Experts: mine cases unrelated
May 29, 2009
The opening in the ground off the Rail Trail that appeared in mid-2008 could have easily swallowed a person.
When the snow caved in underneath a skier at Deer Valley Resort in April, the man fell into the depression, catching himself with his lower arms before he slid further down.
A dog in mid-May, meanwhile, could not stop itself before falling down a hole in the ground at Park City Mountain Resort.
In less than one year, there have been three high-profile episodes involving dangerous openings in the ground that have been tied to Park City’s historic mining industry. But experts say the cases do not appear to be connected. They say it is happenstance that the three occurred within months of each other, not a result of something occurring underneath the surface and stretching from the Rail Trail through the terrain at Deer Valley and PCMR.
"These types of situations can occur one after another in the same vicinity," says Luci Malin, the manager and a 26-year veteran of the Utah Abandoned Mine Reclamation Program, which holds some oversight in cases involving old mines.
According to Malin, a process known as subsidence is happening around Park City. When that occurs, the natural material that is on top of a mine or a cave eventually falls, creating an opening, she says.
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At some mining-era locations in the Park City area, Malin says, enough time has passed that there is the potential of subsidence occurring. She bases the assertion on the 19th century start of Park City’s mining industry and a formula that takes into account the type of dirt and rock at the top of a mine and the thickness of the layer.
"They happen all the time, all over the state, these instances," she says.
Miners founded Park City in the 19th century, and it was a top-tier silver producer for decades after that. In the mid-20th century, as the price of silver slumped, the mining industry faded.
Skiing later took hold, turning Park City into an internationally recognized resort. But mining-era relics dot Old Town and the surrounding mountains. Miles of mining-era tunnels, meanwhile, remain underneath the ground.
The string of three cases that started with the opening off the Rail Trail were dramatic recent episodes, but a City Hall official says there have been other instances in the years since the mining industry faded.
Ron Ivie, City Hall’s chief building official, recalls "significantly bigger events" involving historic mine sites. He talks about a giant opening that occurred close to the site of the now-shuttered Park City Silver Mine Adventure. In that case, an 800-foot-deep hole was exposed, he says.
Meanwhile, a mining site opened up at the location where the Silver King condominiums were built close to PCMR and there was a case at the site where Stein Eriksen Lodge was built in Deer Valley, according to Ivie.
Ivie says City Hall is compiling a catalog of potentially dangerous mining sites around Park City, with assistance from Talisker Corporation, the firm that now holds much of the land that was heavily mined. He says he would prefer having more complete maps of mining-era sites than those that are now available.
Ivie agrees with the assertion from the official with the state abandoned-mine program that the recent cases are not connected. He says, perhaps, soil above the openings became saturated before the incidents. Ivie says there has been a series of complaints this spring about flooded basements elsewhere in Park City, including on lower Park Avenue. There normally are not as many complaints of flooded basements, he says.
"I don’t think there’s anything sinister about it," Ivie says about the three incidents.
The ground below us
Three incidents involving historic mining sites have been reported since mid-2008. Experts say the episodes are not connected.
May 2009: A dog tumbles down a historic mine shaft at Park City Mountain Resort. A firefighter rescues the trapped pet after climbing down a ladder wearing ropes and rappelling gear for safety.
March 2009: A skier at Deer Valley Resort catches himself after the snow caves in around him in ungroomed terrain off the resort’s Lady Morgan Express lift. The incident occurs at the opening of a historic mine tunnel that does not appear on Deer Valley maps showing mining-era sites on the grounds, the resort says. The man says he could see the darkness of the mine shaft below him as he struggled to get out of the caved-in snow. A woman he was skiing with helps him out.
July 2008: A large hole appears off the Rail Trail that is determined to be at the top of a mine shaft. The shaft had been sealed with clay and dirt years ago, a state geologist says. The seal gives way and water from a nearby pond empties into the shaft.