Vol 56 Iss. 1

The concept of “probability” occupies a prominent place in the categorical apparatus of modern science, but a number of issues related to the clarification of the meaning of probability and the conditions of applicability of this concept have not been sufficiently investigated so far. Among them is the problem of the possibility of attributing probability to single events. Considering this question, we will deal only with the mathematical concept of probability and the logical interpretation based on this mathematical concept, leaving aside the philosophical aspect of probability, shown by the author in another work.

The efficiency of processing of numerous types of mining-chemical and mining-metallurgical raw materials (coal, apatite, nepheline, phosphorite, sulfur, copper, iron, nickel ores, etc.) is significantly reduced in the absence of reliable and valid information on moisture content. Obtaining such information is associated with known difficulties, and to date the domestic industry has not carried out serial production of moisture-metric systems. Consider the possibility of building a moisture-metric system on the principle of phase separation of controlled and uncontrolled parameters.

Creation of the system for express discrete determinations of phosphate flour moisture content within 0-3,5% was preceded by the study of its electrophysical properties. For this purpose, the dependence lg r = F₁ (W) (g and W - respectively the volume resistivity and moisture content of phosphate flour) was obtained at direct current.

The rational method of measuring the moisture content of certain materials, the optimal operating frequency at which these measurements will be carried out, and hence the rational scheme of the measuring device can be outlined only by analyzing the frequency characteristics: ρ (ω) - resistivity; ε (ω) - dielectric permittivity; tgδ (ω) - loss angle of the controlled material. The applied methods of obtaining families of frequency characteristics at different moisture contents by broadband bridges with separate readout of active resistance g and apparent capacitance C (for example, bridge of E-10-2 type) are time-consuming and, as a rule, lead to significant errors associated with changes in the parameters of the wet material during the study. It is necessary, therefore, to reduce the time required to obtain the frequency characteristics so that the temporal instability of the material parameters can be neglected. It should also be borne in mind that the methods used involve a large number of individual measurements (several tens and even hundreds).

At present, either electrical resistance (conductivity) or capacitance value is used as an output parameter of electrode sensors used in mineral processing. On the basis of theoretical studies by E. S. Krichevsky and A. I. Nudelman (Leningrad Mining Institute) it is possible to create special circuits that allow to transform the value of resistance or capacitance in electrode sensing devices into the phase angle between the current in the measuring circuit and the voltage supplying this device.

Ceramic masses used in the porcelain and earthenware industry consist of clay and finely ground stony materials. The ceramic masses comprise kaolin, clay, aqueous components and finings. The percentages of the individual components of the ceramic masses depend mainly on their chemical structure and the presence of impurities, as well as on the deposits from which the raw materials are sourced. The liquid mass containing all components is dewatered to the required moisture content in filter presses during the plastic molding process. In this case, the required consistency of the dough is obtained at a moisture content of 16-25%. The deviation of the moisture value from the specified average value should not exceed +0.5% relative humidity.

Control of phosphoric anhydride P₂0₅ content in phosphate rock is one of the most important stages of the technological process of phosphate flour production. At present, the determination of P₂0₅ content in production conditions is mainly carried out by methods of chemical analysis (weight, photocolorimetric and ionic), involving the transfer of phosphorite sample into solution and subsequent determination of phosphorus content in terms of P₂0₅.

The high sensitivity of the NMR spectrometer JNM-3H, BH-2 (Japan electron optics laboratory Co. Ltd.) allows its use for express quantitative analysis of solids. One of the significant difficulties in this case is related to the recording of the calibration signal, which allows taking into account the analysis errors that arise as a result of uncontrolled changes in the hardware parameters of the spectrometer. First of all, these include changes in the goodness of the sensor circuit due to the variability of the electrical properties of the substance under study and changes in the gain of the receiver.

Nuclear magnetic resonance (NMR) is a new method of rapid quantitative analysis. The essence of the NMR phenomenon is the resonant absorption of electromagnetic radiation by a substance at transitions between the energy levels of atomic nuclei. If a substance containing nuclei possessing magnetic moments is placed in a constant magnetic field of intensity H and simultaneously in an alternating electromagnetic field oscillating with frequency f = γ/2π · H (γ is a constant characterizing the given type of nuclei), then under certain conditions the absorption of electromagnetic field energy by the substance will be observed. The change of this value at change of magnetic field strength in the resonance region is perceived and amplified by electronic equipment and recorded in the form of nuclear magnetic resonance signals carrying information about the substance under study. In quantitative analysis, the proportionality of the intensity of NMR signals to the content of nuclei under study in the sample is used.

The process of drying phosphorite concentrate in a rotating drying drum is an object of automatic control with a variety of variables involved in the process and their complex interrelation and interdependence. Obtaining a mathematical description of such an object is a necessary stage of its automation. The description can be represented in the form of a system of differential, integro-differential, integral and similar equations or in the form of transfer functions. Composition of differential equations by analytical method using physical laws of heat and mass transfer leads to a system of equations in partial derivatives, which are not always practically suitable. In addition, some constant coefficients of these equations are unknown and cannot be determined at the actual site.

Drying of phosphorite concentrate is carried out in a rotating drying drum, the output of which should be obtained concentrate of a given moisture content: increased moisture content of the concentrate is unacceptable under the technological conditions, overdrying leads to overconsumption of fuel, spraying losses. Therefore, the task of automatic control of the drying process is especially relevant for the enrichment industry. As an object of automatic control the drying process is very complex. It is affected by numerous disturbing influences, some of which (e.g., unorganized air inflow) are uncontrollable.

Complex automation of the mine ventilation system will increase the safety of mining operations and provide normal ventilation and gas regimes, which is especially important for mines of III category and super-category. One of the primary stages of solving this problem is to ensure continuous monitoring of methane content in the mine atmosphere. Stationary automatic methane analyzer of AMT-2 type provides continuous measurement of methane concentration in the place of sensor installation, preliminary and emergency tele-signaling to the dispatcher (at 0.7 and 1% of methane), automatic power cut-off at emergency methane concentration.

When studying the manifestations of rock pressure, the question often arises about the magnitude of deformations of the host rocks. For example, it is very important to determine the development of deformations in the remaining pillars and the roof of the chambers during the chamber and pillar system of field development. Many methods and devices are known for both direct and remote control of the magnitude of deformations of the host rocks, but they are not always applicable. In particular, it refers to the case when blasting operations during the clearance excavation do not give an opportunity to fix the beginning of the process of chamber roof lowering by the devices of direct control or remote control with the wire system of information transmission. To solve this problem we need devices, the placement of which will exclude the influence of blasting operations on their operability. This requirement is satisfied by the devices allowing measurements via radio communication channels. Therefore, the development of new radio-technical devices and methods of control, which will ensure reliability and safety of measurements of the magnitudes of deformation of the host rocks in production conditions, is of great importance.

Modern development of power semiconductor technology makes it possible to obtain special characteristics of the asynchronous drive, to expand the area of its application. The simplest way to form the required characteristics is to regulate the parameters of the rotor and stator circuits of the induction motor by means of thyristors.For non-contact regulation of the rotor circuit resistance, the rotor circuit of the motor includes a rectifier assembled according to the Larionov scheme of uncontrolled semiconductor valves. A resistance R and a choke L are included in the DC circuit of the rectifier. The resistance can be shunted by thyristor T₁. A capacitance C is used to lock thyristor T₁, which is switched on by thyristor T₂. The auxiliary circuit of inductance L₁ and diode D₁ serves to recharge the capacitance in the process of switching thyristors.

For synthesis and analysis of the structure of multi-cycle circuits, the algebra of events and states, or generalized Boolean algebra including time, is of considerable interest. Let us synthesize with its help the control scheme of branched conveyor lines. The conditions, which the synthesized circuit must satisfy, are determined from the analysis of serially produced circuits.

The result of research of mine electric locomotive pumping on alternating current was the scheme with the use of power magnetic amplifiers, in which the amplifier can be controlled both by the driver and automatically - by electrical signals. The traction motors of the electric locomotive are powered from the AC contact network through a magnetic amplifier with a magnetic key with a DC output. The magnetic amplifier consists of two chokes wound on toroidal cores: one choke C is a power choke, the second choke Y is a control choke. Part of the power winding of the choke C (ax) through the valve D_y is closed to the choke Y. The output voltage of the magnetic amplifier is regulated by a variable resistance R_y, shunting the valve Dy.

One of the prerequisites for increasing the productivity of the coal combine is the rational use of its engine, when at minimum power consumption is achieved separation of the maximum amount of coal from the massif.

When an electric locomotive moves along a rectilinear section of track, the resistance to motion is continuously changing due to changes in the nucleon path profile. In the work of A. A. Rengevich it is pointed out that it is very important to take into account correctly the track gradient, because in mine conditions constant gradients are rare. Moreover, when a train is moving in one direction, there are gradients that vary not only in magnitude, but also in sign. Electric locomotive traction motors have a soft mechanical characteristic, so at low loads the speed of the electric locomotive varies within significant limits. To maintain the set speed of an electric locomotive when traveling along a straight section of track, the driver must continuously manipulate the controller knob. The researches made by V.P. Gudalov in the mines of Donbass showed that on the average for one hour of operation of traction engines of electric locomotive there are more than 700 switching positions of the controller, which unfavorably affects the mode of operation of engines. Creation of an electric locomotive with automatic maintenance of the set speed will considerably facilitate the driver's labor, as well as reduce the conditions of possible wheel slipping during acceleration and movement of the electric locomotive along a straight section of the track at a changing moment of resistance on the engine shaft.

In connection with the development of new equipment for high-performance hydraulic mines the problem of creation of autonomous mining and sinking machines is put on one of the first places in the near future. Such machines can be self-propelled high-pressure hydraulic monitors.

The problem of automatic maximization of self-propelled hydraulic monitors productivity at development of coal seams by hydraulic method has not been solved yet, though practice has long ago established that the dependence between the hydraulic monitor productivity q and the speed of its trunk movement v along the face front has an extreme character. As can be seen from Fig. 1, the top A, which characterizes the optimal operating mode, under the influence of changes in mining and geological conditions drifts...

In mining, processing and metallurgical industries, the measurement of the parameters of random processes is receiving more and more attention. According to the principle of construction, correlation analysis equipment can be divided into three groups.

At present in the mining industry there is an intensive introduction of electronic computing machines for solving various tasks of administrative and economic management of enterprises. The creation of data processing centers and data transmission systems SPD is underway. The latter are necessary for transfer of initial information from remote control objects.

In recent years, mining enterprises have been creating computer centers designed to automate the management of complex production processes and quickly process significant amounts of operational and statistical information. The efficiency of the created data processing centers largely depends on the timely receipt of initial information from the control objects (mines). Mines are often dozens and even hundreds of kilometers away from the plants. However, thanks to the use of telecommunication lines for information transfer to the CP, there are new prospects for the use of electronic digital computers. Therefore, the reliability and survivability of communication networks intended for use in data transmission systems become important.

Unmanned excavation of coal is possible only with automatic control of the position of the executive body of the mining machine according to the power of the seam. Reliable operation of drilling machines, as well as other drilling machines, at considerable depth of boreholes can be ensured only by effective sensors determining the boundary “coal - rock” in the borehole. Creation and implementation of workable automatic devices that control the position of the executive body of mining machines and depending on changes in hypsometry and formation power, is of great importance.