Representatives of the United Mine Workers of American and the Bituminous Coal Operators Association were planning nonstop through the weekend in an effort to reach the first peaceful contract settlement in the eastern soft-coal industry since 1964.

The negotiators are working against a UMWA-imposed deadline of 12:01 a.m. Tuesday, "the absolutely latest time we can go" without at least a one-day strike, according to a ranking UMWA official.

The current three-year pact expires March 27, but the union normally sets aside 10 days for "the timely ratification" of any tentative collective bargaining agreement.

The 130 BCOA companies represented at the bargaining table on the fourth floor of the Capital Hilton produced about 44 percent of the nation's total 825 million tons of coal last year. Coal supplies about 20 percent of the nation's energy, and roughly 25,000 of the miners who produce that energy supply are out of work.

Accordingly, the BCOA and UMWA acknowledge that a serious work stoppage would harm them more than it would the general economy; both have said repeatedly that they want to avoid a strike this year.

But, late yesterday afternoon, the two sides still were arguing over an industry proposal -- supported mostly by big firms such as Consolidated Coal, Peabody and U.S. Steel -- to eliminate a multi-employer pension plan and to replace it with company-by-company pension coverage.

BCOA chief negotiator Bobby R. Brown contaends that the multi-enployer plan, in which member companies pay pension benefits from a common pool, has become too expensive because of the closings of many coal companies. Under the plan, surviving firms are carrying an unfunded liability of "more than $4 billion . . . a burden which our competitors in non-UMWA mines do not have to shoulder," Brown said.

However, UMWA President Sam Church says that company-by-company pension coverage could cause serious financial problems for smaller firms and end benefits for about 25 percent of the 160,000 union miners in BCOA companies. "They're asking us to buy a pig in a poke," Church said.