The article considers one of the most acute problems of open pit mining - the resumption and development of mining operations on temporarily non-working sides of the open pit. The impossibility of timely and full-scale solution of this problem by the majority of enterprises due to spontaneous creation of temporarily non-working faces and difficult economic situation is emphasized. In order to prevent reduction of the limits of open-pit mining and deterioration of performance of enterprises, the need to develop cost-effective ways of re-conservation of temporary faces adapted to the current situation in the national economy and mining industry is justified. A new effective method of pillar re-preservation using artificial creation of the bottom part of the pillar - bulk prism from the blasted rock mass is proposed which allows to reduce considerably (up to 60%) the scope of work to place the temporarily non-working pillar of the open pit in the working position and to increase the speed of its re-preservation. The high efficiency of the proposed method of re-conservation of temporarily non-working sides at the expense of explosive movement of a certain part of rock mass necessary for construction of a bulk prism is noted. The used order of works is described. On the basis of geometric analysis and comparison of costs of rock mass excavation by different methods the economic efficiency of re-conservation of temporarily non-working sides with the formation of a bulk prism is determined. Dependencies allowing to determine optimal parameters of the bulk prism on the basis of the condition of achieving the maximum economic effect are given.
