Patriot Coal in the US has delayed the opening of its West Virginia Federal No 2 until ongoing safety inspections have cleared the mine of any risk of explosion.

Towards the end of last week the coal producer discovered potentially adverse atmospheric conditions in an abandoned area of the mine leading to a temporary suspension of operations.

The company said that although its existing ventilation plan is in compliance with mining regulations, it’s working on an enhanced ventilation plan and will submit it to the US Department of Labor, Mine Safety & Health Administration.

The Federal No 2 mine produced about 3.8 million tons of coal last year, or 12% of Patriot’s 2009 production.