More than 6,000 coal miners marched to the White House yesterday to protest the Reagan administration's plan to reduce the federal black lung program that pays benefits to about 80,850 miners and their dependents.

The demonstrators, carrying signs reading "Coal Dust Kills Coal Miners," "Must Miners Die to Prove Black Lung," and "Stop Black Lung Murder Not Black Lung Benefits," were drawn here by the United Mine Workers, which called for a two-day workmen's holiday to protest the proposed cuts.

Exactly how much money would be cut from the federal black lung fund is unclear. However, the protest yesterday was prompted by a Labor Department recommendation that benefits paid from the two-year-old Black Lung Disability Trust Fund be limited to those miners "who are truly medically disabled by black lung."

Black lung, a form of pneumoconiosis, is caused by the accumulation of tiny coal dust particles in the lung. It affects breathing and often leads to death. The disease is progressive and sometimes may not be detected until years after a miner's last exposure to coal dust.

"Black lung is a killer," said Francis Hank Taylor, a coal miner from Wellsburg, W.Va., who joined a rally in McPherson Square prior to the march. "Mining is a dangerous operation. You put your life on the line. All we want are our rightful benefits," the 52-year-old miner said as he chewed on a wad of tobacco.

Taylor, who has been working in the mines for 30 years, said he has a neighbor who has black lung disease. "He's gone from 190 pounds to 93 pounds. He's in the hospital. It's bad."

Taylor, like many of the miners and their families who gathered here yesterday, said they feared that they or their loved ones may eventually have the disease.

"I worry about it every day," said Germanus Spiridigliozzi, a 28-year-old coal miner from Altoona, Pa. "I'm here to fight for the man who needs the benefits. He needs that extra money to survive."

The Labor Department, in its budget report, contends payment restrictions are needed in the fund because the fund "rapidly is sinking into insolvency" and "producing massive deficits . . . financed from general revenues" from the U.S. Treasury that now amount to $956 million.

The department alleged that 88 percent of all miners certified as eligible for black lung payments "were either not disabled or else could not be proved to have black lung disease."

However, UMW officials and politicians speaking to yesterday's gathering say those figures are inaccurate.

"Today we are fighting for a program that we never thought would be taken away," said UMW President Sam W. Church Jr. to the cheers of the placard waving miners. "All we are asking for is a small compensation for the terrible disease and the damage done to our lungs. . . .It's time to tell Ronald Reagan that we mean what we say."

Labor Secretary Raymond J. Donovan, in a letter sent to Church over the weekend, said "I am truly concerned, as is the President, over the plight of the victims of Black Lung. We believe in the need for this program, and we believe those who are disabled from this disease should receive benefits. The Administration is not going to propose anything that would deprive any miner who is disabled by Black Lung from qualifying for benefits."