AUGUSTA — In a preliminary vote Friday, a state board voted to adopt a set of metallic mining rules aimed at spurring the industry in Maine, a move criticized by environmentalists who say the rules could encourage pollution.

The unanimous vote of the Maine Board of Environmental Protection sends the proposed rules to a legislative committee, where the rules must gain support before going to the full Legislature for consideration.

But sticking points remain in the rules — among advocacy groups and in particular, one board member.

“I really urge the Legislature to kill these rules and start over because these rules are a disaster,” said Nick Bennett, staff scientist at the Natural Resources Council of Maine.

One provision says after mines are closed, operators must ensure that fluid discharges from the site meet water quality standards “as soon as practicable,” but in most cases, no longer than 30 years.

However, operators could allow certain types of contaminants to persist longer than 30 years, as long as the time period is defined and the Department of Environmental Protection approves. Bennett said that makes it possible for companies to extend treatment plans over hundreds of years.

But James Parker, a board member, proponent of the open time frame and former state legislator from Veazie, just north of Bangor, said there may be accepted technologies that mitigate the impact over a longer period, describing that section of the rules as “a tool” left open to the DEP, at their discretion.

“Don’t cross off the option,” Parker said. “At least evaluate it if somebody presents it. Maybe they won’t even present it.”

Board member Susan Lessard, also Hampden’s town manager, said before the board took its final vote that she has great concerns about simply allowing pollutants for 30 years, more than a generation. She said she hoped that change would be addressed by legislators.

If approved there, the rules go back to the board for a final vote, which Robert Foley of Wells, the board’s chairman, said will likely happen in the spring.

Lessard won one small change, getting the board to tighten the geographic limits where surface mining could occur.

Originally, the DEP recommended a 1.25-mile buffer zone between mine sites and protected lands, including national and state parks, state-owned lands and historic sites.

The board later narrowed that zone to just a quarter-mile. But on Friday Lessard recommended — and the board agreed — that it be extended to a mile in most cases.

Bennett said that was a minor change, dwarfed by other negative impacts in the rules. In an email Friday morning, a Natural Resources Council of Maine spokeswoman sent an email to the news media laying out other perceived negatives. Among them, it said the rules fail to ensure that taxpayer money wouldn’t be used to clean up mines if a company goes bankrupt.

The rule change was mandated after a law was signed in 2012 by Gov. Paul LePage, marking the first change to state mining laws in 20 years. It directed the DEP to rewrite its mining rules, the first draft of which came in August.

The set adopted Friday was the third set, with time set aside for public comment on recent changes, which, among other things, allow permitted mining in groundwater, waters of the state and in freshwater wetlands.

Right now, there is no metallic mineral mining, which focuses on precious metals such as gold, silver, copper and zinc, in Maine. There hasn’t been in decades.

Now, there are also no permit applications submitted to the DEP for mining in the state.

However, J.D. Irving Ltd. of New Brunswick has expressed interest in mining gold, silver, copper and zinc at Bald Mountain in Aroostook County, northwest of Ashland. The metal there could be worth as much as $7 billion, according to geologist John S. Cummings of Texas, who discovered deposits there in the1970s.

Enticing mining companies to the state was the goal of the law and subsequent rule change.

Foley said he would have liked the board to have had more time before putting out the rules, but he said the rules won’t allow “carte blanche” — mining companies doing “whatever they want” at the expense of the environment.

“I think that this will protect the environment while allowing somebody at least to explore the possibility of doing mining,” he said.

Michael Shepherd — 370-7652 mshepherd@centralmaine.com Twitter: @mikeshepherdme