EPA Gives Update  On Elizabeth Mine

Strafford — The Elizabeth Mine Superfund site will be an active blast zone for the next three months as the Environmental Protection Agency continues its cleanup of the long-closed mine that straddles the Strafford and Thetford town line.

Although nearby residents may hear the blasting and feel their homes shake, the work will do no damage to structures or affect groundwater systems, according to a fact sheet produced by Nobis Engineering, the prime contractor for the work now being done at the mine. Site monitoring, including seismographs and groundwater sampling, will be conducted to ensure that impacts fall within predicted ranges.

EPA remedial project manager Ed Hathaway hosted a community meeting on Thursday evening at Strafford’s Barrett Hall, where he outlined the progress and plans for the former copper mine, which operated from the early 1800s to 1958.

Hathaway, who was joined by several people currently working at the site, said blasting that began earlier this week will aid work crews in backfilling the pit lakes that formed in the mine cuts. The blasting is being undertaken both to stabilize areas prone to rock slides and provide material for the filling operations.

The project, which includes draining the lakes, will put an end to the mine’s era as a popular swimming-hole destination.

The EPA declared the Elizabeth Mine a Superfund site in 2001 because of the acidic and metal-laden water that was running off from waste rock and mine tailings and contaminating nearby waterways. The cleanup operation entailed, among other things, capping some of the debris, diverting water flowing through the site and building a filtration system. A portion of the site now hosts Vermont’s largest solar array.

In early 2008, iron originating from the waste rock flowed downstream at the rate of 800 pounds per day, and now it’s down to 26 pounds per day, according to Hathaway.

Places where orange-colored water once flowed are now testing for acceptable levels of water quality. The West Branch of the Ompompanoosuc River as well as significant portions of Lord Brook have improved markedly over time.

The latest phase of the project — conducted by Maine Drilling and Blasting — will involve blasting that occurs several days a week, sometimes twice a day. Anyone wanting to be notified of impending blasts can be added to a call list by contacting Hathaway at 617-918-1372.

Hathaway said no one will be allowed in the vicinity of the well-marked, fenced-off area of operations. Orange County sheriff deputies will be patrolling the officially closed site on days when workers are idle.

The explosions will have no structural impact on the homes and wells of nearby residents, according to Ken Smith, an official with Maine Drilling and Blasting. The closest structure to the blasting area is 1,700 feet, according to the Nobis fact sheet — well beyond the 1,320-foot radius of the blast zone.

“That’s well outside the range we can cause physical displacement to the earth,” Smith said.

Up to 80 holes, ranging in depth from 9 to 40 feet, can be drilled each day. The dynamite-fueled explosions within each of them affect only on a small radius and must work in conjunction with adjacent holes for the blasting system to function, according to Smith.

Although the blasts occurring at the mine may sound simultaneous to the untrained ear, they are actually spread out my milliseconds in order to disperse the vibrations and subsequent seismic impact.

Smith, who gave an impromptu mini-presentation during Thursday’s meeting, compared the blasting occurring at the mine to a job his company did at Boston’s Mass General Hospital, where business as usual, including surgery, was conducted within 100 feet of a blasting zone.

“This is a piece of cake,” Smith said of the work now being done at Elizabeth Mine. “This is very simple.”

The Superfund cleanup project could be completed by August 2019, said Hathaway, who added that another community meeting will be held later this summer.