AUGUSTA — In 2006, when Lynn Taylor bought Coffin’s General Store in Portage Lake, considered the oldest continually running country store in Maine, she had four cash registers, 12 employees and six grades of gas.

Today, although she is still open every day of the year, the store — which has been in business since 1902 — is down to a single cash register, one full-time employee and one “very part-time” worker, she said. She sells only three grades of gas.

She’s convinced that mining at Bald Mountain in northern Maine could turn that trend around, she told state legislators Monday at a public hearing on potentially repealing, changing or limiting Maine’s year-old mining law.

Not everyone agrees.

Taylor was one of nearly 100 Maine legislators, residents, lobbyists and researchers who crammed into the hearing on a law passed in 2012 that changed the regulations of mining in the state and, some argue, relaxed the permit process. Opponents of the law have argued that the legislation was rushed into law without sufficient opportunity for public comment and lacks adequate protection for water and air quality.

The proposed amendments — L.D. 1059, “An Act to Protect Maine’s Environment and Natural Resources Jeopardized by Mining,” which would repeal last year’s law; L.D. 1302, “An Act to Amend Maine Metallic Mineral Mining to Protect Water Quality”; and L.D. 1324, “An Act to Protect Local Communities When Project is Terminated” — addressed various environmental and fiscal concerns that have surfaced since the Department of Environmental Protection began working late last year on drafting new rules for permitting and mining operations in the state.

Many of those appearing before the committee supported L.D. 1302, an amendment sponsored by House Majority Whip Jeff M. McCabe, D-Skowhegan, which calls for four revisions to the law:

* improved protection of groundwater at mining sites by requiring that the operation cannot pollute groundwater.

* financial protection for taxpayers by requiring applicants to cover the cost of a third-party evaluation of how much money would be needed to close a proposed mine safely.

* a requirement that mining operations be designed so that they would not require perpetual treatment and maintenance if closed.

* a requirement that any applicant would have to identify a mine elsewhere in the U.S., in a climate and geologic setting similar to Maine’s, that operated at least 10 years without polluting ground- or surface water.

There was little support for the bill that would repeal last year’s mining law, and most speakers, including those who spoke for allowing mining and those who opposed it, focused their comments on the need to move cautiously before permitting mining operations to ensure there was no irreparable, continuing environmental damage.

One key point of contention at the hearing was whether to allow the DEP to continue drafting the rules, or to put amendments in place before revisions were completed. The new rules, which are being written by the DEP in consultation with a private contractor with ties to the mining industry, will apply to any company that applies for a permit to carry out metallic mineral mining in the state.

No applications have been received so far, DEP officials have reported, although JD Irving of New Brunswick has expressed interest in mining at Bald Mountain in Aroostook County.

Although most of the debate about open-pit mining in Maine has centered on Bald Mountain, other areas of the state — including the Western Foothills, the Moosehead Lake area and Cobscook Bay — have been shown to hold metallic mineral deposits.

Both opponents and supporters of the amendments acknowledged that the long-foundering economy in northern Maine could be boosted by mining, which could create jobs and generate indirect income for ancillary businesses, such as restaurants, motels and retail stores.

Potential job growth estimates have ranged from 150 to 700 jobs around Bald Mountain, a region where unemployment ranges from 10 to 20 percent, according to Bob Dorsey, president and CEO of Aroostook Partnership for Progress.

“I don’t know if (the law) will hurt the environment or that it will help the economy,” said Sen. Troy Jackson, D-Allagash, in northern Aroostook County, one of the sponsors of the original bill. Jackson opposed any changes but promised that he would fight the new law if the rule-making process did not result in adequate environmental protections.

“There’s a balance and a trade-off,” he said. “The environment of Maine must be protected.”

Numerous advocacy and environmental organizations, including the Conservation Law Foundation, Natural Resources Council of Maine and Maine Audubon, lined up to ask the committee to review the new mining law and consider a range of options to curb what they see as the potentially damaging environmental effects of mining.

Several environmentalists agreed with backers of the new mining law, saying they did not want to kill the possibility of mining in Maine but wanted to be certain the job was done right.

“I suspect that mining can be done pretty safely — if you have the money,” said Nick Bennett, staff scientist at the Natural Resources Council of Maine. “It’s very expensive.”

If mining cannot be done safely at a cost that is acceptable to the companies, that may affect their decision to come to Maine, Bennett said, “but that’s not our fault. The provisions in L.D. 1302 are steps … and reasonable.”

Some mining opponents backed a moratorium on the industry’s operations in the state and asked that the committee make certain mining proposals be thoroughly reviewed by experts in geology and engineering who have no ties and no financial incentives toward specific findings.

“Be extremely careful,” said Elery Keene, a retired engineer and planner from the central Maine town of Winslow. “Employ someone who is independent. … Clean water is more important than gold, silver and copper.”