Gold Mine In Nevada

A Gold Mine in Turquoise Ridge

At Turquoise Ridge, NV, Barrick Mines drills for gold in open-pit and underground mines. The company transports the ore to a mill, where the gold is extracted, and takes the waste soil, or tailings, to a tailings pond

Barrick, which operates and is 75% owner of the mine, first places a plastic liner on the pond, which can be as large as 100 to 150 acres. The tailings are dumped 10-15 feet deep on top, says Jay Selby, president and owner of Selby’s Soil Erosion Control Co. Inc. in Newcastle, CA.

“It looks like moon dirt,” he says. There are chemicals from the mining and milling processes that Barrick doesn’t want to get into the water table, but the riskier issue is dust.

In the winter, snow covers the pond. In the spring, the snow melts and the pond fills up with water, creating a slurry. By late spring, though, the water recedes back down and the soil is exposed to the hot, dry desert winds.

“That’s when dust becomes a problem,” says Selby. “The high desert has prevailing winds almost year round, and the high winds pick up the soil.”

Selby’s, which performs dust and erosion control services, has been hydroseeding these tailings ponds for five years. The company uses Soiltac from Soilworks in Chandler, AZ, distributed by Horizon, which is also in Chandler.

“We’ve tried various other products,” Selby says. “Soiltac seems to be the most consistent, with the most durability.”

Soilworks created and manufactures Soiltac, which can be used for both dust control and soil stabilization. It’s a liquid polymer mixture that is PM10 and PM2.5 dust compliant, nonhazardous, and biodegradable.

“It has a gluey look and feel,” says Selby. The Soiltac molecules bond with the dust, and as the water dissipates, they form a flexible, durable, and water-resistant mass. Once it is cured, Soiltac becomes transparent.

According to Soilworks, Soiltac can remain effective from weeks to several years, depending on the application rate. At the mine, Selby’s always use the same application rate, which lasts from 12 to 18 months.

The mine, on the eastern edge of the Osgood Mountains in northern Nevada, is in the middle of nowhere, Selby says, and the pond his company treats is inaccessible with any equipment.

Crews drive their 4,000-gallon hydroseeding machine some 70 miles off the last paved road and park at the mine. They put the Soiltac in the machine and use the agitation system to mix it with water. “We also mix in a little wood fiber, mainly to just give our guys a visual,” he says. “When it dries, it dries clear, and it’s easier to monitor if the product is still intact.”

Workers then haul out several thousands of feet of hose and lug it around the perimeter of the 150-acre pond. The only access to the tailings pond is around the perimeter, so “we chase the pond as it recedes. We do the perimeter in early June, then closer to the middle in August or September.”

Even in the summer, crews have to work around the weather. Sometimes the winds are too high, and occasionally the area gets freak rainstorms, Selby says.

Selby’s has a number of hydroseeding machines, but its crews use one from Apex when they work on the mines because all the moving parts are fully enclosed, a Mine Safety and Health Administration (MSHA) safety regulation.

“To be able to work for these mining guys, we do a lot of work behind the scenes,” Selby says. “All of our crews and equipment are MSHA certified, and we have a great safety record.”

After 10 years or so, Barrick restores the land to a natural landscape, leaving rocks, nooks, and other habitats for the desert fauna and flora.

“Barrick Mines is the leader in being proactive in treating these areas,” Selby says. “They have a lot of integrity and don’t mind spending money to get the job done properly.”