Extremely thick sandstone roof slabs frequently occur in mines at depths exceeding one thousand metres. Investigating the fracture, rotational movement, and energy release of these overlying sandstone slabs in large-scale goaf areas with multiple working faces forms the foundation for preventing and controlling rock bursts. Using the second block area of Zhengtong Coal Industry as the engineering context, this paper examines the mechanism of rock bursts in extremely thick sandstone roofs through a combination of theoretical analysis and similar simulations. Research indicates that the initial breaking energy of the extremely thick sandstone roof exceeds the periodic breaking energy. This breaking energy correlates positively with the thickness of the rock layer and the tensile strength, while it correlates negatively with the width of the working face and the overburden load. The disparity between the initial breaking energy and the periodic breaking energy is directly proportional to the width of the working face. Throughout the mining process, the stress within the coal seam increases incrementally as sub-critical layer 1, sub-critical layer 2, and the main critical layer fracture. The main critical layer undergoes three stages during mining: an increase in suspension distance, bending and subsidence, followed by the development of fractures. This research achievement establishes a theoretical foundation for investigating the mechanisms of rock bursts under analogous engineering conditions.