But residents of the historic, fast-growing city fret about the impacts of an expansion intended to help meet construction demands in the Puget Sound region and elsewhere.

The company will hold a community meeting in DuPont on Thursday to explain its plans.

Andy Estep lives less than a quarter-mile from the proposed 177-acre gravel mine expansion in north DuPont. He likes to walk nearby.

Estep, a member of the city’s advisory park agency, said he’s concerned about the company’s plan to clear 184 acres of forest. He also wonders about the ecological effects of digging into an aquifer to get gravel, then diverting the excess water into a creek.

“I can’t imagine looking into this 550-acre hole,” he said. “I have real concerns about the water levels.”

He and others also worry that the mining expansion might threaten an 1839 church mission site where the first American citizens in the region lived.

Pete Stoltz, permit coordinator for Glacier, said the company took four years to address water, cultural sites and other concerns such as noise and dust. It contributed to the city’s environmental study, completed last year.

“We realize the historical importance of DuPont,” Stoltz said.

Glacier can stake a claim to history, too. It was the last of five companies that together spent more than a century mining the gravel north of Chambers Creek in University Place. Today, that site is the county’s 18-hole Chambers Bay Golf Course, which will play host to the 2015 U.S. Open.

Stoltz said the DuPont expansion would help replace what was lost when the Chambers Creek mine closed about four years ago.

His company wants to extract 30 million to 40 million tons of gravel over 14 to 15 years. The existing mine will be depleted in five to eight years. The company barges 80 percent of its sand and gravel.

At the same time, Glacier is trying to expand its gravel mining operation on Maury Island, next to Vashon Island in Puget Sound. That project, which would include a new dock to load barges, has run into opposition from environmentalists and local officials.

The company hopes to have all permits and start the new projects sometime next year, Stoltz said.

After mining in DuPont, Glacier must reclaim the land, which is designated for homes and businesses.

Environmental studies say water quality wouldn’t be compromised by the mine expansion. But some residents worry what would happen to nearby Sequalitchew Creek and a 135-acre wetland called Edmonds Marsh.

Bert Wyant is concerned about the extra water – about eight times the existing creek flow – going into the lower Sequalitchew.

“We’re worried about washing out the lower creek,” he said.

Judy Krill, a former mayor of DuPont, said she’s concerned about how new mining would alter the creek and other parts of the history-rich area.

“They’ll totally change the topography,” she said.

The company said no cultural sites, including the mission and Nisqually tribal burial sites, are within the planned mining area.

Glacier says it would dig the new mine up to 80 feet deep and break into an aquifer. The adjacent water table would drop 10 to 30 feet in the immediate area, and by lesser amounts up to a mile away. No local drinking water wells would be affected, according to the environmental study.

However, the project would reduce by 3 inches groundwater levels under nearby springs used by Fort Lewis for drinking water. It would cut by half the flows in the upper part of Sequalitchew Creek, when that section of creek isn’t dry.

Joe Piek, spokesman for Fort Lewis, said the post is evaluating the impact of the mining expansion.

The mine dewatering also would lower groundwater under Edmonds Marsh from 1 foot up to 18 inches, Stoltz said.

John Darling, DuPont community development director, said the company cannot disturb the big marsh, which the city classifies as a most highly protected wetland.

Stoltz said environmental studies show that marsh surface water levels would remain similar to current levels.

Darling said DuPont’s drinking water wells tap deeper aquifers and shouldn’t be affected.

Glacier would replace 4 acres of less-protected wetlands that mining will take away. The company would create new wetlands alongside the 4,000-foot-long stream it creates to carry off water from the mining pit to lower Sequalitchew Creek.

The additional water in the creek would improve fish habitat, the company says.

The Nisqually Tribe is watching what happens to the water, among other things, and can foresee potential benefits, said tribal attorney Thor Hoyte.

“We might get a run of salmon up the creek,” he said.

Stoltz said more water wouldn’t erode the creek banks because the bed is wide enough to handle it.

People don’t live on the proposed mine site, but some homes are less than a quarter-mile away, and some businesses are 500 feet away.

New mining operations might be noisy on windy nights, so the company proposes building a 20-foot-tall berm to screen digging and heavy-equipment sounds from across Center Drive.

Estep said little DuPont, a former company town, has a history of being overwhelmed by big businesses. Likewise, he predicts this project will go ahead as proposed.

“It looks bad,” he said.

Rob Tucker: 253-597-8374

What: Public meeting about Glacier Northwest’s plans for expanding its DuPont gravel mine

When: 7-9 p.m. Thursday

Where: Chloe Clark Elementary School, 1700 Palisade Blvd., off Center Drive in DuPont