For laboratory studies on models of rock pressure, a number of methods are currently used, including centrifugal modeling. This method was developed by G.I. It was first used abroad in 1934 by F. Bucky (USA) to solve mining engineering problems. In the Soviet Union, centrifugal modeling in the study of mining pressure was used by P. M. Tsimbarevich, I. D. Rivkin, R. P. Kaplunov, I. M. Panin, and S. G. Borisenko. There are now a number of operating facilities designed for research in rock pressure, structural engineering, and soil mechanics and adapted to models from natural or equivalent material.
The practice of development of mineral deposits, including ore deposits, complex mining and geological conditions, application of new development systems, increasing depth from the earth's surface, as well as the requirements of increasing the intensity, safety and profitability - more and more often put forward questions, the solution of which requires an understanding of the physical essence of the processes and identification of relevant regularities. In the field of development systems, rock pressure and deformations of the rock massif, research methods can be both theoretical and experimental. The choice of research method depends on the task at hand. In many cases it is necessary to combine methods.
Control figures for the development of the national economy of the USSR for 1959-1965 provides for a further increase in the production of various ores. It suffices to say that by 1965, ore output in the various branches of the mining industry will have increased from 2 to 3 times as much as in 1958. The major part of this increase will be achieved (mainly at new deposits) at the expense of open-pit mining, but the share of underground works remains high - about 40-50%.
In 1957, the Institute lost an outstanding teacher and researcher, a major specialist in the development of ore deposits, associate professor, candidate of technical sciences Nikolai N. Polyakov.
The economic significance of qualitative and quantitative mineral losses during mining is well known, and therefore the importance of their regulation is obvious. Although mineral losses and dilution during mining are inevitable, their size can be different, and the possibility (and the degree of technical complexity) of reduction depends, on the one hand, on natural conditions, and on the other hand - on the development system, the quality of mining operations and the quality of their control and accounting.
In determination the limit of open pit and underground mining technical and economical factors are to be considered. The ratio of overburden and waste rock stripped to the ore reserve is the principal criterion of utility of the open pit mining. Many attempts were made to give the mathematic solution of this problem, but complicated formulas and mistakes in mathematic interpretation prevented from using it in practice (see Part 3). The purpose of this article is to give the solution of this problem on the base of determination of the most profitable open pit. It is possible to give the general formulas (9) and (10) showing the expenses concerning the mining of the deposit by two variants: a part of deposit (A) is mined by open pit and another part (C) by underground method (Fig. 2); all tonnage of deposit (A + C) is mined by underground method. In the part 8 of this paper a few examples of this method are illustrated.
