HELENA -- The environmental review for a coal mine planned in British Columbia and opposed in Montana is being ratcheted up, likely delaying the mine proposal by up to three years, said Sen. Max Baucus, whose goal is to have the proposal scrapped.

The Montana Democrat said Friday that Canada's ambassador to the United States, Michael Wilson, has confirmed the project proposed by Cline Mining Corp. will be reviewed at the federal level. Earlier plans called for a review at the provincial level.

Cline's plan to mine coal just north of Glacier National Park was challenged by the Bush administration this winter. In a letter to the British Columbia government, the U.S. State Department said the mine could cause environmental damage in the United States. Concern has focused on possible harm to water in the transboundary Flathead River system. Its north fork is Glacier's western boundary.

In a statement released Friday, Baucus said news of the federal review is ''a significant development because it shows that our concerns are reaching the highest levels in the Canadian government. The fact of the matter is this mine will have devastating consequences to Montana's water quality and our outdoor heritage. I get a strong sense that officials in Canada are starting to get the message.''

Kate Thompson, spokeswoman for the British Columbia Ministry of Environment, said the province and the Canadian government often collaborate on environmental review. Thompson did not comment further on Friday.

Cline spokesman Gordon Gormley said the federal review is neither good nor bad news for the company. ''It's just part of the process,'' he said. Responding to the prediction of a delay in the mining project, Gormley said he doubts the federal involvement ''will add significantly more time to the process.''

Montana Gov. Brian Schweitzer opposes the mine, planned for a site about 18 miles north of the state, and recently wrote Canadian officials to request federal involvement in assessing likely effects.

Water management chief Rich Moy of the Montana Department of Natural Resources and Conservation said Friday that Montana wants a comprehensive assessment that takes into account a potential transboundary impact from the mine.

''We're not against coal mining,'' Moy said. ''The only thing is, this is probably the most protected area in the Lower 48 states because of its natural beauty, its uniqueness and species diversity. This area needs to be set aside for future generations.''

Moy said state officials are pleased that British Columbia earlier invited them to participate as provincial officials looked at the mining proposal, and ''we cherish our relationship with British Columbia. We'd love to find a win-win situation with British Columbia, without mining.''

A similar Canadian mining proposal in the Flathead area came to a halt in 1988, amid objections that were raised in Montana and escalated.