Limestone Mine Safe And Efficient Pit Mining Technology Research

With the problems such as low recovery rate,low productivity and poor safety in mining of underground limestone mine,the study of the safe and efficient mining technology in underground limestone has important theoretical and practical value to the the efficient extraction of mineral resources and mine safety.This paper,based on the actual condition of Meixian Duikeng underground limestone mine, with multi-research methods,such as the theoretical analysis, the computer numerical simulation,and field research,mainly to research the original mining technology,the main contents are as follows:Based on analyzing rupture regularity of roof with general lithology,and combined with limestone roof of Meixian Duikeng underground limestone mine,the rupture regularit of the limestone roof is concluded as tensile failure, on this basis, the results of theoretical calculation methods about the thickness of stope roof are consolidated,by using matlab for data fitting,the proper formula between the thickness of stope roof and stope span is derived, also the value of stope span,thickness and pillar was obtained by using semi-empirical formula,which provides basics for the designing of stope structure parameters;Through the applications of ANSYS and FLAC3D, the simulation calculation to each stope structure parameters which based on theoretical calculation is conducted, by the comparative analysis of stress,displacement, distribution of plastic zone and rate of roof safety, and combined comprehensive consideration of the mining conditions, the optimized stope structure parameters is obtained,which is suitable for mining with room and pillar method;To match the new stope structure parameters,the design of blast parameters for medium-length hole blasting with large trackless equipment were ascertained, based on the original horizontally layered room and pillar mining method, pre-cut top mediun-length hole pillar method is formed,three tests of blasting parameters optimization with different blasthole pattern parameters is done,the results show that blasting effects,and improtant indexes of economic and technique are better than before,which provides basics for the designing of drilling and blasting parameters.