Integrated Operation Key To Newmont Nevada Operations
Domestic mine by Harold Hough
Nevada may be one of the largest gold producing regions in the world, but that doesn’t make gold mining any easier. There are hundreds of different types of gold ore in the state, each with a different “ideal” way to process it for the maximum recovery rate. The goal for any gold mine in the state is to obtain the best recovery rate at the lowest cash price per ounce.
This is where Newmont Mining has excelled. Even with record gold prices, a successful Nevada mining operation has to seamlessly merge the strengths of many different gold mines. Together, Newmont boasts the widest variety of processing methods of any gold mining complex in the world. This is critical as the ore grade of its Nevada ore has declined.
Newmont’s challenge is that their 18 different open pits and underground mines produce dozens of different type of gold ore. In fact, the Twin Creeks operation had eight different ores from 40 different zones. Flotation might be better for one type of ore at the mine, while pressure oxidation would be better for another type of ore. There is no single, perfect answer.
The answer was to integrate all Newmont gold operations in Nevada and send the different ores to different processes at different operations in order to achieve the highest recovery rates.
“That is the real advantage we have in Nevada,” said a Newmont spokesman. “Newmont currently operates six open pit mines, five underground mines, and nine process facilities- the widest variety of processes of any operation in the world. We constantly have trucks moving up and down Interstate 80.”
The key to optimizing gold recovery by using several processes is an Optimizer program that assigns an ore from a mine to a specific processing operation that will maximize recovery rates.
While some of the Twin Creeks ore goes elsewhere, the rest of it and other material from Newmont properties are processed in a massive autoclave that provides a 90% recovery rate. These autoclaves are approximately 76 feet long, 19 feet wide and weigh 950,000 lbs. each. By heating and pressurizing the ore, it not only negates the carbon present, it meets the strictest environmental standards. According to Newmont, pressure oxidation has higher capital costs than other methods, but the costs are predictable and there is the benefit of converting arsenic, which occurs during roasting to a stable product.
By having several processing alternatives, Newmont has managed to effectively increase its ore reserves in Nevada. And, by using several processes, Newmont can increase the recovery rate at its current operations.
The flexibility offered by these different processes was critical in deciding to open the Phoenix operation, which was near another operation and contained large low grade gold and copper deposits. It was also critical for deciding to purchase Fronteer Gold and its Long Canyon project in Nevada.
Richard O'Brien, Newmont's President and CEO told investors earlier this year, “The Long Canyon project, with its Carlin trend-like metallurgical and geological characteristics, complements our existing project pipeline in Nevada. This combination of assets will allow Newmont to leverage our expertise and extensive infrastructure in the region…We believe that Long Canyon holds the potential to grow beyond 3 to 4 times Fronteer Gold's current stated resource estimate, with an attractive average gold grade of approximately 2.3 grams per tonne.”
The Long Canyon project has undergone extensive exploration since it was acquired from Fronteer Gold in April. Newmont has completed 190 core drill holes and is planning on 90 km worth of core drill holes in the 2011/2012 season. Long Canyon is expected to come online in 2017. They expect 275,000 to 350,000 ounces of gold to be produced each year.