Abstract: The minimum safety thickness of mined-out roof in Donggou molybdenum mine is calculated by adopting the three-dimensional finite element numerical simulation method, so, the minimum safety thicknesses of safety of mined-out roof of different spans are obtained. The calculation results can provide theoretical foundation for mined-out comprehensive treatment and open-pit safety mining.

Key words: Mined-out comprehensive treatment, Minimum safety thickness of roof, Three-dimensional finite element numerical method