The testwork showed gold recovery improved by 7% compared with the November 2019 preliminary economic assessment and showed the ability to produce a 26%-30% copper concentrate with gold and silver.

"The results … are being used to assess potential refinements to the flowsheet and our operating and capital cost estimates as well as improvements in revenues generated by upgraded recoveries," said CEO Nick Mather.

The testwork, to be used in the pre-feasibility study underway, will inform process flowsheet optimisation. Testwork confirmed low levels of deleterious elements such as arsenic, bismuth, cadmium, fluorine and others which can cause smelters to impose penalty charges on concentrate producers.

"The flotation tests have demonstrated the ability to produce a high-grade dominantly chalcopyrite concentrate throughout the modelled mine life and confirms the Alpala project to be a very low deleterious content deposit," said GM process and metallurgy Greg Harbort.

SolGold plans to undertake a bulk sampling programme to generate 20-to-30 tonnes of material for pilot plant evaluation. This will include vendor thickening and filtration tests, transportable moisture limits for shipment, rheology tests for concentrate and tailing pipelines and further tailing characterisation work. In addition, selected sample will be used for crushing tests and pyrite concentrate will be produced for further leach evaluation.

Shares in SolGold are trading at C48, valuing the company at $914 million.