W.A. (Tony) Boyle, 83, a former president of the United Mine Workers of America who was convicted twice of murder in the slayings of union insurgent Joseph A. (Jock) Yablonski and his wife and daughter, died yesterday in the coronary care unit of Wilkes-Barre General Hospital in Wilkes-Barre, Pa. He had suffered from heart and stomach ailments for the past 10 years.

At the time of his death, Mr. Boyle was serving three consecutive life terms at the Pennsylvania state prison at Dallas. He had been found guilty of ordering the murder of Yablonski, a former UMW lobbyist who challenged him for the union presidency in an election held Dec. 9, 1969.

Mr. Boyle claimed victory by a two-to-one margin. Yablonski charged foul play and said he would appeal the outcome to the Department of Labor.

On Dec. 31, 1969, three years before a new election was held under orders from the Labor Department, tragedy struck in the form of assassinations in the night. Yablonski, 59, his wife Margaret, 57, and their daughter Charlotte, 25, were shot to death in their beds at their home in Clarksville, Pa.

In 1974, Mr. Boyle was convicted of ordering the killings. In 1977, the Pennsylvania Supreme Court ordered a new trial on the ground that he had not been permitted to present an adequate defense. The second trial took place in 1978. The jury deliberated for four hours and 50 minutes before returning a verdict of guilty.

Eight other persons -- three of them high UMW officials -- either confessed to having taken part in the murder plot or were convicted of having done so. Three men from Cleveland were found guilty of carrying out the killings for a fee of $5,200.

In another proceeding, Mr. Boyle was convicted in federal court of misusing union funds for political purposes.

Through it all he denied any wrongdoing. "I am innocent of the crimes of which I have been convicted, and I want everyone to know that," he said when he was sentenced at the second murder trial.

Mr. Boyle came to power in the UMW as a protege of John L. Lewis, a lion of the American labor movement. Lewis brought the small, dapper miner from the coalfields of southeastern Montana to union headquarters in Washington in 1948. Lewis resigned as union president in 1960 in favor of the aging and ailing Thomas Kennedy.

When Kennedy died in 1963, Mr. Boyle was elected president. He held the post until 1972. He lost it that year to Arnold Miller, a reform candidate who defeated him in the election ordered by the Labor Department as a result of the fraud that had colored the 1969 election in which Mr. Boyle beat Yablonski.

Mr. Boyle's departure from union office marked an important turning point in the history of the UMW.

He had inherited from Lewis a strongly centralized organization in which the rank and file had little power. Mr. Boyle, who usually sported a rosebud in the buttonhole of his suits, is said to have spent $200,000 on portraits of UMW leaders. He and his colleagues allowed themselves limousines and other comforts.

Bargaining with coal industry representatives in those days often took place behind closed doors, and there were charges of collusion between the union and the companies. In 1968, the UMW and the Consolidated Coal Co. were fined $7.3 million for violations of the Sherman Antitrust Act.

Yablonski, in issuing his challenge, took note of these issues. But he put most of his emphasis on the need for greater job security and health and welfare benefits, including compensation for "black lung" disease.

After Yablonski's death, Miller made these issues his own. In addition to improved health and welfare provisions, he initiated such democratic practices as ratification of contracts, election of district officials and a wide-open union newspaper. If the coalfields often were wracked by strikes and other disruptions, the days were over when the union leadership controlled virtually all aspects of the membership's lives.

In response to Mr. Boyle's death yesterday, the UMW issued the following statement:

"The death of former UMW prsident Boyle marks the final passage in a tragic chapter in the union's history. The union's recovery from the events of the late '60s and early '70s is complete."

William Anthony Boyle was born at Bald Butte, Mont., a mining camp. His parents were James P. Boyle and Catherine Mallin Boyle. The family was of Irish origin and had produced several generations of miners in England and Scotland. Young Tony got a high school education and followed his father into the pits. He also began to take part in union affairs.

He rose rapidly. By 1940, he was president of District 27 of the UMW, which covers the western states. During World War II, he was the UMW representative on several government boards dealing with manpower and production. He later was the labor representative on the Montana State Unemployment Compensation Commission.

When Lewis brought him to Washington, Mr. Boyle became his mentor's chief trouble-shooter. He also became a union vice president and gradually took into his hands the administration of the organization. He continued this through the brief presidency of Thomas Kennedy.

Mr. Boyle had a notable capacity for hard work. His manner could be abrupt and his gaze under jutting reddish eyebrows was piercing. It was said that he had no interests other than the union and his family.

Survivors include his wife, the former Ethel V. Williams, of Washington; a daughter, Antoinette Engebregson of Billings, Mont.; a brother, Richard J., also of Billings; one grandson, and one great-grandson.