Zincing outside the box: Metallurgical wizardry boosts zinc stash by 240% at Challenger’s Hualilan project

Zinc recovery from Challenger’s Hualilan project can more than triple to 211,500t
Metallurgical testwork shows zinc can be recovered at head grades as low as 0.4%
Incorporating more zinc to the resource estimate, plus increased gold and silver recoveries, could add more value to the $1.15bn project

Special Report: Metallurgical testwork on Challenger Gold’s 2.8Moz Hualilan gold project in Argentina has increased recoverable zinc by 240% within the current resource, from 62,000t up to 211,500t.

Zinc prices are on their way up, recently tipping past US$3000/t after a series of mine closures including Tara, the largest zinc mine in Europe.

Coupled with lower smelter prices, the shortfall of supply could mean we are seeing the beginnings of a surge in demand for the galvanising metal.

More than triple the zinc endowment

A recent scoping study has development of Challenger Gold’s (ASX:CEL) Hualilan’s resource of 2.8Moz for 116,000ozpa gold, 440,000ozpa silver and 9175tpa of zinc raking in >US$1 billion in earnings across seven years.

That zinc figure is based upon a total 62,000t endowment, which conservatively added US$132m to the overall revenue of US$1.15bn according to the scoping study.

A metallurgy breakthrough has now more than tripled that figure to 211,500t.

Metallurgical testwork has shown zinc at head grades as low as 0.4% can be economically recoverable compared with the 1.5% cut-off grade used in the scoping study. The testwork also achieved a higher zinc concentrate grade of 55%, compared to 50% in the scoping study, which will notably enhance zinc payability using a simplified flowsheet with lower reagent consumption – potentially reducing operating costs.

Other material opportunities found from the testwork include the inclusion of a heap leach alongside a floatation circuit, to capture value from the low-grade portion of the Hualilan orebody, which was excluded under the low-risk, high-grade, low-tonnage scoping study strategy.

Other results included:

Increased gold recovery of 97.5% (94.9% in the scoping study)
Increased silver recovery of 93.0% (90.8% in the scoping study)
Anticipated lead recovery of 80-85% (76.8% in the scoping study)
Superior recovery of the Au/Ag into products with the highest Au/Ag payability

The next phase of testwork (evaluating performance at a range of Zn and Au head grades) is underway to allow this pathway to be incorporated into the upcoming Hualilan pre-feasibility study.

“We are excited to announce that our latest metallurgical testwork has significantly improved our Hualilan Project,” CEL MD Kris Knauer says.

“By unlocking the potential to economically recover zinc at head grades as low as 0.4%, we are now able to access 211.5 kt of zinc within the Hualilan Mineral Resource Estimate.

“This is a substantial increase compared to the 62 kt of zinc initially included in the Scoping Study mine plan.

“The testwork also achieved a higher zinc concentrate grade of 55%, which will notably enhance zinc payability.

“Alongside zinc, we have also seen improvements in gold and silver recoveries, reaching 97.5% and 93.0% respectively. The simplified flowsheet reduces reagent consumption, also has the ability to potential lower our operating costs.”

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.