Analysis on Protective Seam Mining Affected to Stability of the Lower Seam Roadway in 1000 Meters Deep Mine

In order to study the mining in the protective seam affected to the stability of the lower seam roadway under the high stress and inclined strata in deep m ine shaft, according to the geological conditions of No. 12 Mine in Pingdingshan Coal Mining Group, based on the test on the similar material, a simulation study was co nducted on the mine pressure law of the gateways in the coal mining face in J15seam under the protective seam J14seam in mining.The results showed that before and after the mining of the protective seam, the air retuning gateway at the outside of the coal mining face in the protective seam was always affected to the horizontal high stress.After the air retuning gateway driving forward with 60 cm, due to the initial mine pressure role of the coal mining face, the stress of the left sidewall along the gat eway was suddenly increased from 3.42 kPa to 50 kPa and the deformation occurred at the two sidewalls of the gateway was high. The deformation failure of the roof al ong the transportation gateway right under the above the mining face in the protective seam was serious during the upper protective seam in mining operation.After the mining operation completed in the upper protective seam, the vertical stress of the roof was reduced from 42 kPa t0-17 kPa and the pressure releasing effect was obvio us.