The Pioneer Mine began operation in 1888. Shafts No. 1 and No. 2 were abandoned and replaced by vertical A Shaft, which was sunk in 1909, and in 1943 an incline from 8th level to the surface was completed. Men, timber for support, and equipment were lowered in A Shaft. In 1924 electric hoists replaced coal-fired steam hoist equipment, and railroad cars alongside the Captain's Dry House carried loads of coal for that purpose. Surface and seepage water was pumped at a rate of 1,000,000 gallons per day into Shagawa Lake. When the Pioneer Mine closed, the pumps were shut off, and the water steadily rose to the present level in Miners Lake. In 1962 new steel-making technology was introduced in which oxygen was blown directly into liquid steel through large ceramic lances, so the heavily oxygenated Vermilion ore was no longer needed to make steel. When the mine closed in 1967, it had reached the 17th level at 1626 ft., employed 450 men, and shipped a total 41,112,8587 long tons of iron ore.