Abstract: The width of the narrow coal pillar of roadway driving along goaf is the key factor affecting the surrounding stability of the mining roadway in fully mechanized top coal caving face. Based on the abutment pressure distribution characteristics and the ultimate balanced theory, the reasonable width of narrow coal pillar should be chosen between 4.1m and 7.2 m, combined with the engineering condition in workface 3309 of a mine in Shandong. In order to optimize the width of the narrow coal pillar, the effect of plastic area distributions and stress distribution characteristics of the two sides of coal pillar under conditions of different width of narrow coal pillar have been studied by numerical analysis. The optimal width of coal pillar is 5 m. The validity of the optimal coal pillar width was verified by the engineering practice in workface 3309. Field monitoring has indicated that the surrounding rock deformation of the mining roadway could meet the requirements of safety production.

Key words: roadway driving along goaf, narrow coal pillar, limit equilibrium theory, surrounding rock stability