Multi-method synergistic determination of the development height of the water-conducting fractured zone in the 82,209 working face.

Accurate determination of the water-conducting fractured zone (WCFZ) height is critical for preventing roof water inrush in coal mines. Taking the 82,209 near-horizontal fully mechanized caving face of the No. 22 coal seam in Lijiayao Coal Mine as the research object, we established a multi-method synergistic system combining empirical formula calculation, key strata theory prediction, surface borehole field measurement and numerical simulation. Empirical formulas produce highly scattered results (32.94-135.00 m) and are only suitable for preliminary estimation. Key strata prediction and numerical simulation agree well with field measurements, with relative errors of 0.69%-4.15% and 1.36%-4.56%, respectively. The final WCFZ height is 64.52 m at Borehole 1 and 113.58 m at Borehole 2. Numerical simulation reveals a three-stage evolution law: initial development, rapid expansion and stable development. The multi-method system achieves accurate WCFZ determination and provides a valuable reference for water disaster prevention in similar mining conditions.