Breckenridge was also discovered in 1859, with placer gold the first
attraction. The placers gave out in 1862 after about $3,000,000 in gold
had been recovered. Earliest attempts to mine the rich silver and lead
veins of the district were in 1869.
As at Leadville, the sedimentary rocks of the area were intruded by
granitic masses in Tertiary time, but here the sedimentary rocks are
mostly Pennsylvanian sandstones and shales. These rocks were badly
faulted and broken during the intrusion, and the ores were deposited as
the granitic material cooled. The lode deposits occur mostly in small
veins well hidden by surface sands and gravels. Some of the veins
yielded exceptionally beautiful crystallized wire and flake gold,
specimens of which are on display at the Colorado School of Mines
library in Golden and in the Denver Museum of Natural History.
Dredging for alluvial gold was attempted in 1898 in the Breckenridge
district, but this method of extracting gold was not successful until
1905. A number of dredges operated between 1910 and 1925. These floating
behemoths shovel up gold-bearing gravels from the bottom and one side of
the pond on which they float, sort out the gold in giant sluiceboxes,
and spew out the leftover gravels in great arc-shaped heaps that can be
seen near Breckenridge and Fairplay and in a number of other valleys in
Colorado. They depend for their operation on a plentiful supply of water
and a shallow water table, but they can sift through quantities of
gravel at relatively low cost. All told, about $7,000,000 in gold has
been dredged from this district.