Later this month President Clinton will vacation on a ranch near Jackson Hole, Wyo. Here is a modest suggestion for him. The President should take a short flight in one of his military helicopters to the upper reaches of Henderson Mountain in Montana, just over the Wyoming border. There he will discover a beautiful and fragile wilderness. He will also see the proposed site of a huge gold, silver and copper mine that a Canadian conglomerate wants to build.

This mine and its lethal wastes will threaten not only Yellowstone National Park, which lies three miles away, but also the adjacent wilderness. This is a catastrophe-in-waiting. The risks to the crown jewel of the national park system are so grave that Congress should appropriate $35 million to compensate the mining company, Noranda, for its exploratory expenses and then tell it to go away.

The present anti-environmental Congress is unlikely to take such a step. It is also unlikely to pay much attention to an imaginative proposal offered by Representative Bill Richardson, Democrat of New Mexico, to put the area off limits to mining by establishing a national recreation area.

That is where Mr. Clinton comes in. If Congress will not stop this mine, he must. The Federal Government cannot simply seize the property; Noranda has established lawful title. But it has enough regulatory authority to make it onerous for the company to proceed. So far, the officials who have those powers have been reluctant to exercise them. Mr. Clinton needs to see that they do.

Under the 1972 Clean Water Act, for example, the Environmental Protection Agency and the Army Corps of Engineers can prohibit development on wetlands. Noranda proposes to dig out 56 acres of wetlands high on the mountain, where it would then build a deep reservoir the size of 70 football fields to store acid wastes. Geologists say any such structure, no matter how beautifully engineered, is bound to crack at some point given the region's extreme weather and its history of earthquakes. That would send poisons directly into the watershed. If the E.P.A. and the Corps deny Noranda the necessary permits, the company will have to look elsewhere to store its toxic material. Alternative sites could be prohibitively expensive and the company might simply fold its tent.

On June 1 Mr. Clinton told a town meeting in Billings, Mont., that he was "very worried" about the mine but wanted to let negotiations between Noranda and various state and Federal agencies run their course. The way things look now, the agencies are likely to give Noranda the go-ahead in exchange for pledges that it will spend whatever is required to prevent environmental damage. That would be good but not good enough. Even if Noranda takes extraordinary precautions every step of the way, it cannot guarantee that the poisons produced now can be safely contained for future generations.

Mr. Clinton, or his Vice President, should summon the key players -- Interior Secretary Bruce Babbitt, Carol Browner, the E.P.A. administrator, and Jim Lyons, who oversees the Forest Service -- and tell them to work out a plan. He may also have to come up with some money, but geologists say fair compensation to Noranda should not be more than $50 million. That is a good deal less than the $200 million Mr. Babbitt recently paid to oil companies to buy out drilling leases in sensitive coastal waters.

Mr. Clinton has been making an effort in recent days to polish up his environmental credentials. Figuring out a way to stop this mine would surely help. He alone can make this the national issue it deserves to be. At risk is the oldest and greatest of our national parks.