Mining in the Centralia West Quadrangle
The Centralia Fault Zone limited mine expansion in the east-west direction. The high-angle normal faults that make up the fault zone have enough displacement to hinder any efficient crossing. Fracturing related to the faults may have contributed to roof falls. Glenridge Mine (mine index 207), operated the longest, from 1906 to 1963. The Herrin Coal was generally about 6 feet thick, and over 500 feet deep.