Abstract: To analyze the site stability of the small coal mine goaf area, this paper presents a case history evaluation of a newly constructed ash storage yard for a power plant in Guizhou. The site stability is analyzed according to the coal mining mode and final mining time, the natural balance arch height of the roadway roof and the load influence depth under the different surcharge height are estimated. The ground deformation under the surcharge is analyzed combined with the numerical analysis. The results show that the current condition of the proposed site is in a stable state, under the action of subsequent surcharge, the local collapse of the roadway distribution area is more likely. After taking corresponding deformation improvement measures according to the roadway buried depth and surcharge height, the proposed site is suitable for the construction of the ash storage yard, which can be used for a reference in the stability evaluation of similar goaf sites.

Key words: Small Coal Mine, Goaf Area, Surcharge Effect, Stability