Heap Leach Success Paves the Way for Full-Scale PFS at Argentina’s Standout Gold Project
SYDNEY, AUSTRALIA (9 July 2025) – Challenger Gold Limited (ASX: CEL) has announced the commencement of final metallurgical testwork for its Pre-Feasibility Study (PFS) at the flagship Hualilan Gold Project in San Juan, Argentina. The milestone follows a breakthrough heap leach program that delivered exceptional gold recoveries and unveiled a potentially transformative development pathway for the project.
The advanced testing, scheduled for completion by early Q4 2025, includes sequential flotation grind optimisation, a full comminution program, and large-diameter column leach testing. These are the final technical inputs required before delivering the full-scale PFS.
Managing Director Kris Knauer stated:
“These final stages of metallurgical testwork mark a major milestone as we move toward delivery of a full-scale PFS for Hualilan. The outstanding heap leach results confirm the viability of processing low-grade material that was previously excluded from economic evaluation. This could materially enhance the scale, economics and development pathway for Hualilan, positioning it as a standout gold project in Argentina.”
Why This Matters
The recent heap leach column tests returned average gold recoveries of 75%, peaking at 85%, well above the global industry average of 60–65% for this technique. Importantly, the process is viable even at very low grades (e.g., 67% recovery from just 0.15 g/t Au).
These results challenge the assumptions made in CEL’s earlier Scoping Study, which only considered 7.2 Mt of high-grade material. The new data opens the door to economically exploiting a vastly larger mineralised envelope, up to 74.3 Mt grading 0.2 g/t AuEq, previously regarded as waste.
By potentially integrating heap leaching for low-grade halo material and maintaining flotation for high-grade zones, Challenger is positioning Hualilan for significantly increased throughput, extended mine life, and lower unit costs.
Game-Changing Metallurgy
The work to date has explored multiple crush sizes (¼”, ½”, 1”) and lithologies (dacite, lutite, calcite), consistently achieving gold recoveries between 64% and 91% depending on rock type and grade. Crucially, recoveries remained strong even with coarser ½” crush sizes a more practical option for commercial-scale heap leaching.
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Dacite and lutite returned best results, with recoveries >85% in some tests
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Recoveries >60% even at grades below 0.2 g/t
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Column leach performance rivalled world-class operations like Veladero and Lindero, both also in Argentina
Scaling for Success
Large-diameter (6") column tests have now commenced to validate full-scale heap leach pad design and assess percolation at commercial scale. This is expected to directly inform the design of a standalone heap leach circuit within the final PFS.
CEL anticipates that the expanded mine plan will support an open-pit operation with significantly larger scale and lower mining costs, offering a compelling contrast to the underground-focused scenario presented in 2023.
Why You Should Take a Closer Look
This is not just another testwork update, it’s the inflection point in Challenger’s shift from explorer to developer. With robust metallurgical results and a clear pathway to unlock nearly 3 Moz AuEq, Hualilan is shaping up to be one of the most economically flexible and technically feasible gold projects in Argentina today.
About us:
Challenger Gold (ASX: CEL) is a gold and copper exploration company. Challenger Gold Limited’s aspiration is to become a globally significant gold producer.
The Company is developing two complementary gold/copper projects in South America with a 2.8 million ounce resource estimate recently announced for the Hualilan Gold Project in San Juan, Argentina. In the 100% owned portion of its El Guayabo project in Ecuador the Company has announced a maiden 4.5 million ounce resource estimate.
The Company strategy is for the 100% owned Hualilan Gold Project to provide a high-grade low capex operation in the near term while it prepares for much larger bulk gold operations at both Hualilan and El Guaybo in Ecuador.
Contact details:
Jane Morgan
[email protected]