Vol 44 Iss. 1

Mining science and mining industry of the Soviet Union suffered a great loss. In the heyday of creative forces and his great talent, a prominent scientist - Professor, Doctor of Technical Sciences Pavel Ivanovich Gorodetsky died suddenly.P. I. Gorodetsky was born in December 1902 in Vyshny Volochok, formerly Tver province.P. I. Gorodetsky received his higher education at the Leningrad Mining Institute, which he graduated in 1929 with a degree in “development of ore deposits”. From that time his whole life was inextricably linked with the domestic mining science and mining industry.

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.

The study of rock pressure on models with quantitative measurement of loads is a rather difficult task. In order to obtain satisfactory results it is necessary not only to select a model material that meets the specific conditions, but also to have reliable measuring equipment. Dynamometer base was first applied in 1955 in the All-Union Coal Institute (V.G. Bochkarev), and then in the Institute of Mining Engineering, USSR Academy of Sciences, and some experiments were conducted by VNIMI.

In the practice of field development under reservoirs and large aquifers very difficult in theoretical and practical terms is the choice of a safe depth for mining operations. This explains, on the one hand, the frequent abandonment of large reserves of minerals in pillars, and on the other hand - water breakthroughs, causing disruption of work and accidents.In Donbass, Kuzbass, Moscow region and other basins accumulated considerable experience of mining coal seams under water bodies.

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 optical method of modeling the stress state, as it is known, opens wide possibilities of studying the stress state of the rock massif of inter-chamber and ceiling pillars and other elements of the mining system. Until recently, this method was used mainly to solve the problems of stress distribution around single (preparatory) workings. In this paper we set a volumetric task of studying by photoelasticity the stress pattern in the conditions of the pilot block of the Altyn-Topkan mine.

Optical method of stress modeling is now widely used in the study of stress distribution in various building structures, in solving problems of hydraulic engineering, theoretical mechanics and is becoming more and more widespread in mining. The most important issue in this research method is the quality of the material of models, as its properties determine the possibilities of the method and the technique of the experiment. The application of the polarization-optical method to the study of rock pressure issues is particularly difficult because elastic properties are not equally inherent in all rocks. In a number of cases, rocks reveal properties of plasticity, anisotropy, have fractured or layered structure.

In the practice of ore deposit development, the need to maintain the rocks surrounding the ore body being mined in static equilibrium for a long period of time arises in connection with cleaning operations under structures, reservoirs or under active open pits. This can be accomplished by leaving ore pillars of sufficient size or by excavating all of the ore but constructing artificial supports to keep the surrounding rocks stable. In the first case, the ore is extracted from the chambers by highly efficient systems, while the ore pillars remain or, after they are no longer needed, are extracted, but usually by low-performance systems, under difficult conditions and with great loss. In the second case, when artificial supports are used, their erection is associated with additional work and costs.

In the practice of the mining industry, there are cases when the release of manganese ore from the chambers has to be carried out under a rock fill, which is lowered after the ore and is continuously added as the ore is released. The need for this may be encountered when the rocks of the hanging wall or the inter-chamber ore pillars are not stable enough. In this case, the stockpile lies directly on top of the ore or a slab is used to separate the ore and the stockpile to prevent the stockpile material from stripping the ore. However, the overlap may not always fulfill this role. For example, if the dip angle is not steep enough and the floor is high, it will drop to the lay side early, and a significant amount of ore will then be released virtually uncovered. The overlap falling on the lying side, together with the stockpile lying on it, may also clamp some of the ore, which will then be lost. This is due to the tendency of the ore pieces, the backfill and the slab itself to move vertically downwards under the influence of gravity.

Already at the first stage of design there is a need to determine the volume of total and annual transportation of ore, rock and the upper contour of the open pit. From the volume of work for the design year, the capacity of the open pit Ap for ore is known in advance and the volume of rock work Bp is unknown, which must be determined for all subsequent calculations. Design calculations on the annual volume of rock works can be represented by the following dependencies.

Bulk rock is characterized by the following: 1) loose rock massif consists of separate, not connected with each other pieces of hard rock; 2) pieces of rock are small enough in comparison with the width of excavation, which practically excludes the possibility of vaulting; 3) the shape of pieces and their location determine the possibility of lateral spreading forces by mutual wedging under the action of load. Often it is necessary to support excavations under the collapsed rock or stockpile, the properties of which are often close to loose rock.

The most important operational characteristic of a hopper is the uniformity of material flow when the outlet opening is open. If this process is disturbed, numerous difficulties arise, often necessitating emergency operation or serious disruption of the entire plant (concentrator, metallurgical plant, power plant).

The Norilsk polymetallic deposit is developed by underground mining in difficult mining and geological conditions. The ore deposit is located in the permafrost zone, has intensively developed fracturing, a thick thickness of covering rocks and is characterized by the release of methane into underground workings from coal seams underlying the ore deposit. At the Zapolyarny mine (formerly named No. 7/9) disseminated ores were mined using a chamber-and-pillar system with ore storages or with stripping from sub-stage drifts. These systems were abandoned because they did not provide safe working conditions for miners and stability of inter-chamber pillars.

The study of the regularities of wave propagation excited by explosion in rocks is of great importance in various fields of science and technology. Studies have established that they play a significant role in the general process of hard rock destruction. However, a rigorous theoretical consideration of this issue presents enormous difficulties.This paper presents some qualitative and quantitative results of the experimental study of the patterns of propagation of stress waves in hard rocks caused by the explosion of a charge of spherical shape. On the basis of generalization of experimental data and some theoretical assumptions, approximate empirical dependences are obtained, which allow to calculate their main parameters.

In recent years, more and more work has been carried out on the introduction of rod fasteners in mining, capital and preparatory mine workings at mines and mines in the Soviet Union. The rod supports are tested in various mining and geological conditions as permanent, temporary and auxiliary supports, as well as to prevent rock sloughing at the bottom of workings.