Alliant Techsystems Inc. will expand its northeast Mississippi plant to make composite structures for commercial aircraft, Gov. Haley Barbour announced Monday.

The Minneapolis-based company will keep the 176 jobs it already has in Iuka, Miss.

Barbour said the plant will have 800 jobs by 2017 with an average salary of about $53,000.

Alliant is also known by its New York Stock Exchange trading symbol ATK. The aerospace and defense contractor makes ammunition, propulsion systems and aerospace supplies.

Company spokesman D. Bryce Hallowell said Mississippi competed with several states to be the site for the expansion. Hallowell wouldn’t name any of the other states.

In December, the Utah Governor’s Office of Economic Development approved a $32.7 million incentive to try to get the project. Utah has 5,800 ATK employees.

Hallowell said in a telephone interview that Alliant has “had a good experience with the work force” in Mississippi.

Barbour said the company will spend about $200 million to expand the Iuka plant, in the northeastern corner of the state near Alabama and Tennessee. Mississippi is giving a $25 million grant that Alliant will repay by 2016. Tishomingo County is contributing $5 million.

Tishomingo County had an 11 percent unemployment rate in December, significantly higher than the state rate of 7.6 percent.

Brandon Grissom, one of Tishomingo County’s five supervisors, said the area has been hurt by layoffs at Caterpillar Inc. and at other plants.

“These are jobs that we need real bad,” Grissom said of the Alliant expansion.

Alliant announced last week that said it had received a contract worth more than $200 million to produce composite aft fan cases for Rolls-Royce’s new Trent XWB engine.

Hallowell said the company expects to receive orders in the next few weeks that could “surpass a billion dollars” for work to be done in Mississippi.

Alliant announced last Thursday that its fiscal third-quarter profit rose 12 percent as sales and profit margins improved.

On the Net:

Alliant Techsystems Inc.: http://www.atk.com