Canada's Coalcorp Mining Inc declared force majeure at its La Francia mining operations in Colombia, citing the inability of one of its main customers to accept shipments due to shiploading issues and the impact of a rail strike on coal shipments from the mine.

"As a consequence of these events, coal inventory at La Francia has reached levels which create an operational hazard," the company said.

Coalcorp said it was taking all necessary steps to resume its mining operations.

Some 600 employees of the Fenoco transportation firm began a work stoppage on March 24 to demand recognition of their labor union. The protest had stopped 130,000 tonnes of coal per day from being transported by rail to Caribbean ports from northern Colombian mines. The strike was lifted last month.

Coalcorp shares, which have gained 44 percent in the past month, were trading at 17 Canadian cents Wednesday afternoon on the Toronto Stock Exchange.