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ISSN - 2391-9361

Volume 6, issue 3

Edition circulation: 130 copies


1 vol. 6, iss. 3/1

Piotr BAŃKA, Tomasz CICHY
The architecture choice of the neural network used to describe changes in size of induced seismicity

Abstract: The article presents results of researches which have been done to define optimal architecture of neural network used to forecast changes in size of seismicity induced by mining works in progress. The set that had been used to learn neural network has included value of indicators that characterize changes of elastic strain energy (estimated with edge task translocation of spatial theory of elasticity given by H. Gil) and information about recorded level of seismicity, described by density of seismic events energy. While doing the research the influence of neurons number in the hidden layer of the network (from 1 to 16) was analyzed and neuron's characteristic (following activation functions have been considered: linear, logistic and hyperbolic tangent) for accuracy in describing induced seismicity changes when appropriately trained neural network is applied. Influence of neural network architecture on exactitude of change forecast of energy expenditure of rock mass shocks has also been checked. Calculation results for the region that is extremely at risk of shocks (region of mining works that are in progress in one of GZW coal mines) have confirmed possibility of using neural networks to estimate changes in size of induced seismicity connected with deposit exploitation. It has been also stated that forecast accuracy can be achieved by using not a very expanded neural network consisted of only two neurons in the hidden layer, however as an activation function it is favorably to use hyperbolic tangent.

Keywords: elastic strain energy, induced seismicity, neural networks
p. 11 pobierz
2 vol. 6, iss. 3/2

Piotr BAŃKA, Ewelina LIER
Use of neural networks to calculate the velocity and acceleration of ground vibrations caused by mining tremors

Abstract: In many mines there is a problem with ground vibrations caused by severe tremors induced by carried out mining works. In the areas, where surface vibrations occurred due to highenergy tremors it is necessary to forecast the velocity and acceleration of vibrations that may occur during the future excavation process. This paper presents results of studies describing the possibility of using neural networks to forecast ground vibrations caused by mining tremors. During those studies data from highly seismically endangered region of Upper Silesian Coal Basin were used. The results of calculations proved the possibility of using neural networks to calculate the velocity and acceleration of ground vibrations caused by mining tremors. For the considered set of observations more precise results than, from widely used, a simple linear regression model, were obtained.

Keywords: induced seismicity, ground vibrations, neural networks
p. 24 pobierz
3 vol. 6, iss. 3/3

Mirosław CHUDEK, Stanisław DUŻY, Grzegorz DYDUCH
Technical condition of galleries lining as a source of roof falls hazard

Abstract: The article addressed the issues, connected width maintenance of galleries stability at the deterioration of lining technical condition. Described methods of diagnostic galleries lining and presented influence of lining technical wear on this technical condition. Indicated necessity of trainings for staff towards diagnostic and evaluating the technical condition of lining and lead constant monitoring of galleries in terms of hazard from roof falls.

Keywords: technical condition, gallery, roof falls hazard, corrosion
p. 35 pobierz
4 vol. 6, iss. 3/4

Stanisław DUŻY, Piotr GŁUCH, Adam RATAJCZAK
Study or roof fracturing zone of a longwall gate for the purposes of maintenance of safety ta the longwall-gate crossing protected by chock and rockbolt supports

Abstract:The maintenance of the longwall gangway crossing is one of the most important technological activities conducted along the exploitation of a longwall. Years of experiences in the application of chock supports bolted using two sets of anchor bolts (lenght of 2.7÷3.1) without installing additional reinforcements protecting of the longwall gangway crossing, have indicated the full technical and economical viability of the system for the support of crossing in concern. The underground studies the measurements of the reach of the zones of fracturing and roof stratification (using endoscopes and wire-type stratification metres) and the laboratory tests (using a test stand) have allowed to determine the safety factor for maintenance of the longwall gangway crossing, directly resulting in the necessity to install additional reinforcement.

Keywords: exploitation, longwall gangway crossing, roof bolting, work safety
p. 46 pobierz
5 vol. 6, iss. 3/5

Marian GOROL, Tadeusz MZYK
Post factum: on the possibility of exposing the entities concealing the facts and determining the amount of illegally mined mineral product – a case study

Abstract: The article presents a case of large-scale violation of the Polish Geological and Mining Law. Under a disguise of geological works, an entrepreneur has conducted a regular mine working of clay for a production of ceramic construction products. Finally, forced to conduct a geodesic measurement of open-cut working and to provide the statement on the resources, they have understated estimated the amount of the illegally acquired mineral product 11-fold. This has been proved that using the methodology for the calculation of resources using sections method. The practice was encouraged by the hesitant activities undertaken by the licensing authority.

Keywords: mineral deposit, clays, overburden, mineral product, band, open-cut working, mined rock, resources, sections method
p. 59 pobierz
6 vol. 6, iss. 3/6

Study on the phenomenon of dilatancy of numerical models of rock samples

Abstract: The paper presents results of research to determine the dilatancy in the triaxial and uniaxial compression of cylindrical samples of granular material. Simulations were carried out using the PFC2D and PFC3D programs which allow to build numerical models based on discrete elements method. To describe the effect of dilatancy the stress-strain curves were generated. On the basis of course of those curves parameters describing dilatant behavior of rock samples were assigned.

Keywords: rock mass, numerical simulation, dilatancy
p. 68 pobierz
7 vol. 6, iss. 3/7

Using of the x-ray spectral microanalysis for the determination of elements associated with minerals of zinc-lead ores from the Klucze I deposit

Abstract: Elements associated with lead-zinc ores arouse a particular interest of scientists, especially that some of them are included to the group of critical elements. Now, in the European Union the obtaining a new sources of them is one of the priorities of the economy. Instrumental methods, which in the most accurate and reliable way, allow for determination of the concentration and occurrence forms of elements associated with sphalerite, galena and marcasite, should be used. One of such technique is X-ray spectral microanalysis, which was used in the researches of ore minerals from Klucze I deposit. In several micro areas of galena, sphalerite and marcasite, the qualitative and quantitative composition of elements was marked; on this basis, it has been found, that sulfides of zinc, lead and iron, beside cadmium Cd, arsenic As, thallium Tl and antimony Sb, contain elements included to the group of critical elements: tungsten W, dysprosium Dy, and iridium Ir. W, Dy and Ir were not previously described in the literature as associated elements of Zn-Pb minerals; in the studied minerals, these elements are dispersed mainly in sphalerite and marcasite. Their presence can be the premise regarding the possibility of obtaining alternative sources of critical elements.

Keywords: minerals of Zn-Pb ores, X-ray spectral microanalysis, critical elements
p. 79 pobierz
8 vol. 6, iss. 3/87

Henryk KLETA
Assumptions for systems monitoring shaft lining in the light of various defects

Abstract: The article presents the principles of the system monitoring the condition of the lining, taking into account the technical conditions of the mine workings in the light of the common practice of mining types of damage to the housing. In their assumptions for the system monitoring the condition of the housing includes spatial and environmental conditions occurring in the shafts, together with the ways to identify damage to housing and assessing the safety of housing. The assumptions of the system of monitoring the state of the housing shafts have been used in an international research project carried out Intelligent Deep Mine Shaft Monitoring.

Keywords: shaft, lining shaft, monitorig lining shaft
p. 92 pobierz
9 vol. 6, iss. 3/9

Variability of sulfur content and sulfide mineralization of coal petrographic components in selected coal seams Poruba (620) and Zaleskie beds (405)

Abstract: The paper presents the results of investigations on variability of sulphur (total, pirytic, sulfatic, organic) content in coal samples of the 620 and 405 seams (”Sośnica-Makoszowy” coal mine). Varied degree of sulphide mineralization (piryte) of the investigated constituents: microlithotypes, carbominerites and minerites were observed. The percentage content of these forms in lump samples lithotypes was calculated. Varying degrees of sulphides mineralization of micropetrographic constituents syngenetic, diagenetic and epigenetic in origin were found. In lithotype samples from both coal seams, the highest quantities of microlithotypes grain with sulphides dispersed forms were observed in the analyzed micropetrographic constituents. These compoments could be a problem during the mechanical processes of coal enriching.

Keywords: sulphur content, micropetrographic constituents, sulphide mineralization, syngenetic, diagenetic and epigenetic sulphide
p. 101 pobierz
10 vol. 6, iss. 3/10

The analysis the causes of the linear discontinuous deformation in selected mine in the western part of the upper silesian coal basin

Abstract: Linear discontinuous deformations are usually the result of conduct of mining activities in the area of tectonic faults and mining to one common edge which is associated with the formation of the so-called slope supplies. Discontinuous deformations in given cases show up in the form of slots, thresholds and faults field causing the most damage to road infrastructure objects. The paper presents an analysis of the causes of linear deformation of discontinuous drawn up on the basis of: inventory thresholds field, coal seam maps and the scope of mining exploitation in the selected area.

Keywords: mining exploitation, discontinuous deformation, deformation prediction
p. 111 pobierz
11 vol. 6, iss. 3/11

Clean coal technologies – chance for development of mining sector

Abstract: Fossil fuel reserves and forecasts of their consumption indicate that coal, in the medium to long term perspective, will have a significant role as a source of energy and raw materials for the chemical industry. This applies both to Poland and world economy. Coal can also be a valuable source of hydrogen, whose multi-tonnage production is the basis for the development of new energy directions within Hydrogen Economy. The key directions of coal technologies development are related to increase of energy efficiency and radical reduction in environmental impact, with particular emphasis on CO2 emission, which contribute in to global warming and climate change. The paper presents the main directions for the development of Clean Coal Technologies (CTW), which covers both, coal preparation processes and coal processing into energy and valuable chemical products including liquid and gaseous fuels. Particular attention has been paid to CO2 separation processes and coal gasification technology as a source of synthesis gas for energy and chemical applications. The principles of the gasification process and state of development of commercial solutions were shown. The results of national research aimed at the development of in-house, technology were also discussed. An important part of the paper is also presentation of the current situation in the field of activities aimed at the implementation of the first commercial gasification technology in Poland.

Keywords: hard coal, clean coal technologies, fuel processing and preparation, Energy generation, gasification, CO2 emission and reduction, greenhouse effect
p. 121 pobierz
12 vol. 6, iss. 3/12

Laboratory and statistical efficiency of fine coal enrichment in the spiral separator reichert LD-4

Abstract: The article presents results of coal slurry enrichment using Reichert LD4 type spiral concentrator. Slurry enrichment process was performed for feed density of β = 350 g/dm3 and β = 300 g/dm3. The study has shown that it is possible to obtain slurry concentrates with ash content of few to dozen or so percent. Achieving the goal requires verification of thesis, which states that introduction of optimal technological model will make the process of slurry concentrate production economically viable.

Keywords: coal slurry enrichment, spiral separator, statistical analysis
p. 136 pobierz
13 vol. 6, iss. 3/13

Evaluation of the projected exploitation in the main shafts pillar in terms of protection shafts and processing plant

Abstract: This article shows the evaluation method of projected exploitation in the main shafts pillar for the protection of objects located within the safety area of the pillar. According to this plan the Mine intends to exploitate within the main shafts pillar the longwall I, III and IV in the coal seam 713. Exploitation will affect the shafts 2 and 4, the objects near them, as well as the buildings of processing plant. Analysis of size of the designated deformation in relation with the technical condition of objects, made possible to assess the realization of exploitation of these longwalls for the protection of shafts and processing plant buildings.

Keywords: influence of mining exploitation, deformation indicators, parameters of influence theory
p. 150 pobierz
14 vol. 6, iss. 3/14

Tadeusz MZYK, Marian GOROL
Evaluation of mining areas for construction regions of old shallow mining operation

Abstract: The article presents the problem of assessment of geological-mining areas of closed mines. It has been demonstrated the need to involve a designer and building investor in the identification and recognition of the risks of deformations in particular with localized shallow excavations. Presents the problem of scattering materials and basic information. The issue of assessing the suitability of land for building shown in the example chosen.

Keywords: planning, shallow excavations, conditions of a building foundation
p. 160 pobierz
15 vol. 6, iss. 3/15

Justyna ORWAT
Appraisal of effectiveness of the models used to a reprognosis of the values of mining area curvatures made in relation to the average courses of their measured values

Abstract: In this article was presented the way of obtaining the average values of mining area curvatures. They were measured on the segments of a measuring line established by “Budryk” hard coalmine. It was located perpendicularly to the runs of four longwalls. The values of curvatures were measured after the termination of an exploitation in one, two, three and four longwalls. The mean courses of curvatures were calculated via the difference of mean values of mining area inclinations (they were measured on the neighboring segments) divided by an average length of the neighboring segments which was measured during the subsequent observation cycles. Before that, were calculated the average values of inclinations via the difference of mean values of measured mining area subsidences divided by length of the segments which was measured during the subsequent observation cycles. The average values of observed subsidences were obtained by the use of smoothed spline functions. To compare the empirical data with their average courses, the values of standard deviations between the measured and mean values of curvatures (σK) and the variability indicators of curvatures’ random dispersion (MK) were calculated. Then it was made an appraisal of an effectiveness of reforecasting the values of mining area curvatures (by the use of the S. Knothe’s influences theory and the J. Białek’s formulas) with reference to the average courses of their measured values. There were calculated the values of deviations ΔK and dispersions MΔK of the used models.

Keywords: Knothe’s influences theory, the J. Białek’s formulas, a random scattering (fluctuation), an approximation, the curvatures of mining area
p. 171 pobierz
16 vol. 6, iss. 3/16

Justyna ORWAT, Ryszard MIELIMĄKA
Agreement between the theoretical and average courses of inclinations obtained from geodesic measurements carried out on observation line

Abstract: In this article was presented a comparison of the theoretical values of mining area inclinations with their average courses calculated from the results of geodesic measurements. The inclinations were calculated by the use of the S. Knothe’s theory and the J. Bialek’s formulas. The mean values of observed inclinations were obtained from the average values of measured subsidences. They were calculated on the way of an approximation by smooth spline. It was shown that in the case of inclinations, an error of the J. Bialek’s model is smaller than the S. Knothe’s model. The negative inclinations, they have been arised outside of an exploited longwall, are describing more precisely than the positive inclinations, they were arised above of an exploited longwall.

Keywords: Knothe’s influences theory, the J. Bialek’s formulas, a random scattering (fluctuation), an approximation, the inclinations of mining area
p. 181 pobierz
17 vol. 6, iss. 3/17

Piotr PAWLIK, Sandra UTKO
Physicomechanical properties of adhesives used for rock mass reinforcing in hard coal mines

Abstract: The article presents comparison of properiets and required parameters of twocomponent polyurethane adhesives used in hard coal mining in Poland, Germany and Czech Republic. Typical adhesives used in preventive works in mining have been experimentally compared. With regard to application safety under altering exploitation conditions and high binding efficiency, new parameters have been proposed, which are suggested to be considered as new certification requirements.

Keywords: injection, rock mass reinforcement, polyurethane adhesive
p. 191 pobierz
18 vol. 6, iss. 3/18

Tadeusz PINDÓR
Restructuring of the global coal industry as a key driver for global competitiveness

Abstract: This paper presents an analysis of the deep and multi-faceted restructuring processes undertaken by Coal Mining Companies both in response to the 1973-1980 price shock on international oil and natural gas markets and to the increasing stringent sustainability and sustainable development criteria evident from the beginning of the 80’s of the XX century. In the introduction, the main goal of this restructuring on a mezzo and micro-economic level is presented being the maintenance or development of an international competitive position for a specific Industry Sector, Region or Company. A key aspect discussed in the paper are the developments introduced by coal mining companies in response to evolving demand levels or demand patterns emerging as a result of new technologies, new environmental requirements or different economic conditions. These include (among others): the growth of International Knowledge Transfer Processes for innovations and technologies used in coal extraction and enrichment processes; a “Pro-export” focus to planning and development projects for the exploitation of new reserves; development of Infrastructure for coal transportation from mining regions to export ports; implementation of International Cooperation models between Mining Companies, their major Customers and Coal Intermediaries which are based on platforms such as one developed by the World Coal Association. The conclusion presents the paper’s main finding that coal is maintaining its competitive position in the Global Economy as a Primary Energy Source and as an Industrial Raw Material primarily as a result of the restructuring which took place in the Global Coal Industry between 1980 and 2015.

Keywords: hard coal sector restructuring, hard coal production, hard coal export, global competitiveness
p. 202 pobierz
19 vol. 6, iss. 3/19

The use of the Geolisp software to build a dynamic information system about the mining area

Abstract: The paper briefly presents the possibility of Geolisp in the preparation of various documents, such as: a cross section through the rock mass, the development of forecast altitudinal map, search for plots with specified quality parameters, wall thickness diagram, borehole card, transformation between different coordinate systems, topology control, prediction of the selected parameter in a given area kriging method, and many others.

Keywords: Numerical Mineral Deposit Model, planning for coal production
p. 213 pobierz
20 vol. 6, iss. 3/20

Grzegorz SMOLNIK
An analysis of the influence of the single pre-existing crack on the state of stress and displacement in the vicinity of the circular horizontal opening

Abstract: An analysis has been conducted to address the fundamental question in rock and strata mechanics: how valid are the estimates obtained for the elastic stress distribution around a circular opening when the boundary of an opening is intersected by a plane of weakness? Five, the most frequently found orientations of the plane of weakness have been analyzed and it has been assumed that the discontinuity has zero value for tensile strength and cohesion, and is nondilatant in shear so it is a crack in nature. As a result it has been concluded that, in some cases, planes of weakness may have little or no effect on the boundary stresses. In cases where the boundary stresses are affected by the rock structure, the most important factors contributing to alteration of the elastic stresses have been found to be the orientation of the joint, joint shear strength and/or far field stress state in a rock mass.

Keywords: Kirsch solution, plane of weakness, elastic stress distribution, circular opening
p. 223 pobierz
21 vol. 6, iss. 3/21

Grzegorz STROZIK
Assessment of impact of physical properties of fly ash – water mixtures used for filling of shallow mine voids on the discontinuous ground deformation hazard

Abstract: Shallow underground voids represent potential source of discontinuous deformations, especially sinkholes, which it is possible to prevent through the filling of the voids with appropriately selected materials. In order to make the fall of rocks and backfilling of the void with loose overburden rocks impossible, material applied for the filling must be incompressible, waterproof, and fulfil other criteria required for mixtures intended to fill underground voids. In the article an assessment of impact of such properties as sedimentation, set and binding time, compressive strength, soak resistance and compressibility of chosen kinds of ash-water mixtures on the process of filling and stabilization of overlying rocks has been conducted, including the influence of the time on the change of the value of these parameters. Next the compressibility of ash-water mixtures and ashes in the dry and humid state have been compared. On this base an influence of a kind of fill material on the height of caving and fractured zones over a void has been determined, which position in relation to the hard rock roof and ground surface are essential for appearing of discontinuous ground deformation.

Keywords: filling of underground voids, protection of ground surface, discontinuous deformations, fly ash – water mixtures, physical properties of stabilized backfill
p. 235 pobierz
22 vol. 6, iss. 3/22

The use of electrical resistivity tomography for identification of shallow voids inside the rock mass

Abstract: The necessary condition for sinkhole creation on the surface there is a void occurrence inside the rock mass, located at shallow depths. Such voids may be of natural (eg. karst phenomena) or anthropogenic origin (as an effect of underground mining works). Whatever the nature of the void is, it creates a serious threat to the broadly understood public safety, due to the risk of discontinuous deformations. For this type of threat to be eliminated, it is necessary to precisely recognize the location of the void firstly, then its liquidation should be done, eg. by filling in with appropriate material. One of the non-destructive ways for determination of the shallow cavities location inside the rock mass are geophysical methods. In the paper, an example of using the electrical resistivity tomography for identification of shallow anthropogenic voids has been presented. The study concerns the mining area of one of the Upper Silesian Basin mines, where in the past the mining works were carried out at shallow depth. This area was chosen because of the relatively well-recognized geological and mining situation, but above all for the sake of macroscopically visible changes in the terrain morphology, corresponding to the location of the mine workings identified on the basis of mining maps and the sinkhole created in the past in this area.

Keywords: discontinuous deformations, shallow extraction, electrical resistivity method
p. 249 pobierz
23 vol. 6, iss. 3/23

Magdalena TUTAK
The using CFD to determine the impact of ventilation systems on the location a zone particularly endangered by endogenous fires in longwall goaf

Abstract: In underground coal-mining during ventilating of operating longwalls takes place migration of parts of airflow to rockfall goaves. In a case when in these goaves a coal susceptible to self-ignition occurs, then the airflow through these goaves may influence on formation of favorable conditions for coal oxidation and subsequently to its self-heating and self-ignition. Endogenous fire formed in such conditions can pose a serious hazards for the crew and for continuity of operation of mining plant. In the paper results of numerical analysis of airflow through rockfall goaves ventilated in “U-type” from boundaries system and „Y-type” are presented. The aim of the analysis was to determine in these goaves a zone particularly endangered by endogenous fıres. For determined mining-geological conditions, the critical value of velocity of airflow and oxygen concentration in goaves, conditioning initiation of coal oxidation process were determined.

Keywords: CFD, endogenous fire, longwall, rockfall goaves, air flow
p. 257 pobierz
24 vol. 6, iss. 3/24

Krzysztof TOMICZEK
Numerical analysis of the influence of roof rocks properties ability to reduce roof fall to the free working face

Abstract: One of the primary factors affecting the safety and permanence of the process of longwall mining excavation is to ensure the stability of rocks occurring in the roof and in the working face in front of the roof bar of the powered roof support and the prevention of uncontrolled roof fall to the free working face. Based on the examples of the operation of three longwalls with roof caving: S-2, S-3 and S4 on 403/1 coal bed were conducted simplified numerical analysis using the finite difference program FLAC2D (Itasca CG). The influence of properties of roof rock and coal to propagation of areas plasticity and damage of rocks in front of and above the working face. The analyzes conducted negative verification of activities carried out so far causing the weakening of the rock and pointed need of such tending to strengthen it.

Keywords: longwall with roof caving, roof fall, rock slide, strength and deformation properties of coal and rocks
p. 274 pobierz
25 vol. 6, iss. 3/25

Designing the course of exploratory boreholes for drainages of the underground water reservoir on the example of selected coal mine

Abstract: Underground water reservoirs are source of possible water hazards for safe digging of mining excavations, located within immediate vicinity. In order to eliminate existing water hazards, exploratory boreholes drainages of water reservoirs are performed. The effective designing of the course of exploratory boreholes is particularly important, in order to efficiently drain underground water reservoirs, to lower the water table to the level that ensures safe digging of the mining excavations. The paper presents designing of the course of exploratory boreholes, which drain underground water reservoir. For this study the underground water reservoir, located in old workings of the selected coal mine of the Upper Silesian Coal Basin (USCB), was chosen. In result of the map’s analyses, the courses of the boreholes were designed. Moreover, the drilling parameters for the planned drainage of the water reservoir were determined. The design of boreholes presented in the article allows for safe digging of the mining excavations, located significantly close to the underground water reservoir. The boreholes were designed with the use of AutoCAD program. Designed boreholes were presented in the form of sketches.

Keywords: exploratory borehole, underground water reservoir, the USCB
p. 285 pobierz
26 vol. 6, iss. 3/26

Numerical model of CO2 emissions from a closed shaft

Abstract: The results of numerical simulations into carbon dioxide emissions from a closed shaft are presented in the article. FDS programme including Pyrosim mode was applied to computing. The programme belongs CFD (Computational Fluid Dynamics) group which are designed for simulations of fluid flow. Validation was based on experimental data obtained during „insitu” measurements above closed Gliwice II shaft. The concentration of CO2 in assumed mixture was 3,24%vol. (maximal detected value) and two wind variants were set up. The first was for wind velocity 1,0m/s from the south (according to measurements conditions). The second variant was for wind velocity 0,0m/s. Then the results were compared. Comparing the variants, the difference in gas stream distribution in vicinity of the shaft was observed. In contrary to assumed wind velocity as 1,0m/s, under „no wind” conditions gas flowing out of the shaft can create local hazardous accumulation. It is crucial when safety procedures for post – mining areas are elaborated. Created model can be easily modified and applied in the future for many aspects of possible gas flow from an underground to the surface, eg. during mine closure, CCS (Carbon Capture Storage) or UCG (Underground Coal Gasification).

Keywords: CFD, gas emissions, carbon dioxide, mine closure
p. 295 pobierz


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