HUNTINGTON, W.Va. (AP) _ Armed with a $100 million strike fund and a congressional reprieve from the thorniest issue facing the coal industry, the United Mine Workers union is ready to start negotiating for a new national contract.

The union Monday notified the Bituminous Coal Operators Association, which represents the nation's largest coal companies, that it is ready to start talks after the Sept. 7 Labor Day holiday.

The BCOA had no comment on the union's announcement. The actual start of talks will be set by agreement of both sides.

The current National Bituminous Coal Wage Agreement, which was signed in February 1988, will expire Feb. 1, 1993. Negotiations will be held in Washington, D.C., the union said.

The announcement follows the Senate's adoption last month of a plan to rescue the financially troubled United Mine Workers Health and Retirement Funds, which provide health care to some 120,000 retired coal miners and widows.

The Senate proposal, which is now before a House-Senate conference committee, eliminated one of the most contentious issues facing the union and the industry, according to UMW President Richard Trumka. He described health care as ''the number one problem in U.S. contract negotiations today.''

''There's no question that the resolution of the Health and Retirement Funds' crisis takes what could have been a major stumbling block to a new agreement off the table,'' Trumka said.

''We want to build on that success and, in these contract talks, demonstrate exactly what can be achieved when that issue isn't hanging over the heads of workers and management,'' he said.

Meanwhile, the union notified its members in the August-September issue of the United Mine Workers Journal that the UMW strike fund now totals $100 million. Effective Aug. 30, members no longer will have to pay the selective strike assessment which finances the fund, the union said.

The BCOA represents 14 of the nation's largest coal companies, but the UMW- BCOA agreement sets the pattern for many other contracts. Some 300 coal companies, not members of the BCOA, are parties to the 1988 contract under what are known in the industry as ''me-too'' agreements.

The union's last two national agreements, in 1984 and 1988, were reached without a nationwide work stoppage. However, strikes were called against major producers that refused to sign the agreement negotiated with the BCOA.

In 1984, the union struck A.T. Massey Co. and in 1988 it went on strike against The Pittston Co. in a dispute over the financing of retiree health care.