Study On Regularity Of Surface Subsidence Due To Repeated Mining Taking Daliuta Coal Mine As Example

As the increase of coal mining depth, there are more and more destructionproblems caused by repeated mining. In order to reduce disaster loss, repeatedmining surface movement regularity and prediction methods were studied based onDaliuta coal mine in the paper and mainly on the following areas:(1) Based on measured surface movement data of22201and52304repeatedmining areas, the surface movement regularity, characteristics of deformation curvesand the prediction parameters were summarized in the paper.(2) After comparatively analyzed the repeated and initial mining data, thedeformation mechanism of repeated mining was illuminated and the effect of goafcoal pillar to surface movement was studied. The conclusions are drawn that thesurface movement extent of repeated mining is bigger than initial mining and theeffect range of goaf coal pillar to subsidence is larger than to horizontal movement.(3) According to the surface crack data in repeated mining areas, thedistribution laws and formation factors of surface crack were studied. Then theinfluence of surface crack on curve of surface movement was analyzed. Studies haveshown that relative position of mining and mined work face will affect the size,position and trend of surface crack.(4) In the paper, a new prediction method for surface crack in repeated miningareas was established. By comparing the prediction results, it is obvious that theprediction of new method is more believable than crack angle method.(5) Due to the surface movement regularity of repeated mining areas, theprobability integral method was modified to fit the repeated mining situation inDaliuta mine area.