... 30~120mm Water injection and hole-sealing device for coalUsecoal injection,dust-fall,coal pressure reduction,coal-crack.methane drainage,ect.Function1 ... watercourse on the operation field,put the device into the drill hole,Under certain pressure,the hose will expand to come ... insert and retrieve the hole device with pressure.4.Allow no person in front of the working device. Water Injection And Hole- ...