North of 60 Mining News - The mining newspaper for Alaska and Canada's North

A plan to expand the remote Kemess copper-gold mining operation in northern British Columbia has met with significant opposition from members of First Nations communities in the area.

The protests surfaced during a series of public hearings held by the Canadian Environmental Assessment Agency between Oct. 30 and Dec. 7. The hearings are part of the provincial and federal environmental assessment process.

Northgate Minerals Corp., operator of the Kemess South Mine, wants to extend the life of its mining operation by developing a lower grade, higher sulfide copper-gold deposit about 3 miles north of its existing open-pit operation. Kemess South is the second-largest metal mine in British Columbia with annual production of 16.4 million tonnes of gold and copper concentrate.

Northgate is managed by Hunter Dickinson Inc., the same team that oversees Northern Dynasty Inc., which proposes to develop the huge Pebble copper-gold deposit in southwestern Alaska.

A major area employer, the Kemess South Mine with 475 employees and contract workers was developed on a gold-copper porphyry deposit about 267 miles northwest of Prince George. Its remaining reserves of 68 million tonnes should be mined by 2009.

The C$500 million Kemess mining and milling complex consists of the Kemess South open pit mine, a 52,000 tonnes-per-day mill and tailings impoundment as well as roads and other infrastructure.

The proposed Kemess North Gold-Copper expansion has the potential to extend the productive life of the mine by another 14 years. Northgate hopes to produce 85,000 to 100,000 tonnes per day of copper-gold concentrate from estimated ore reserves in the northern deposit, according to company officials.

One viable option

But the new project hinges on Northgate's plan to dispose of waste rock in nearby Duncan Lake and Attacelley Creek. Unlike Kemess South, the Kemess North deposit is in mountainous terrain, which makes construction of a separate tailings disposal structure uneconomic, according to Northgate.

Duncan Lake (also known as Amazay Lake) is a deep, steep-sided, low-nutrient, headwater-lake with a drainage area of about 15 square miles and an overall surface area of 88,440 acres. The lake supports rainbow trout, Dolly Varden char and mountain whitefish.

Studies of the breeding and feeding behaviors of these species show that each species uses the lake habitats differently, according to Northgate. While rainbow trout and Dolly Varden char breed and feed in Duncan Lake, the absence of mountain whitefish less than two years old suggests that mountain whitefish spawn in other areas of the Attycelley system, and the young move back into the lake around age two. The limiting factors to fish production in Duncan Lake are steep slopes, low nutrients and a lack of spawning habitat for both Dolly Varden char and rainbow trout, the company said.

Northgate plans to comply with B.C.'s no-net-loss regulations for fish habitat by collecting and relocating the fish in Duncan Lake to two other nearby lakes and eventually rehabilitating the lake for fish and other wildlife.

First Nations worried

Four First Nations, the Gitxsan House of Nii Kyap, Kwadacha First Nation, Takla Lake First Nation and Tsay Keh Dene First Nation have traditionally used the area surrounding the Kemess North deposit.

Members of the Tse Kay Dene and Kwadacha nations testified at the public hearings that dumping mine waste into Duncan Lake and nearby creeks could irretrievably harm fish, wildlife and the communities in the area. They further expressed worries that damming the watershed could endanger small communities in the area.

Some witnesses also accused mining companies, such as Northgate, and the Canadian government of making decisions that harm First Nations lands and people behind closed doors and then conducting public hearings to give an appearance of including the community in the decision-making process.

However, Northgate noted that it first consulted with First Nations' communities in the area about the project before it filed its permit application of the Kemess North expansion in 2003 and since has kept the four groups in the loop. However, company officials also acknowledged that the consultations and their efforts to provide jobs to First Nations' members have met mixed success.

In developing a mine plan, Northgate said Kemess North has naturally occurring acid rock drainage.

Water draining from the area has acidic pH of 3 to 5 and contains relatively high metal concentrations.

On the western side of the deposit, that water naturally drains into Duncan Lake where it is neutralized by alkaline runoff from limestone bluffs on the ridge to the west of the lake.

Water from the eastern side of the deposit flows through Cirque Creek into Attycelley Creek and combines with runoff from mineralized areas in the upper Attycelley watershed.

The resulting water quality in the main stem of Attycelley Creek is neutral to slightly basic, and contains elevated cadmium and occasionally copper and zinc levels that are slightly above the British Columbia guideline for the protection of aquatic life, the company said.

Northgate plans to deposit waste rock from the Kemess North mining operation safely underwater and, to prevent runoff, the lake and the creek will be dammed. The resulting water levels in the tailings dam will be monitored to avoid accidental discharges according to company officials.

In response to numerous questions about the extent of monitoring for the planned tailings impoundment, spillway and water treatment facility, Northgate officials said they have developed an emergency management plan, along with an early warning system. The dam also will be subject to annual inspections and reviews once the mine closes, they added.

A consultation and accommodation agreement that mitigates the effects of the mine expansion on First Nations' traditional territories still needs to be finalized and signed by both parties.