Stress Evolution Characteristics of Lower Slice Coal Body During Mining the Thick Coal Seam

Slice mining is commonly used in mining thick coal seam (i.e., mining height greater than 3.5 m), where there is risk of coal and gas outbursts. After mining the upper slice workface, stress fields of lower slice coal body would change, which would affect the safe and efficient mining of the lower slice workface. Based on the slice mining practice of the Qudi coal mine in China, stress distribution characteristics of lower slice coal body with two adjacent upper slice workface being mined are studied by numerical simulation. Research results from numerical simulation were used to choose the location about the crossheading and prevent the outburst of the lower slice workface. Finally, rationality of numerical simulation is verified by field measurements.