Boundaries of open pits are the most important parameter of open-cast mining of deposits, methods of determination of which, unfortunately, are still not correct enough, which negatively affects the efficiency of open-cast mining. The Department of Open-Cast Mining and Rock Destruction conducts continuous research on the development and improvement of methods for establishing the final contours of pits, approving the results in the design studies of specific deposits. The last object of the research was the iron ore deposit Kurkenpakhk of AO Olkon, which is currently not exploited. In the course of the research there was a doubt in the expediency of using the traditional method of levelling the bottom of the pit. The authors propose a new method of levelling the bottom of the pit.

On the example of Mikhailovsky and Yakovlevsky deposits the problems of development of rich iron ores of KMA related to their deep occurrence, taking into account difficult engineering-geological conditions of construction of underground mines and harmful consequences of ore mining by open pit for the natural environment are considered. The results of complex tests of physical-mechanical properties of loose rich ores, which have not been sufficiently studied yet, are presented. Forecast of land alienation and soil contamination caused by an increase in the volume of overburden during further exploitation of Mikhailovsky open pit is given. For the Yakovlevsky mine, the most effective layered systems of development of the ore body with stowing of the mined-out space were studied. The descending order of mining of blocks with the device on the top layer of protective overlap to prevent subsidence of the overlying strata with the formation of channels of hydraulic connection with the coal aquifer is recommended.

Determination of open pit boundaries is one of the main tasks of designing the field development. Its solution is usually carried out in three stages. The boundary stripping ratio is calculated, then the method of delineation is selected, and, finally, according to the selected method, the quarry is delineated.

Correctly chosen productivity of the open pit on mineral resources has always been the key to sustainable and economical operation of the mining enterprise. And the more complex the geological structure of the deposit, the more difficult the task of determining the productivity. Apatit's Koashvinskoye apatite-nepheline deposit is a very complex one. It is represented by four ore bodies with a configuration characterized in plan view and at depth by frequent swellings and overhangs.