Research on the Grouting Thickness of Roof Purdah in the Mining of Karstic Water-filling Deposit

摘要

The orebody roof grouting water protecting curtain technology is to drill hole in the orebody roof to enter into the limestone strong aquifer, forming grouting water protecting curtain. The reasonable thickness of ore deposit roof water protecting curtain is critical for the effective precautions against permeability of Karst flood deposits and the safety in production during the mine service period. Currently, there is no uniformly distributed water protecting thickness design specifications for the orebody roof curtain grouting. In allusion to the design conditions of the curtain grouting mining for Gujiatai iron ore, this paper utilized coal, tunnel specifications to determine the thickness of water protecting curtain. On this basis, this paper applied numerical analysis method to conduct simulation analysis and calculation for the stability of the water protecting curtain thickness. The results showed that the curtain thickness based on the empirical formula could not meet the watertight requirements, and it should properly increase the thickness of water protecting curtain in accordance with the sphere of stope room mining influence to ensure safety of exploitation, providing a basis and guidance for the design and construction of water protecting curtain, which had certain important theoretical and practical significance for the mining of Karst water ores.