At the same time President Jimmy Carter has promised to increase coal production as a necessary part of a national energy policy, he has promised to sign into law a bill regulating the strip mining of coal.

According to the coal industry, those two promises are incompatible. Federal regulation of strip mining will hamper coal production and actually reduce it, at least temporarily, they say.

According to environmentalists, both promises can be and must be kept. To save fragile, arid lands in the West, and important agricultural lands in the Midwest, strip mining must be limited, they say.

Thought the overwhelming bulk of the national's coal reserves can be extracted only by underground mining, more than half the current production comes from strip mining, the fastest, cheapest method, and environmentalists say it is time to force the mine operators in the direction they must eventually take - toward deep mining.

Strip-mining legislation was first introduced in Congress in 1940, but serious work on a bill didn't begin until 1971. Since then, strip mining has been one of those bills that something always happens to on the way to enactment, even though support for it has grown. In 1974, it was delayed to the point where President Ford was able to pocket veto it after Congress adjourned. In 1975 he vetoed it again and the House failed by three votes to overide his veto. In 1976, it was stalled in the House Rules Committee.

Since Democrats now have overwhelming majorities in Congress and Carter has promised to sign a bill, this should be the year strip-mining legislation is enacted into law.

However, congressional opponents are cautiously optimistic, because of industry opposition, the increased need for coal, the new make-up of the House Interior Committee - and the bill'suncanny knack for getting into trouble.

Both the House and Senate Interior committees plan to finish hearings and begin markups in March, and to have a bill on the President's desk by early summer.

Despite the loss of White House backing, National Coal Association President Carl Bagge remains "unwilling to concede" there will be a bill.

He points to the membership of the House Interior Committeeas one reason for hope. Of the eight freshmen Democrats appointed to the enlarged 46-seat committee, Austin Murphy (Pa.), Lamar Gudger (N.C.) and Jerry Huckaby (La.) are considered doubtful on strip mining. Combined with the conservative Democrats and Republicans on the committee, it could make a difference, at least in the kind of amendments that are passed.

Committee Chairman Morris K. Udall (D-Ariz) acknowledges that "the Interior Committee doesn't reflect the Democratic majority in the House." He says the industry tried to "stack" the committee. Udall counts 23 sure votes and is reasonably certain he can get one more on strip-mining amendments.

Bagge also contends that the Carter administration may take a different view when it realizes that the bill would halt production of great amounts of coal, he prohibitive to small mine operators who couldn't afford to comply with all the bureaucratic requirements, and cause unemployment.

Ian MacGregor, chariman of the board of the American Mining Congress and Amax, Inc., a lare mining company, contends no law is now necessary because 38 states have mined land reclamation law's" enacted in the past few years. "If coal production is reduced or expansion of coal production is significantly retarded by prohibitive legislation, shortages will cause price increase, thereby added to inflationary pressures" and raising electric utility rates 10 to 15 per cent, MacGregor says.

Louise Dunlop of the Environment Policy Center, denies that strip-mining legislation would hurt coal production or lift consumer costs.

"No one is seeking a bill that would hurt coal production. Environmentalists are actually seeking to legitimize coal, by criticizing nuclear energy. But here is so much coal we can afford to be selective in where and how we dig it," said Dunlop. She quotes Russell Train, fromer Environmental Protection Agency administrator, as saying that only 3 per cent of the nation's 400 billion tons of coal reserves is strippable.

Moreover, since the Arab oil embargo, the costs of coal have gone up in proportion to the cost of Arab oil, not to the cost of mining coal. Though the cost of coal is now about $40 a ton, getting it to the surface still costs $8 to $12 a ton.

Dunlop argues that state strip-mining laws simply are not enforced. Moreover, according to John C. Doyle of the Environmental Policy Center, strip-mined agricultural land simply can't be returned to the high-yield land it was before.

In a study of Illinois farmland, Doyle concludes, "The process of reconstructing agricultural soils after strip mining will take something on the order of 10 to 30 years and even then there was will be no guarantee of re-establishing pre-mining agricultural yields in an acceptable time frame."

Strip miners are now eyeing the western states, which have large reserves of the cleaner-burning low-sulfur coal. Environmentalists are particularly concerned because grazing and agricultural lands and water are at a premium there and the aridity and fragility of the land makes it more difficult to reclaim.

When the two sides come down to it, most of th fights will be over western lands. In the Senate, Lee Metcalf (D-Mont.) has already re-introduced a provision originated by former Sen. Mike Mansfield that would prohibit strip mining of federally owned coal on land where the federal government own: mineral rights and the surface is owned by ranchers or farmers who are making a living from it. The House bill allows them to consent to strip mining but not make a windfall profit.

Both House and Senate versions also require preservation of alluvial valleys in the semi-arid Western states; their underground water makes them the most suitable for grazing and farming. They also have rich deposits of coal near the surface, but the coal helps bring the water to the surface, and environmentalists feel mining could destroy the water system.

Bagge says it is impossible to define preservation of the valleys. He says the provision amounts to a prohibition against mining which, when added to the surface owners' prohibition, would take vast amounts of western land out of production. "This is a land-use bill," Bagge says, not just a measure to reclaim strip-mined land.

Another criticism comes from West Virginia mine operators, who contend leveling off mountain land rather than returning it to a slope allows its development, a statement environmentalists contest.

Though environmentalists would like to phase out all strip mining, in the end the fight will probably come down to surface owners' rights, alluvial valleys and restoring the slopes.

In the end, "We'll probably wind up fairly close to where we were last year," Udall predicts. And he says he's not looking for vengeance, he just wants a bill.

So does Interior Secretary Cecil Andrus, who has told Udall's Committee that the Carter administration will support Udall's bill rather than offer its own. Though the administration will offer some amendments, Andrus said, the Udall measure is "a good place to start."