Study on safety pushing forward speed of island coal mining face under hard roof and hard seam and hard floor conditions

In order to ensure a safety and high efficient mining of the island coal mining face under hard roof and hard seam and hard floor conditions, a theoretical calculation method was applied to analyze the pushing forward speed of the coal mining face affected to the mechanism of the mine pressure bump, and the lab test an d numerical simulation test method were applied to analyze the coal mechanics features under different loading speed.The numerical simulation method was applied to analyze the mining speed of the coal mining face affected to the pilot stress distribution and the results and the theoretical analysis results were well ftted.Based on the stress obtained from the numerical simulation, the elastic energy distribution condition of the surrounding rock along the gateway was calculated.The results showed th at under hard roof and hard seam and hard floor condition, the safety pushing forward speed of the island coal mining face should be less than 3.6 m/d.The site microse ismic event results were the same to the theoretical calculation and numerical simulation results, therefore, the pushing forward speed of the coal mining face should be less than 3.6 m/d rationally.