Study on Stability of Goaf Pillars in Daqiao Phosphate Mine: Theoretical Calculation and Field Investigation

In order to obtain the stability of the goaf pillars in Daqiao phosphate mine, two methods of the theoretical calculation and field investigation were used to carry out a series of the study on stability of the goaf pillars. Some useful results can be obtained. The reliability of the theoretical results is verified by the field investigation. The small pillars are generally in a unstable state. The sizes of the pillars are inconsistent, which could cause the small pillars to be crushed easily. The buried depth of the pillar has significant effect on the stability of the pillar. The distribution density of the pillars also affects the stability of the pillars. The 8433 goaf is the most unstable, followed by 623 goaf, 328 goaf and 9-2 goaf. The exploration of ten goafs in the Daqiao phosphate mine shows that seven goafs are in a stable state. According to the field investigation and theoretical calculation, the goafs are generally in a stable state. The research methods and results in this paper can provide reference for similar mine goaf treatment.