Ouray was settled in 1875, when gold and silver deposits were found near
Mount Sneffels. Since 1877, mines in Ouray County have produced over
$35,000,000 in gold and $32,000,000 in silver. The district is still
quite active: in 1965, mines in this area produced more than $9,000,000
in gold, silver, copper, lead, and zinc, about a third of total Colorado
production of these metals for that year.
[Illustration: A few miles south of Ouray, along Uncompahgre Gorge, an
old mine clings to the slope below the Million Dollar Highway (U. S.
550). Abrams Mountain rises in the background. The Precambrian
Uncompahgre Quartzite outcrops up to about the road level; Miocene
Sunshine Peak Rhyolite caps the peak. (Jack Rathbone photo)]
A mile north of Ouray a prominent intrusive stock marks the center of
mining activity closest to Ouray. The richest deposits of the Ouray
area, however, lie about five miles southwest, near Mount Sneffels and
Red Mountain Creek. There, several large mines, including the famous
Camp Bird mine, have operated for many years, extracting ore from
hundreds of veins that underly the surface. Some of these veins are two
to four miles long. They are in Tertiary volcanic rocks of the San Juan
Formation. Quartz and calcite are the common gangue (non-economic)
minerals, and pyrite, sphalerite, galena, and chalcopyrite are the most
abundant ores. Most of the silver is in the galena; gold occurs in
streaks and nodules associated with quartz.
About ten miles south of Ouray, along the “Million Dollar Highway” (U.
S. 550), the Red Mountain district lies on the northwest edge of the
Silverton volcanic cauldron. It contains a number of small pipelike
bodies very rich in silver-copper and silver-lead ores. Following the
mid-Tertiary volcanism and ore intrusion, surface rocks in this area
were intensely oxidized: resulting iron oxides now form the gaudy reds
and yellows of Red Mountain and the slopes near Ironton. This
alteration, as well as the fact that much of the area is covered with
fallen rock, stream gravels, or glacial deposits, compounds difficulties
of locating the small though high-grade ore deposits.
The Idarado Mine, on the east side of U. S. highway 550 near Red
Mountain, used to produce ores from nearby volcanic pipes; now it
produces from veins some distance to the northwest. The area is
honeycombed with tunnels and shafts.