Dr. Geller is the Director of the Geology Museum at the Colorado School of Mines. His Phd. dissertation was an acclaimed geological study of Front Range gold districts. His talk was originally presented at the Spring 2008 Gold Show at the Denver Museum of Nature and Science.
An understanding of gold geochemistry begins with the relationship of elements to each other. Gold comes in solution, not in a molten state. In Colorado, pyrite or "fools' gold" is not for fools because most gold is contained within pyrite or related minerals. Gold tellurides are also economically important. Tellurides are usually tiny and do not look like gold. They often oxidize to a dark dull matte. Elsewhere, gold is more commonly found in the native element or "free" state.
In its history, Colorado has produced about 45 million ounces of gold. More than half of this has come from the Victor-Cripple Creek area. Most of the remainder is from the Colorado Mineral Belt which extends from the San Juan Mountains northeastward through the Central City and Boulder districts. Significant gold producers include Telluride-Mt. Sneffels with 6.8 million ounces and Central City-Idaho Springs with 6.2 million ounces.
The first known discovery of gold in Colorado was by officers from Fort Massachusetts in 1852. Later, William G. Russell made a discovery south of present day Franktown. The first documented discovery was panned by the Russell group in Clear Creek near its confluence with Ralston Creek. Dr. Geller points out that even in today's high-tech world, panning is still an important exploration technique.
The first commercial discovery was made by George Jackson in 1858-59 near Idaho Springs. This was closely followed by John Gregory's lode discovery below Central City, which helped trigger the "Pike's Peak" gold rush. By 1876, "Colorado" had attained statehood as "The Silver State" because by then the silver discoveries at Leadville had surpassed the value of earlier gold.
But in 1890 gold's star rose once more with silver's crash and the discovery of Cripple Creek by prospector "Crazy Bob" Womack. Winfield Scott Stratton is the best known and richest of the mining promoters of this era. The Gold Coin mine was discovered in a hotel excavation in Victor. In the Cresson Mine, a single vug (cavity) yielded 40,000 ounces of gold.
Exploration interest also led to other discoveries such as Tom Walsh's Camp Bird Mine in the San Juans. In 1887, the largest gold nugget, "Tom's Baby," was found near Breckenridge. In 1972 it was "rediscovered" in a Denver bank vault. Some of it was missing.
Gold, like all commodities, is cyclical in value with interest in it rising and falling with the waves of economic time. There was a resurgence in 1934 when, in the depths of depression, the government raised the price from $20 to $34 dollars per ounce. In 1972 gold was released to free market forces and soared for the rest of the decade. Today the only significant primary gold mine in Colorado is in the old Cripple Creek-Victor District, where modern mining and heap-leach technology currently produce about 325,000 ounces per year. Other minor gold is recovered from sand and gravel operations.
Will gold exploration and mining again boom in Colorado? Who can say. But if history is a view of the future, then it may come to pass!
Visit the Geology Museum at the Colorado School of Mines in Boulder, Colorado, and see a breath-taking collection of gold and many other mineral specimens.