An evaluation of roof support plans at two coal mines in Illinois using numerical models

- Roof control plans at two mines are compared using strain-based rock mass failure criteria.
- Shearing strains at pillar corners near the roof and floor are critical for failure initiation.
- Shear and tensile strains at the coal-floor interface are also critical.
- High compressive strains along the pillar ribs in entries result in cutter roof.
- Failure initiation occurs around the mid-height of pillar ribs and progresses downward.