Reasearch On The Proportion Of Cemented Filling Materials And Process Design Of Gangue Filling Grouting

A large number of residual corner pillar resources in the mine are mainly recovered by filling mining,and paste filling is a common filling mining method.However,there are also some problems in the implementation of paste filling,such as high construction cost of filling system,complex material preparation process,high material mass concentration and frequent pipe plugging accidents during transportation.Gangue throwing grouting cemented filling and paste filling also use coal gangue,fly ash and other materials,but their processes are different,which can solve the problems of high paste filling cost and material transportation.This method refers to a filling mining method in which the gangue is piled into the roadway by using the gangue throwing machine,and then the gangue is cemented into a stable filling body by grouting,so as to gradually realize the recovery of corner coal resources.Dumping gangue grouting cemented filling can not only deal with a large number of mine waste gangue and reduce its pollution to the environment,but also solve the problem of poor effect of filling and roof connection with gangue.It is an innovative filling mining method.Based on the background of dumping gangue grouting cemented filling mining,this paper makes an experimental study on the proportion of coal gangue,fly ash and other filling materials used in dumping gangue grouting cemented filling.At the same time,the grouting cementation test of coal gangue is carried out by using grouting equipment,the factors affecting the strength of grouting cementation are tested and analyzed,and the corresponding filling mining technology is designed.The research results are as follows:(1)The particle size distribution of coal gangue affects the bearing capacity of gangue accumulation.Under the same load,the compressive shrinkage of large-size coal gangue with single particle size gradation is greater than that of small-size gangue,and after the optimization of particle size gradation,the bearing capacity of accumulation can be significantly improved.(2)The grouting cementation material with fly ash as the main content is prepared.The strength growth rate and various properties of the material can meet the requirements of grouting cementation of coal gangue.(3)Continuously graded coal gangue has higher stacking compactness and lower porosity than single size graded coal gangue.In the actual grouting and cementation,if the amount of cementation material is to be reduced,continuously graded coal gangue should be used for filling.(4)Age,weathering and particle size grading of coal gangue are important factors affecting the strength of cement.Increasing the grouting pressure can not significantly improve the strength of the grouting cement,but the excessive content of small particle size powdery gangue in the coal gangue accumulation body will worsen the grouting cementation effect and reduce the strength of the cement.(5)The mining technology of dumping gangue,grouting and cemented filling is designed,which can realize the parallel operation of main processes such as coal mining,gangue stacking and grouting,and can realize the efficient recovery of corner coal pillar resources.