WASHINGTON (AP) _ The AFL-CIO has officially welcomed the United Mine Workers into the federation, ending the union's more than 40-year break from labor's umbrella organizations.

''This is one of the greatest pleasures I've had in the trade union movement,'' AFL-CIO President Lane Kirkland said at a brief ceremony Thursday at which he presented UMW President Rich Trumka with the union's affiliation charter.

Kirkland also returned to the UMW a note the American Federation of Labor received from UMW President John L. Lewis on Dec. 12, 1947.

''We disaffiliate,'' said the short note from Lewis, who quit because of a political fight with other federation leaders.

Just two years earlier Lewis had pulled the UMW from the Congress of Industrial Organizations, which he had helped form as a rival to the AFL.

The AFL and CIO merged in 1955.

''It's been a long time in coming,'' said Trumka, who embraced Kirkland and credited him with creating the atmosphere that led to the UMW's decision to join the 14 million member federation.

The UMW requested the affiliation Oct. 8 and it was unanimously approved by the AFL-CIO's executive council. The UMW, which has about 150,000 members, becomes the 90th union to affiliate with the federation.

The only major unions not part of the federation are the nation's largest, the 2 million member National Education Association and the United Electrical Workers, with about 200,000 members.