This photograph from an astronaut on the International Space Station features the former U.S. Borax mine, located to the northwest of Boron, California. Now owned by the Rio Tinto Group, it is the largest open-pit mine in California and is among the largest borate mines in the world.
Borates are chemical compounds that include the element boron (B) and are important as providers of an essential plant micronutrient, for metallurgical applications, and as components of specialized types of glass, anticorrosive coatings, fire retardants, and detergents.
Borate minerals such as borax,kernite, and ulexite are found in the deposits at the Rio Tinto mine. The geologic setting is a structural, nonmarine basin—a permanent shallow lake—fed by thermal springs rich in sodium and boron that existed approximately 16 million years ago. The first mining claim in the area was filed in 1913 following the discovery of boron-bearing nodules during well drilling. Much of the mine workings were underground until 1957, when U.S. Borax changed to open-pit mining.
The mining complex—tailings piles, open pit, processing facilities, settling ponds—spreads across approximately 54 square kilometers (21 square miles). Concentric benches along the pit wall are accentuated by shadows and mark successive levels of material extraction. Mine tailings are visible as stacked terraces along the northern boundary of the mine. Ore processing facilities occupy a relatively small percentage of the area, and are located directly to the west of the open pit.
The Rio Tinto mine is one of Earth’s richest borate deposits. Together with mines in Argentina, they produce almost 40 percent of the world’s supply of industrial borate minerals.
Astronaut photograph ISS037-E-22990 was acquired on October 30, 2013, with a Nikon D3X digital camera using a 1000 millimeter lens, and is provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Center. The image was taken by the Expedition 37 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by William L. Stefanov, Jacobs at NASA-JSC.
otswana ranks first among the worldâ€™s gem-quality diamond producers, and diamond mining makes up 70 percent of the nationâ€™s export revenue. The Jwaneng Diamond Mine, in south-central Botswana, sits atop the convergence of three kimberlite pipesâ€”diamond-rich geologic formations. Because the pipes meet just below the surface and cover some 520,000 square meters (128.5 acres) at ground level, the diamonds are mined from an open pit rather than a mine tunneled below the surface.
Although this photograph may appear to be a small pit mine as seen from the air, it is actually a pit mine that is about a mile wide and just over a thousand feet deep as photographed by astronauts orbiting the Earth on board the International Space Station. The New Cornelia Mine is located just south of Ajo, Arizona. Small-scale mining of copper in this area began with the Spaniards and Mexicans as early as 1750. This large-scale, systematic operation began in 1912 and expanded rapidly for the next 50 years. Since the mid 1980s, activity has been limited because of low prices for copper on the world market. Note the tailings deposits to the east (right) and the larger containment ponds for extraction processes to the northeast.
One of the largest open-pit copper mines in the world, the Cananea mine produced over 164,000 tonnes of copper in 2006. The active, 2-kilometer-diameter Colorada Pit is recognizable by the concentric steps, or benches, cut around its perimeter.