2 Nevada City toxic mine sites poised for cleanup | TheUnion.com

2 Nevada City toxic mine sites poised for cleanup

With the backing of $600,000 in federal funds, a representative of Sierra Stream Institute outlined plans Wednesday to clean up two abandoned mine sites riddled with toxic substances around Nevada City to that town’s council.

Nevada City has partnered with the nonprofit Sierra Streams because qualification of the Environmental Protection Agency grants required ownership of the proposed sites.

So with Nevada City acting as the financial agent, Sierra Streams is moving forward with plans to clean up the mines.

“Since 2010, there has been a lot of assessment of the sites and planning for the clean up,” prefaced City Manager David Brennan. “The cleanup is actually about ready to begin.”

The first site, Stiles Mill, is a 2.14-acre property located across Deer Creek from the downtown area at the confluence of Gold Run and Deer Creek, just upstream from the Pine Street Bridge, according to Parks and Recreation Director Dawn Zydonis.

It was active as a mine during the mid- to late 1800s with a hard rock mine and a quartz stamp mill that crushed and processed gold ore.

While the mill has been removed, a partially collapsed shaft and mine waste pile remain, said Kyle Leach, a Sierra Streams geologist.

“There are some fairly high levels of arsenic and lead there,” Leach said.

The proposed $200,000 project would clean up the waste pile, block off mine entrances (while possibly leaving grates for bats) and encase possibly toxic substances in soil, mulch and vegetation, Leach said, noting that Sierra Streams is well versed in grant applications.

“We can find money to do that if that is what thecity wants to do,” he said.

The Stile site serves as something of an informal park already, Leach said, noting that once cleaned up, it could make a suitable official park if the city wanted.

“We don’t have any specific plans for Developing The site as a park. In the long run … there are some ideas floating around,” Leach said.

With city approval, the project could begin by September and be completed by mid-October, when the EPA grant deadline expires, Leach said, acknowledging that the deadline could be moved if necessary.

The second site, Providence Mine, is much larger and has double the budget of Stiles Mine. It is a 39-acre site located at the end of the road that bears its name, along the south side of Deer Creek, about a mile downstream from downtown, according to Zydonis.

Providence Mine was a hard rock mine and was in operation from 1851 to 1919. It consisted of a stamp mill and chlorination works and produced an estimated $20 million in gold, the park manager noted.

With a lead concern, the site has a large steep slope (with an active landslide) where mine waste has been measured to be seeping into Deer Creek.

With a $400,000 budget, proposed work includes excavation and partial disposal of lead-contaminated soil, regrading the steep slope to limit erosion, stream bank restoration and coverage of contaminated soil on site.

If all goes smoothly, the Providence Mine site cleanup could begin in the spring of 2014 and be completed sometime that summer, Leach said.

“We’re going to do as much as we can with the money we have so we don’t go over budget,” Leach said.

Sierra Streams and the city had also initially applied to clean up a portion of Pioneer Park but was deemed ineligible for funding because when the city filled in a swamp to create the park, it did so using soil from an old mine site, Leach said, not knowing that soil’s contamination.

“That was too bad. The site would have been a good one to clean up, as well,” Leach said.

“… It’s not an imminent threat because the grass is there, and there isn’t a lot of exposure of those toxins, but we’d still like to clean that one up.”

Several members of the pubic spoke on issues related to the cleanups.

The first was a man who identified himself as Patrick Wagner, who challenged Leach and the council to produce evidence that the substances deemed toxic at the sites were actually dangerous to human beings.

“The question is: Has it been proven scientifically that those toxins are dangerous to human beings?” asked the man.

Leach noted that he is not a toxicologist and simply deferred to the state Department of Toxic Substances Control’s standards that Sierra Streams is using to qualify for funding.

“We have to go with the numbers they consider toxic,” Leach said.

To contact Staff Writer Christopher Rosacker, email crosacker@theunion.com or call 530-477-4236.

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