In the process of coal extraction, a fractured zone is developed in the overburden above the goaf. If
the fractured zone is connected with an aquifer, then water inrush may occur. Hence, research and analysis
of the height of overburden fractured zone (HOFZ) are of considerable significance. This study focuses
on the HOFZ determination in deep coal mining. First, general deformation failure characteristics of
overburden were discussed. Second, a new method, numerical simulation by orthogonal design(NSOD),
have been proposed to determinate the HOFZ in deep coal mining. Third, the validity of NSOD is verified
in the practical application, compared with empiric al formula in Chinese Regulations and in-situ test.
These three methods were applied to determine the HOFZ of working face No. 111303 in No. 5 coal
mine. The pre dicted HOFZ of NSOD is found to be similar to the result of the in-situ test (8.9% relative
error), whereas the HOFZ calculated by the empirical formula has extremely large error (25.7% relative
error). Results show that the NSOD can reliably predict the HOFZ in deep coal mining and reduce time
and expenses required for in-situ test.