RENEE MONTAGNE, host:
And high gold prices are creating a new gold rush in the American West. In remote mountain and desert areas, mining companies have been reopening old gold mines and are using complex methods to extract the precious metal.
From member station KPBS in San Diego, Ruxandra Guidi has our report.
RUXANDRA GUIDI: The Mesquite gold mine is an enormous collection of pits carved out of ancient rock in California's Imperial Sand Dunes. It's near a military bombing range, just 10 miles north of the Mexico border, and not far from Yuma, Arizona.
Mr. LUIS PLANCARTE (Mesquite Mines): This map back here shows all the places where we drilled and got samples.
GUIDI: Mesquite Mine's Luis Plancarte is facing a chart with large, yellow blocks of color, showing the areas that contain the most gold.
Mr. PLANCARTE: So you can see out here, it was less interesting, you know, we drilled and didn't find anything. Here, we drill, and it's like hmm. Mm-hmm.
GUIDI: Mesquite mine managers are pleased, because the price of gold in the international market is steadily rising, more than five-fold in the last decade, alone. It's currently selling for about $1,500 an ounce.
Mr. PLANCARTE: So let's go ahead and go. And you can leave that here. Yeah, that's fine.
(Soundbite of beeping)
GUIDI: Plancarte climbs onto his SUV and drives to Big Chief, a 19th century pit within the Mesquite Mine. The crew is preparing to use dynamite to blow up a corner of the site.
Mr. PLANCARTE: When we blast, what we do is we drill a series of about 33-feet deep pits. And the purpose of the blast is primarily to soften the dirt, so that as the shovel digs, it can dig easier.
Unidentified Man: Fire in the hole in five, four, three, two, one. Fire in the hole.
(Soundbite of blast)
GUIDI: Minutes after the blast, giant trucks begin moving the heaps of loosened rock and soil out of Big Chief. This is not 19th century gold mining, no pickaxes or panning here. This dirt has a low concentration of gold, which is sprayed with a cyanide solution, so the gold particles can be separated from the carbon. The process is known as heap leaching.
Jerry Hepworth is Mesquite's environmental manager. He says this 19th century mine reopened in 1986. His company purchased it three years ago, and has stepped up the work in order to increase profits.
Mr. JERRY HEPWORTH (Environmental Manager, Western Mesquite Mines, Inc.): Over the 25 years or so that they were mining here before us, they mined about three million ounces of gold from here. And we're hoping to get almost the same amount out in our mine lifetime, too.
GUIDI: Hepworth says the Mesquite Mine's lifetime is 12 more years, which could yield as much as $6 billion in gold. But some fear that after the gold is gone, this mine will leave a toxic legacy.
Mr. NICK ERVIN (Conservationist): Ultimately, it's a big scar on the land. While you're mining, it's a source of air pollution.
GUIDI: Nick Ervin is a long-time desert conservationist in Southern California.
Mr. ERVIN: And with cyanide heap leach mining, you have the leftover cyanide solution collected in, usually, now-covered ponds. But whether of not those will not leak is still an open question.
GUIDI: Cyanide ponds can leak into the soil, polluting groundwater and poisoning birds and other wildlife. The Canadian company that owns Mesquite, New Gold, says it's using the latest technology, a water-tight plastic lining, to prevent this from happening. Once it's done with the Mesquite Mine, New Gold says it plans to use this desolate site to develop other precious resources found in this desert, solar and wind energy.
For NPR News, I'm Ruxandra Guidi, in San Diego.