Long valued for its ornamental,monetary, and even scientific applications, gold has attracted speculators and miners throughout human history. The greatest quantities of gold mined today occur in ore—rock containing trace amounts of valuable materials. Obtaining even small quantities of gold usually requires extracting huge quantities of ore from open-pit or underground mines.
One of the largest open-pit mines is the “Super Pit” Mine near the city of Kalgoorlie in Western Australia. On February 15, 2010, the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured this true-color image of Super Pit and part of the neighboring town of Kalgoorlie. The pit that gives the mine its name appears in the center of the image, and some of the steep pit’s walls appear in shadow while others are illuminated by the Sun.
Related mining operations form a rough semicircle on the eastern side of the pit; a cluster of buildings east-northeast of the pit is Fimiston Mill, where ore is processed. Waste dumps and gray-white tailings ponds sprawl over the arid landscape. Tailings are the rocks and chemicals left over after the gold is extracted. Because the chemicals used to separate gold from rock are often caustic, tailings usually pose hazards to human and/or environmental health and must be treated carefully.
The metropolitan area of Kalgoorlie, marked by street grids and manicured green spaces, extends almost to the mine’s central pit. An airport, marked by a long runway, appears along the city’s southern margin. Founded during a late-nineteenth-century gold rush, Kalgoorlie, like the neighboring mine, occurs near an area nicknamed the “Golden Mile,” which is considered especially rich in gold deposits.
As the beige and reddish colors in the image indicate, vegetation in the area is sparse. Like much of Western Australia, the area around Kalgoorlie and Super Pit is semi-arid, with hot summers and cool winters. January (summer) temperatures in Kalgoorlie frequently reach 40 degrees Celsius (over 100 degrees Fahrenheit).
NASA Earth Observatory image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Michon Scott.
Acquired February 15, 2010, this true-color image shows the Super Pit Mine in Western Australia and part of the neighboring metropolitan area of Kalgoorlie.
The rugged, mineral-rich Andes support some of the world’s biggest mines (gold, silver, copper, and more). This image looks down the bullseye of Peru’s Toquepala copper mine, a steep sided and stepped open-pit mine.
Mined for gold, silver, and copper, the region of Butte, Montana, had already earned the nickname of “The Richest Hill on Earth” by the end of the 19th century. Demand for electricity increased demand for copper so much that by World War I, the city of Butte was a boomtown. Well before World War I, however, copper mining had spurred the creation of an intricate complex of underground drains and pumps to lower the groundwater level and continue the extraction of copper. Water extracted from the mines was so rich in dissolved copper sulfate that it was also “mined” (by chemical precipitation) for the copper it contained. In 1955, copper mining in the area expanded with the opening of the Berkeley Pit. The mine took advantage of the existing subterranean drainage and pump network to lower groundwater until 1982, when a new owner suspended operations. After the pumps were turned off, water from the surrounding rock basin began seeping into the pit. By the time an astronaut on the International Space Station took this picture on August 2, 2006, water in the pit was more than 275 meters (900 feet) deep.