Research on reasonable length of steeply dipping coal seam working face based on the fuzzy comprehensive evaluation method

The study employed the Analytic Hierarchy Process, Coefficient of Variation method, and fuzzy mathematics to determine the optimal working face length through evaluation of six key cost factors. The application of economic optimization principles and operational safety standards yielded an optimal working face length of 260 m. Numerical simulations and field data indicate that the 260 m working face achieves lower roof stress levels and reduced machinery wear. Field tests demonstrated that the roof subsidence was maintained below 0.37 m, with higher consistency between the predicted and actual stress distributions, validating the reliability of the method for the working face length in steeply dipping coal seams.