Method for screening key stratum for overburden separation grouting in coal mine

A method for screening a key stratum for overburden separation grouting in a coal mine, comprising:

• selecting overall analysis objects based on coal mine planning;
• conducting a primary screening of the analysis objects based on a scope of a subsidence zone;
• conducting a secondary screening of the analysis objects based on whether there is an existing goaf;
• determining key stratums for screened-in analysis objects based on a key stratum theory;
• prioritizing the key stratums based on a number of separation spaces and a range of a separation height;
• setting a safe separation height for key stratums of 50 m based on a diversion fissure zone;
• and prioritizing numbers of groutable layers based on a potential separation space and a water resistance of a rock stratum;
• prioritizing the groutable layers based on a fault impact;
• and
• comprehensively analyzing grouting priority levels of the key stratums based on results of the three prioritizations, and grouting separation layers of the key stratums in order of priority levels,
• wherein the key stratums are comprehensively ranked based on the results of the three prioritizations and are given a priority level of superior, medium, or inferior, and the key stratums are grouted in order of their priority level.