Challenger Gold’s heap leach testing reveals hidden depth at Hualilan beyond initial toll mining

• Heap leach testing has unlocked economic viability of low-grade gold mineralisation at Hualilan
• Strong recoveries up to 85% averaging 75% for gold, exceeding typical results of 55-79%.
• Potential to add up to 100,000 ounces to mine plan

Special Report: Better-than-expected recoveries from heap leach metallurgical tests have unlocked a low-grade halo of gold mineralisation at the Hualilan gold project in Argentina.

Challenger Gold (ASX:CEL) says the results are potentially transformative for the larger stand-alone project, offering an opportunity to materially expand the scale and economics of Hualilan after the initial toll mining period.

The company is in the metallurgical testing stages of a pre-feasibility study for the project, assessing various optimisation options for gold production.

Recent column leach tests on Hualilan mineralisation outperformed global averages, resulting in recovery rates of up to 85% for gold (75% on average), compared to typical levels of between 55% to 79%.

Importantly, tests on very low-grade mineralisation still produced strong results, including 67.2% on a sample grading just 0.15 g/t gold, below the current resource estimate cut off of 0.2 g/t gold.

Those numbers offer an opportunity to include gold mineralisation previously considered waste rock in the mine plan – CEL estimates potential for 100,000 ounces of gold to be added to Hualilan’s resource estimate.

Challenger Gold managing director Kris Knauer said the metallurgical results marked a major milestone as the company aims to deliver 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,” Knauer said.

“While toll milling remains our immediate focus this could materially enhance the scale, economics and development pathway for Hualilan, positioning it as a standout gold project in Argentina.”

Ongoing PFS metallurgical testing

Apart from the column leach tests on Hualilan mineralisation, Challenger is also working on several other PFS-related streams.

The company is most of the way through a sequential floatation grind optimisation test cycle, assessing trade-offs between grind size and recovery percentages.

CEL is also looking at larger diameter column leach test work, investigating how best to scale-up from the most recent metallurgical testing.

Challenger will begin PFS-level crush and grinding test programs in the coming weeks, with plans to complete all metallurgical testing and inputs for the PFS by early in the fourth quarter of 2025.

The company is keen to expand the scale of its testing beyond the original scoping study for Hualilan, which assessed only a high-grade 7.2Mt portion of a 74.3Mt total resource estimate.

This article was developed in collaboration with Challenger Gold, 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.