The Idaho Springs miners strike of 1903 was a labor strike by members of the Western Federation of Miners (WFM) against gold mines in the vicinity of Idaho Springs, Colorado. It is one of the strikes of 1903-1904 that are collectively known as the Colorado Labor Wars. The union demanded a reduction in the working day to eight hours, without a corresponding reduction in pay. The strike began on 1 May 1903, and was called off on 1 September 1903. The strike is noted for a dynamite attack on the Sun and Moon mine, and the forcible deportation of 19 union officials and union members from the area.