Abstract: In this paper, aiming at the mining of the portal and industrial area pillars, the author decided to adopt the paste backfilling with slicing descending mining method and figured out that the allowable subsiding ratio is 0.15. Based on this mining method, the portal deformation prediction was conducted. As a consequence, the conclusion was that the portal would subside and the stretching deformation could become greater with the working face advancing towards the portal. What's more, the portal deformation would become stable when the working face was approximately 50m in the front of the portal. Addition to that, protecting measures were chosen on the basis of the predicting results.

Key words: Paste backfill mining, Portal deformation, Deforming prediction, Portal protecting