Control of Weighting Accident and Its New Monitoring and Forecast for Mining Coal Seam with Hard Roof of Thick Layer Sandstone

摘要

The technology of mining all height at one time with single hydraulic prop and new monitoring and forecast methods for mining pressure were proposed according to the technology problems of production safety in the process of mining the coal seam with hard roof, such as high roof pressure, unstable supporting system and frequent weighting accident. The secure and efficient mining for coal seam with unsteady occurrence and hard roof of thick layer sandstone was realized finally. The relation among supporting strength, advance speed and roof fracture is discussed and the result indicates that the position of roof farcture relates to the mining weighting accdient closely. Based on the theoretic analysis of motion parameter for roof, the supporting scheme is designed for wall face quantitatively. The field practices indicate that the mining without coal pillar can lessen the weighting strength and improve the coal recovery rate greatly. The accuracy of weighting forecast for hard roof is increased obviously by introducing new comprehensive technologies which are separation telemetry and electromagnetic radiation for pressure forecast. The combination of long-term and short-term forecast for roof weighting can ensure the safe production of working face with hard roof. These research achievements have been used in several mines with hard roof in western Beijing and play a demonstration role for similar mining.