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 prefeasibility 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," general manager of process and metallurgy Greg Harbort said.

SolGold plans to undertake a bulk sampling program to generate 20-30 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.

Peel Hunt analysts said the work further supported Alpala's tier one status.

"The results should also help further any offtake or streaming discussions currently underway," they said.

Shares in SolGold jumped 8% yesterday to 29p, valuing the company at £557 million.