TSX- and NYSE-listed i-80 Gold has announced the results of a preliminary economic assessment (PEA) for the Granite Creek underground project in northern Nevada, highlighting strong production potential and opportunities for resource expansion.

Granite Creek underground is the first asset in i-80 Gold’s pipeline to be redeveloped and is currently ramping up to full production. The project is situated at the intersection of the Battle Mountain-Eureka and Getchell gold trends, a prospective region hosting significant gold deposits.

The PEA outlines an eight-year life-of-mine (LoM) plan for a high-grade underground gold operation, with average production of 60 000 oz/y following ramp-up. The project’s measured and indicated gold resources stand at 261 000 oz at a grade of 10.5 g/t, with an inferred resource of 326 000 oz at 13.0 g/t.

CEO Richard Young noted that ongoing exploration drilling was expected to add to the resource base. “Our exploration results at Granite Creek underground to date suggest significant potential for resource growth and expansion. An extensive drill programme is planned in the coming years to realise that potential. The PEA also demonstrates that once our Lone Tree autoclave is refurbished as anticipated in 2028, production and cash flow are expected to increase materially,” he said.

The PEA does not include drilling completed in 2023 and 2024, nor the effects of underground water management planned for 2025. As a result, the company’s 2025 production forecast, currently under development, differs from the PEA’s schedule. i-80 Gold expects to produce between 20 000 oz and 30 000 oz of gold from Granite Creek this year.

PROJECT ECONOMICS
Based on a gold price of $2 175/oz, the project has an undiscounted after-tax cash flow of $197-million and an after-tax net present value (NPV) of $155-million, assuming a 5% discount rate. At a spot price of $2 900/oz, the after-tax cash flow increases to $420-million, with an NPV of $344-million.

The mine’s construction is complete, and LoM development and sustaining capital are estimated at $105-million.

MINING AND PROCESSING
The mine employs an underhand drift-and-fill method. Refractory ore mined through to 2027 is expected to be processed at a third-party autoclave facility, incurring about 30% lower payability until the company commissions its Lone Tree facility in 2028. Once operational, Lone Tree is expected to significantly improve recoveries and reduce costs.

LoM ore grade is estimated at 11.6 g/t gold, with an overall recovery of 78%. However, from 2025 to 2027, payability is expected to be around 58% owing to third-party processing constraints. Following the commissioning of the Lone Tree autoclave, recovery rates are expected to rise to 92%, increasing production and enhancing project economics.

A feasibility study for Granite Creek underground is planned for release in the fourth quarter of 2025, incorporating additional drilling and updated operational parameters.