Grouting/Shotcreting/Bolting Support Technology of Gateway with Extreme Loose Coal Mass

In order to solve the support difficulty of the air returning gateway with soft and powder coal in No.2404 coal mining face of Longmen Mine, a control prin ciple of the shotcreting and bolt inner and outer loading structure in the gateway with the ultra soft coal was provided.A large scale pre-grouting consolidated coal techn ology with a self drilling type screw rod pilot long borehole was applied.The chemical liquid spraying technology for coal ribs was provided.The high strength bolt suppor t system was applied to the enhanced support and the drilling, grouting and bolting integrated quill grouting bolt was applied to the second grouting reinforced technolog y.The mine pressure observation showed that during the gateway driving period, the convergence between the two ribs was about 400 mm, the roof falling value was ab out 150 mm and the floor heave was about 50 mm.The continued large deformation of the gateway surrounding rock was effectively controlled and the gateway mainten ance could meet the requirements of the mine production.