material, with the goal of achieving pre-feasibility parameters of 95% TGC and 91% recovery.
Graphite purity of 95% TGC was achieved after the fourth run, with each subsequent run achieving at least the same grade.
Recovery improved up to 94.8% in the seventh production run, with an average recovery of 93%.
Additional production runs have been planned, with the pilot plant program targeted for completion by end November.
Renascor said the positive pilot runs echo earlier PFS grade and recovery replication test results conducted by five independent laboratories in Australia, Germany and Canada.
They support flowsheet parameters for Siviour and offer potential process improvements in upcoming test programs to support the planned DFS.
“The results from [our] pilot plant production offer strong support for the validity of flowsheet parameters adopted for the PFS, as well as suggesting the potential to improve recovery at DFS stage,” the company said.
Renascor launched the Chinese pilot production program to generate marketing samples in support of a DFS for the Siviour project.
Prior to the first production run, Renascor completed batch flotation tests of reverse circulation chips to understand the expected changes in final product particle size distribution.
These tests confirmed the purity of the concentrate would not be affected, but that the concentrate would have an overall reduction in particle size consistent with the nature of the finer sample material.
Variability testing will be performed at batch-scale on diamond core samples obtained from a current drill program at Siviour to further assess particle size distribution for DFS purposes.
This month, Renascor completed the first phase of its DFS drill program at Siviour, consisting of 99 reverse circulation and air core drillholes for 4691 metres.
Closed-space drilling was conducted to verify the continuity of mineralisation within the project’s indicated resource area, with all holes intersecting the graphite zone.
The program also included resource expansion drilling aimed at expanding near-surface, high-grade zones expected to make up part of the mining schedule for the project’s first five years.
A second phase, 15-hole, 800m diamond core program will produce samples for metallurgical testwork and marketing purposes.
Renascor is also progressing with additional DFS work programs including optimisation mineral process testing, detailed engineering and procurement, regulatory approvals and offtake negotiations.
With a probable reserve of 45.2mt at 7.9% TGC for 3.6mt of contained graphite, Siviour has been considered one of the largest graphite reserves in Australia and amongst the largest of its kind in the world.
At mid-afternoon trade, shares in Renascor Resources were steady at $0.17 per share.