Western Australia’s Mount Ridley Mines’ Grass Patch Prospect Holds World’s Largest Publicly Reported Scandium Resource: Gallium and Heavy Rare Earths Add to the Resource: Its Selectro Processing Tech is Key

     Western Australian mining company Mount Ridley Mines recently re-assayed its drilling results across its Grass Patch Prospect acreage. According to Penny Taylor of the West Australian:

“Rather than launch an expensive drilling blitz, the company effectively mined its existing data. Phase one of its 2026 re-assay program sent 3271 stored pulp samples from historical aircore and diamond drilling back to the laboratory, revealing broad, near-surface scandium beyond previous resource boundaries.”

“With those assays folded into the update, Block 1 now stands at 367.45Mt at 50.3ppm scandium for 18,475t of metal. Further north along the same geological corridor, the larger Block 2 contributes 578.63Mt at 49.9ppm for 28,882t.”

“Together, the separately modelled areas cover about 44.5 square kilometres and make up the 946Mt resource.”

     That total makes it the world’s largest publicly reported scandium resource. There's more:

“…the two areas also host 122.5Mt of heavy rare earths resources and 536.2Mt of gallium resources. The wider project’s gallium inventory stands at 838.7Mt.”

     The company hopes to cut capital and operating costs by simplifying material handling and implementing shared processing for the different mineral ores. All three minerals- scandium, gallium, and the rare earth elements have the potential to decrease reliance on China for them.

     The company is currently re-assaying across Grass Patch to chase extensions.

“Density testing is underway to support potential upgrades into higher-confidence resource categories.”

“Flotation test work will assess whether valuable minerals can be concentrated before leaching, after TIMA analysis identified rare earth-bearing phosphate minerals that could respond well to flotation. Engineering firms are also discussing a scoping study to help design and cost a demonstration plant to test the process at a larger scale.”

     They are testing recovery rates with processing with its minerals processing method known as Selectro and evaluating the economics of commercialization. They may also license Selectro technology to third parties.

     The Grass Patch prospect is 25km northeast of Esperance, with a nearby deep-water port, road, and power infrastructure providing an advantage over more remote critical minerals projects.

     Scandium is used in lightweight aluminum alloys for aerospace and defense, as well as in solid oxide fuel cells. It is a critical mineral in high demand, and new supplies from a friendly country would be very welcome in the U.S.

“Testing of a composite compiled from historical Grass Patch drill samples achieved 77-83% recovery of heavy rare earths and 70-77% recovery of light rare earths while managing to recover a robust 56% of the gallium, which compares with hydrochloric (HCL) acid leaching failing to recover any gallium.”

“The process also achieved scandium recovery of 80%, which is significantly higher than results from a baseline hydrochloric acid test and a significant result given the Grass Patch Complex is one of the largest resources globally.”

     The excellent test results of the processing method and the fact that it can process all three sets of ores simultaneously is a big boon for the project.

     Selectro is Mount Ridley Mines’ proprietary hydrometallurgical leaching technology developed to recover multiple critical minerals through a single process. It was developed to achieve high metal recoveries using lower-cost reagents, while incorporating reagent recycling through a closed-loop processing system. As all three graphs below show, the testing indicates much higher mineral recovery rates than with hydrochloric acid (HCl) leaching for all four mineral streams (scandium, gallium, heavy REEs, and light REEs).

References:

 

Mount Ridley grabs global scandium crown with 946Mt WA resource. Penny Taylor. The West Australian. 26 August 2026. Mount Ridley grabs global scandium crown with 946Mt WA resource | The West Australian

Mount Ridley Project. Mount Ridley Mines. Website. Mount Ridley Project - Mount Ridley

Mount Ridley’s proprietary Selectro process more than doubles REE recoveries. The Australian. August 12, 2026. MRD doubles Grass Patch recoveries with proprietary tech | The Australian