Astute Metals strengthens Red Mountain commercial potential with test results

Red Mountain testwork delivers strong beneficiation results which confirm upgrade potential and a route to market.

Results represent the systematic de-risking of the Red Mountain project in Nevada. Pic: Getty Images

Special Report: Beneficiation testwork at Red Mountain in Nevada has produced lithium clay concentrate grades of up to 4,480 ppm, confirming the capacity to upgrade mineralisation and outlining a clear pathway to commercial production.

• Follow up beneficiation testwork delivers encouraging results at Red Mountain
• These include upgrading a sample from 3245ppm to 4481ppm lithium 
• Attrition scrubbing beneficiation underway 

Building on the April results that confirmed proof of concept, the second phase of Astute Metals’ (ASX:ASE) beneficiation testwork has demonstrated strong upgrade potential - reducing sample mass by 51.8%, increasing lithium grade by 38% and achieving a 66.6% overall lithium recovery.

This program, conducted by Sepro Laboratories, utilised high clay drill core samples from hole RMDD002 which intersected 86.9m at 1470ppm lithium from 18.3m. 

The follow up testing was designed to establish how high-clay material performed using the Falcon method for comparison with results from the previous test conducted on lower grade mineralisation.

Background on Red Mountain 

ASE first staked Red Mountain in central-eastern Nevada in August 2023.

It is adjacent to the Grand Army of the Republic Highway (Route 6), which links the regional mining towns of Ely and Tonopah.

The project hosts broad mapped tertiary lacustrine (lake) sedimentary rocks known locally as the Horse Camp Formation.

Sedimentary rocks elsewhere in Nevada host large lithium deposits such as Lithium Americas’ 62.1Mt LCE Thacker Pass project, American Battery Technology Corp’s 15.8Mt LCE Tonopah Flats deposit and American Lithium’s 9.79Mt LCE TLC project.

ASE chairman Tony Leibowitz said that demonstrating a commercial pathway to a lithium product was a logical next step following the definition of a mineral resource. 

“It is for this reason that Astute has actively advanced workflows for both exploration drilling and metallurgical testing at Red Mountain, in tandem,” he said. 

“These positive results, which reinforce the previous results from the project, represent the systematic de-risking of what continues to emerge as an important US-based critical metals project.”

Test results and looking ahead 

Previous testing on lower-grade material, achieved a 36.3% mass rejection and a 22% associated increase in lithium grade at 77.8% recovery. 

The current results achieved about the same mass rejection (37.8%) after 11 stages, increasing the lithium grade by a greater 24.5% (to 4,043ppm), albeit at a slightly lower 73.9% recovery. 

After a further four stages of concentration the resulting lithium grade increased by another 13% to 4,481ppm, however overall lithium recovery to the light fraction was reduced to 66.6%.

The reduction of calcium from the head to the tails concentrate was replicated in the current results, however, was significantly more pronounced than in the earlier testwork. 

Calcium and carbon concentrations in the current testwork were reduced by 43.5% and 48.8%, respectively. 

ASE says the reduction in calcium and carbon, interpreted to indicate removal of the mineral calcite, is an excellent outcome, as calcite is likely to be the most acid-consuming mineral in the processing of lithium clays such as those found at Red Mountain. 

The potential reduction in acid consumption will be confirmed in future leach testing of the head sample and products of the Falcon testwork.

Meanwhile, ASE has engaged Colorado-based Hazen Research to undertake a comparative beneficiation method, Attrition Scrubbing, on the Red Mountain mineralisation. 

This article was developed in collaboration with Astute Metals, a Stockhead advertiser at the time of publishing. 

This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.