The union said Monday the certification was made by Alberta Relations Board after a company vote last week reflected a preference for union representation by a vote of 140-96.

"We are extremely pleased to welcome these miners into the UMWA family," UMWA International president Cecil Roberts said.

"Their courageous struggle to organize the UMWA at their mine is an inspiration to all our members, both in Canada and the United States. We look forward to sitting down with the company to negotiate a fair and equitable collective agreement as soon as possible."

The union boasts more than 105,000 active and retired coal miners as well as manufacturing workers, public service employees, health care workers and professional employees in North America.

Grande Cache has both underground and surface operations as well as an active preparation facility, and its leases total more than 22,000 hectares. It is currently developing and awaiting regulatory approvals for the new No. 8 surface mine and the No. 12 South B2 underground mine.