US based coal company Alpha Natural Resources and some of its wholly owned subsidiaries have filed for bankruptcy under Chapter 11, in the Bankruptcy Court in the Eastern District of Virginia.

The company said that the bankruptcy protection will help the company to operate normally and allow it to keep its customer commitment, pay wages and benefits to its employees.

Alpha Natural Resources chairman and CEO Kevin Crutchfield said: "While a difficult decision, this voluntary Chapter 11 filing is the right strategy at the right time for the future of our business.

"It will enable us to build on the significant steps we have taken over the past several years to restructure our debt and protect our operations.

"I am confident Alpha will emerge from this process as a stronger company, with a diversified resource base and better positioned for the future."

The announcement has come at a time when new measures to reduce greenhouse gas emissions from coal-fired power plants is being introduced in the US.

The company said that the regulations have toughened up for coal companies and preference is being given to renewable energy, which has resulted in fall in coal price.

Alpha Natural has liabilities worth $7.11bn, and has reported adjusted losses for the past 14 quarters, reported Reuters.

However, the company mentioned that it had secured an 18-month debtor-in-possession financing of about $692m.