TSX-V-listed Minera Alamos finds in a prefeasibility study (PFS) on the past-producing Copperstone project, in Arizona, a net present value (NPV) of $537-million for the project at current spot gold prices of $4 500/oz.

The PFS outlines an internal rate of return (IRR) of 154% and a payback period of 0.8 years, with the ability to generate cash flow of $725-million over its initial 6.3-year lifetime - at current commodity prices.

The base case scenario, at gold prices of $3 500/oz, shows the Copperstone project has an NPV of $374-million, an IRR of 108% and payback period of 1.2 years for net cashflow of $512-million.

The total initial capital cost is estimated at $58-million, while the sustaining capital expenditure is estimated at $77-million over the life-of-mine.

Minera Alamos confirms Copperstone can produce 291 000 oz at an average rate of 46 000 oz/y at total cash costs of $1 070/oz and all-in sustaining costs of $1 314/oz, which points to a resilient, low-cost mine plan.

With the board already having made a formal investment decision on the project, the company envisions initial production in mid-2027, which, once online, will double Minera Alamos' current yearly gold production. Minera Alamos currently produces between 32 000 oz and 38 000 oz of gold a year from the Pan mine, in Nevada.

Based on the PFS, project construction is expected to take about one year. Full-scale engineering, procurement and construction activities will start in June.

Meanwhile, Minera Alamos confirms that about half of Copperstone's measured and indicated resources have not been converted to reserves and that further drilling and mine development could increase the likelihood of future conversion to reserves.

The company will also evaluate the down-plunge expansion potential of the underground Copperstone mineralisation once production starts.

Copperstone has an extensive history of both openpit and underground mining, and while Minera Alamos only considered underground-accessible resources in the project's PFS, extensive resources exist in near-surface areas in proximity to the historic openpit excavations, meaning there is potential for gold to be extracted through openpit mining methods.