The firms were part of a large group of mining firms operating in protected forests that froze their operations following the enactment of new forestry legislation in 1999, which banned open-pit mining in those areas.
This ‘up-scaling’ is generally accommodated easily in open-pit mines, but in underground workings the creation of large caverns brings with it problems of rock mechanics and increased risk of instability.
Chicago-based Oil-Dri Corporation of America, the world's largest producer of cat litter, has been fighting for several years to develop two open-pit clay mines on Bureau of Land Management property ten miles north of downtown Reno.
When scientists hunt for dinosaur tracks they look for areas where ancient layers of sedimentary rock are exposed, such as cliffs, sea coasts, quarries, open-pit mines, desert arroyos, and along the banks of rivers and streams.
The Trend's first open-pit mine came in 1965, but it was the steep rise of gold prices in the 1980s and the introduction of cyanide heap-leaching that made mining such low-grade ore profitable.
Additional drilling at the site of the proposed open-pit mine allowed the company to increase its estimates to roughly 26 tons of gold, it said in a statement.
The Marquette iron range, which has hosted more than 240 mines since its beginning in 1845, now features only two open-pit taconite mines.
In an effort to convert copper rock into quick cash, he tried to open-pit mine the lode to extract ore as fast as possible.
The firms were part of a large group of mining companies forced to suspend operations following the enactment of a new forestry law in 1999 that banned open-pit mining in protected areas.
The Galactic Mining Company, Vancouver, British Columbia, had secured a permit for a massive expansion of its open-pit mine which would gobble up the quarry.