Phoenix Copper (AIM:PXC) announced on Monday that it has increased the proven and probable mineral reserves at its Empire open-pit mine in Idaho to 13.27 million tonnes, a 31.49% rise in ore tonnes against the May 2024 inaugural estimate.
The AIM-quoted base and precious metals developer said the updated reserve contains 118.78 million lbs of copper, 134,600 ounces of gold and 5.41 million ounces of silver, equivalent to 83,959 tonnes of copper equivalent metal, a 26.31% increase on the prior estimate.
Empire sits in the Alder Creek mining district near Mackay, Idaho, where Phoenix holds an 80% stake in the historic underground mine that previously produced copper, gold, silver, zinc and tungsten, now the basis for a proposed open-pit operation.
The reserve estimate, prepared by Hardrock Consulting under NI 43-101 standards, follows the company's appointment of Hardrock alongside metallurgist Deepak Molhatra and Valley Science and Engineering in August to update the Empire open-pit pre-feasibility study and resource and reserve figures.
"I am very pleased to report the 2026 Empire open-pit mineral reserve update," said chief executive Ryan McDermott, adding that consultants are now updating the 2024 pre-feasibility study using the new reserve as its basis, with the revised study "to be published and reported in due course."
The September 2024 pre-feasibility study had put Empire's pre-tax net present value at US$87.86 million with an internal rate of return of 46.4%, based on proven and probable reserves of 10.1 million tonnes.
That earlier study used trailing average prices of $4.45 per pound of copper, $2,325 per ounce of gold and $27.25 per ounce of silver; at its half-year results in September, Phoenix noted copper, gold and silver were all trading well above those levels, which management said should improve the project's economics once reflected in updated figures.
Read more about Phoenix Copper
- 11/09/26Phoenix Copper widens loss as cash runway extends to Q4
- 04/08/26Phoenix Copper clears Indigo Capital loan in full
- 06/07/26Phoenix Copper raises £2.3m to repay Indigo debt and advance Empire Mine engineering
Phoenix has been working to shore up its balance sheet ahead of the study update, having raised roughly £2.3 million in a combined placing, subscription and retail offer in July to repay the US$1.564 million principal owed to Indigo Capital under a convertible loan.
At its interim results, the company reported a loss of $1.21 million for the six months to 30 June, against $0.76 million a year earlier, with net assets of $38.21 million, and said cost-cutting and the sale of non-core assets in Mackay had extended its cash runway into the fourth quarter.
Phoenix has flagged that further funding will be required before the end of September 2026 to advance the Empire project beyond the current near-term runway.