Longwall mining is one of the major methods in the coal mining industry. A main concern in this method is roof cavability and caving step or required advance length to make the roof to cave; this is specifically important when roof is relatively hard and caving is controlled by discontinuities within the roof rock. In this research roof caving is studied for different advances and various specifications of discontinuities. A rating method is suggested to characterize the rock mass based on the developed models. A graph has been constructed using the proposed rating system, which can be utilised to predict necessary caving step for the roof.