A reserve is the part of a deposit a company can argue, on technical and economic grounds, is mineable — and Empire's just got materially bigger. Phoenix Copper's November 2 update is a reserve statement, not a discovery: no new drill grades, just a larger, re-estimated open pit in the Alder Creek district.
- New reserve: Proven and Probable reserves of 13.27 million tonnes at the Empire open-pit mine near Mackay, Idaho, where Phoenix holds an 80% stake in the historic Empire property.
- Contained metal: 118,781,100 pounds of copper, 134,600 ounces of gold and 5,407,400 ounces of silver — 83,959 tonnes of copper-equivalent metal in total.
- The change: a 31.49% increase in ore tonnes and a 26.31% increase in copper-equivalent metal against the inaugural May 2024 estimate of 10.1 million tonnes.
- Who estimated it: Hardrock Consulting, using methods the company describes as consistent with internationally recognised mineral reserve reporting standards, including NI 43-101-related requirements. Technical information was reviewed by Dennis Thomas, a company co-founder and chartered mining engineer, as Qualified Person under the AIM Rules.
- What happens next: consultants are updating the 2024 pre-feasibility study (PFS) using the new reserve as its basis, for publication in due course — no publication date was given.
Why the reserve grew
The August appointments set this up: Hardrock, metallurgist Deepak Molhatra and Valley Science and Engineering were brought in to update the Empire open-pit PFS and its resource and reserve figures, factoring in higher metal prices since the 2024 study. A reserve re-estimated at higher prices can legitimately include material that was rock at the old price deck and ore at the new one — that is how reserves normally grow between studies, and it is also why a reserve increase is not the same thing as finding more metal in the ground. CEO Ryan McDermott framed it plainly: "I am very pleased to report the 2026 Empire open-pit mineral reserve update," with the revised PFS to follow.
Empire sits on a historic underground mine that previously produced copper, gold, silver, zinc and tungsten, now the basis for the proposed open-pit operation.
The honesty box
A mineral reserve is not a mine. Empire remains a development project: the revised PFS that would attach updated economics to this reserve has not been published yet, and the figures from the earlier study — a September 2024 PFS pre-tax NPV of US$87.86 million at a 46.4% IRR on the old 10.1-million-tonne reserve — do not carry over to the new reserve until that work is done. Phoenix has previously flagged that further funding will be required to advance Empire beyond its near-term runway, and permitting and construction still lie ahead. Proven and Probable are confidence categories within a reserve estimate, not a guarantee of production.
What to watch
Publication of the revised pre-feasibility study and the economics it puts on the 13.27-million-tonne reserve; any updated mine life and production profile that comes with it; and how Phoenix funds the next steps — final feasibility engineering and an updated Plan of Operations.