PORTLAND — A New Hampshire-based investment group is poised to complete its purchase of a pair of idled Maine paper mills.

A deal with the current owner, Brookfield Asset Management Inc., will be completed by Friday, said Richard Cyr, senior vice president of Cate Street Capital in Portsmouth, N.H. The purchase price for the mills, in Millinocket and East Millinocket near Mount Katahdin, wasn’t disclosed.

Cyr, who will serve as the new company’s chief executive officer, said he plans to have employees working to reopen the East Millinocket mill on Monday and to ship out the first order of newsprint to overseas markets by the end of October. The new company will be called Great Northern Paper Co. LLC, the name of the former long-time owner of the mills.

Reviving the Great Northern brand is a respectful nod to the long tradition of papermaking in the area, Cyr said.

“It’s a great brand,” Cyr said Thursday. “We felt people had a good feeling about it, both the people up there and people in the marketplace who know Great Northern.”

A spokesman for Brookfield Asset Management said the company by policy does not comment on transactions until they are completed.

The sale was made possible with a flurry of activity this week.

Millinocket and East Millinocket town leaders voted Tuesday to approve deals that will lower the mills’ property taxes for Cate Street. Unionized workers in East Millinocket accepted a five-year contract Wednesday night. And state lawmakers helped earlier this year by approving the purchase of contaminated landfill viewed as an obstacle to the deal.

Cate Street still has to obtain the necessary environmental permits from the Maine Department of Environmental Protection, which is why it and Brookfield Asset Management agreed to an escrow sale, in which the purchase money is being put aside. The deal will be formally closed once the permits are issued, probably by the end of the month, Cyr said.

With the purchase, the long tradition of papermaking in the Millinocket region will continue. Paper mills have operated in the Millinocket area for more than a century, and the mills at their peak employed more than 5,000 workers.

The Millinocket mill closed in 2008, putting about 150 employees out of work. The East Millinocket mill closed in April, idling another 450 workers.

Toronto-based Brookfield Asset Management this summer said it planned to liquidate the mills if a buyer couldn’t be found by the end of July. But it delayed its plans to give the state more time to find a buyer.

Cate Street officials said they plan to immediately reopen the East Millinocket mill and hire up to 250 employees. The company hopes to begin operating a second papermaking machine and bring the mill to capacity in 12 to 18 months, which would require a workforce of 400 to 450, Cyr said.

In time, the company also plans to reopen the Millinocket mill. Besides making paper there, it hopes to bring in new technology and make what is known as torrefied wood, a coal-like product except it comes from a renewable source and has reduced emissions. Cyr said there is a potential market for the product from power plants in Europe.

Although worldwide demand for paper has fallen, Cyr said the company can make a go of it because papermaking capacity also has shrunk. Former mill workers will be rehired to operate the plant, he said, while Cate Street will focus on marketing, sales and building the Great Northern brand.

“While we’re acutely aware the economics of the paper industry has changed,” Cyr said, “we have every intention of running that very successfully.”