Name of the Project
Black Butte copper project.

Location
The project is located on private land near Helena, Montana, in the US.

Project Owner/s
Sandfire holds an 85% interest in Black Butte, through Canadian listed company Sandfire Resources America Inc (formerly Tintina Resources).

Project Description
Black Butte is one of the top ten undeveloped copper projects by grade worldwide.

The project development is focused on the Johnny Lee copper deposit, which has a measured and indicated undiluted resource of 10.9-million tonnes at 2.9% copper, including a Lower Copper Zone with a copper grade of 6.8%.  

The project involves the development and underground mining of the Johnny Lee deposit.

This will be a relatively shallow underground mine accessed by a 1 700 m decline to access first the Upper Copper Zone (60 m to 200 m), followed by additional development to reach the Lower Copper Zone (300 m to 500 m).

A drift-and-fill mining method will use cemented paste backfill, eliminating subsidence and placing almost half of the tailings back underground.

The other half of the tailings will be safely stored in a high-density polyethylene double-lined cemented tailings facility as a dry solid.

The operation will use a conventional process of crush-grind-froth flotation processing.

Potential Job Creation
The project is expected to create 240 jobs in the area.

Net Present Value/Internal Rate of Return
Not stated.

Capital Expenditure
Not stated.

Planned Start/End Date
Not stated.

Latest Developments
The project has received a positive record-of-decision (RoD) for its permit. 

Tintina Montana can now develop and mine the Johnny Lee deposit at Black Butte.

The Montana Department of Environmental Quality (MTDEQ) has 40 days in which to finalise a financial bond calculation, which, once done, will pave the way for construction to start at Black Butte.

The company’s subsidiary has concurrently received its preliminary air-quality permit and a Montana pollution discharge elimination system permit.

“We are now looking forward to completing the Black Butte feasibility study, progressing project funding options and, subject to a positive final investment decision, building what we expect to become a showcase mine with state-of-the-art technology that we will all be very proud of,” Sandfire America CEO and VP of project development Rob Scargill has said.

The technical studies for the feasibility study have been completed, but the company has said that the timing for completion of the study might be delayed, owing to the global health and financial crisis caused by Covid-19.

The RoD stipulations require an incremental bonding approach, allowing for an initial bond increment for Phase 1 development work of surface preparation of the mine site. This will be followed by a second bond increment to cover all underground development, mill construction and any activities involving beneficial water use. There is also a reclamation bond calculation and final design requirement for the agency-(?)modified alternative closure plan, before the second increment of bonding the bond and any Phase 2 development work or mining.

The MTDEQ has said that this is the most protective hard-rock mining permit the agency has ever signed.

Key Contracts and Suppliers
GR Engineering Services (definitive feasibility study); Mining Plus (mineral reserve statement) and SRK Consulting (mineral resource statement).

Contact Details for Project Information
Sandfire Resources America Inc VP of Communications Nancy Schlepp, tel + 1 406 547 3466 or email nschlepp@sandfireamerica.com.