Government land surveyors made the first recorded notice of the mineral deposit in 1846 while surveying township lines one-half mile to the west, reporting an almost inexhaustible quantity of specular iron ore and a needle turning in almost every direction. Early mining exploration in the area began in 1854 and continued through the end of the 19th century, and numerous companies were formed to exploit the potential of various explorations, though none except the Republic Mine developed into long-term profitable ventures. The mines were located near the Michigammee River along an ore body called the Republic Trough, where specular hematite and magnetite were found, and the ore bodies could pull a compass needle 30 to 60 degrees from magnetic north or prevent it from functioning at all. Kloman Mine, also known as Columbia Mine, opened in 1873 and shipped 94,813 tons of iron ore between 1873 and 1883 before lying idle after 1883. Riverside Mine opened in 1887 and shipped 16,160 tons between 1888 and 1893. Magnetic Mine was an old exploration and shipped 292 tons of iron ore from stockpile in 1906. West Republic Mine, also known as Toledo Mine, opened in 1881 and shipped 133,077 tons from 1881 to 1889 before later being incorporated into Republic Mine. Republic Mine opened in 1871 and shipped 8,430,093 tons of iron ore between 1872 and 1926, reaching a greatest depth of 2,910 feet. Erie Mine, also known as Fremont Mine, opened in 1876, closed in 1885, and shipped 9,194 tons between 1876 and 1883. North Republic Mine, also known as Metropole Mine, opened in 1888 and shipped 289 tons that year. Chippewa, Beria, Cannon, Standard, and Northwest Republic remained explorations, with no information available for most of them and no reported ore shipments from Standard.