Borax mine in California - USA - Rio Tinto borax mine - California: The Rio...

Borax mine in California - USA - Rio Tinto borax mine - California: The Rio Tinto Borates mine is an open-air borate mine located in Boron, California, USA. It is the largest open-air mine in California. Image taken from the International Space Station (ISS) on 30 October 2013. The mine, currently owned by the Rio Tinto Group, is the largest open-pit mine in California (covering approximately 54 km2) and is among the largest borate mines in the world. Borates, chemical compounds that include the element boron, are important both as providers of an essential plant micronutrient; for metallurgical applications; and as components of specialized types of glass, antirosive coatings, fire retardants, and detergents (among other uses). Borate minerals such as borax, kernite, and ulexite are found in deposits at the Rio Tinto borax mine. The Rio Tinto mine is one of the 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 was acquired on October 30, 2013 from the International Space Station (ISS)