Evaluation of Effect of Longwall Coal Stope's Progress on the Behavior of Gallery Post 5 of Pabedana Coal Mine

Convergency measurement is one the most utilized methods to analyze the behavior of underground openings. In this research، the extraction effects of the coal stopes «245 advance» and «245 regressive» on the gallery Post no. 5 of Pabedana coal mine are considered. This gallery has experienced difficult loading conditions which are caused many stability problems like high deformation and yielding of steel sets. Convergences are recorded for about 1 year implementing tape extensometer and 3-point convergence monitoring arrays. Results of analyzing the recorded convergences of 12 stations showed that more than 92% of displacements are occured behind the stope face. Critical displacements occur under the gob zone، i. e. between 7-22m behind the stope face. Also، it is concluded that the rate of coal extraction in longwall stopes has a key role on stability of gallery.