Study On The Key Technology Of Sub-level Caving Mining In Extremely Thick Coal Seam With Dirt Band

How to increase mining rate of top coal and to reduce refuse content is the key that whethersuccess or not of this technology in sub-level caving mining. In particular,when the thickness ofcoal seam is large, the hardness is high, containing dirt band with complex structure, and thecaving craft is not reasonable,these conditions have been seriously affected the mine’s safety,high yield and high efficiency production.The basic ideas in terms of increasing mining rate ofsub-level caving mining are:the first one is to make top coal fully broken,the second one is to usereasonable caving craft to Release the top coal. Consequently,the research and design offragmentation mechanism of top coal with dirt band in complex structure, mechanics laws of dirtband, and deep hole pre-blast on top-coal with dirt hand have become a urgent academic andtechnology difficult problem in mining engineering field, especially in the mine of this condition.This thesis according to problem of how to improve recovery ratio of sub-level caving mining inextremely thick coal seam with dirt band, and set Jinzhuang coal mine of Tongmei Grounp indetroit, then use theoretical analysis of mining pressure and strata control, mining science, elasticmechanics, theory of blasting and other related knowledge; use numerical simulation analysis ofFLAC3D、UDEC、LS-DYNA and other software; and also use field following measurementanalysis and other research methods, then the thorough researches have been done,which containfragmentation mechanism of top coal with dirt band, mechanics laws of dirt band, caving laws oftop-coal with dirt band, technology of deep hole pre-blast weakening, production processmeasurement analysis and parameter optimization in fully mechanized caving face, mainresearch contents as follows:(1) This thesis analyzed the4partitions of the top coal natural failure in fully mechanizedcaving face，summarized stress and deformation sharacteristics of thick top-coal with dirt band,and analyzed stability of dirt band. On this basis, the thesis use theoretical analysis of miningpressure and strata control material mechanical, elastic mechanics, fracture mechanics and otherrelated knowledge, established cantilever beam model and shell model of dir band’s breakingand instability.(2)On the basis of influencing factors analysis of caving property of top-coal with dirt band,according to the research on arching mechanism of top coal with dirt band, by using numericalsimulation software UDEC, analyzed different horizons, layer numbers and thickness of dirtband, reached the conclusion that top coal and dirt band’s caving features of sub-level cavingmining in various occurrence conditions of dirt band.(3)According to the research findings of elastic mechanics, fracture mechanics, damagemechanics, modern theory of blasting and other related knowledge, the thesis combines with the production actual of Jinzhuang8203mining face, calculated the three regions’ radius of coal anddirt band in the condition of coupling charge and decoupling charge, then reached the reasonablehole spacing, last by using LS-DYNA dynamic analysis software, simulated the law which affectthe broken effect of dirt band blasting by relative positions of dirt ban and blasthole, blastholearrangement and detonation mode, etc, then it takes into account the actual field conditions,anddesigned deep hole pre-blast scheme on thick top-coal with dirt hand in8203mining face ofJinzhuang mine.(4)Production process measurement analysis in8203mining face have been done in theworking shift class, put forward the concrete scheme of craft manner and parameter optimizationin fully mechanized caving face.It ensure the safety and high efficient coal mining of sub-levelcaving mining face in the condition of extremely thick coal seam with dirt band.