By Kathy McCarty
Staff Writer
ASHLAND, Maine — Officials with expertise in the field of geology and water quality were on hand for a special mining meeting — held at Ashland Community School on Jan. 9 and hosted by the Central Aroostook Chamber of Commerce and the towns of Ashland and Portage Lake — to discuss how past mining operations differ from those being undertaken today. The purpose of the evening was to educate the public on mining procedures and not to discuss Irving’s specific plans for Bald Mountain. Dr. Robert Marvinney, Maine state geologist and director of the Maine Geological Society, and Carol White, who’s been responsible for a variety of hydrogeologic investigations, water supply studies and hazardous waste investigations, provided PowerPoint presentations reflecting how mining procedures have evolved over the past century.
Holly Umphrey, former Portage Lake town manager, served as moderator for the event.
“Mining is a very hot topic in the state and whether mining can be done successfully. We need to educate the public that it can, provided it’s done correctly and safely,” said Umphrey, as she introduced Marvinney.
Marvinney explained how mining is related to volcanic activity and that mines often are located along major volcanic belts.
“Those are the most likely places for major mineral deposits,” Marvinney said.
He discussed at length how mining is done in stages, beginning with exploration of a site. He said the basic process includes: discovery, funding, production and reclamation. He talked about production and the grinding process used to get the desired minerals from the rock at the site. Marvinney stressed the importance of keeping waste material from contact with the elements, favoring the use of a cover of some type to prevent rain from washing exposed arsenic away from the site.
Marvinney’s primary focus was on explaining the difference between “legacy mines” and “modern mines.” He said for decades, the procedure had been with legacy mines, once a deposit was discovered, to mine the site, then address concerns when it was time to close. But with modern mines, the procedure is reversed, with the closing of the mine being planned long before mining begins.
“With the ‘legacy,’ there were no environmental regulations in place at the time. They were active before the Clean Water Act or EPA came about. The difference between the legacy and modern mines is that with the modern mine, you start at the beginning by planning for the end,” said Marvinney. “You don’t deal with problems at the end, you deal with them in the beginning.”
Marvinney discussed the Bingham and Callahan mines and how Bald Mountain is only a fraction the size of the Bingham site. Located in Utah, the Bingham site is the largest open-pit mine in the U.S.
White addressed water concerns, noting how “most metallic mines are intensive water users.”
“Water’s necessary in the process of mining. You have to make sure you have enough water to use in the process. That’s the quantity part. There’s also the quality aspect,” said White.
She explained the difference between open-pit and underground mines and how water issues differ between the two.
“An open-pit allows sulfide materials to oxidize. With underground, it creates a big pipe system. You have less exposure of the surface area to be oxidized but are dealing with a higher concentration of ores. It’s a trade-off on the types of problems you might have,” she said.
White discussed how a pond was used at the Callahan mine in Brooksville, Hancock County. Water now fills the pit, preventing materials from oxidizing.
“Precipitation events are a big concern. They flush acid into the environment. Debris, or tailings, can be vegetated,” said White, explaining how different procedures can be used to secure waste material once a mine is closed.
Agreeing with Marvinney, White said procedures have changed over time, to better address environmental concerns.
“People used to walk away when done with a mine. Now they’re required to leave money for reclamation — don’t wait till the end to plan reclamation, it’s an ongoing process,” White said.
Marvinney and White took questions from the audience, advising the audience that they were not able to answer specific questions about Bald Mt. Mine but rather were there to address comments and concerns about mining operations in general. Questions ranged from concerns over earthquakes hitting a mining site to volcanic activity in the region. Both Marvinney and White said such occurrences, while possible, weren’t likely and would have to be addressed if and when they took place.
When an audience member asked, “can you guarantee no water impact,” White responded, “no, nothing can be predicted 100 percent.”
“When mines were being developed (years ago), there was no awareness. Then came awareness and progress. We’ve come a long way in addressing the environmental impact. We now evaluate and understand the long-term impact,” said White. “Knowledge has evolved.”
Marvinney and White urged the audience not to use facts and figures from other mines for comparison purposes, since geology, water sources and more vary from site to site. They also reminded everyone of the difference between legacy mines and modern mines and the importance of planning ahead.
Umphrey closed the meeting, noting “we need to educate ourselves” and as new things come along, “we have to adapt with the process. We’ve gone from legacy mines to where we are today.”
Umphrey said this won’t be the last of the public forums.
“We plan to move them around, bring more people and continue to educate the public about mining procedures,” said Umphrey.
