*Article* **Theoretical Analysis of the Movement Law of Top Coal and Overburden in a Fully Mechanized Top-Coal Caving Face with a Large Mining Height**

**Li Li 1,2,3,\*, Xiao Zhang 1,2,3, Jianqiao Luo <sup>4</sup> and Bin Hu 1,2,3**


**Abstract:** In recent years, with the rapid development of equipment manufacturing and advances in the research on mine pressure and rock mechanics, large-mining-height comprehensive mechanized coal mining technology has become increasingly widely used in thick-seam mining. On this basis, because the free space extracted is several times that of layered mining, the occurrence of strong ground pressure caused by the violent movement of the basic roof and the low recovery rate of the top coal have become the main problems. In this study, Dong Liang Coal Mine was taken as the engineering background by which to study the three typical movement forms of the basic roof, and the critical fracture conditions of the three forms were obtained through theoretical calculations. The movement result state of the basic roof strata was taken as the different overlying boundary conditions of the top coal to simulate its impact on the recovery rate, to explore the interaction mechanism between the basic roof strata and the top coal, and for use as a theoretical basis to guide engineering practice to improve energy recovery rates and safety efficiency.

**Keywords:** fully mechanized caving; large mining height; extra-thick coal seam; cantilever beam; top-coal boundary conditions; finite element numerical simulation
