Alma Metals (ASX:ALM) reports encouraging metallurgical test results from the Briggs Copper Project in Queensland, indicating the potential for a long-life operation. Locked-cycle flotation testwork achieved copper recoveries of up to 95% at 29% concentrate grade, and 94% recovery at 23% concentrate grade. These recoveries were achieved at coarse grind sizes up to 212µm, potentially reducing processing costs.
The positive results will be incorporated into a Scoping Study, expected to be completed by mid-2025, to evaluate the economic viability of mining at Briggs. While molybdenum recovery wasn’t a primary focus, the testwork showed an overall recovery of 62% for the intrusive master composite. Alma Metals Managing Director Frazer Tabeart highlighted that the ability to produce high-grade copper concentrates gives them a competitive advantage for both domestic and international sales, reinforcing Briggs as a major undeveloped copper project in Australia.
Exploration and evaluation are funded by Alma under a joint venture with Canterbury Resources (ASX:CBY), where Alma holds a 51% interest and can increase it to 70% by June 30, 2031. Canterbury Managing Director Grant Craighead noted that the resources and achieved recoveries enhance the development potential of Briggs, potentially positioning processing costs at the lower end for porphyry copper projects.
An updated resource estimate is expected in the coming weeks, and additional testwork to assess copper recoveries at even coarser grind sizes of 300µm will begin shortly, which may further reduce power consumption for mineral processing. Further metallurgical testwork will focus on providing more variability data for both comminution and flotation to improve resolution of the geo-metallurgical domain modelling at Briggs, along with optimisation and improvements to the flowsheet design.
