The company said Tkachuk’s departure, effective immediately, was for personal reasons.

Tkachuk, who was elected to the senate in 1993, is the deputy chair of the transport and communications committee.

He is also is a member of the energy and environment, banking, trade and commerce and the national security and defense committees.

Cline’s directors now consist of parliamentarian Bill McKnight, who serves as chairman and director; mining consultant principal Dale Hendrick; and former deputy premier and chief-of-staff to the premier in the province of Alberta Peter Elzinga.

Officials told regional newspaper the Raton Range in late November that Cline’s New Elk coal mine in Colorado could re-open in the first quarter of 2013. However, no official confirmation or update on deals with interested coal buyers has been made.

New Elk has been closed since July. Officials have said the closure was temporary, and mining would resume “pending improved market conditions”

Cline Mining holds significant metallurgical coal property interests in both Colorado and British Columbia.