Preliminary test work on core samples from the Mustang project in the US has produced metallurgical recoveries of up to 88% lithium for owner Red Mountain Mining (ASX: RMX).
The program was designed as a proof-of-concept that lithium can be extracted from drill samples through the use of sulfuric acid as a metallurgical process.
Four samples were pulverised to a target size of 100% passing 0.106 millimetres.
Approximately 500 grams of solids were leached with a target 150g/L sulfuric acid solution at 25% solids by weight for up to 72 hours.
For three of the samples, the lithium continued to be recovered faster than acid consumption over the period, suggesting that further test leaching beyond 72 hours is warranted.
Increasing lithium recovery
Red Mountain chairman Troy Flannery said future tests on a wider range of samples would aim to reduce acid consumption while increasing lithium recovery.
“We have now confirmed the mineralisation discovered in our maiden Phase 1 drilling program responds very positively to acid leaching, with test results showing high recoveries at low acid consumption rates,” he said.
“We are excited to continue our drilling at Mustang in the hope of encountering further thick mineralisation to eventually build an economic resource.”
Additional mining claims
In August, Red Mountain confirmed it had staked an additional 88 mining claims north of its current tenure at Mustang.
The claims cover 7.35 square kilometres and are prospective for claystone-hosted lithium within the hydrologically-closed Monte Cristo Valley in Esmeralda County.
The company now has a total of 228 claims at Mustang over 19.06sqkm.
Lithium claystone
Assays received in July showed the company intersected high-grade lithium claystone in 80% of drillholes during the maiden campaign.
Seven out of 10 holes hit thick and consistent lithium from or near surface.
Fast-tracked assays featured best results of 48.77 metres at 687 parts per million lithium from 3.05m; 30.5m at 629ppm lithium from surface; 28.96m at 564ppm lithium from 4.5m including 3.05m at 690ppm from 30.5m; 32m at 639ppm lithium from 6.1m; and 29m at 600ppm lithium from 1.5m.
