More than 40 years after mining activity ended in the Park City area, Richardson Flat is still storing toxic soils with heavy metals like lead and arsenic.
Now the U.S. Environmental Protection Agency (EPA) is laying out a plan for removing tailings — the waste material left after separating valuable minerals from ore — that remain in the floodplain and are moving slowly downstream.
At a public open house Monday, the EPA shared plans for the Richardson Flat Tailings Site with interested locals. The site spans from Prospector Square in Park City to Interstate 80 and has four unique sites called operable units.
Unit 1 is the 258-acre Richardson Flat Impoundment, which holds about seven million tons of tailings. Cleanup is largely complete on this site, which also houses the Richardson Flat Park-and-Ride.
Two more consist of about six miles of tailings deposited in Silver Creek and its floodplain, which runs from Prospector Park to I-80 and covers the Rail Trail.
Unit 4 is the Prospector Drain, which collects the area’s shallow groundwater and discharges it into a wetland.
EPA remedial project manager James Hou said cleaning up the entire site would cost over $70 million and is ineligible for federal funding.
The EPA will pay for the remediation using money from negotiated agreements with so-called responsible parties, including United Park City Mines Company. To date, the agency has collected about $18 million.
“One of the hard challenges is trying to figure out the best way to utilize that $18 million that provides the most benefit, you know, your best bang for your buck,” Hou said.
That’s why the cleanup plan focuses on the Silver Creek floodplain, where simpler remediation tactics, like installing a six-inch cap of clean soil over contaminants, aren’t possible.
“All the material is sitting within the floodplain, and so it's constantly saturated with water, and it's constantly leaching that metals content back out into the water,” Hou said. “Just capping it in place wouldn't work. We need to physically isolate it from the water.”
The current proposal would first remove tailings at Richardson Flat Road and move north as funding allows. After removal, Utah leaders and the U.S. Fish and Wildlife Service will work on restoration, including planting vegetation to prevent erosion.
John Hall was one of roughly three dozen Park City-area residents on hand as the EPA shared its plans for Richardson Flat.
Hall said he’s considering buying a home nearby and wanted to understand the health risks. He said he’s been skiing in Park City for around 10 years and knew it used to be a mining town, but didn’t fully understand the pollutive effects.
“It's one thing to come up and, you know, enjoy a weekend of skiing, but you don't think about what the implications are in the rivers and the riparian areas and so forth,” Hall said.
After hearing from state and federal officials, he said he’s not overly concerned. For the contaminated soil to impact public health, locals would need repeated exposure over years through breathing dust or eating dirt.
Developers were also interested in hearing more on EPA’s plans, including Cheryl DeMarco, an architect with DRE Group.
She said she wanted to know what kind of development could be possible in the area.
“I'd like to know how they're going to do it and make sure that it's done properly, and so that developments could be put there. It'd be nice to have some open space too, though,” DeMarco said.
The goal is to have shovels in the ground by summer 2027. The public comment period for the plan is open through June 8.
