One of the biggest copper and gold ore deposits in the world has received an environmental assessment certificate to begin development of a mine near Stewart in northwestern B.C.

KSM mine property includes four ore bodies that contain silver and molybdenum as well as gold and copper. The company plans a combination of open-pit and underground mining to extract ore and a pair of tunnels to transport up to 120,000 tonnes a day to a processing area 23 km away.

Seabridge expects a construction period spanning 20 years and a mine life of 50 years, with 1,800 construction jobs and more than 1,000 employees to operate the mine.

Energy and Mines Minister Bill Bennett said the recent completion of the Northwest Transmission Line to extend the BC Hydro electricity grid to the region made this mine possible, as well as a molybdenum mine at Kitsault and the Red Chris copper-gold project near Dease Lake.

Seabridge has a benefits agreement with the Nisga'a Nation, whose territory was defined by a treaty in 2000, and the province has agreed to a 37.5 per cent share of provincial mineral royalties to be paid to the Nisga'a.

"This is one of the biggest mines that's ever been permitted in the province," Bennett said.  "It's on a scale with Highland Valley copper [near Kamloops], with Fording River or Elkview coal mines in the southeast, major mines that will really make a difference in our economy."

The KSM project still requires federal approval, expected by this fall. The company says the federal review has also determined it will meet environmental standards and is completing a public comment period before issuing its permit.

The site is near the border with the Alaska panhandle. Bennett said during the provincial review, the company changed its design to move the tailings and processing facility away from the mine site to address concerns by the fishing and tourism industry in Alaska.