The risk of fatalities from rib failure is still prevalent throughout the coal mining industry which prompted further industry research into understanding rib deformation and rib support interaction. This paper provides the results of a rib deformation monitoring project at Moranbah North Mine as part of ACARP project C25057. Moranbah North Mine provided funding and mine site access to assist this research into the risk of rib failure within the industry. Two rib monitoring sites were installed to monitor rib and roof deformation and rib bolt loads under both development and longwall retreat stress scenarios. The monitoring highlighted the progression of rib deformation from the minor deformation and bolt loads experienced on development, through to the significant deformation observed under longwall abutment loads. The stability of the Tonstein Band (10 to 15 cm claystone/siltstone band located approximately 1 m above the floor), was highlighted as a key factor in the rib deformation both on development and retreat. The monitoring provided observations of the progression of deformation and highlighted a step change in rib stability. The rib deformation stepped from near rib deformation within the bolted zone to a significant increase in depth of softening under longwall abutment loading. It was inferred from the monitoring data that shear failure along the Tonstein Band in the lower section of the rib resulted in the increased deformation for the middle and upper rib. Computer modelling was also used to examine the failure mechanisms.