Abstract The key parameters in gob-side entry retaining formed by roof cutting and pressure releasing in thin coal seams at the working front 1610 in the Nantun coal mine were studied. The presplitting cutting height of roof,the presplitting cutting angle,the distance between presplitting blasting holes were determined as the key parameters based on the analysis of the stress state of roof in the process of mining. The results of numerical simulation show that,when the height of immediate roof is much higher than the height of gob and the presplitting cutting height meets the requirement of the tensile failure of immediate roof,the presplitting cutting face should deflect a certain angle towards gob in order to cut off effectively the stress transfer between the roof of gob and the roof of retaining roadway and achieve the collapsing of roof. Based on the results,the optimum distance between presplitting blasting holes was determined through field presplitting blasting test. The results have been successfully applied to an engineering project.
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Received: 23 October 2013
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