There are many parameters which affect caving processes in longwall coal mines, such as roof and floor strata conditions, thickness of immediate roof, excavation geometry and magnitude and direction of principles stresses. Estimation of first weighting distance, in this context is rather complicated. In this paper, the results of numerical modelling of the first weighting mechanism by using the finite difference code FLAC2D at the E1 longwall panel of the Parvade1 underground mine, which is located in the Tabas area at the central part of Iran, are presented. The obtained first caving distance is 11.2 m. In addition, the results of numerical modelling have been compared with some conventional methods such as Peng‟s method. The results show good agreement with each other.