Gold mining is big business. Nevada currently produces 79% of all the gold mined in the United States. One of the most famous and most-producing gold mine in the United States is the Carlin Trend.
1. The Carlin Trend has since produced more gold than any other mining district in the United States. Gold was discovered in Carlin in the 1870s, but the deposits were considered too small to cause much excitement. Gold was found again in 1907, but like before, the amounts were too small for anybody to make a big deal about it. By 1961 however, the Newmont Mining Corporation hit gold, literally. They had found that while the gold was of unexciting low-grade quality, there were literal tons of it in the ground. By the 1970s and the high inflation of that era, the mining companies finally began to rush in. By 2008 the Carlin Trend produced over 70 million ounces, worth around $85 billion in 2010 prices. The Trend produced 1,322,001 ounces of gold in 2007.
How was the biggest producing gold mine in the United States skipped over for a hundred years? It's simple: The gold at the Carlin trend is actually mostly invisible to the naked eye. Much of the gold at the Carlin Trend actually comes in atomic size! That's tiny! So how is it this done? It is accomplished by a method called cyanide heap leach recovery. As a matter of fact, the Carlin Trend is the place where the method of open-pit mining with cyanide heap leach recovery that is today used at large low-grade gold mines worldwide was first discovered and introduced. The method works by the simple principle that gold is dissolves in a solution of akaline cyanide. Using sprinklers similar to lawn sprinklers to spray cyanide over a heap of ore, the dissolved solution drains into the center of an asphalt pad. The gold is then separated from the solution at a later step when it is precipitated using powdered zinc. It becomes a black powder that collects at the bottom of vat as it falls out of the original cyanide solution, which is removed for further processing. While the process seems complicated and expensive, in fact the heap leaching process only costs a company $320 per ounce. With gold prices at $1420 as of December 6, 2010, that is an $1100 profit per ounce, more than enough to offset heap leaching costs.
The Carlin Trend is owned and operated by Newmont Mining Corporation. It also pays a 1% royalty to Bullion Monarch Mining, another, smaller, mining company.
2. The Round Mountain Gold Mine in Nye County, Nevada is similar to the Carlin Trend in that it is primarily a large open-pit heap leach gold mine. Unlike the Carlin Trend where most of the gold found is invisible, this mine is actually famous for its spectacular gold formations. Production was healthy is 2007, mining out 587,445 ounces of gold in 2007. Ore reserves are estimated to be about 1.8 million ounces of gold. And business is booming: The Bureau of Land Management recently (July 2010) approved an expansion of the Kinross Gold mining operation, ensuring the stability of over 800 jobs in the sparsely populated Nye County.
This mine is owned 50% by Kinross, 50% by Barrick and has produced well over 10 million ounces since its opening in 1906, worth about $9.5 billion in today's prices.
3. The Cortez Gold Mine has been in continuous production since 1862, making it the oldest active gold mine in Nevada. It was originally a silver mine, but morphed into a gold mine once the silver ran out. Finally the gold production ran out in 1976. With the advent of heap leaching in the seventies and the high price of gold of that era, production at the mine was reopened in the early 1980s. There are three sites currently producing gold are the Pipeline, South Pipeline and Cortez Hills. The two Pipelines are open pit mines, Cortez Hills uses both underground and open pit mining techniques.
In 2009 Cortez’s production totaled 518,000 ounces of gold at total cash costs of $510 per ounce, up from the 534,173 ounces produced in 2007. The Company’s proven and probable mineral reserves as of December 31, 2009 are estimated at 14.1 million ounces of gold, which as of today's price (11-8-2010) of $1400 USD would value the mine roughly at $19 billion USD. It is owned and operated by Barrick Gold, is Barrick's largest gold producer in Nevada.