Study on Thickness Variation of Thin Base Rock Affected to Mine Pressure Behaviors of Coal Mining Face

A safety miming problems under an ultra thin base rock roof conditions with thick loose coverer was a key to restrain the high production and high efficient mine in Shendong Mining Area.In combination with the mine pressure measured information of No.22614 coal mining face in Daliuta Mine,the paper studied the mine pressure behaviors law features of the base rock thickness tuned to thin zone and to thick zone.From the view of the mine pressure control,the paper discussed the different mechanism of the mine pressure behaviors strength in the base rock thick and thin variation zone.The study results showed that the weighting strength of the base rock thin varied zone would be lower than the base rock thick varied zone.The min thin zone of the base rock would easily cause sand inrush accident occurred.The base rock normal zone before the thin varied zone and the base rock normal zone after the base rock thick varied zone would have a same weighting strength.When the base rock thickness was thin,the periodical weighting interval would be short and the periodical weighting strength would be high.In a same base rock grade region,the base rock thin varied zone would have short periodical weighting interval,smaller weighting strength and dynamic load coefficient than the base rock thick varied zone.