Gold was discovered in the San Juan Mountains of southwest Colorado in
1870. The earliest mine, near what is now Silverton, was located by a
group of prospectors sent out by Governor Pile of New Mexico Territory.
Since the site was on Ute Indian land, real mining did not begin until a
treaty allowing it was ratified in 1874.
Production in the Silverton district has been from veins in Tertiary
volcanic rocks within an elliptical area known as the Silverton
cauldron. Here the volcanic rocks, part of the several thousand feet of
lava flows and ash falls of the San Juan volcanic field, were cracked
and faulted by a second period of igneous activity. Ores formed in the
cracks and fissures.
In the 1870s the Silverton district was very remote, and difficulties
with transportation retarded activity there. In 1882, however, a
narrow-gauge railroad was built connecting Silverton with Durango, and
the problem of transporting ore out of the isolated mountain valley was
simplified. The railway still exists; a train makes daily passenger runs
during the summer—the only remaining operating narrow-gauge line in the
United States. The track follows the Animas River canyon, whose cliffs
and crags are dotted with long-abandoned mines, prospect holes, and mine
buildings, monuments to the tenacity and determination of the men who
mined here.
Production in this district was more than $22,000,000 in gold and
$20,000,000 in silver between 1874 and 1923. New activity is evident
here, as in other silver-rich areas of Colorado, because of recent
demand for silver, lead, and zinc.
[Illustration: Silverton lies in a remote mountain valley in the San
Juan Mountains. Silver, gold, lead, and zinc have been mined here since
1874. Storm Peak, composed of Tertiary volcanic rocks, forms the
backdrop; the narrow-gauge railroad track is visible in the foreground.
(Jack Rathbone photo)]