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International Union of Mine, Mill, and Smelter Workers


INTERNATIONAL UNION OF MINE, MILL, AND SMELTER WORKERS. In its first incarnation as the Western Federation of Miners (WFM), established at a convention in Butte, Montana, on 15 May 1893, the International Union of Mine, Mill, and Smelter Workers (IUMMSW) organized workers who mined copper, bauxite, nickel, uranium, lead, zinc, gold, and silver as well as those who smelted and refined copper. Earning a reputation as one of the leading radical institutions in the American West, the union won some important organizing drives in its early years, including a key victory at Cripple Creek, Colorado, in 1894.With ownership of mining companies increasingly consolidated among a few corporations, however, the WFM dissolved a number of its locals and was nearly defunct by World War I. Hoping to put aside its radical reputation, the union reemerged as the IUMMSW in 1916.

In the anti-union atmosphere of the Roaring Twenties, the IUMMSW remained a shell of its former self. As with many other industrial unions, however, its leadership seized upon the promise of the New Deal to reassert its presence in the western mines. After a five-month strike in Butte and Anaconda, Montana, in 1934, the IUMMSW was not only revitalized as a labor organization, but also firmly established as a partner in the New Deal coalition of labor leaders, social reformers, and other activists. Yet internal divisions continued to plague the union under the presidency of Reid Robinson, elected to office in 1936 under a pledge to renew the union's aggressive organizing and bargaining stance. Robinson roused controversy when he appointed Communist Party member Maurice Travis to an international IUMMSW office. Anticommunist IUMMSW members forced Robinson's resignation from office in 1947 over the move, but were further incensed when Travis succeeded Robinson as IUMMSW president. Although Travis formally severed his ties to the Communist Party in order to meet the Taft-Hartley Act's prohibition against labor leaders holding member-ship in the party, the publicity over the flap drew national attention to the union at the height of the McCarthy-era red scares.

Further sapping the union's energy was its expulsion from the Congress of Industrial Organizations (CIO) in 1950.Although it was a founding member of the CIO in 1935, the IUMMSW was one of eleven unions expelled in a move to eliminate communist elements from the organization. The IUMMSW also faced renewed charges of communist influence with the 1954 movie Salt of the Earth, based on a strike against Empire Zinc by IUMMSW Local 890 in Hanover, New Mexico. With its producer, director, screenwriter, and lead actor already on a movie industry blacklist for their leftist activities, the film appeared to justify suspicions of communist dominance in the IUMMSW at the time of its release.

During the 1950s, the IUMMSW faced numerous challenges from the United Steel Workers of America (USWA), which used anticommunist and racist rhetoric to raid the union's locals. Although it retained about 37,000 members in 300 local unions, IUMMSW officials voted to merge with the USWA on 30 June 1967.An additional 13,000 workers in Canadian IUMMSW locals joined the merger the next day. IUMMSW Local 598 in Sudbury, Ontario, however, refused to agree to the merger, and after 1985 retained an affiliation with the Canadian Auto Workers union.


Jameson, Elizabeth. All That Glitters: Class, Conflict, and Community in Cripple Creek. Urbana: University of Illinois Press, 1998.

Mercier, Laurie. "'Instead of Fighting the Common Enemy': Mine Mill versus the Steelworkers in Montana, 1950–1967." Labor History 40, no.4 (1999): 459–480.

Zieger, Robert H. The CIO, 1935–1955. Chapel Hill: University of North Carolina Press, 1995.

Timothy G.Borden

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