By Steven Greenhouse

BIRMINGHAM, Ala., March 19 -- Decades ago, Alabama's mining companies had more than their share of battles with the mine workers' union. In one confrontation, the National Guard shot a pro-union minister to death in 1921. In recent years, however, Alabama coal fields have been peaceful.

Now the state's largest mining business, the Drummond Company, has been accused of encouraging the assassination of three union leaders at its giant coal mine in Colombia. In a federal lawsuit filed here last week, a union in Colombia and the families of the dead leaders assert that Drummond's Colombian managers signaled paramilitary gunmen that they wanted the officials killed. Unions from Colombia have filed suits against Drummond and a handful of other American companies doing business in that country, hoping to create legal and public pressure to stop the assassinations. In the last decade, more than 1,500 union officials have been killed in Colombia, where leftist guerrillas are battling the government and business.

"We have evidence that the paramilitaries who killed the three union leaders were in fact working for Drummond," said Terry Collingsworth, president of the International Labor Rights Fund, a Washington advocacy group that has worked with the United Steelworkers of America in suing Drummond.

"We believe a lot of American companies are, in essence, taking advantage of a bad situation in Colombia, where union leaders can be assassinated with impunity," Mr. Collingsworth said.

The lawsuit states that the director of the Colombia mine made veiled threats to the union's leaders, warning at one point that a fish dies from opening his mouth.

One human rights expert said the plaintiffs would have a hard time tying Drummond officials to the killings.

Mike Tracy, a Drummond spokesman, denied that the company had anything to do with the killings.

"We're not involved with the paramilitaries in these types of activities," Mr. Tracy said. "We really feel for these victims. Our sympathy goes out to their families."

In Birmingham, reaction to the lawsuit has been disbelief. The Drummond family, which has built a company with more than $700 million in annual sales, is business royalty in a city that has been the South's steel and coal capital for more than a century.

"I'd be utterly amazed if there was any complicity by any Drummond executives," said Charles Haynes, an engineering professor at the University of Alabama who is a friend of the Drummond family's.

Garry Neil Drummond, the company's chief executive, declined to be interviewed. He rarely talks publicly, but when he does, he usually tells his family's rags-to-riches story.

His father, Heman, opened a mule-and-wagon coal mine in 1935 in the hills outside Birmingham. He had four employees -- three of them his sons -- and in 1943, he had to borrow $300 to stay afloat, using his three mules as collateral.

By working hard, leasing some mineral-rich plots and making shrewd use of technology, the Drummond family became rich.

In the 1990's, with forecasts that Alabama's coal reserves would soon be depleted, the Drummonds looked to Colombia.

Some miners and others accused the company of betraying its hometown because it closed several Alabama mines after opening its Colombia operation. Drummond has invested more than $500 million in its Colombia mine.

"There's still a lot of worry about mines closing," said Earl Hudson, as he was leaving Drummond's one remaining Alabama mine, Shoal Creek, after finishing his 11 p.m.-to-7 a.m. shift underground.

Soon after Drummond opened its huge La Loma mine in northern Colombia in 1994, it was caught up in the country's civil war. Two years ago, the largest rebel group, the Revolutionary Armed Forces of Colombia, kidnapped four Drummond workers for ransom but eventually released them. Company officials say they have refused the rebels' extortion demands.

The rebels have also bombed Drummond's coal trains.

Last March, when the mine was in a bitter dispute with its union, the union's president, Valmore Lacarno Rodriguez, and its vice president, Victor Hugo Orcasita Amaya, were assassinated.

The recent lawsuit, brought under the Alien Tort Claims Act, contends that several paramilitary gunmen stopped a company bus carrying miners back to their villages and ordered Mr. Lacarno and Mr. Orcasita off.

"Several witnesses heard the paramilitaries say that they were there to settle a dispute that Lacarno and Orcasita had with Drummond," the lawsuit said. Fearing assassination, Mr. Lacarno and Mr. Orcasita had asked the company to let them sleep at the mine. Drummond officials refused, correspondence cited in the lawsuit indicates.

Last October, seven months after the two officials were killed, Gustavo Soler Mora, the new president of the union at Drummond's mine, was ordered off a bus by gunmen. Farmers later found his body. He had been shot twice in the head.

To protect its mines and workers, Drummond asked the Colombian military for help. But Human Rights Watch contends that many members of the military cooperate closely with paramilitary groups.

"Drummond could have stopped these assassinations, but they chose not to," Francisco Ramirez, secretary of the Colombia Federation of Mine Workers, said in a telephone interview. "We've brought suit in the United States as a last resort because there is no punishment in Colombia against those who commit crimes against union leaders."

Many of the Drummond workers in Alabama, members of Local 1948 of the United Mine Workers, say Drummond is a good employer, and they voice sympathy for the dead men. Some do not know what to make of the suit.

Fred England, an electrician at Drummond's Shoal Creek mine, said, "You don't know what to believe."