Vol 29 Iss. 1

Honored Professor of the Leningrad Mining Institute, a major scientist and engineer, the founder of a new direction in mining science, Boris Ivanovich Bokiy was born on July 23, 1873. In 1890, he entered the St. Petersburg Mining Institute, where he graduated with first class honors in 1895. All of B. I. Bokiy's activities were aimed at resolving the main and most pressing issues of the mining industry. The activities of Professor B. I. Bokiy can be conditionally divided into two periods. The first 12 years (1895-1906) he worked mainly in production - in the Donets Basin. From 1906 until the day of his death (March 13, 1927) - at the Leningrad Mining Institute, where he was invited by the Institute Council to head the Department of Mining Art. As the list of his works shows, Professor B. I. Bokiy strove to resolve the most pressing problems of the coal industry. This is also characteristic of the works written in the same period of review articles (see article).

The urgent task is to create and implement reliable and highly productive methods of mechanized fastening of working faces. The article presents various types of shield support for the development of thin and medium-thickness steeply dipping seams in strips down the dip: 1) sectional shield support; 2) U-shaped shield; 3) L-shaped flexible shield; 4) self-braking shield. The horizontal arrangement of the working face and the development of the seam in strips down the dip significantly facilitate the creation of a simple and efficient shield support. In order to reduce the load on the shield elements, reduce metal consumption and ensure the most reliable operation, it is necessary to prefer flexible shields consisting of support frames or short sections (0.5-1.0 m) connected by a flexible connection. With a seam thickness from 0.6-0.8 to 3.0-4.0 m, the use of L-shaped shields is most appropriate. U-shaped shields are less rational due to their excessive bulkiness and difficulty in controlling them when lowering. The proposed shield support can be used in the development of steeply dipping seams with a thickness of 0.6-0.8 to 3.0-4.0 m, with an angle of incidence greater than 50-55° and with medium-hard and strong wall rocks.

The geometry of the subsoil (mining geometry) took shape as an independent discipline in the post-October period on the basis of the socialist mining industry, which set the tasks of rational exploration, development and use of the subsoil in a new way. This article, which does not claim to cover the issue in detail, sets itself the goal of characterizing the study of some issues of the geometry of the subsoil and clarifying the content of further research work in this area. It briefly touches on all sections of mining geometry, starting with projections used in solving mining geometry problems and ending with the accounting of the movement of reserves, losses, dilution and production.

In the coal mining industry, the development of thick seams presents the greatest difficulties. In the matter of improving the methods of developing thick steeply dipping seams, the most promising direction should be considered the improvement of known and the creation of new systems that provide for the development of the seam without dividing it into layers with maximum use of natural conditions: high seam thickness, steep dip, etc. Systems for developing thick steeply dipping seams without dividing them into layers, in turn, can be divided into three groups: 1) systems that provide for the development of the seam with chambers (systems of engineers I. N. Koznin, G. A. Lomov, and others); 2) systems that provide for the development of the seam in strips along the dip or rise (the system of Professor Chinakal, the VUGI system); 3) systems that provide for the development of the seam with long columns along the strike (the system of engineer P. I. Kokorin, and others). The proposed article is devoted to the third group of systems that provide for the development of thick steeply dipping strata with long columns along the strike without division into layers. These systems are distinguished by their greatest simplicity, versatility and high efficiency.

The dynamic braking system has recently become widely used in coal mines for inclined lifts in cases where it is necessary to lower cargo or people at reduced speed. Compared to the counter-current mode, dynamic braking is more economical. In appropriate cases, dynamic braking can also be used for vertical lifts.

When designing, the excavator drive is calculated for maximum loads without taking into account the possible conditions of machine use and the forces that arise. As a result, the drive power often does not match the bucket capacity, which leads to incomplete use of the machine. The purpose of the author's research was to study the static lifting force during digging under various excavator operating conditions. When designing excavators, it is necessary to construct diagrams for all possible operating modes, on the basis of which a choice can be made of the optimal drive modes, its power and regulation. The proposed calculation method is simple and clear. It is of particular importance for the design of high-power excavators intended for specific conditions with previously known geological data.

A new method for selecting power supply elements is presented for discussion, which allows for increasing the accuracy of calculations for traction networks and substations for mine electric locomotive haulage. This calculation method allows for taking into account all the main factors that determine the conditions of electric locomotive traction: the productivity and length of haulage sections, track slopes, the size of the train, travel time, etc. Unlike existing methods, the time of movement of the electric locomotive under current during the trip is taken into account separately, which significantly affects the total load value. The calculation completely excludes the subjective method of selecting calculation parameters: cross-sections according to schedules, train placement on the line, the number of simultaneously operating electric locomotives, the number of electric locomotives in starting mode, etc. Load currents are taken as average integral values, related to the time of movement of the electric locomotive under current, and not to the total time of movement or trip. During calculations, it is possible to check not only the magnitude of the overload, but also the duration of its action and the repetition frequency. The new calculation of power supply elements is part of the general calculation methodology for electric locomotive traction. It is based on the initial data for determining the rolling stock elements (number of cars in the train, total number of electric locomotives) and on the calculation of the elements of the movement of the electric locomotive haulage (traction force, speed, current value and travel time). The technical calculation when choosing the most advantageous option includes elements of economic comparison.

Theoretical and experimental studies have established that the highest productivity of cutting machines and coal combines can be achieved by automatic equalization of the load on their electric motors using appropriate automatic regulators. The load on the electric motors must be equalized by changing the feed rate of the machines at a constant cutting speed. The choice of the structural diagram of the regulator, its individual elements and the parameters of these elements is determined by the properties of the regulated object. To determine the properties of the regulated object, it is necessary first to consider the nature of the change in the load on the electric motor during the regulation process, and then find the equation of motion of the machine. When the load on the electric motor changes during operation, the regulator will change the feed rate by changing the gear ratio between the motor shaft and the feed drum shaft until the motor power is restored to the nominal value.

Currently, the excavator drive of the generator-motor system with continuous electric machine regulation has become widespread. Our analysis of currently existing systems (drives of excavators SE-3, EGL-15, ESh-75/10) made it possible to propose a classification for electric drives of single-bucket excavators with continuous electric machine regulation. The classification is based on two features: the regulation principle and the excitation system in which the control links are located. The proposed classification made it possible to identify the advantages and disadvantages of individual systems, showed the prospects for their development and the expected properties of individual electric drive systems. The final choice of the optimal excavator drive system can only be made with strict consideration of the geological and mining conditions of the deposit, the development systems used, typical load schedules, technical conditions of regulation and economic indicators.

The terminology in the field of mining still contains many imprecise, polysemantic definitions and foreign words. This often complicates the correct understanding of the essence of the issue being presented and is the cause of mutual misunderstanding even between specialists in the same field. The struggle for the purity of the Russian language, the utmost precision and reflection of the technological meaning of special terms is extremely important. The work on the creation of a unified, correct terminology, which began several decades ago, is not finished and the terms developed by the Committee for Technical Terminology of the USSR Academy of Sciences are being adopted slowly. The establishment of uniformity of terminology in mining is a matter of extreme importance both in technical and legal terms. We will dwell only on some concepts related to opening and development systems, as well as the terminology of mine workings.