- Deposit Type: Vein, Breccia and Stockwork
- Commodity: Gold, Silver
- State/Province: CO
- Country: United States
- Latitude: 39° 43' 1'' N
- Longitude: 105° 36' 52'' W
The Dixie Mine
Free gold in matrix from Dixie Mine. Specimen size 6x3.5x2 inches
The Dixie Mine, a precious metal vein system, is a notorious past producer of high-grade gold and silver ore. The property is in the Cascade mining district, in Clear Creek County, about five miles west-southwest of Idaho Springs, Colorado. The mine is accessible year round, about one mile off Colorado Highway 103 along a county-maintained gravel road. Idaho Springs is about a half hour west of Denver, Colorado along Interstate 70.
GeologyThe Dixie occurs within an east northeast-striking vein system that follows the trend of the Colorado mineral belt. The vein system appears to be restricted to the granitic rocks of the Boulder Creek granodiorite (a Precambrian batholithic mass dated at about 1700 MA), which intrudes metasedimentary rocks of the Idaho Springs Formation. Northwest- and northeast-striking faults and folds are the dominant structures in the area. Structural relationships are obscure, but northwest-striking faults are typically transected by northeast-striking faults and fractures.
Although there are no Tertiary intrusive rocks in the district, ore deposition is most likely related to the emplacement of Laramide stocks that characterize the Colorado mineral belt. Thus, the ore deposits are probably Tertiary in age and were concentrated along preexisting, east northeast-striking, Precambrian shear zones.
The Dixie vein strikes about N60E and dips steeply to the northwest. It occurs along the Dixie shear zone, named by FW Christianson in 1957. The shear zone is a well-developed fault characterized by gouge and breccia. The vein ranges from 1 to 5 feet in width and ore-grade is seemingly consistent over the known vertical extent of the vein. The vein has been explored and mined through 6 levels and the workings extend to over 300 feet below the surface.
Ore minerals that occur in the dominantly quartz-carbonate veins include electrum, cinnamon-colored sphalerite, galena, tetrahedrite, chalcopyrite, and pyrite. Gaudy crystals of native gold may be common in high-grade pockets, and silver is presumably tied up in either galena or tetrahedrite. Wall rock is dominantly Precambrian granite.
Mining HistoryDevelopment of the Dixie Mine began in December, 1936. Operating for 20 years, the mine produced 17,747 oz of gold and 57,809 oz of silver. With the death of the owner production ceased, and the mine has been idle for most of the time since. During peak production years, the mine produced coarse, high-grade gold. At $32/oz gold, a total of 22,540.7 tons of ore yielded an overall average of $25.77 per ton. Average ore grade is 0.5 oz/ton gold and 1.5 oz/ton silver. Mint and smelter returns for the period 1938 to 1956 equaled $579,128.85.
Most production occurred between 1936 and 1956. In 1957, a very complete report was done on the mine by F. W. Christianson. Since few tons of ore have been removed from the mine since the report was written, it is believed that his report is still valid. In the 1970's, Christianson's samples were cross-checked, and several reports were written by William Bird to bring values up to date.
Between 1957 and 1965, the U.S. Bureau of Mines reports about 1,000 tons of production. A sixth level was developed during that period and was driven approximately 400 feet along the vein. Ore was reportedly very high grade, but there is no evidence to prove this. The mine was purchased by the current owners in the 1960's. The mine has been leased 2 times since then but there was little or no production. The mine has been flooded since the early 1980’s.
ExplorationSince the mine has been underwater, evaluation has been difficult. In 1977, William Bird checked some of Christianson's samples and recalculated reserves at $175 gold. Bird reported 23,928 tons of proven and probable ore with an additional 154,460 tons of possible ore.
Access to the Dixie Mine is through the M & M Tunnel, a crosscut about 750 feet in length that intersects the Dixie at the third level. The levels above the M & M Tunnel are caved and those below are flooded.
A small rock-chip sampling program was undertaken in 1986 (Chemex Labs). Sample D04 was from a clay zone on the third level of the mine. Samples D01-D03 were also from the mine. Samples D05-D10 were taken from a small dump near the original Dixie shaft. Another small rock-chip sampling program was run in 1992, and the results are also included (Cone Geochemical). All 1992 samples were collected from the surface, and the results are most encouraging.
Sampling ResultsSampling Results
D01 Ag .58 oz/T, Au <.003 oz/T
D02 Ag .16 oz/T, Au <.003 oz/T
D03 Ag .40 oz/T, Au <.003 oz/T
D04 Ag 19.57 oz/T, Au .017 oz/T
D05 Ag .28 oz/T, Au <.003 oz/T
D06 Ag .43 oz/T, Au .026 oz/T
D08 Ag 6.05 oz/T, Au .254 oz/T
D09 Ag 3.25 oz/T, Au 1.392 oz/T
D10 Ag 1.3 oz/T, Au .198 oz/T
92-D-01 Au <.002 oz/T, Ag .20 oz/T
92-D-02 Au <.002 oz/T, Ag <.05 oz/T
92-D-03 Au .009 oz/T, Ag .05 oz/T
92-D-04 Au .169 oz/T, Ag 5.73 oz/T
92-D-05 Au <.002 oz/T, Ag <.05 oz/T
92-D-06 Au .006 oz/T, Ag .31 oz/T
92-D-07 Au .025 oz/T, Ag .05 oz/T
92-D-08 Au .879 oz/T, Ag 2.06 oz/T
By all estimations, a potential for high grade ore still exists in the Dixie Mine and in the district. In addition to the Dixie, there are sixteen other claims in the package. There has been little exploration on any of these claims.