Contaminated former gold house site to be capped this month

By Megan Gannon
Later this month, Nomeites can expect to see a work crew moving fill over a 1-acre area near Dry Creek. NovaGold, which inherited the site of the former Alaska Gold processing facility there, plans to install a cap over soil that’s still contaminated with chemicals like arsenic and mercury.
“Our belief is, the erosion issue is the most significant, as well as potential surficial exposure,” said Ron Rimelman, Vice President of Environment, Health, Safety & Sustainability for NovaGold. To keep the contaminated soil stable, the company will cap it with at least two feet of fill material, including boulders from Cape Nome.  
Rimelman presented the plan in a sparsely attended public meeting on Friday Aug. 26.
He explained that around 1975, the Alaska Gold Company built the so-called former New Gold House at Dry Creek. Mercury was part of the process to remove gold from the placer ore, and when operations shut down in 1988, traces of the substance remained at the facility. NovaGold acquired Alaska Gold Company’s operations in 1999, and in 2004, they removed the gold house.
At the meeting, Larry Pederson recalled that almost 20 years ago, when he was working for Bristol Engineering, he was part of that initial cleanup crew. He entered the old building equipped with a respirator, protective gear and shop-vac to suck up tiny balls of free mercury, or quicksilver.
“They were kind of hard to see unless you shined a light on it,” said Pederson. He found enough mercury to fill two flasks. Pederson is now Vice President of Nome Operations for Bering Straits Native Corporation, the contractor providing the materials and labor for NovaGold’s capping project.
In that earlier cleanup job, Rimelman said 13 tons of mercury-contaminated soil were removed, along with a 15,000-gallon water tank. “Physically there isn’t anything left at the site,” Rimelman said. “The building’s gone, there’s one 250-gallon old empty fuel tank, there’s a small manmade pond, but there if you go out there you can’t see any evidence that the gold house existed. The site is pretty well vegetated.” A fence was installed around the area in 2007 to prevent any access to the site, though occasionally a musk ox does find its way in.
Today, the amount of mercury at the site is no longer visible. But the soil still contains traces of arsenic, mercury and methylmercury leftover from the gold house, and hydrocarbons that seeped down to the site from old power facilities and machine shops that were up on the bluffs near the Foster Building.
“The concentration is on the order of a few milligrams of mercury in a kilogram of soil, but the state’s cleanup level is .36 milligrams per kilogram,” said Phil Welker, a California-based environmental engineer with GeoEngineers who is working on the project for NovaGold.
Rimelman said NovaGold began taking a deeper look at the contamination of the site in 2009, and nearly each year since 2013, the company has taken samples from the soil, surface water, groundwater and sediment. Those monitoring efforts allowed the company to define an area of about 1-acre where the soil is contaminated. The company also started looking at what would be the most appropriate long-term remediation method. Welker explained that they weighed a variety of approaches, from more aggressive ones, such as excavating large amounts of old soil, to taking no action. In 2021, the company finally created the engineering plan for the cap.
“The recommended and approved remedy is engineered fill cap, because it really addresses the most important exposure pathway, which is erosion,” Welker said. “And it does it in a way that doesn’t put you at risk of there being even more erosion created by putting in the remedy, so it’s a non-invasive approach.”
He added that the cap is designed to withstand flooding, and it will limit, but doesn’t totally eliminate, infiltration from precipitation. The manmade pond will be filled. The cap will be at least two-feet thick. A new fence will be installed as well as new boulder barriers. Monitoring wells will be replaced. And in the spring, the fill will be seeded so that the cap is covered with vegetation.
Their design was approved by the Alaska Department of Environmental Conservation earlier this year.
Rimelman did not give an exact number for the cost of the project but said the company has spent millions to monitor and clean up the site. He expected NovaGold would have to keep monitoring the site for at least another five years to say whether the cap is effective.
“It’s a pretty high hurdle to walk away from something like this,” he said.