21st century gold mining: Bet on things being big

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The Cripple Creek & Victor Gold Mining company’s operations cover 5,847 acres, and are visible from space. Last year, CC&V recovered 329,625 troy ounces of gold.

One hundred and fifteen years ago, the discovery of gold in Cripple Creek fueled the growth of Colorado Springs from a sleepy resort to an over-the-top boomtown.
Spencer Penrose and Winfield Scott Stratton accumulated great fortunes within a few years, and scores of tough-minded, adventurous young men became overnight millionaires.
They built houses on Cascade and Wood avenues, started clubs, got into fistfights over women, developed The Broadmoor and claimed the city for their own.
Today, their successors are still mining gold near Cripple Creek, but in ways that the old-timers could never have imagined.
Fifteen years ago, when the Cripple Creek & Victor Gold Mining Co. acquired control of the historic Cripple Creek Mining district, it faced an obvious dilemma.
After decades of mining, virtually all the high-grade ore had been mined. There was still plenty of gold, but could it be recovered?
While the high-grade ore that fueled Cripple Creek’s boom years sometimes contained several ounces of gold per ton, today’s ore scarcely deserves the name. The average value is .03 ounces per ton.
The gold is present in microscopic flakes, mostly invisible to the naked eye, and evenly disseminated through the ore bodies. It’s easy enough to extract, using processes that would be familiar to the mining chemists who worked in Cripple Creek a hundred years ago. You need only crush it and use a cyanide solution to leach the gold.
There’s one obvious problem: you need to process a lot of rock to make it economically feasible.

CC&V Community Affairs Manager Jane Mannon stands beside a 300-ton haul truck at the Cresson Mine.

After years of exploratory drilling and small-scale mining by predecessor companies, CC&V began engineering for the modern Cresson Mine (named after its historic predecessor) in 1993. Construction began in 1994, and required a three-year investment of about $100 million.
The end result: a mining operation that’s literally mind-boggling.
Let’s start with the most basic information: physical area.
The mine’s “permit boundaries” encompass 5,847 acres, of which the “disturbance area,” where mining takes place, is 4,184 acres. An aerial view of the property shows a vast, denuded landscape of rock and gravel. Nothing remains of the historic mining structures, mines and mine tailings that once defined the landscape.
Miners a century ago took an ancient volcanic caldera, a place of grassy, sparsely forested rolling hills, and transformed it into a picturesque, mined-out wasteland. Today’s miners are transforming it once again.
What visitors see today doesn’t resemble past mining operations. Visualize an immense series of quarries, hundreds of feet deep, where enormous machines mine and load ore 24 hours a day, 365 days a year. Seen from above, the trucks and loaders look like Tinkertoys – but they aren’t.
The 300-ton capacity haul trucks, which transport ore to the crusher, are nearly three stories tall. The crusher, which reduces the rock to gravel with a uniform diameter of three-quarters of an inch, and does so at the rate of 75,000 tons per day, dwarfs the trucks.
Once crushed, the ore is transported to the Valley Leach Facility (VLF), where a dilute solution of sodium cyanide percolates through the gravel mounds, removing the gold. The entire facility is underlain by an impermeable membrane, effectively isolating the leach pad from the surrounding environment.
And how large is the leach facility? It covers 850 acres, 1.3 square miles. The “pregnant” leachate is captured at the lowest point of the VLF and pumped out to the recovery facility at the rate of 13,500 gallons per minute. A simple, multi-step chemical process removes gold and silver from the solution, which is recycled to the VLF.
Last year, CC&V mined 20 million tons of ore, from which 329,625 troy ounces of gold were produced, as well as 140,000 ounces of silver.
Every day the refinery pours out one (or more) “button,” a 98 percent gold-silver mixture, it looks like a giant Hershey’s Kiss. Weighing more than 70 pounds, it’s worth several hundred thousand dollars.
The mine has more than 300 employees, most of them Teller County residents. And while historically women in a mine were believed to bring bad luck, that’s not the case anymore, said CC&V Community Affairs Manager Jane Mannon.
“We don’t discriminate — in fact, 20 percent of the haul truck drivers are women,” she said. “Actually, the maintenance guys like the women drivers better because they don’t ‘hot dog’ the trucks.”
CC&V also understands the role it plays as a member of the community, she said.
“Our offices are in Victor — we restored an old building downtown,” Mannon said. “I think our taxes account for about 70 percent of the town’s budget. We try to be good citizens and good neighbors.”
But cyanide heap leaching operations elsewhere have been anything but good neighbors.
In 1991, the Summitville Mine in southern Colorado released water contaminated with toxic metals and cyanide into the Alamosa River, killing all aquatic life. By 1992, the problems had worsened and the Summitville Consolidated Mining Co. simply walked away, forfeiting a $3 million cleanup bond. The company subsequently declared bankruptcy.
To date, the cleanup has cost the federal government more than $150 million.
In Montana, similar problems led to the passage of a residents’ initiative in 1998, which phased out open-pit cyanide leach mining statewide.
In South Carolina, Honduras and Australia, such mines have repeatedly released toxic chemicals into the environment.
Commenting on a proposed mine near the Kvichak River in Alaska, known to anglers as the most abundant salmon stream on the planet, Montana mining engineer David Chambers said: “I know the folks [building the mine] are going to do a good job. What I can say is there will be problems. I’ve never seen a mine that doesn’t have them.”
But CC&V insists that its operation is different.
Mannon points out that geography makes it relatively easy to isolate mining operations from the surrounding environment. The kind of sloppy engineering that produced Summitville has no place at CC&V.
“The facility is designed to contain a 100-year storm event — and we had to comply with very stringent permitting,” she said.
CC&V’s parent company is Anglo Gold Ashanti, the world’s second largest gold producer, but unless new ore bodies are discovered, the mine will cease operations in 2016. Reclamation will continue until 2020.
So, what will the site look like then?
Much as it did before 1891 — at least, that’s what the company expects. The open pits will be filled with spent ore, toxic chemicals will be removed, topsoil replaced and the site revegetated.
CC&V has preserved many of the historic mining structures, which will be relocated to site.
The end result: rolling, partially forested hills where, decades hence, no trace will remain of a mine so vast that, like the Great Wall of China, it’s visible from outer space.
John.Hazlehurst@csbj.com