Name of the Project
Black Butte copper project.

Location
White Sulphur Springs, in Montana, in the US.

Project Owner/s
Sandfire Resources America, a subsidiary of Sandfire Resources.

Project Description
Sandfire Resources America has announced the results of a feasibility study on the Johnny Lee deposit, the cornerstone of the Black Butte project. The deposit comprises the upper copper zone and the lower copper zone; both are characterised as being high-grade, laying at low angles and with relatively narrow widths. All deposits have anomalous silver and cobalt mineralisation; however, copper is the only economic product considered in the feasibility study.

The feasibility study is underpinned by a maiden reserve for the Johnny Lee deposit of 8.8-million tonnes at 2.6% copper for 226 100 t of copper.

The deposit underpins an eight-year mine life and is designed to be mined at 1.2-million tonnes of ore a year. Forecast production totalling 805 000 dry metric tonnes of copper concentrate containing 189 500 t of copper metal is forecast over the life-of-mine.

The Johnny Lee deposit will be accessed by one main ramp driven from surface. The mining method will be a combination of drift-and-fill and cut-and-fill, depending on the height of the orebody. Metallurgical testwork indicates that the copper in the upper and lower copper zones can be recovered to a concentrate by crushing, grinding and froth flotation processes. The upper copper zone ore requires a fine primary grind (38 µm P₈₀) and a very fine regrind (10 µm P₈₀) of the rougher concentrate to achieve optimised recoveries. The lower copper zone ore does not require such fine grinds to achieve optimised recoveries. However, as it will be blended with upper copper zone ore in small volumes, the blended ore will be treated using the process as optimized for upper copper zone ore.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has a pretax net present value, at a 5% discount rate, of $124.9-million and an internal rate of return of 17%, with a payback of three years from the commissioning of the mine.

Capital Expenditure
$247.7-million.

Planned Start/End Date
Not stated.

Latest Developments
Sandfire Resources’ US subsidiary has welcomed the District Court’s decision to allow its development of the Black Butte copper project.

The court issued  an order on July 5 on remedies that would allow for Phase 1 construction of Black Butte to be completed under the existing permit.

The order pertains to the April 8, 2022, ruling in a lawsuit against the Montana Department of Environmental Quality (DEQ) and Tintina Montana, a wholly owned subsidiary of the company, challenging the project.

The ruling found that the Montana DEQ had violated aspects of the Montana Environmental Policy Act and the Montana Metal Mine Reclamation Act in its granting of a mine operating permit for the project.

On July 1, 2022, plaintiffs and defendants filed a joint motion recommending a stipulated order for remedies.

By granting the stipulated motion, the Judge’s order allows Tintina Montana to complete Phase 1 construction under the existing permit while it pursues an appeal of the April 8 order. 

Key Contracts, Suppliers and Consultants
None stated.

Contact Details for Project Information
Sandfire Resources America VP of communications Nancy Schlepp, tel +1406547 3466 or email nschlepp@sandfireamerica.com.