The purpose of this study was to analyze the effects of strata behavior on longwall panels caused by mining. The study was focused on the weighting phenomena and their effects on front abutments, and the chain pillar stability and pillar design under various roof conditions. Using the three-dimensional finite element, the overburden depth, mechanical properties of the immediate roof and the main roof, panel width, and size of the chain pillar were analyzed. Four models were used to simulate various phases of panel production under various combinations of the above parameters. Model 1 simulated the beginning of panel mining, model 2 simulated the passage of the longwall face of more than half the panel length, model 3 simulated the completion of panel productions, and model 4 simulated the second panel mining. By applying the multiple- regression model to analyze the finite element results, the following were devloped: (1) a formula that classifies the type of roof strata at the face area, (2) formulas that predict the first weighting and periodic weighting lengths, and (3) a formula that designs, the chain pillar size.