A river runs through the valley surrounded by several houses and trees.
An aerial view of the Pennamaquan River in Pembroke. Worried about the harm a mine could inflict on water quality, voters in the small Washington County town could ban large-scale metal mines. Credit: Courtesy of Ryan Malagara

Voters in Pembroke could ban large-scale metal mines next month in an attempt to halt a Canadian company’s exploration of a silver mining operation in the small Washington County town.

Concerned over the harm a mine could do to the area’s water quality, the Friends of Cobscook Bay collected signatures for a citizen’s initiative to ban industrial metallic mineral mines.

This is the latest in a history of opposition to metal mining in Maine. In 2017, dozens testified in Augusta against controversial large scale mining rules. And as recently as last year, opposition arose to proposed metal mining in the Katahdin region.

A vote on the proposed ordinance will take place at a May 4 special town meeting and comes as Wolfden Resources explores the potential of mining silver and other metals in an area of town known as Big Hill.

The concerns come down to the impact metal mining has on the environment. Pembroke, which relies on groundwater and an aquifer for its drinking water, is also heavily dependent on its wetlands, lakes, ponds, streams and rivers for recreation and jobs, according to the citizens group.

“Pollution of our groundwater affects the entire bay,” the group wrote in a letter to town officials in the fall. “Metallic mineral mining threatens the quality of these economic, recreational, environmental resources and the people that depend on them.”

The Passamaquoddy Tribe at Sipayik has also come out against mining in the area, saying that the public benefits are murky but the risks to drinking water are “obvious and immense.”

One of the biggest fears is the potential for sulfuric acid to drain into the ground and contaminate local waters. Metal mining can expose sulfide deposits to air or water, forming the acid. If the acid gets into the ground or water, it can be difficult to mitigate or remove, according to a geologist report commissioned by the Pembroke Clean Water Committee, another group in favor of the ordinance.

“The idea of an industrial scale mining operation landing in the midst of this community raised all kinds of concerns,” said Agnieszka Dixon, an attorney who helped draft the proposed ordinance.

Several other towns in Maine have also enacted local regulations restricting mining activities, including Cherryfield, Harrington, Hancock, Lamoine, Bridgton and Tremont.

If passed, the ban would apply to any metallic mine in town that annually extracts more than 10,000 tons of mine waste, has a mining area of more than three acres or extracts more than 10,000 tons of bulk sampling materials during exploration drilling. It would not affect smaller mining operations, nor would it apply to mining for gravel, sand, clay or peat.

Wolfden Resources, which has not yet successfully operated a mine, did not respond to a request for comment this week. The company’s 463-acre area dubbed “Big Silver” has been sporadically looked at for mineral mining since the 1960s and has had limited mining for lead and zinc going back to the late 1800s. In March, the company said it was encouraged by the results of exploratory drilling during the fall and winter and hoped to do more.

“Our goal is to discover and delineate an underground resource of 20 million tonnes or more, which appears achievable with this type of mineralized system,” Don Dudek, the vice president of exploration, said at the time.

There are currently no licensed metallic mineral mining sites in Maine.

Wolfden submitted work plans for drilling and surveys at the Pembroke site and doesn’t need a permit from the Maine Department of Environmental Protection as long test pits and trenches were kept to a certain size.

Even if the ban doesn’t pass and Wolfden does decide to pursue a full-scale mine, it will likely take several years to happen.

To operate a mine, the company would need to apply for a permit from DEP and supply two years worth of environmental monitoring data. Before that, Wolfden would probably want to do more advanced exploration of the site, which could also trigger a permit and monitoring process, said Michael Clark, a mining coordinator with the DEP.

The state enacted stricter mining regulations in 2017 and Wolfden is the first company to explore and develop projects under the new laws. But the clean water committee would rather not take any chances when it comes to water.

“We as a town have the right to regulate land use within our municipality,” said Severine Fleming, one of the leaders with the committee. “We have to make sure that everyone understands this historic moment and gets over there and votes.”

Wolfden previously proposed another mining operation in northern Penobscot County that drew scrutiny from environmental organizations but the company later withdrew its rezoning application last year from the Maine Land Use Planning Commission.