Mintabie opal field
The Mintabie opal field , over which the Aborigines of the Anangu hold a native title , is about 200 km² and is located in South Australia in Australia , about 25 kilometers from Marla and 980 kilometers from Adelaide . About 25 kilometers from the opal field , there is a settlement with around 200 to 250 miners and Lake Mintabie .
The Mintabie opal field lies on the borders of the Eromanga Basin , which was formed about 1.5 billion years ago and consists of granites and gneiss . On the western borders lie the sediments of the Officer Basin , which consists of sandstones , quartzites and claystones that are over 500 million years old . The sedimentary rocks formed hills like the Mount Johns Range near Marla. Mintabie's opals occur in a sandstone complex.
The geology of Mintabie differs from the other opal fields in Australia as the opals are located in rocks from the Paleozoic Era . The opals occur in rock structures beneath the layers of the early Cretaceous , which date from the Ordovician . The opals are mined near the surface to a depth of 30 meters.
Larry O'Toole found the first opal in Mintabie around 1920. This discovery made it clear that the Aborigines who had previously sold black opals similar to those from the Coober Pedy area came from Mintabie.
The opal seekers who invaded the Mintabie area after World War I had no heavy opal mining equipment, and the sandstone resisted mining because it was much stronger than that of Coober Pedy. It was not until the 1970s that Mintabie was run, mainly bulldozers that are able to dig deep.
In 1986, for the first time in 65 years, the Mintabie opal fields produced more opals than Coober Pedy's.
See also
Individual evidence
- ↑ pir.sa.gov.au : Opal , in English, accessed on February 20, 2012
- ↑ a b "Mintabie Opal Fields" on mineshaft.com.au. Retrieved February 13, 2012 .
- ^ Allan W. Eckert: The World of Opals. S. 112. New York 1997. ISBN 0-471-13397-3 Online on Googlebooks (English)
Coordinates: 27 ° 18 ′ 37.1 ″ S , 133 ° 17 ′ 47.8 ″ E