NewPage Corp. has filed a joint Chapter 11 plan with the United States Bankruptcy Court for the District of Delaware.

The company, which operates a paper mill in Rumford, made the announcement Tuesday morning. The Rumford plant employs approximately 900 people.

Also Tuesday, the company requested a time extension to file the disclosure statement related to the plan.

“The filing of our plan of reorganization is an important and positive step forward to a successful completion of our financial reorganization,” George F. Martin, president and chief executive officer, said in a statement. “Discussions with and among our major creditor groups regarding the plan are ongoing. We are hopeful that these discussions will lead to broad support for our plan.”

NewPage filed for bankruptcy in September 2011. It was purchased  by private equity investment firm Cerberus Capital Management a few years ago.

However, Ron Hemingway, president of Local 900, United Steelworkers of America, said Tuesday afternoon that he believes NewPage Corp. is likely owned by at least a couple of large banks while the company goes through the Chapter 11 bankruptcy process.

Part of the bankruptcy plan calls for the judge to agree with the recent three-year contract offered by mill ownership and accepted by all unions in the company’s seven mills, according to Hemingway.

He said during bankruptcy proceedings, all employees must be paid. He said about 750 employees in the Rumford mill are union members.

Hemingway also said that one of the parts of the plan calls for extending the deadline for the judge to decide whether to accept the components of the agreed-upon contract. He said this is the second postponement.

Tuesday’s announcement will allow time for all the major creditors of NewPage to decide who will own that company and who will operate it, Hemingway said. He said each creditor will learn how much value can be recouped.

“Chapter 11 is a good thing because it gives time to reorganize. Chapter 7 means liquidation. Somebody will end up owning this company,” he said.

He said, too, that the mill has been running well, with orders coming in at a steady pace. No one has been laid off, he added.

“The bankruptcy has had no affect on the day-to-day operation of the mill. I believe we are profitable, but we’ve got to finish up with the bankruptcy bills,” Hemingway said.

According to the statement, NewPage is the leading producer of printing and specialty papers in North America with $3.5 billion in net sales for the year ending Dec 31, 2011.

NewPage is headquartered in Miamisburg, Ohio. In addition to the plant in Rumford, the company owns paper mills in Kentucky, Maryland, Michigan, Minnesota and Wisconsin, which can produce approximately 3.5 million tons of paper annually.