VANCOUVER, British Columbia — Teck Cominco Ltd. on Friday lost a battle in the Supreme Court of Canada to stay a lawsuit filed against the mining company by its insurers concerning environmental damage to the Columbia River.

The decision means Teck now faces legal action in both the United States and Canada related to damages alleged to have occurred in Washington state, downstream from Teck’s smelter site in Trail, British Columbia.

The ruling upholds a decision made in the British Columbia Supreme Court and its Court of Appeal, both of which refused to grant the stay sought by Teck.

In its decision, the Supreme Court dismissed Teck’s argument that the case should be heard in the United States because it was filed there first, saying it would “encourage a first-to-file system, where each party would rush to commence proceedings in the jurisdiction which it thinks will be most favorable to it.”

The court also said that while the damages faced by Teck in the U.S. environmental action are not known, “it is expected to exceed the limits underlying each of the policies, which collectively total over $779 million (Canadian).”

Teck was sued in the United States in 2004 and called upon its insurers for coverage, saying it was included in their policy.

The insurers, Lloyd’s underwriters, Seaton Insurance Co. and Lombard General Insurance Co. of Canada, sought court orders to not have to defend or indemnify the company in the matter.

Legal actions over the alleged Columbia River damage were filed both in British Columbia and Washington state.

The case in the United States involves allegations that Teck’s giant lead and zinc smelter in Trail, about 10 miles north of the border from where the Columbia enters northeastern Washington, discharged slag into the river and that the waste material accumulated in the Upper Columbia and Lake Roosevelt in Washington.

Teck sought to stay the British Columbia court proceedings on grounds that related cases were under way in the United States.

The decision Friday comes as Teck tries to cope with a crushing debt load it built up from its $14 billion purchase of Fording Canadian Coal Trust last fall.

It has about $10 billion of debt on its books, and has been selling assets, cutting production, its dividends and staff to try and cope with the loan and falling commodity prices in the current recession.

On Friday, Teck announced two assets sales worth a total of $100 million.