More than two centuries after people began exploiting the resources buried in the hills of Vermont, a river of pollution that flowed from what was once one of the most important copper mines in the United States has been tamed, and life has returned to downstream waterways.
Two decades after the planning began for the cleanup of the Elizabeth Mine and 16 years after the beginning of on-the-ground work, the work — paid for with about $90 million from the federal Superfund program — is winding down, and the Environmental Protection Agency is getting ready to turn the site over to the state for long-term monitoring.
The work rerouted the Copperas Brook, and buried and sealed millions of tons of waste rock so rain and groundwater wouldn’t travel through the concentrated waste and leach iron, copper, cadmium, cobalt and zinc into the West Branch of the Ompompanoosuc River.
“For the longest time, going upstream, (water quality) was good to excellent, hit Copperas Brook, and I think ‘nuked’ was the best term,” said Ed Hathaway, the EPA manager who has been working on the Elizabeth Mine project for years.
“It’s clearer now,” said Stuart Rogers, chairman of the town board in downstream Thetford, who lives along the river and unofficially monitored the cleanup by the changing color of the water. “So a couple years ago it was noticeable because we got kingfishers — you don’t get kingfishers along the river unless it’s clean water — and herons.”
While the Elizabeth Mine cleanup is almost done, more work remains to rid Vermont’s Orange County of its toxic industrial legacy.
In nearby Vershire, planning continues to clean up the smaller Ely Mine, another Superfund site, where work will begin once the funding, now estimated at about $24 million, becomes available. A third, even smaller complex of two abandoned mines, known as Pike Hill, in Corinth is also on the Superfund list and awaiting attention.
Early settlers discovered ore in what became known as Vermont’s copper belt in 1793, two years after statehood. But it wasn’t until 1809 that people began to make copperas, an industrial chemical made from iron sulfide used to make inks and dyes and for other industrial applications, also common in the area.
At the time it was important enough to the economy of the young United States of America that in 1817, President James Monroe visited the site.
By the 1840s, the Thetford mine satisfied 75% of U.S. demand for copperas, but in the 1820s the location also began to produce copper, needed for ornamental uses, brass and, later, wire for electricity and communications.
Copperas operations were abandoned in the 1880s due to low market prices, high production costs and competition from less expensive sources, according to an EPA history of the site.
The operations at the mine, named for the wife of the owner in the 1880s, waxed and waned over the decades with economic conditions.
But the copper mine was reopened at the start of World War II to help fill government orders for the metal, vital in war production. Its importance continued through the Korean War, and during the 1950s it was among the country’s top 20 producers.
By the time the mine closed for good in 1958, it had produced more than 100 million pounds of copper, about 90% of that from World War II onward. The closure left behind 7,800 feet of tunnels; abandoned buildings; equipment; huge piles of rock, known as tailings; and other mining debris.
The exposed mineral and chemicals that were carried by water first into the Copperas Brook and then into the West Branch of the Ompompanoosuc, killed most of the fish and other life in an otherwise idyllic stretch of rural Vermont about 10 miles northwest of Hanover, New Hampshire.
Vermont environmental officials first began to note the condition of the river, which drains into the Connecticut River and there to Long Island Sound, in the 1960s.
By the late 1990s, officials became worried that a dam that was holding back the tailings could fail and leave destruction downstream in addition to the chemical contamination. Planning for a remedy began in earnest in the late 1990s.
In 2001, the Elizabeth Mine was added to the Superfund list. In 2003, the work began.
There was some local resistance and over the years. People around the mine have complained about truck traffic, which hasn’t been kind to roads not built to withstand such heavy vehicles.
Over the years, workers moved about 300,000 cubic yards of debris so it covered the original tailings pile. They rerouted the Copperas Brook and engineered a drainage system that has reduced what comes out of the tailings to a relative trickle.
After the work on the cap was finished, about 20,000 solar panels capable of generating enough power for an estimated 1,300 Vermont homes were installed as a way to find a use for part of the 45 acres.
The EPA estimates the amount of copper flowing into the Ompompanoosuc has fallen 99%, while the concentration of iron dropped 95%, prompting environmental officials to remove the river from the list of Vermont waterways deemed too impaired to support aquatic life.