Surface mining at Grande Cache Coal Corporation (GCC) is conducted presently at the No. 12 South B2 Mine. This area had originally been mined from 1998 to 2000. In 2003, the Energy and Utilities Board transferred the licence for this mine to GCC. In spring 2004, GCC upgraded the pit design of No. 12 South B2. Mining approvals were obtained in August 2004 and mining commenced immediately.
GCC initially hired contractors to develop infrastructure for its No. 12 South B2 Surface Mine and No. 7 Underground Mine and to operate the surface mine through the initial high strip ratio phase of mining. When this stage of operation was completed (November 2006), GCC phased out the contractors on site and transitioned to an owner-operated surface mining fleet. Mining equipment for the No. 12 South B2 Surface Mine began arriving August 2007 and GCC’s surface mine operations have since expanded into the South Lobe Pit.
The surface operations employ conventional open-pit mining techniques using truck and shovel methods. Similar open-pit mining techniques will be employed at the No. 8 Mine and No. 16 East Mine. Overburden is drilled and blasted with explosives and loaded onto large trucks by shovels and loaders and hauled to waste rock dumps outside of the pit. Once the overburden is removed, the coal is loaded onto trucks for transport to the coal processing plant. The coal processing plant employs rotary breakers to break the coal to a predetermined size and remove rock. The coal is then washed using a variety of techniques, dried and conveyed onto a clean coal stockpile.
The geology is typical of the Rocky Mountains with significant folding and thrust faulting. Coal seam dips range from flat to almost 80 degrees. The mineable seams in No. 12 South B2 include: 4 Seam (average 6.8 metres thick), 5 Seam (avg. 1.6 metres), 6 Seam (avg. 1.2 metres), and 7 Seam (avg. 4.5 metres).