Vol 12 Iss. 3

Generalizing the Catalan problem about the motion of a point rotating on a polished surface, the author searches for surfaces that allow the motion of a point rotating in a spiral with a vertical axis in the presence of friction, and explores the nature of the stability of the motion of a point of rotation on a spiral located on a rough helical surface with a vertical axis, and also the influence on this movement of the resistance of the environment, depending on the speed, and the rotation of the surface around the aerodynamic propellers.

Currently, to study the shape, size, deformation and movements of various bodies, their perspective photography is widely used, which served as the beginning of a number of new sciences, such as aerial photography and filming. This work is an introduction to the theory of the mentioned methods and contains elements of measuring perspective , i.e., solving metric problems in perspective. In addition to the specified practical goal, the methodological goal of the work is to use the coordinate method to systematically solve the main problems of descriptive geometry using the conical design method. In accordance with the above, this work is divided into two parts: the first includes the basic principles of the conical design method and methods for solving metric problems, and the second contains a number of solutions to typical examples that can be used in presenting a course in descriptive geometry.

This article is in the nature of a preliminary report on some principles of flotation in a non-aqueous medium. The practical possibility of flotation in hydrocarbon liquids (kerosene, xylene, benzene) of hydrophilic minerals (quartz, table salt) and the absence of flotation of a more hydrophobic mineral - pyrite, is shown, thanks to which it turned out to be possible separate the quartz-pyrite mixture. From a large number of tested substances, those that are capable of producing the effect of collecting minerals were found - alcohols of the limiting series. True, their consumption in flotation is unusually high, and the stages of loading them into the pulp are of significant importance. The greatest collecting effect is produced by the middle members of the homologous series (ethyl, isopropyl alcohols). The phenomenon of temporary cessation of foaming was observed with large one-time loads of alcohol into the pulp. A parallel is drawn with “over-oiling” during flotation in water. The phenomenon of excess alcohol is related to the size of the radical of the alcohol molecule. A number of examples show the effect of water on the floatability of quartz. It turned out that very small amounts of moisture worsen the process, and a subsequent increase in water to a certain extent improves the flotation of quartz. It has also been shown that during flotation in hydrocarbon liquids there is an optimal liquefaction of the pulp, at which flotation proceeds most successfully.

A quick glance at scientific papers and articles, practical manuals, textbooks or teaching aids on flotation is enough to draw attention to the unanimous opinion of all authors about the invariably harmful role of organic hydrophilic protective colloids in flotation. All authors agree that organic protective colloids are identical to flotation poisons and have exclusively one function of suppression, depression of all minerals during flotation. At the same time, there are no indications in the literature of work on the study of the flotation properties of organic protective colloids, but quite often there are examples of the successful use of various protective colloids in flotation practice (starch, glue, tannin, soaps, etc.). As a result of this inconsistency, the categorical statements of the cited authors about the harmfulness of protective colloids in flotation become unconvincing and the need arises for a systematic study of the flotation properties of these substances. It is precisely these considerations that prompt the formulation of this work and the appearance of this article, which presents an incomplete summary of the experimental data obtained.

In 1936, in the laboratory of mine ventilation, associate professor V. B. Komarov and assistant A. A. Geskin carried out work to determine the resistance coefficients of turns of ventilation pipelines while simultaneously narrowing them. This work set itself the task of determining the resistance coefficients of turns of channels mine fans, designed in various ways. The work was divided into two parts: a) determination of the rotation coefficients with simultaneous compression of the air stream, b) determination of the rotation coefficient with simultaneous expansion of the air stream. This work presents the second part of determining the resistance coefficients of channel turns. The work done by the authors makes it possible to clarify a number of provisions related to the design of fan channels when fans operate to pump air into the shaft.

The purpose of this topic is to analyze the basic operating conditions of excavators such as a mechanical shovel, which have (compared to other types) the maximum application at our mining enterprises; using the example of Mounts Magnitnaya, Vysokaya and Elenovskie quarries, study, analyze and generalize the experience of excavator operators; establish ways of the most rational organization of excavation work. The above reasons for excavator downtime and its unproductive use are the most important and undoubtedly overwhelmingly removable. If we turn to other reasons, they can be exhausted by the following list: refueling and lubrication of the excavator, routine repairs, emergency repairs, cable re-hooking, cable change, bucket cleaning, path preparation, lack of energy, lack of spare parts, lack of contact network, change of crews , others. A significant part of these reasons can also be eliminated by proper organization of the entire mine economy, coherence of all workshops and responsible management and supervision of engineering and technical personnel, representing a reserve for increasing the productivity of the excavator.

When mapping in Mountainous Dagestan in the summer of 1937, in the Upper Cretaceous deposits, I observed horizons of crushed rocks among quietly lying sediments. These horizons, as well as the underlying and covering rocks, are represented by light, strong, layered limestones, characteristic of the Senonian deposits of Dagestan. Small domes composed of Upper Cretaceous rocks among Tertiary sediments are observed near the villages. Gubden, then in the north of the region - the dome of Maraulark and to the north of it - the dome of Eldam. The region of interest to us is transitional from the area of development of normal folding to the area where dome-shaped structures appear. Apparently, dome formation also occurred here in the Upper Cretaceous, but the dome-shaped structures that appeared were obscured by subsequent folding. At the same time, it is quite natural to assume that during folding, the anticlinal folds were located corresponding to these domes. Indeed, against the background of elongated anticlinal folds, we often observe dome-shaped uplifts. This situation fits very well with the general picture of the distribution of landslide breccias in the study area. It is characteristic that everywhere landslide breccias are confined to synclinal zones and are absent in the crests of anticlines (against the background of a general synclinal fold). In the arches of anticlines, a sort of loss of horizons and local unconformity are sometimes observed. It is very likely that these domes were the uplifts along whose slopes the movement of sediments occurred.

The main library of the LGI, which arose in 1773 together with the Institute, founded only 7 years later than the world's first higher mining school, the Freiberg Mining Academy, is not only a powerful educational support institution, but also one of the first mining technical libraries of the Union. Among other libraries USSR it has the most complete collection of journals and monographic literature on mining, geological exploration and related disciplines, since the Mining Institute in pre-revolutionary Russia for a long time was the only center for the accumulation of mining, geological and technical knowledge. Over the 165 years of existence and operation of the Main Library, two stages of its activity can be distinguished: 1. Library of the Mining Institute from 1773 to 1917. 2. Library of the Mining Institute from 1917 to the present (see article). We consider it necessary to continue to develop the work of the library with even greater energy, both in relation to information, disclosure of the contents of the library’s collections, and finding the best methods for serving the reader, storing books, etc.