The weekend passed with little word from the Washington, D.C., hotel suite where coal operators and the United Mine Workers union are working on a contract under the eye of a federal mediator.

Gov. Gaston Caperton Monday shed a little light on the progress of the talks. He said he received a fax from the office of Bill Usery, special mediator."The parties have been negotiating in marathon session," Mr. Caperton said. "For the first time, I am cautiously optimistic. That's all I can say."

Mr. Caperton declined to elaborate on his statement or the details of Mr. Usery's fax.

The talks resumed last Wednesday after a two-week recess, "continued almost nonstop" through Friday evening, then went on through the weekend, Mr. Usery said.

"Every effort must be made to find a mutually acceptable agreement," the mediator said late Friday night.

At the time, Mr. Usery also said he was "optimistic that a settlement can be reached soon," raising hopes that an end was in sight to the UMW's strike against selected members of the Bituminous Coal Operators Association.

But spokesmen for the operators and the UMW said there was nothing new to report Sunday night.

The UMW began its strike May 10 in a dispute over job security and future employment for UMW members. The union says it has about 17,500 members on strike in West Virginia, Virginia and five other states.

As the strike nears the six-month mark, political and financial pressure is mounting on both sides.

On Thursday, Labor Secretary Robert Reich met separately with negotiators

from each side. He also met with the chief executives of some of the operators' parent companies, Mr. Usery said.

Mr. Reich "expressed the absolute necessity for everyone involved to find a fair and responsible solution," Mr. Usery said.

The meetings followed a letter to Mr. Reich from 14 coal-state congressmen who demanded to know "what the Labor Department has done to encourage a settlement."

Third-quarter earnings and coal production show the effects of the work stoppage on the operators. And the UMW's largest district, Charleston-based District 17, reportedly has laid off secretaries and elected officers.

Recent statistics showed the following:

* Coal production east of the Mississippi was down 7.6 percent to 407 million tons in the third quarter from 441 million tons in the same period last year. Of the major Eastern coal producing states, Illinois' production was down 25.1 percent, followed by an 11.7 percent decline in West Virginia.

* Ashland Coal Inc.'s sales dropped $44 million between July and September. The company said production was down 47 percent at its Hobet Mining subsidiary and 11 percent at its Dal-Tex operations. More than 1,000 Ashland employees are on strike.

* Rochester & Pittsburgh Coal Co. production at its strikebound subsidiaries was down 2 million tons as of Oct. 31. Thomas Garges, company president, said striking employees had lost $9 million in wages.

* Earnings fell 48 percent in the third quarter for Hanson PLC, the parent company of Peabody Holding Co., which owns Peabody Coal Co. and Eastern Associated Coal Co.

Hanson has said the strike would cost it about $44 million for the quarter.

* Arch Mineral Corp.'s president, Steve Leer, distributed a memo to all employees Oct. 20 saying, "The strike continues beyond what anyone would have predicted. We must now take measures to conserve cash."

Among cash-saving measures, Mr. Leer asked employees to "voluntarily defer nonessential dental or medical visits."

* UMW District 17 laid off secretaries and several elected officials, the Charleston Daily Mail reported earlier in the week. Bob Phalen, District 17 president, did not return messages seeking confirmation.

"It isn't like we have no incentive to get a settlement," said Tom Hoffman, Consol Inc. vice president and spokesman for the operators' negotiating committee. "This is costing millions."