Abstract: The storage bin at the bottom of the chute in Shenshan Limestone Mine are collapsed after the completion of excavation. The collapse of the middle part of the roof arch of the crushed chamber shows an inverted funnel-shaped cavity. The bolt-mesh support system was damaged and failed at this site. The rock mass suspended along the edge of the funnel-shaped cavity was unstable and incompletely collapsed， so there was a hidden danger of secondary collapse. The main reason for that above is the poor self-stability of rock mass， and disturbance to rock mass during the blasting excavation of storage bin at chute. According to the actual situation of the site， the principle of from top to down is adopted to reinforce the upper rock mass of collapse area with long bolts. Shotcrete support for roof in collapsed area are used to make the roof reinforcement at the current collapsed goaf by long-bolt and net spraying. Practice shows that the safe operation under the goaf roof can be guaranteed by using coarse sand backfilling to deal with the collapsed area. Continuous development of collapsed area can be controlled in time by using shell-expanding prestressing bolt. This scheme effectively ensures the safety of roof and has good engineering experience for dealing with large-scale collapsed goaf.

Key words: Collapse of ore storage bin, Cavity, Support design, Filling and reinforcement