Backed by the words "Partnering to Protect Our Shared Environment," Montana Gov. Brian Schweitzer and British Columbia Premier Gordon Campbell signed an agreement that bans mining and coal and gas development in the transboundary Flathead River drainage.

Schweitzer and Campbell met Thursday in Vancouver, B.C., to finalize the pact to protect land north of Glacier National Park.

Schweitzer called it a "historic" agreement and Campbell predicted it "will stand the test of time with the people of British Columbia and Montana."

Schweitzer noted that "for four hundred generations, people have found a way to pass the landscape along to the next generation ... Today, we celebrate something historic. We share an opportunity and today we share a destiny."

The deal halts ongoing exploration and prohibits future development of coal, oil and gas in much of the Flathead River Basin, which sprawls across some 9,000 square miles of rugged terrain and straddles the U.S.-Canadian border.

Since the 1980s, Montana political leaders and groups have resisted a series of proposed mining projects in the Canadian Flathead drainage.

The Canadian Flathead forms the headwaters for Montana's North Fork Flathead River, which flows south along Glacier National Park's western boundary and on to Flathead Lake.

Every project was turned back, but the threat of future development projects persisted.

In a telephone interview following the signing ceremony, Schweitzer said he is confident the memorandum of understanding signed on Thursday will lead to permanent protection in the basin on both sides of the border.

"This is a unique area that deserves special attention," said Campbell. He stressed that the agreement allows for sustainable forest management and recreation that has been carried out in the Flathead for decades.

Also attending the press conference, which was streamed live on the Internet, were Kathryn Teneese, chairwoman of the Ktunaxa Nation; Mike Kenmille, representing the Confederated Salish-Kootenai Tribes; and Dennis Rounsville, an executive with Tembec, a Canadian wood products company.

Teneese and Kenmille signed the memorandum of understanding as witnesses.

"While we may not be a party to the agreement, we have a responsibility to ensure that the agreement is upheld and that's something we intend to do," Teneese said.

Schweitzer said the agreement was reached after several years of "quiet diplomacy" involving detailed negotiations.

"Every word in the document has been negotiated," he said.

Schweitzer praised Campbell as "a bold leader" and said there are a "lot of people to be thanked, people in the Flathead, the congressional delegation. There are people who have spent a good part of their life on this issue."

For his part, Schweitzer said, "Someone handed me the baton and I just ran like the dickens with it. There were many people who ran laps before me and there will be more that will run laps in the future."

Most notably, Montana's congressional delegation will need to pursue legislation and funding that will lead to the retirement of old mineral leases that still exist on the Flathead National Forest in the North Fork drainage, and to help the British Columbia government compensate leaseholders north of the border.

Schweitzer said the costs are uncertain but "will be worked out."

The agreement specifies environmental protection measures, including the removal of "mining, oil and gas, and coal development as permissible land uses in the Flathead River Basin."

Logging still will be allowed.

It calls for cooperating on fish and wildlife management with the Ktunaxa Nation and the Confederated Salish-Kootenai Tribes, to collaborate on environmental assessments for any project of cross-border significance, to share information on proposed projects and to collaborate in responding to emergencies that have potential for environmental harm.

It also includes "climate action" and renewable and low carbon energy provisions.

Efforts to stop mining in the region began three decades years ago when a U.S.-Canada joint commission rejected an open-pit coal mine in the valley because of potential environmental damage.

Another coal mine was proposed in recent years. Oil and gas companies also have been eyeing the area. And in December, Max Resource Corp. said it had extracted samples of high-grade gold from a ridge about 10 miles north of Glacier.

A 2003 British Columbia land-use plan set mining as a high priority and said other uses, such as wildlife habitat and recreation, "will not preclude ... approval of mining activities."

In January, a team of U.N. scientists recommended a moratorium on mining in the valley.

After signing the agreement, Schweitzer gave Campbell and the province's minister of intergovernmental relations Montana-made bolo ties. In return, Schweitzer got a pair of the popular red Canadian Olympic mittens.