Note: The following is an extract from Eric Twitty, “Guide to Assessing Historic Radium, Uranium and Vanadium Mining Resources in Montrose and San Miguel Counties, Colorado, Multiple Property Listing,” a National Register of Historic Places documentation report prepared for the Colorado State Historic Preservation Office, Colorado Historical Society, July 15, 2008, ppE01-E02, E07.  The full report (136 pages) describes in detail the following periods of mining: The Chrome Copper Discovery[, 1880’s]; The Radium Interest, 1898-1905; The Radium and Vanadium Boom, 1906-1922; The Quiet Years, 1923-1934; The Depression-Era Revival, 1935-1940; World War II, 1941-1945; The Atomic Era 1946-1963; The Transition Period, 1964-1973; The Last Boom, 1974-1980; and the Epilogue.  The report can be downloaded from  here, accessed October 27, 2015.

INTRODUCTION
In terms of mining history, western Montrose and San Miguel counties rank among the most important regions in the United States and the world. In 1898, Montrose County hosted one of the world's first radioactive metals discoveries in the form of carnotite ore. During the late 1890s, the Curies [Marie and Pierre] and other leading scientists in Europe were only beginning their experiments with radioactivity and prized carnotite for its metals content. Limited only to the Colorado Plateau, carnotite had never been recognized or classified prior to the late 1890s and was, in essence, a new mineral. European scientists found that carnotite carried uranium, radium, and vanadium, all of which would figure prominently in national and world history.

Between 1899 and around 1910, Montrose and San Miguel counties were center to the world's most important radium mining industry. Radium was the first of several radioactive metals in carnotite to come under measurable demand. European scientists wanted the metal for research, and the medical industry used it for health applications. Because carnotite had the highest radium content of known ores, the world turned to Montrose and San Miguel counties for its radium. In association with this, the first radium mines and mills in the United States operated in Montrose County.

Between 1910 and 1922, vanadium came under heavy demand as an alloy for steel. San Miguel County offered the richest deposits in the form of roscoelite ore, with carnotite a close second. As with radium, Montrose and San Miguel counties were among the world's most important sources of vanadium. The alloy metal factored heavily into the domestic steel industry, as well as for weapons production among European nations embroiled in World War I.

While the above historical trends are obviously important, it was uranium mining that left the greatest impact on Montrose and San Miguel counties. The Federal Government relied heavily on carnotite for the Manhattan Project during World War II. Carnotite, principally from the two counties, was the only significant domestic source of uranium for nuclear weapons through the 1940s. Uranium was fundamental to the Cold War, and during the early 1950s, the two counties remained among the most important centers of mining and milling. By the latter half of the decade, other regions in the Southwest became as significant, but the counties maintained their prominence.

From the late 1960s through the end of mining around 1980, Montrose and San Miguel counties generated uranium for the nuclear power industry. Their production was substantial and contributed to the viability of this alternative energy source. When uranium prices collapsed around 1980, most of the mines closed and the region lost its economic foundation.