Application of Rotary Drilling Rig in Large Diameter Rescue Hole Drilling in the Collapse Accident in Pingyi Gyp-sum Mine

In the collapse accident in Pingyi gypsum mine rescue, the underground channel was blocked.The rescue plan with large diameter drilling rig was determined to avoid the secondary accident.Several drilling rigs were put into use, BG26 and BG38 rotary drilling rigs were used for upper hole drilling segment and RB-T90 and T200XD multi-function drill for lower segment.The trapped persons were rescued while getting to the final depth, which created the first rescue case by drill-ing hole from the ground in the history of China’ s mine rescue.The paper introduces the control on key technologies of rotary drilling rig in rescue hole construction process, such as bit selection, protection tube embedment and verticality control in borehole drilling;borehole collapse was avoided by protection tube lowering, skilled operation and dry-hole drilling.