EAST MILLINOCKET, Maine — Clouds that shrouded mighty Mount Katahdin on a still November morning gradually lifted above its mile-high summit as the day wore on, just as a pale of gloom is giving way to a glow of optimism in two Maine towns below.

Paper-making, for generations the lifeblood and soul of Millinocket and East Millinocket, is back, and a closely related new industry knocks on the door. And mill workers and those who draw a living from one of Maine’s traditional industries say they finally have something to be thankful for this Thanksgiving.

“For a long time, we’ve felt like there’s a black cloud over these communities, and maybe that’s going away,” said Rick Nicholson, who’s back to work at Great Northern Paper Co.’s mill in East Millinocket helping to turn out newsprint. That mill’s reopening is fueling optimism that the new owner will soon restart operations in its plant in neighboring Millinocket.

“Send a message,” said James Jano, another re-employed mill worker. “People are very thankful for being back to work.”

Both Millinocket and its smaller sister town have been knocked to the ropes by off-and-on cutbacks and closings as the two Great Northern mills, which provided 1,500 jobs 15 years ago and several thousand in their heyday, passed through a succession of owners and name changes.

Long-secure mill workers and their families left as jobs became scarcer, stores and schools closed and the local economy atrophied. Millinocket’s population has withered from 7,900 in 1980 to 4,506 last year, while East Millinocket’s slipped from 2,372 to 1,828 over the same time frame.

The Millinocket mill closed in 2008 and by last April, the East Millinocket plant was shuttered, both falling to a mix of factors including high fuel prices, global competition and a tight market.

In a deal brokered by the state, Cate Street Capital, an investment group based in Portsmouth, N.H., bought the mills from Toronto-based Brookfield Asset Management Inc. In October, more than 200 workers returned to their jobs in East Millinocket, an event deemed significant enough to draw Gov. Paul LePage from Augusta 150 miles to the south to welcome them back.

With the rechristening of the mills under their traditional Great Northern name that evokes memories of boom days for local paper-making, a new sense of optimism blossomed, even along East Millinocket’s Main Street, a hodgepodge of open and shuttered businesses on one side, the sprawling mill monopolizing the other, and one red light.

“The town kind of regained its identity,” said Canaan York, manager of Rick’s Market on Main Street.

Word of the East Millinocket mill’s restart so excited Beth Clark that she came out of retirement and left a home with a pool in South Carolina to return to her roots. A Millinocket native, Clark started out in 1975 as a laborer at the old Great Northern, pulling logs from stacks and pushing them with a spiked pole into a sluice for grinding into pulp.

Rising through the ranks at several mills in the East, Clark held onto her dream of coming home, and the lure of being part of Great Northern’s resurgence was too much to resist. Since returning, “I’ve never seen a better attitude in my life” among the paper workers, Clark said. “People say we’re going to do it this time.”

Clark, who works in customer service, and other employees say the reopening is also widely viewed as a last chance to rebuild the mills into something resembling what they once were. That sense of urgency is prompting workers to go extra yards to keep things growing, to take on tasks they wouldn’t have had to in the past, they say.

Gene Conlogue, town manager in Millinocket, also sees a positive sign in Cates’ willingness to make plant investments where past owners didn’t and in formulating a strategy to move forward. In his town, there’s “guarded optimism” that the mill in that town will reopen in the not-too-distant future.

“People will be on edge until they see smoke coming out of our stack,” Conlogue said.

Just in case, some folks already have their job applications in, said Nancy Campbell, who works in the Appalachian Trail Cafe downtown. One of them is her son.

There are very good reasons for local people to be optimistic, said spokesman Scott Tranchemontagne of Cate Street Capital, a private equity firm that’s raised over $6 billion to finance more than 40 projects in the last 15 years. The firm specializes in renewable energy and green technology projects.

In Millinocket, the company now is actively engaged in developing a process to make torrefied wood. The biomass-based, coal-like product is made into pellets that are in demand in overseas power plants that must meet tough emission standards, said Tranchemontagne. While it’s not paper-making, the process uses the same basic raw material — wood — that’s so plentiful outside the mill’s back door.

“We are actively moving forward with this,” said Tranchemontagne. “The future is bright. This is not pie-in-the-sky. We have done our due diligence and are moving forward with torrefied wood.”

The startup of the Millinocket mill’s paper-making machine, which produces a glossy paper used in catalogues and flyers, is less certain. Cate is watching the market for that product to see when the time may be right to restart that machine.

But the torrefied wood process alone is expected to generate 80 to 100 jobs, said Tranchemontagne.

In East Millinocket, where 215 people have already gone back to work, the company has invested $20 million in upgrades and has asked managers to list other capital improvements that could make the plant more productive and efficient, the spokesman said.

“We are in this for the long haul and we know there is a market for the newsprint we are producing,” Tranchemontagne said.

In East Millinocket, Rick’s market manager York sees “a kind of a tempered optimism” for the mill’s future. At the Blue Ox East bar across the street from the mill, newly rehired millwright Roger Pelkey said people have to be upbeat because the alternative to another closing is not pretty.

“It’ll be a ghost town without the mill,” Pelkey said.