In 1847 the Northwest Copper Mining Association formed but was shortly reorganized as the Northwest Mining Company with increased capital stock. It operated until 1860, by which time it had exhausted its capital. Reorganized again as the Pennsylvania Mining Company which divided in 1863 and the Delaware Mining Company was organized. The mine was idle between 1865 and 1872 but was purchased by a Philadelphia investor who organized the Delaware Copper Mining Company in 1876. Five years later, in 1881, the Conglomerate Mining Company took possession. Their articles of incorporation included Northwest, Pennsylvania, Delaware, Pennsylvania, Maryland and Wyoming properties. In 1888 the property reorganized as the Lac La Belle Mining Company but did not resume operations. Oneida Copper Company incorporated in 1899 and did some exploratory work on fissures, Allouez conglomerate and various amygdaloids. It was later acquired by Calumet and Hecla Mining Company.