|A worker in a gold mine|
Thursday, June 16, 2011
Gold Occurrences in Texas
Gold was first discovered by the Spaniards in
in 1756 where they discovered gold and silver on Texas . They made their discovery of gold in the central mineral district around the Llano Uplift. It was in the same area that the Spaniards discovered the lost San Saba Gold Mine that according to tradition was worked by Mexican miners after they gained their independence from Riley Mountain sometime in the early 1800s. The Spaniards lacked any technology to keep mines from flooding caused by the inrush of groundwater. This was the reason why the Spaniards limited their mining to those areas that were above the water table causing these mines to exist as long trenches that have long since been eroded away. The consequences of this weathering are that today these old gold mines are hard to find, and for the most part were operated as placer deposits. Spain
The peculiar thing about the Llano Uplift is because it is composed of Grenville aged rocks that are around 1.2 billion years old that are actually an extension of rocks that are often found in the
Appalachian Mountains instead of the Rockies. It is in these ancient rocks that gold is found usually in small deposits that are quite numerous; these deposits are similar to those that were found during the Klondike Gold Rush where the gold had eroded from the rocks and formed large placer deposits.
In many of the rivers and streams that drain the Llano Uplift placer gold can still be found. There have been tales of gold occurring in this area for the past 250 years many of these tales are more credible than others. It is tales of this sort to drive the prospecting business even though gold is found in small quantities throughout the area. It is the hope of virtually all prospectors that they will eventually strike a Bonanza or even find
itself. El Dorado
The Llano uplift itself is pre-Cambrian in age, but is surrounded by rocks of Paleozoic age making it very similar to the Gold Belt of the
Southeastern United States. Most of The state is an ocean of sedimentary rocks having an occasional outcrop of older crystalline rocks. It is in these rocks that you are apt to find gold. Gold can be found in rocks of both the Proterozoic and Phanerozoic ages.
The rocks found in the hills overlooking Presidio in the
are probably closely related in age to the Central Texas Mineral Region. With sedimentary rocks you often find a situation where occasionally older rocks do get exposed at the surface. This was what is happening here as well in the southern gold belt ( Rio Grande Valley Piedmont) in the Appalachian Mountains.
On the southern flank of the
overlooking Presidio is the Prasidio Mine that was active from 1880 until 1942 when the War Production Board closed all the gold mines in the Chinati Mountains to free the gold miners for other wartime production. This one mine produced 92% of the silver and 73% of the gold ever produced in United States . Texas
There is also gold associated with a sandstone of Eocene age located in the Gulf Coastal Plain. This is gold that probably eroded out of the Llano Uplift rocks.
Nowhere in the state however is gold mining ever been extensive because the amount of metal available in the state appears to be limited. The Presidio and Hazel mines in
West Texas and the Heath mine Llano have produced a total of 8,277 ounces of gold that end in 1942 when the government closed on all gold mines in the as part of the war effort during World War II. The last minute was in production in United States was the Presidio mine where production and that in 1942. Texas