Construction workers in the United Mine Workers Union reached a tentative agreement last night with the Associated Bituminous Contractors (ABC), possibly removing the last obstacle to full resumption of soft-coal production in the East and Midwest.

The 40-month agreement -- the same length as the contract ratified June 6 by the UMW's rank-and-file miners -- now must be approved by the union's estimated 11,000 construction workers. Ratification could take up to 10 days. e

Many of the miners in the 160,000-member union returned to work June 8. But picket lines generated by the lingering construction dispute kept as many as 50,000 miners off the job, according to UMW secretary-treasurer Willard Esseltyn, who represented the union in the construction talks.

Esselstyn told reporters after a three-hour bargaining session at the Capital Hilton last night that the construction package will be presented to the union's bargaining council today. He gave few details of the tentative agreement but said he expects that the contract will be ratified.

"I feel as though it is the best pact that can be reached at the time, I think we got a fine pension deal, a fine dental plan," Esseletyn said.

The contract ratified June 6 by the mining contingent of the UMW provides a 38 percent increase in wages and benefits over the next 40 months. Union sources said last night that the terms of the construction agreement are similar.

Elmo Hurst, ABC president, appeared with Esselstyn last night to announce the tentative pact, which Hurst called "a good contract for the construction worker."

The three-year contracts covering construction workers and miners expired March 27, precipitating simultaneous strikes. Negotiators for the miners, who bargain separately with the Bituminous Coal Operators Association, reached an initial tentative agreement March 23, but it later was rejected by more than 2 to 1.

Earlier this month, the miners voted by more than 2 to 1 to accept a second tentative agreement. Now the construction workers, who customarily reach contract agreements after the miners do, will have their chance to vote on a settlement.