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.