For prevention of unwanted originating of non-working leases of a bead and running by them it is necessary to systematize and to analyse the reasons of their creation. The reasons of temporarily-non-working walls (TNWW) forming are expedient for partitioning on two base categoriesplanning and off-schedule. The internal reasons of creation TNWW are, as a rule, result of errors both defects at budgeting and conducting mining operations. Such reasons arise in internal system of activity of the operation.