i-80 Gold Corp.

Metallurgical testing has demonstrated that the Ogee, Otto and South Pacific zones at Granite Creek Underground contain predominantly single refractory material and require an oxidation process to increase gold extraction using cyanidation. While samples responded to both alkaline and acid pressure oxidation, significant metallurgical testing has demonstrated that an acidic autoclave environment achieved higher sulfide oxidation and superior gold recovery rates. These results confirm that the Project’s ore can be processed via the Lone Tree Plant’s acid pressure oxidation (“POX”) conditions once the Plant is recommissioned.

The PFS incorporates an updated processing strategy that assumes third-party toll milling arrangements and associated over-the-road trucking costs through tomid-2027. To maximize the proportion of Granite Creek Underground sulfide material processed at the Company’s Lone Tree Plant and reduce reliance on third-party processing, the mine plan assumes the stockpiling of sulfide refractory material beginning approximately six months prior to the planned commissioning of the Company’s wholly owned Lone Tree Plant in late 2027. Beginning in 2028, the PFS incorporates the anticipated lower processing costs associated with hauling refractory ore and processing it through the Lone Tree Plant.(6) The acidic environment has higher operating costs versus alkaline, however, the higher costs are mostly offset by higher recoveries. The PEA envisaged a combination of acidic and alkaline operating environment.

Oxide mineralization is present in all zones within all deposits. Mine operations to date have encountered a higher proportion of oxide ore than what has been defined in the resource estimate and PFS. The oxide mineralization not accounted for in the PFS presents an opportunity to process this material in the Lone Tree Plant throughout the LOM with lower overall operating costs. Work is underway to determine the cost benefit. The PFS only incorporates a small component of oxide mineralization in the Ogee Zone. Oxide ore will be sold to a third party under an existing sales agreement untilmid-2027 and then stockpiled similarly to the refractory ore. The oxide ore will be processed directly by thecarbon-in-leach (“CIL”) circuit at the Lone Tree Plant, bypassing the POX circuit.

Ore at Granite Creek Underground is screened before shipping to remove oversize material, reducing the tonnes shipped and processed while increasing the grade delivered for processing. The potential economic benefits of this practice continue to be evaluated and were not incorporated into the PFS, representing a potential opportunity for future optimization.

A LOM processing schedule is illustrated in Figure 6.

Table 6: LOM Mining and Processing Unit Costs

Note to table above:

Figure 6: LOM Annual Processing Schedule