CORTEZ MINE ONE OF THE LARGEST AND LOWEST PRICED GOLD PRODUCERS
Barrick has a good right to feel good. In a time of sky high gold prices, it owns one of the largest and lowest priced gold producers in the world – the Cortez Mine in Nevada. Production in 2012 is anticipated to be 1.20-1.25 million ounces at total cash costs of $300-$350 per ounce. That’s up from the 2011 cash cost of $245 an ounce but reflects higher proportion of underground ounces and lower open pit grades.
The Cortez Mine is 100 kilometers southwest of Elko and is in the center of one of the most promising goldfields in the state of Nevada. The area also had its part in the heap leaching revolution. The United States Bureau of Mines built a heap leaching pilot plant nearby in 1969. This pilot project proved the heap leaching technology that would revolutionize Nevada gold mining.
The Cortez operation is not new. Production at the Cortez Mine began with the Old Cortez Pits in 1969. These deposits lie along Nevada’s Cortez/Battle Mountain Trend and contain microscopic gold particles. As the reserves ran low, mine engineers and geologists began to look for more economic deposits.
The current operation is a result of the discovery of the Pipeline orebody by Placer Dome and Kennecott. The Pipeline deposit was responsible for an annual output between 1998 and 2005 of over one million ounces of gold per year. The Cortez Hills deposit was discovered in 2002 and was a result of Placer Dome’s exploration philosophy of carrying out extensive exploration in the area of current operations. In 2006, Barrick Gold acquired 60% in Cortez when it purchased Placer Dome. It acquired the remaining 40% from Rio Tinto in March 2008.
The Cortez property covers approximately 2,800 square kilometers. The underground Cortez Hills deposit is 4 kilometers southeast of the original Cortez milling complex. The Pipeline and South Pipeline deposits are mined by conventional open-pit methods. Cortez employs three different metallurgical processes to recover gold. Lower-grade oxide ore is heap leached, while higher-grade non-refractory ore is treated in a conventional mill using cyanidation and a carbon-in-leach.
Addressing Environmental Issues
The Cortez Mine has had its share of environmental issues. Fortunately, Barrick has a pro-environment record that impressed regulators. It reforested hillsides that were clearcut in the 1800s and removed an old ore roaster. Working with the BLM and the Nevada Department of Wildlife Cortez has already revegetated some of their old waste dumps by placing alluvium over the waste rock and revegetating the area.
Another major issue is groundwater that comes from the mines. Pipeline pit water is pumped to ranch land to be reintroduced into the groundwater supply. The mine keeps two streams of water, a contact water stream in which the water has come into contact with the mining operation, and a non-contact water stream where the water has not come into contact with the mining operation. The 'contact water stream is recycled and reused in the mining operation where the noncontact water is pumped off site.
Barrick has also been a strong advocate of environmental restoration in Nevada. Nevada is home to a large game fish called the Lahontan Trout. Unfortunately, commercial fishing 100 years ago, dams, and water diversion had reduced the Lahontan’s range to three percent of its former habitat.
Barrick helped to reverse that trend. Not only did the company donate thousands of dollars to preserve the trout, it also provided engineering skills for making Mary’s River an interconnected habitat for the fish. The mine replaced culverts that restricted trout migration, engineered a bridge to replace a culvert, and provided money for its construction. Meantime, volunteer groups of miners restored the river’s banks. While some of the efforts like placing rocks to create pools created rapid results, much of the miners’ work was aimed at improving the fish’s chances for the long term. These volunteers planted willows, which shade and cool the water. They also installed fences to keep the cattle out and stabilize the bank. The result is that Lahontan Trout populations are growing in the Mary’s River for the first time in decades.
Barrick has also teamed up with the Nature Conservancy to restore fish and bird habitat along a five mile stretch of the Truckee River in Nevada. Through the support of Barrick the Conservancy has been able to buy 20 river miles and 20,000 acres of flood plains, wetlands, and forest.