Study On Rock Burst Induced By Roof Falling And Its Control Methods In Gypsum Mine

According to the statistic data of State Administration of Work Safety (SAWS), thecasualty and economic loss caused by roof failing has surpassed that caused by trafficaccidents, and gone up to the second place. Especially in non-coal mine, the roof fallingaccidents have led to serious consequences. The large-area roof falling in gypsum hasproved to be rock burst.At present, the research on rock burst in non-metal mine fall behind that of coaland metal mine. The problems of mining dynamic damage such as mine pressure androck movement usually appeared during the underground mining of non-metal mine, asseen in gypsum mine where large-area gob falling often take place.Through the survey of typical accidents and presentation features before and afterrock burst, the types and conditions of rock burst emergence and its influencing factorsin gypsum mine has been figured out. The finite differential software FLAC-3D isapplied to analyze the stress state of roof and floor, then the process and mode offracture of pillar, roof and floor is discussed.The accidents of large-area roof falling in gypsum mine are the result of rock burstafter the roof rupture. Through analysis of interaction between mining method andgeological condition, it is concluded that the mining method, the structure parameters ofstope and non-disposal of gob are the substantial conditions and result in the roof fallingin gypsum.The gobs are the hazardous sources of mines, so the author has put forward theconcept of "gob hazard mine", and also presented the methods of classifications andhazardous ratings for this kind of mine.According to the features of gypsum ore deposit, the improved sublevel cavingmethod is recommended to raise the recovery ratio and eliminate the underground gobs.