Daniel Brockway was linked with several mining operations during his lifetime. The Atlas mine was located on property adjacent to the famous Cliff mine in Keweenaw County. Brockway is reputed to have been owner, director and agent for the company from 1849-1883. Although it was always hoped that the Atlas would uncover rich Cliff ores, the property never actually panned out. The Michigan mine, located south of Mosquito Lake (now Lake Medora) in Keweenaw County, was also an unsuccessful venture. Little information is available about the New England Copper Company, and it is unclear if Brockway had any real association with the company or if he merely recycled the surviving Cash book for use in the store years later. In addition to these properties, it is claimed that Brockway discovered and developed the Cape Mine (1849-1850) and served as agent for the Northwest Mine (1849-1850?), both in Keweenaw County. Brockway was made agent of the Cliff Mine following the death of Oliver Farwell (another son-in-law) in 1881. Although the mine was well past its prime, Brockway continued to search for profitable ore bodies until the mine was purchased by the Tamarack Mining Company in 1895. The records also indicate that Brockway undertook at least two trips west (1879 and 1886), prospecting properties in the Dakotas, Idaho and Colorado.