TORONTO (miningweekly.com) – The US Forest Service and the Montana Department of Environmental Quality has given TSX- and NYSE MKT-listed project developer Mines Management conditional approval to proceed with development of its $550-million Montanore silver/copper mine, underneath the Cabinet Mountains Wilderness, in northwest Montana’s Kootenai National Forest.

With the final records of decision (RODs) in hand, Washington-based company the Spokane group said that it now planned to pursue various avenues of financing and/or strategic business combinations to advance the project through evaluation and feasibility, as well as development of the project.

The agencies’ decisions approved the project defined in the preferred alternative as outlined in the joint final environmental impact statement (EIS), announced on December 21, and provided a path forward for development of the project.

“We have crossed the goal line. The ROD is the major approval to complete the final evaluation and development of the project contingent upon compliance with its conditions. We are excited to have completed the eleven-year permitting process that included two draft EISs and at least three rounds of public comment,” stated chairperson Glenn Dobbs on Friday.

SIGNIFICANT DEPOSIT
The Montanore deposits were discovered in the 1980s and explored by previous operators at a cost of more than $100-million, which ceased in the 1990s when metals prices were low. Since acquiring Montanore in 2002, Mines Management had spent more than $7-million on the dewatering and partial rehabilitation of the 4.3 km decline, as well as on construction of site infrastructure, revised and updated resource estimates and a preliminary economic assessment (PEA). The $7-million also went towards re-permitting the entire project.

Mineralised material within two zones was estimated at 81.5-million tons, with grades of 2.04 oz/t silver and 0.75% copper, for more than 230-million ounces of silver and nearly two-billion pounds of copper, not considering dilution or subeconomic mineralised zones.

The Montanore project was situated at the northern end of a trend extending south to the Coeur d'Alene silver district, which had historically produced more than one-billion ounces of silver.

Mineralisation was open in several directions, and a third zone of mineralisation had been identified, all of which management believed to have potential to expand the resource.

An independent PEA published in 2011 described an underground bulk mining scenario using conventional crushing and flotation processes that would extract a high-quality concentrate for sale to smelters at low underground mining and processing costs.

Mines Management planned initial throughput of 12 500 t/d to produce more than six-million ounces of silver and 50-million pounds of copper a year, with potential for expansion up to a permitted capacity of 20 000 t/d.

GREEN CONCERN
The Montanore project, as currently permitted, included more environmental protections than what were originally approved in 1993. Other outstanding individual permits and authorisations would be issued following the RODs, according to their respective processes and timelines.

These would include the US Army Corps of Engineers’ Section 404 permit for the tailings impoundment, required by the Clean Water Act, as well as a Montana Pollutant Discharge Elimination System permit and water rights.

Mine Management advised that mitigation efforts were a significant element of all permits for the project, which were required to protect the environment and critical habitats necessary for wildlife and threatened and endangered species to flourish.

However, the approvals drew widespread criticism from environmentalists, who decried evidence that the project would degrade the wilderness area’s pristine rivers.

In the final EIS, released in December, the mining company’s own consultants predicted the mine would diminish flows in the overlying wilderness rivers and streams for centuries.

“Montana’s decision admits that the planned mine would violate State water quality laws, but the Forest Service recklessly approved the full mine anyway. Once the company starts excavation and has inflicted the damage, there is no going back and fixing the problem. No amount of study is going to change that,” stated Mary Costello of Save Our Cabinets, a local nonprofit organisation.

The Montanore project was already subject to litigation. Nongovernmental organisations Save Our Cabinets, Earthworks and Defenders of Wildlife, represented by  environmental law firm Earthjustice, filed a lawsuit against the Montanore project in July last year for the mine’s impacts on threatened grizzly bears and bull trout.