i-80 Gold obtains construction permits and begins underground development at Archimedes Project, Nevada
i-80 Gold Corp. [TSX: IAU; NYSE American: IAUX] reported has received all required permits and commenced construction at the Archimedes Project as planned.
The environmental permits secured from both the Nevada Division of Environmental Protection and the Bureau of Land Management allow the company to proceed with underground mining activities. Located on the Ruby Hill property, Nevada, Archimedes is the company’s second planned underground mine and lies approximately 180 km from the company’s wholly owned Lone Tree autoclave and carbon-in-leach (CIL) processing facility. Archimedes is expected to begin contributing to production in the fourth quarter of 2026.
“The receipt of permits and commencement of construction at Archimedes marks a major milestone for i-80 Gold as we advance Phase One of our growth strategy in Nevada; Phase One is expected to increase annual gold output from less than 50,000 ounces to a target range of 150,000 to 200,000 ounces of gold by 2028,” stated Richard Young, President & CEO. “We are excited about the exploration potential at Archimedes. The lower zone remains open to the north and south, offering substantial exploration potential that we believe can extend the current 10-year mine life. We have accelerated the infill drill program covering both the upper and lower zones to support a feasibility study anticipated in the first quarter of 2027, ahead of the original timeline included in the preliminary economic assessment.”
The company’s three-phase development plan is expected to increase gold output to an annual target of 600,000 ounces in the early 2030s. Phase One of the development plan includes the ramp up of Granite Creek underground, construction of Archimedes, as well as the refurbishment and commissioning of the Lone Tree autoclave and CIL processing facility. The Lone Tree refurbishment Class 3 engineering study remains on schedule for completion in the fourth quarter of 2025, followed by the feasibility study for Granite Creek Underground planned for completion in the first quarter of 2026. Unless otherwise stated, all amounts referred to herein are in U.S. dollars.
The current phase of permitting and development at Archimedes covers mining activities above the 5100-foot elevation, a threshold consistent with previously approved permits for open pit mining on the Property. This phase of the project is anticipated to provide development and production mining into the first half of 2028. Permitting activities below the 5100-foot elevation are underway with an estimated completion in the first half of 2027. This phased approach to permitting allows the Company to begin mining the Archimedes upper zone while simultaneously pursuing the remaining technical work and permits for the lower zone.
Development Work: The construction of surface infrastructure, such as a maintenance shop and offices, to support the Archimedes underground portal is complete. Utilities such as water, power and compressed air are in place, and the highwall around the portals has been secured. Small Mine Development, L.L.C. (SMD) has been contracted to develop Archimedes to the 5100-foot elevation and is currently mobilized to advance the development drift.
Underground development above the 5100-foot elevation is expected to be completed by mid-2027 and will include two underground portals, the main haulage decline, a series of raises for ventilation and secondary access, exploration bays and supporting infrastructure. The development contract with SMD is consistent with the cost estimates outlined in the Preliminary Economic Assessment of the Ruby Hull Project (PEA) filed on March 31, 2025.
Based on the PEA, Archimedes is expected to have an after-tax net present value of $644 million, assuming a 5% discount rate, with an internal rate of return of 81% at a gold price of $3,000/oz. Archimedes anticipates an initial mine life of approximately 10 years, with an average annual gold output of approximately 100,000 ounces at an all-in-sustaining cost of $1,877/oz following ramp-up to a steady state. Mine construction capital is estimated to be $47 million and life-of-mine development and closure costs are estimated to be $106 million.
Beginning in the fourth quarter of 2026, material mined at Archimedes is expected to be processed at a third-party autoclave processing facility in the region. Once Lone Tree is commissioned in early 2028 as anticipated, material mined at Archimedes will then be processed at Lone Tree. Additionally, operations at the property are expected to be supplemented by on-site heap leaching during the initial years.
Archimedes hosts 436,000 ounces of gold in the Indicated mineral resource category at 7.6 g/t and 988,000 ounces in the Inferred mineral resource category at 7.3 g/t. Planned infill drilling and exploration are expected to further upgrade and expand resources providing potential to extend the current mine life. The lower zone (Ruby Deeps) at Archimedes is open to the north and south, offering substantial exploration potential.
The timing of the infill drill program and Archimedes feasibility study has been accelerated by approximately 12 months compared to the timing outlined in the PEA. Accelerating the drill program and feasibility study is expected to increase the cost of drilling by a range of approximately $10 million to $25 million primarily due to drilling from higher elevations resulting in longer drill holes.
Initial infill drilling of the upper zone is scheduled to begin from underground in the fourth quarter of 2025, followed by underground infill drilling of the lower zone planned in the first quarter of 2026. Collectively, these infill programs are anticipated to include more than 175 holes for approximately 60,000 metres of core. Results from the infill drilling will be included in a feasibility study which is targeted for completion in the first quarter of 2027.
The next steps will focus on three areas: resource drilling, permitting, and metallurgical testing. Resource conversion drilling will commence as the underground decline advances with results incorporated into an updated resource model. On permitting, related actions to meet National Environmental Policy Act and Nevada Department of Environmental Protection requirements for mining below the 5100-foot elevation will be carried out. Metallurgical test work will target initial Ruby Hill production areas to confirm metallurgical recoveries with the anticipated Lone Tree process conditions, including comminution, pressure oxidation under both alkaline and acidic conditions, and CIL testing on oxide material.
This anticipated Archimedes feasibility study will be prepared in accordance with NI 43-101 standards.