Copper developer Sandfire Resources America has been given the green light to proceed with the construction of its Black Butte project, after the Montana Supreme Court reversed a 2021 district court decision that invalidated the mining permit.

The positive ruling, delivered with a 5-2 decision, supported the 2020 decision of the Montana Department of Environmental Quality (MT DEQ) to permit copper mining at the Black Butte project.

The legal battle was initiated in 2020 against the MT DEQ and Sandfire America subsidiary Tintina Montana.

“Today’s victory in the Montana Supreme Court is a validation of the thoughtful and deliberate efforts of the Sandfire America team to design a world-class, environmentally safe mining project from the beginning. The fact is, ours is the most reviewed and examined proposed project in the history of Montana mining. The Court record stands at over 90 000 pages of testimony, information, and analysis. We thank the justices for their ruling, and their ability to recognise the amount of effort and extensive work that has gone into this project,” said Sandfire America CEO Lincoln Greenidge.

Senior VP Jerry Zieg emphasised the diligence and professionalism of MT DEQ staff in considering Tintina’s permit, underscoring the project’s commitment to safety and environmental protection.

With all the necessary permits secured, Black Butte is poised to advance responsibly.

Stipulated agreements for water rights, granted through the Montana Department of Natural Resources and Conservation, have been finalised. However, a challenge to the Montana Constitution’s definition of the “beneficial use of water” remains, with an appeal scheduled for March 29, at the Montana Supreme Court. This challenge, while ongoing, does not currently impact the company’s water rights package.

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.

Black Butte's development is centred around the Johnny Lee deposit, which has a reserve 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.