Name and Location
Montanore silver/copper project, Montana, US.

Client
Mines Management Incorporated.

Project Description
The project envisages an underground mining operation using conventional grinding and flotation processes. The deposit will be bulk-mined 350 days a year and use an inclined room-and-pillar mining method, producing at a nominal rate of 12 500 t/d, although the mine is being permitted for a throughput of up to 20 000 t/d.

Over the 15-year mine life, an estimated 59-million tons of process feed will be treated at average grades of 1.88 oz/t of silver and 0.72% of copper, yielding 96-million ounces of silver and 767-million pounds of copper.

Under the current mine plan, 40-ft-wide topslices will be mined on strike below the hanging wall contact. Connection drifts between adjacent top cuts will be mined following the hanging wall contact at a gradient of 15%, forming obliquely angled permanent stope pillars. Mineralisation below the topslice will be mined using a longhole bench.

Mining at Montanore is planned to be highly mechanised, using large high-tech mining equipment, including modern load-haul-dump units and trucks and computer-controlled drilling jumbos.

Net Present Value/Internal Rate of Return
The project has a net present value of $485.6-million and an internal rate of return of 17.4%.

Value
Total project costs are estimated at $552.32-million in the 2011 technical report.

Duration
Not stated.

Latest Developments
Mines Management has received records of decision approving development of the Montanore mine from the US Forest Service and the Montana Department of Environmental Quality.

The agencies’ decisions signal the approval of project development.

Key Contracts and Suppliers
None stated.

On Budget and on Time?
Not stated.

Contact Details for Project Information
Mines Management, tel +1 509 838 6050.