the Terlingua Mining District
, or Quicksilver
, is derived from a red-colored ore known as cinnabar.
Cinnabar (sample at left)
was used by Native-Americans as a durable pigment, and there are many places in Big Bend where traces of ancient drawings are found.
In the early 1890's, cinnabar was discovered in the Terlingua area, and by 1900, four enterprises had recovered and refined over 75,000 pounds of the rare liquid metal. The Chisos Mining Company was incorporated in 1903 and by 1918 it was the largest single producer of mercury in the US.
Mercury is extracted by heating the crushed ore to a temperature of approximately 360 degrees, at which point the metal is released as a dense vapor. The vapor is condensed, and the pure liquid form is then recovered and stored in metal flasks. Finding enough fuel for the furnaces was a constant problem, as all available timber for many miles was quickly exhausted. Low-grade coal deposits were discovered nearby from which miners produced a flammable gas containing methane to fuel the process.
Transportation was very difficult. All the processed metal was carried 100 miles to the nearest railroad in heavy freight wagons drawn by teams of 8-12 mules. All machinery and heavy equipment for the mines, some pieces weighing as much as 18,000 pounds, was imported
in the same manner, the trip sometime taking weeks through the rugged terrain. Although the first commercial use of an automobile in Brewster County took place in 1917, wagons and mules remained the primary means of heavy transport in the district until the early 1930's.
Although used in many different products and processes, a primary market for mercury was in the manufacture of explosives. The fortunes of the Terlingua Quicksilver District rose and fell in concert with periods of large-scale warfare, notably between 1912-1921 and 1936-1944. Much of the mercury for European munitions industry was produced in Spain, and when conflict interrupted normal deliveries, the Terlingua deposits became extremely valuable both economically and strategically.
The Chisos Mining Company went bankrupt in 1942, and operations ceased permanently in 1944. Most of the structures and equipment was dismantled and sold as salvage in the years that followed. The site was largely unused until 1967, when the world's first Chill Cook Off was held in Terlingua Ghost Town. The International Chill Championship is still held nearby on the first Saturday of each November.
How did the Mercury get here?
100,000,000 years ago:
Limestones (1) and clays (2) are deposited on the sinking floor of a warm shallow sea.
The limestone bedrock (1) begins to warp upward and fracture, as the North American Continental Plate and the Farallon Pacific Basin Plate collide. The same tectonic collision uplifts the Rocky Mountains.
45,000,000 years ago:
Enormous heat generated by the friction of the Farallon Plate sliding below the North American Plate melts the subducted rock. Magma (3) begins to rise along fault planes and fractures.
35,000,000 years ago:
Renewed uplift and faulting occur during active and often violent volcanic episodes. Superheated, highly acidic mineral water, mixed with corrosive gases (4) under tremendous pressure, dissolve passages through the limestone layers and force their way upwards until stopped by caps of impermeable clay (2). As these volatile mixtures cool, many rare minerals are deposited including mercury, gold, silver, copper, molybdenum, and lead.
20,000,000 years ago:
North America extends westward as compressional forces are released, creating the familiar Basin and Range series of tilted, fault block mountains (6).