Use of reliability theory to calculate the required number of reserve longwall faces

In active pits in the Donbass, plans for loading and cyclic working involve a reserve of extraction faces. However, in most cases the norm for the reserve is fixed arbitrarily because we have no scientifically based methods of calculat ing it. This norm cannot be the same for all cases, and must be determined for the particular conditions prevailing. However, in most Donbass pits the reserve factor of active longwall faces is about 1.3.