Preliminary report on the Jo Reynolds area, Lawson-Dumont district, Clear Creek County, Colorado

Geology of uranium and associated ore deposits, central part of the Front Range mineral belt, Colorado

“…In 1951, intensive studies were made in the Quartz Hill and Justice Hill areas of the Central City district by F. C. Armstrong and in the Lawson area by B. F. Leonard and J. E. Harrison. The results of Armstrong's studies were not published, but they are partly incorporated into this report. A report on the Jo Reynolds mine in the Lawson area was published previously (Harrison and Leonard, 1952). As a result of investigations in 1951, Leonard ( 1952) proposed that uranium in the Front Range was related to hypogene mineral zoning.…”

Altered wallrocks in the central part of the Front Range mineral belt, Gilpin and Clear Creek Counties, Colorado

“…For a description of the Tertiary intrusive rocks of the region, the reader is referred to a paper by Wells (1960). Several papers ('Harrison and Leonard, 1952;Moore and Butler, 1952;Wells, 1955;Hawley and Moore, 1955;Sims, 1956;Sims and Tooker, 1956;Tooker, 1956;and Drake, 1957) describe some details of features of the uranium deposits.…”

Geology of uranium deposits in the Front Range, Colorado

“…Although numerous uranium-bearing veins are known in Clear Creek County, none of them has proved economically significant, and production has been .negligible. Pitchblende was identified in the Jo Reynolds mine, 6 miles west of Idaho Springs, as early as 1886, and in 1919, this mine produced 8 tons of uranium ore that assayed 72 percent U 3 0 8 (Harrison and Leonard, 1952). More recently, a little more than a ton of low-grade uranium ore was shipped from the Martha E tunnel, 3 miles southwest of Idaho Springs (Harrison and Wells, 1959, p. 72).…”