Vol 17 Iss. 18

The author of this note has repeatedly emphasized the important role of ferruginous chlorites in the composition of the ores of a number of tin deposits. However, as prospecting practice shows, the existing information is still clearly insufficient. At present, there are sufficient grounds to assert that ferruginous chlorites are specifically characteristic minerals for a large group of tin deposits belonging to the so‑called cassiterite‑sulfide formation. For example, in almost all ore districts of the vast northeastern metallogenic province, we now know representatives of the “chlorite” variety of cassiterite‑sulfide deposits. The value of chloritization as a prospecting indicator is further enhanced by the fact that chlorite‑rich deposits are almost indisputably among the highest quality concentrations of tin, both in terms of reserves and ore grade. In any case, the proportion of deposits of industrial interest in this group is very high. Thus, although ferruginous chlorites are not exclusive to tin deposits, their value as a prospecting indicator for tin ores remains almost in full force.

Effective operation of an air lift must be ensured by the correct choice of its main elements; at present, however, such a choice based on calculation presents significant difficulties and is often made at random, without a guarantee of reliability. The reason for this lies in the imperfection of the existing theory of airlift operation. Or rather, a unified theory of this device, so simple in design, still does not exist: we can only talk about various theoretical studies based on different principles. All these studies, to a greater or lesser extent, suffer from unfoundedness, vagueness and even fallacy of their main provisions and assumptions, as well as experimental unverifiedness. The objective of this work is to identify unacceptable provisions of these theories, and to reconstruct the airlift theory on the principle of elastic emulsion expansion, eliminating errors inherent in previous works. At the present stage, however, it may already be possible to apply operational curves to airlift calculations, as we did in this work (see the article).

The Cheremkhovo deposit, both in terms of geological and mining operational conditions, differs significantly from other coal deposits of the USSR. In view of this, with respect to the specified conditions, it is not possible without special observations to make a confident conclusion about the nature of the process of surface displacement under the influence of mining. Meanwhile, such issues as the speed of the subsidence process, the amount of surface subsidence, the magnitude of subsidence angles, etc., are practically important issues, the clarification of which is necessary not only for the correct construction of safety pillars and the solution to the question of the possibility of building on previously undermined areas, but also for choosing a method for managing the roof and establishing a rational sequence for mining the lower and upper layers of the main seam of the Cheremkhovo field. In accordance with the above characteristics of the rate of attenuation of the process of surface displacement in the conditions of the Cheremkhovo deposit, it was recommended: 1. Allow the construction of wooden buildings in areas undermined by longwalls one year after the extraction of coal. 2. The construction of stone buildings is allowed after 1-2 years (depending on the permanence of the building) after the excavation of coal under the site.

Eyepiece scales are known in surveying practice under the name of Bratgun scales, by whom they were proposed for observing the fluctuations of the plumb line instead of the usual scales installed near the plumb lines. Bratgun's proposal was used for orientation through two shafts, and for this purpose mining theodolites are equipped with an additional eyepiece elbow with an eyepiece scale and reticle. To use the eyepiece scale, the eyepiece tube of the theodolite telescope is replaced with a tube containing an eyepiece scale. The scale is applied mechanically or photographically to the glass. The value of one scale division depends on the focal length of the sighting tube; in mining theodolites it is made equal to about 50″. The high accuracy of the scale markings and the small value of the scale divisions make it possible to use eyepiece scales not only when orienting through two shafts, but also through one. This article proposes a method for using eyepiece scales to solve one of the most important tasks in surveying: the orientation of mine surveys. This method introduces technical improvements in the production of orientation and reduces the time for its execution. The proposed methods of using eyepiece scales increase the speed of orientation, do not require capital and bulky platforms for scales, and allow the observer to make measurements and observations in the mine in better conditions.

The success of mineral processing by flotation depends on very many factors. However, the literature has not yet paid due attention to this issue. The optimal values of all factors that mutually influence one another for each object of study are established experimentally, which, given the large number of factors, makes it extremely difficult to establish the optimal flotation regime. Below we briefly present the results of a study of the influence of some flotation factors on the enrichment of hübnerite ore, which are usually not attributed much importance (see the article). From the above materials it should be concluded that during the flotation of hübnerite ore in the presence of oleic acid and sodium oleate, a sharp improvement in flotation results is observed with fractional loading of the collector (7-8 portions, with a total consumption of 0.5-0.7 kg/t), adding potassium bichromate as a deflocculator, with a high pulp density (33-50% solid). Establishing the optimal values of the listed factors made it possible to sharply increase the degree of concentration during primary flotation, and this circumstance, in turn, provided the possibility of effective cleaning operations.

Currently, in the Kuznetsk basin, the boundary of productive (Yerunakovskaya, Balakhonskaya) and unproductive formations and subformations is considered to be the last or first layer of working thickness (more than 0.70 m). However, recently a lot of data has accumulated that contradicts this assumption. The paleontological division will not coincide with the industrial one. A more objective criterion could be a quantitative, i.e. statistical, approach to various lithological features. Based on the idea of the cyclic structure of coal-bearing strata and knowing the differences between the typical cycles of the Ilyinskaya and Yerunakovskaya subformations, primarily in scale, we made an attempt to statistically test changes in the average and maximum thickness of cycles in a specific section. Statistical, i.e. quantitative, analysis of a number of lithological characteristics (mainly thickness) reveals the possibility of establishing a sharp and fundamental boundary corresponding to a sharp change in the average amplitude of cycles. Other features of the cycles are closely and genetically related to this change, for example, the thickness of the basal sandstones of the continental facies, the thickness of coal seams, and therefore a sharp increase in the number of working seams, i.e. purely practical consequences. This allows us to recognize that it is more rational to draw the boundary of two subformations, Ilyinskaya and Yerunakovskaya, on the basis of the cyclicity of about 41 layers, which has a number of advantages (see the article).

The issue of determining the size of interchamber pillars is a very important issue, since it is closely related to issues of mineral loss. Factors such as the width of the chambers, the length of the chambers, the height of the pillar, the cross-sectional shape of the pillar, the physical and mechanical characteristics of the pillar rock should be reflected directly in the calculation formulas, and such factors as the nature of the complex of roof and floor rocks, the characteristics of the immediate roof and floor, the presence of aquifers, the shape and area of the excavation site – should be reflected in determining the magnitude of the load on the pillar and the nature of the pillar's work and, finally, the duration of the pillar's operation, work with or without backfilling of chambers, excavation of chambers with or without the use of blasting operations should be taken into account when choosing a safety factor.

Free fall is theoretically defined as the fall of an isolated grain in an unlimited space of a surrounding medium (water or air). Practically, it is considered as the fall of a set of grains at a concentration where the movement of any grain is not significantly disturbed, either directly or through the surrounding medium, by accompanying grains. Free fall is of particular importance in the process of precise classification, where the movement of grains is considered to be uniform and occurring at a constant terminal velocity. As the grains fall through the medium, they displace the medium from the places that they successively occupy. Strictly speaking, their shapes and internal mass distributions do not remain constant during such movement, but these changes are so small that they are unconditionally neglected. In all cases of grain‑liquid interaction, we observe the same phenomenon: the flow of the medium around the grain. This flow, caused by the impermeability of the space occupied by the grain to the liquid medium, causes a change in the motion of the oncoming flow of the medium. The motion is accompanied by friction at the boundary between the grain and the medium. The question of the magnitude of the resistance experienced by a moving body is one of the oldest problems in dynamics, but to this day no final theoretical solution has been achieved, which has led to attempts to directly determine the resistance experimentally and has given rise to the successful development of experimental hydro‑ and aerodynamics.

The brown coal deposits of the Ural-Emben region, known since the last century, did not attract serious attention for a long time. And only in recent years, the growth of local industry in connection with the development of the raw material base of this area forced attention to be turned to these deposits. Brown coal deposits of the Ural-Emben region can be a serious energy base that fully meets the needs of a rapidly growing industry, freeing up oil and high-quality coal for their more rational use. In the specifics of geological exploration work in the Ural-Emben region, a major role is played by structural issues, covering, on the one hand, the structure of the entire region with the distribution of these deposits, and on the other hand, the structure of individual deposits, which is related to issues of their volume, quality and conditions of their use. Correct structural analysis of these forms is the main basis for their study and exploration. The present work is the first attempt at such an analysis. Brown coal deposits of the Ural-Emben region are still in the initial stages of their study and use. The structural analysis we have given in this work of the entire region and its individual deposits goes towards the upcoming large-scale work of prospecting and exploration of new deposits.

Chekanovsky, during his trip to the Olenek in 1875, established for the Mesozoic deposits developed along the Olenek and Lena two divisions, which he named: the lower (dark clayey shales with Inoceramus retrorsus) — the Surak stage, and the upper (light gray sandstones with I. retrorsus and aucellae) — the Inoceramian stage. The first mention of this is in the article by Lagusen, who described the fauna of these deposits and came to the conclusion that in age they can be compared with the Volgian stages, and the Inoceramian stage is apparently even younger than the upper Volgian stage. Later, D. N. Sokolov, in connection with the question of the age of I. retrorsus, recognized that the Surak stage corresponds to the upper part of the upper Volgian stage or the Berriasian; but he was inclined to consider the Inoceramian stage to be merely a facies change of the Surak stage, differing from it in the co‑occurrence of inoceramids and aucellae, or even in the predominance of the latter. The idea of the position of both Chekanovskii’s stages at the Jurassic‑Cretaceous boundary or at the very bottom of the Lower Cretaceous was accepted by all subsequent authors and transferred to summary works on the geology of Siberia.

The issue of reducing gold losses in tailings during the enrichment of non-ferrous metal ores is currently receiving special attention. The presence in most non-ferrous metal ores of significant quantities of pyrite, which goes simultaneously with gold into the tailings, gave grounds to explain the loss of gold in the tailings by its close association with pyrite. It is necessary to establish whether gold is really closely associated with pyrite and is in such a finely disseminated state that it is not released during the most intensive grinding and remains inaccessible to solvents in subsequent hydrometallurgical processing operations. Experiments in the synthesis of gold sulfide and gold-containing iron sulfides have shown that pyrite and pyrrhotite formed at temperatures of 400°C are capable of including measurable amounts of finely dispersed gold, undetectable under a microscope even at the highest magnifications. Submicroscopic gold in some cases can be represented by sulfide dissolved in iron sulfides. Such finely dispersed gold in some cases may be a product of the decomposition of primary gold sulfide dissolved in iron sulfide. The form of gold released from pyrite in our experiments corresponds to the forms of natural gold in pyrites of some deposits.

In the pre-war years, in the laboratories of the Department of Geophysical Exploration Methods of LOLGI, the development of new methods and new techniques for electrical prospecting using low and high frequency currents was carried out. A number of new electrical prospecting methods have been developed: a method for measuring anomalous fields at high frequencies, a method for measuring fields out of phase with the generator field, electrical profiling on alternating current with compensation for the normal field, etc. All of them are based on measuring only anomalous parts of the field, which leads to greater sensitivity of the methods and their extraordinary portability. At the same time, the technology and methodology of already existing electrical prospecting methods were developed and, for example, for the intensity method, equipment was designed that makes this modernized method completely different from the old method. Below are some results of part of the extensive work carried out (see article).