Sandfire Resources (ASX:SFR) has released an updated pre-feasibility study for its Black Butte Copper Project in Montana, USA, highlighting growth in both resources and reserves.
Sandfire holds an 87% stake in Sandfire Resources America, which owns 100% of the project, including the Johnny Lee and Lowry deposits.
The Johnny Lee PFS confirms the potential for a low technical risk underground operation, supported by a 1.2 million tonnes per annum processing plant.
Initial production is projected at approximately 35,000 tonnes of contained copper per year over the first four years, averaging 29,000 tonnes annually over an eight-year mine life.
The updated mineral resource for Johnny Lee stands at 22.3 million tonnes at 2.4% copper, while ore reserves total 9.5 million tonnes at 2.9% copper, reflecting a 64% increase in resource tonnes and 33% more contained copper since 2019.
Meanwhile, the Lowry deposit, located about three kilometers from Johnny Lee, now has a Mineral Resource of 9.3 million tonnes at 2.3% copper, with potential to extend the mine life at low capital cost by accessing it via planned Johnny Lee underground workings.
Sandfire CEO Brendan Harris emphasised the milestone, noting that high-quality resources, full permitting, and strategic positioning make Black Butte one of the few near shovel-ready copper projects in the US.
At the time of reporting, Sandfire Resources' share price was $16.62.