Abstract: To address the challenge of overburden failure height prediction in Panel 3106 of Menkeqing Coal Mine,this study combines key stratum theory with multi-source monitoring technologies to systematically investigate the failure evolution mechanisms and validate the developmental height of the water-conducting fracture zone (WCFZ). Rock mechanical testing characterized lithology-dependent fracture propagation patterns,while deflection compatibility criteria and a fixed-end beam model enabled key stratum identification,yielding a theoretical WCFZ height prediction of 109. 5 m. Field validation employed surface-based fully distributed optical fiber sensing (DFOS) and underground electrical resistivity tomography (ERT).The DFOS system detected critical tensile strains exceeding 9 000 με below 94.2 m depth,while ERT revealed high apparent resistivity anomalies up to 102 m. Synthesizing these results,the operational WCFZ height was constrained to 94.2～102 m,exhibiting a 5.3% ～7.6% reduction compared to theoretical estimates. Discrepancies were attributed to spatial heterogeneity in rock mechanical parameters, oversimplifications in key stratum models (neglecting fracture zone interactions and dynamic confining pressure effects),resolution limitations of geophysical monitoring,and residual stress coupling from adjacent mined-out areas.