Park Sees Bright Prospects for Ending Old Mine Shaft Perils

Chris Holbeck balances unsteadily at the edge of the abandoned mine shaft, a gaping, ominous hole known only as Mine No. 63, and gently tosses in a rock.

“Listen to what happens,” says the park biologist, framed by a fiercely blue desert sky. “You don’t hear it hit bottom. It just keeps falling and falling into the inky blackness.”

Like some modern-day prospector outfitted with computer printouts and satellite technology, Holbeck is shedding light on a dangerous legacy of California’s mining past: the countless shafts gouged into the earth by often-luckless stake claimers that a century later have turned into a considerable public health hazard.

Holbeck, 38, heads an ambitious five-year program to catalog and make safe about 300 abandoned mine sites scattered across the park’s 794,000 acres--including 141 shafts deep enough to cause serious injury or death if someone fell into them.

Officials say Joshua Tree is the first national park to systematically inventory its neglected mines and take steps to refill them or turn them into sites explaining the state’s mining history.

Holbeck is also making widespread use of a unique mine-capping technique, filling the mouths of mines with polyurethane foam. The process, in which the expanding foam is squirted into the mouth of the shaft to form a 15-foot-thick plug that permanently closes the hole, is an environmentally safe way to solve the problem, officials say.

“This is the first time polyurethane is being used on a parkwide basis with the idea of making safe all abandoned mines out there,” said Joe Zarki, Joshua Tree’s chief naturalist. “We’re already getting interest among other parks across California and the West.”

State officials estimate that there are as many as 120,000 abandoned mine shafts across California. Each year, half a dozen people die in falls into abandoned shafts across the United States and scores are injured or require rescue, they say.

Many of the injured are people who wander from marked trails, amateur spelunkers, Indiana Jones wannabes and hobbyist prospectors seeking to get rich.

“Most people don’t realize that there are hazards to these holes other than the obvious peril of falling into them,” said Gail Newton, manager of the abandoned mine lands unit of the state Department of Conservation.

“There are poisonous snakes lurking near the openings, trapped gases such as carbon monoxide, and viruses from the urine of rodents who inhabit these shafts. Once kicked up in the dust, they can get into the human system. And they can kill people.”

For Holbeck, mapping and shoring up the mines has involved treks from dusty volumes of San Bernardino County mining records to some of the park’s loneliest reaches, following century-old roads hewn through the rocks, past the rusted hulks of 1920s-era trucks and mining equipment.

The Park Service decided to close the mines in the late 1970s, when a father sued the agency after his son fell into a mine shaft and was killed. But it was only recently that the technology was found to adequately cope with the problem, Holbeck said.

Past efforts involved back-filling old mine shafts, but there was never enough displaced dirt remaining to fill the hole, he said. Makeshift safety solutions such as wire mesh or grates were clumsy and sometimes attracted the curious, who pulled them off to see what was underneath.

As part of a project financed primarily by park entry fees, Holbeck purchased a portable polyurethane spraying machine that he can transport to even remote areas for capping jobs without using heavy equipment that would damage the fragile park environment.

Sprayed as a liquid, the polyurethane foam expands to 20 times its original volume and hardens to a strength that can withstand 10,000 pounds of pressure per square foot. The cap is then covered with earth, erasing all traces of the mine’s aperture.

But Holbeck’s job involves more than just technical problems. It has also been a walk through a minefield of special interests, from naturalists to historians. The concerns include closing off mines considered both animal habitat and a critical part of the state’s past.

Before sealing off the first mines earlier this year, Holbeck consulted with several groups, including bat naturalists who say the nation’s abandoned mines have become prime habitat for several bat species that have been driven from over-explored caves and natural crevices.

In an agreement with environmentalists, Holbeck agreed to use angled steel barriers that prevent human entry but allow continued bat use of mine shafts.

“Normally, both geologists and naturalists would like to leave these mine shafts open as windows to the underground--even if they are man-made,” said Sheryl Ducummon, director of the bats-in-mines program for Bat Conservation International of Austin, Texas. “But the Park Service is giving a good effort to preserve these habitats.”

Dan Abeyta, chief of the state historical preservation office, said all efforts are being made not to cap mines that are significant for reasons that include their owner, the era in which they were dug or the mining techniques that were employed. Other methods will be used to keep out the public, he said.

Before any mine is capped, officials will examine its historical worth. And the polyurethane, which seals the mine like a cork in a bottle, leaves open the option of future exploration, Abeyta said.

‘No matter how historically significant, we don’t want these mines left open at the expense of someone’s life,” he said. “Many are public nuisances that need to be dealt with.”

The shafts, with names like Anaconda, Lucky Boy, Gold Standard and Lost Horse, date back to the Gold Rush days of the 1850s, when mom-and-pop prospectors were lured south to the Mojave Desert by stories of fantastic veins of gold and silver. Most mines were abandoned soon after World War II.

Today, the wooden scaffolding that spanned mine entrances is long gone. The mines remain untended open shafts that can be 10 feet across and reach 120 feet or more into the rocky red earth.

Standing above Mine No. 63, whose depth remains unknown, Holbeck described the allure that such pits hold for some desert wanderers.

“This mine wasn’t safe when it was made at the turn of the century and it’s not any safer now,” he said, kicking up pebbles that cascaded into the black hole. “But people want to go stand over the mouth and stare down into the gaping maw.

“And some people insist on going inside. There could be an ore cart left down there. Or a huge stack of gold, the fruits of some old miner who had a heart attack on the spot and left the mother lode behind. They’re all incredible dreamers.”

Some find the shafts by accident, like the two Marines from Twentynine Palms who drove their Jeep into an abandoned mine known as Little Italy, located just outside Joshua Tree National Park. The passenger was killed on impact and the trapped driver ignited one of the Jeep’s tires to signal for help--which came just as he died of smoke inhalation.

Another Marine rappelled into the Lost Horse Mine and came to the end of his rope far above its floor. He spent 24 hours clinging to a ledge before help came.

And then there was the rescue of the endangered desert tortoise that was found after biologists picked up a strange radio signal from its electronic collar emanating from 100 feet below ground.

“He fell into a mine,” Holbeck said. “They had to go down and bring him back up.”