Signature Aluminum has notified government officials that it is closing its plant in Mercer County by the end of the month, eliminating about 300 jobs.

The company said about 275 workers were already in temporary layoff from the Greenville plant because of a drop-off in orders and the deteriorating economy.

Signature had planned to bring back all the employees within six months of their layoffs but could not negotiate for the additional funding needed to keep operations going, according to a letter to the state Department of Labor and Industry from Christopher Durniok, director of human resources at Signature.

"We believed that we had a realistic opportunity to obtain the necessary financing and that announcing a closing of our Pennsylvania facility would have precluded our obtaining the needed capital," he wrote. "Our efforts proved unsuccessful, however, and on March 9, our bank informed us that it would not extend additional loans and was calling our existing debt."

The closing is permanent, Mr. Durniok said.

More than 200 of the workers are represented by the United Steelworkers, with another small group represented by the International Machinists and Aerospace Workers.