Figure 1

Different failure types of the caving mechanism: (a) surface abrasion, (b) fracture of the pin shaft, (c) bend of the pin shaft, (d) tooth wear, (e) impact crater of the top surface, and (f) bend of jack.

Different failure types of the caving mechanism: (a) surface abrasion, (b) fracture of the pin shaft, (c) bend of the pin shaft, (d) tooth wear, (e) impact crater of the top surface, and (f) bend of jack.