Isolated overburden grout injection technology mining and grouting parameters discussion and optimization

The Isolated Overburden Grout Injection Technology is employed for the "Three down" coal resource mining, ground subsidence management, and fly ash waste treatment, exemplifying the concept of environmentally friendly mining. The analysis of Isolated Overburden Grout Injection Technology can be effectively conducted utilizing the large-deflection inclined thin plate combined with the slurry model. However, differences in stratigraphic parameters, such as main roof and principal key strata (PKS), among different mines, as well as variations in design parameters like working face dimensions, mining height, coal seam angle of inclination, mining speed, and grouting parameters such as the number of grouting holes, start and finish times. These parameters lead to variations in outcomes such as PKS deflection and Bed-separation development, as well as the maximum subsidence and extent of the ground subsidence basin. To guarantee accurate and effective safeguarding of village structures, exploitation of coal resources, and appropriate management of fly ash waste, it is crucial to assess each parameter's influence in the model thoroughly. This analysis aims to clarify the mining and grouting process and enhance the logical design of the essential parameters. This paper classifies and examines the influence of each parameter on the results, utilizing the case study of the 7221 work face grouting operations in Huaibei, Anhui Province, China. The mining and grouting parameters were re-optimized to meet the protection requirements of the Gaochangying and Houlou Gaojia villages. The changes assessed the possible advantages of enhancing the initial design of coal seam resources and including fly ash backfill.