Proposed lithium mine in western Maine clears key hurdle

Spodumene at Plumbago North. Spodumene is a mineral that contains lithium oxide, from which lithium can be extracted. Photo courtesy of William Simmons

The Board of Environmental Protection has unanimously agreed to amend Maine’s strict mining rules to allow for open-pit excavation of certain metals, including those fueling the country’s transition to clean energy, as long as the extraction will not pollute the environment.

The provisional amendment – the result of a state law adopted last July intended to overhaul the mining law to allow for the extraction of non-reactive minerals like spodumene, the hard rock source of lithium – now heads back to the Legislature for final consideration.

If adopted, these rules would allow Mary and Gary Freeman, retired rock hounds who split their time between Maine and Florida, to begin the rigorous testing needed to build an open-pit mine over a large lithium-rich mineral deposit they discovered while hunting for gemstones in Newry in 2018.

“This has been a big lift,” board Chair Susan Lessard, the town manager of Bucksport, said of the regulation change. “I think the department has done a very good job of trying to enact some rules to go along with what the Legislature adopted in the most protective way that they were able.”

The Newry deposit is a potential piece in the global ramp-up of lithium production to make batteries for storing clean wind and solar energy and powering electric cars. Alternative lithium-free batteries are being tested, but for now, lithium is still used in most electric vehicles and grid batteries.

Despite government and industry interest in building up a domestic lithium market, Nevada currently has the country’s only operational lithium mine. The Silver Peak mine, which began operating in the 1960s, pumps lithium-rich brine from underground into large evaporation ponds.

But the United States has at least a hundred domestic lithium mines that are hoping to get the permits needed to compete with the likes of Australia, Chile, China and Argentina, which currently dominate the world market, according to conservation biologist Patrick Donnelly of the Center for Biological Diversity.

Unlike most U.S. deposits, however, the Freeman find is a hard rock deposit of lithium, similar to those in Australia. They form when hot magma intrudes into the crust and then cools into metal-rich crystals. Hard-rock lithium is costlier to mine, quicker to market and yields a more valuable form of lithium than brining.

In a 2020 paper detailing the discovery, the Freemans claimed the 10 million metric-ton Plumbago Mountain deposit had the highest average lithium content of any known spodumene deposit, including gigantic 36-foot-long crystals embedded deep inside the coarse brown and white rock face.

Initially, the Freemans said they wanted to sell to the battery market, something that would likely require chemical processing on-site or nearby. Later, they said they wanted to sell raw spodumene ore with the highest levels of lithium to scientific glass manufacturers, which could eliminate the need for processing.

Neither the Freemans nor their attorney responded to emails and telephone requests for an interview.

The provisional rule requires applicants seeking an open-pit mining exemption to prove the operation does not have the potential to violate state water quality standards or expose radioactive materials that would endanger human health or the environment.

The applicant would have to conduct extensive testing and sampling to show the deposit would not react when exposed to the air or water of an open-pit mine. Spodumene is non-reactive, but other metals like copper and silver will create a harmful acid discharge when exposed.

For example, the Newry spodumene deposit is believed to contain some galena, the blue-black mineral that contains lead sulfide, which has the potential to leach lead and often occurs in combination with iron sulfide, the major culprit in causing acidic mine drainage.

“We are uncertain if galena is present at levels that are dangerous, but the only way to know would be through detailed characterization of the deposit in the manner that these rule amendments propose,” said Nick Bennett, a staff scientist at Natural Resources Council of Maine.

NRCM supported the provisional rule in part because the Board of Environmental Protection decided to add back in requirements that an applicant would have to conduct real-world testing, or kinetic testing, to ensure there is nothing reactive in the deposit before a mining exemption is granted.

“We are supportive of the proposed rules that DEP drafted and BEP approved because we believe they would only allow open-pit mining of metallic minerals when that extraction presents a very low risk to water quality and the environment,” Bennett said.