Feasibility Research on Grouting and Filling Mining in the Overburden Abscission Layer Zone in No.2 Panel Area of Zhaozhuang Coal Industry

In view of the problems such as limited stoping of "three under" overburden resources, difficult control of surface subsidence, high pressure of gangue storage and others in No.2 panel area of Zhaozhuang Coal Industry, a grouting and filling scheme for overburden abscission layer is proposed, the sub key layer III is determined as the grouting target layer through overburden rock structure exploration, and a mining layout with a mining width of ≤ 267 m and isolated coal pillar width of ≤ 30 m is proposed, full section grouting and high-pressure water holding servo control technology are adopted to form system parameters with a burial depth of 349.05 m, grouting pressure of 4.0-4.5 MPa, water solid ratio of 1.7∶1, and daily grouting volume of 4700 m³. The surface deformation prediction indicates that the maximum subsidence amount is decreased from 1822 mm to 253 mm, meeting the level I protection standard and effectively guaranteeing the safety of railway collection stations and surrounding villages. Meanwhile, the annual consumption of coal gangue is 742 500 tons, and the grouting volume is 1.55 million m³, resource utilization and emission reduction benefits are achieved. The research shows that this technology has good application value and provides technical support for efficient stoping of complex overburden resources and green mine construction.