Nauki Ścisłe i Nauki o Ziemi

Archives of Mining Sciences

Zawartość

Archives of Mining Sciences | 2019 | vol. 64 | No 3 |

Abstrakt

This paper presents mathematical models enabling the calculation of the distribution and patterns of methane inflow to the air stream in a longwall seam being exploited and spoil on a longwall conveyor, taking into account the variability of shearer and conveyor operation and simulation results of the mining team using the Ventgraph-Plus software. In the research, an experiment was employed to observe changes in air parameters, in particular air velocity and methane concentration in the Cw-4 longwall area in seam 364/2 at KWK Budryk, during different phases of shearer operation in the area of the mining wall in methane hazard conditions. Presented is the method of data recording during the experiment which included records from the mine’s system for automatic gasometry, records from a wireless system of eight methane sensors installed in the end part of the longwall and additionally from nine methane anemometers located across the longwall on a grid. Synchronous data records obtained from these three independent sources were compared against the recording the operating condition of the shearer and haulage machines at the longwall in various phases of their operation (cleaning, cutting). The results of the multipoint system measurements made it possible to determine the volume of air and methane flow across the longwall working, and, consequently, to calculate the correction coefficients for determining the volume of air and methane from measurements of local air velocity and methane concentration. An attempt was made to determine the methane inflow from a unit of the longwall body area and the unit of spoil length on conveyors depending on the mining rate. The Cw-4 longwall ventilation was simulated using the data measured and calculated from measurements and the simulation results were discussed.

Przejdź do artykułu

Abstrakt

CO2 emission from combustion fossil fuels is considered as the primary factor in the global warming. Different methods for separation CO2 from combustion flue gases are extensively used across the world. The aim of this study is to analyze the most important technological solutions of CO2 separation. For this reason chemical absorption, physical absorption, adsorption approach, membrane filtration and cryogenic process were researched. Concluding, selection of the right method for carbon dioxide capture separation is a complex issue and a range of technological and economic factors should be taken into consideration prior to application on the industrial scale.

Przejdź do artykułu

Abstrakt

This study shows the results of flotation concentration of mica minerals from kaolinised granite taken from the “Bašića bare” deposit – Kobaš, Srbac, The Republic of Srpska (B&H). Mineralogical composition of kaolinised granite is as follows: kaolinite, feldspar, quartz, and mica. After separating >0.630 mm, and <0.043 mm size class where kaolinite is concentrated, the rest is –0.630+0.043 mm class containing quartz, feldspar and mica. The mica concentrate was obtained by the flotation concentration, while feldspar and quartz were in the flotation underflow. According to the mineralogical analysis, the most abundant minerals are mica and chlorite/clays, while quartz and feldspar occur much less, and accessory minerals are represented in trace. The semi-quantitative mineralogical analysis obtained by the X-ray powder diffraction (XRPD) method of the mica concentrate amount to: mica ≈55%, chlorite/clays ≈35%, quartz ≈5%, feldspars (plagioclase and K-feldspars combined) ≈5%.

Przejdź do artykułu

Abstrakt

A lithological profile and measurements of the orientation and spacings of natural discontinuity planes were carried out in the Górka-Mucharz sandstone excavation (Krosno Beds, Outer Carpathians, Poland). In addition, the density of the discontinuities was assessed by measuring their spacings using oriented digital photographs of the quarry walls. An orthophotomap was also used in assessing the orientation and density of fractures with the tools available in QGIS. It was shown that digital image analysis can be used as an alternative to direct field measurements, especially in situations where access to an outcrop is difficult. The distributions of spacings larger than 40 cm, obtained by direct measurements and based on digital images of the quarry, were comparable. As a consequence, both measurement techniques yielded similar values of the quantity of blocks (QB), which differed by less than 2% for the minimum block volume in the range 0.4-1.0 m3 and by 6-7% for larger blocks. On the other hand, measurements of discontinuity spacings that were taken on the basis of an orthophotomap can only serve to estimate the approximate maximum value of this parameter. However, the use of orthophotomaps gives a more explicit spatial pattern of the main vertical joint sets than direct measurements in the quarry.

The analysis results also showed the following: (i) the presence of tectonic disturbances visible at the highest level of the deposit; (ii) higher density of set A fractures with planes deepening in the NE direction and a considerable reduction of the QB parameter, particularly in the peripheral NE and SW parts of the deposit; (iii) differences in the orientation of the discontinuity system between particular beds. The variable density of the discontinuities in the excavation is related to the presence of the faults that limit the Górka-Mucharz deposit.

Przejdź do artykułu

Abstrakt

The draw theory is the foundation for decreasing ore loss and dilution indices while extracting deposits from mines. Therefore, research on draw theory is of great significance to optimally guide the draw control and improve the economy efficiency of mines. The laboratory scaled physical draw experiments under inclined wall condition conducted showed that a new way was proposed to investigate the flow zone of granular materials. The flow zone was simply divided into two parts with respect to the demarcation point of the flow axis. Based on the stochastic medium draw theory, theoretical movement formulas were derived to define the gravity flow of fragmented rocks in these two parts. The ore body with 55° dip and 10 m width was taken as an example, the particle flow parameters were fitted, and the corresponding theoretical shape of the draw body was sketched based on the derived equation of draw-body shape. The comparison of experimental and theoretical shapes of the draw body confirmed that they coincided with each other; hence, the reliability of the derived equation of particle motion was validated.

Przejdź do artykułu

Abstrakt

The role of the hard coal mining sector in ensuring energy security of the country has been presented in the paper. An analysis of its current status was made based on the results obtained by the sector in 2017. Moreover, the determinants which are the precondition for further sustainable and efficient operation in the years to come have been defined.

Przejdź do artykułu

Abstrakt

Entries in steeply pitching seams have a more complex stress environment than those in flat seams. This study targets techniques for maintaining the surrounding rock mass stability of entries in steep seams through a case study of a steep-seam entry at a mine in southern China. An in-depth study of the deformation and instability mechanisms of the entry is conducted, employing field measurement, physical simulation experiment, numerical simulation, and theoretical analysis. The study results show that the surrounding rock mass of the entry is characterised by asymmetrical stress distribution, deformation, and failure. Specifically, 1) the entry deformation is characterised by a pattern of floor heaving and roof subsidence; 2) broken rock zones in the two entry walls are larger than those in the roof and floor, and the broken rock zone in the seam-floor side wall is larger than that in the seam-roof side wall; 3) rock bolts in the middle-bottom part of the seam-floor side wall of the entry are prone to failure due to tensile stress; and 4) rock bolts in the seam-roof side wall experience relatively even load and relatively small tensile stress. Through analysis, disturbances were found to occur in both temporal and spatial dimensions. Specifically, in the initial mining stage, the asymmetrical rock structure and stress distribution cause entry deformation and instability; during multiple-seam multiple-panel mining operations, a wedge-shaped rock mass and a quasi-arc cut rock stratum formed in the mining space may cause subsidence in the seam-floor side wall of the entry and inter-stratum transpression, deformation, and instability of the entry roof and floor. The principles for controlling the stability of the surrounding rock mass of the entry are proposed. In addition, an improved asymmetrical coupled support structure design for the entry is proposed to demonstrate the effective control of entry deformation.

Przejdź do artykułu

Abstrakt

In the extra-thick coal seams and multi-layered hard roofs, the longwall hydraulic support yielding, coal face spalling, strong deformations of goaf-side entry, and severe ground pressure dynamic events typically occur at the longwall top coal caving longwall faces. Based on the Key strata theory an overburden caving model is proposed here to predict the multilayered hard strata behaviour. The proposed model together with the measured stress changes in coal seam and underground observations in Tongxin coal mine provides a new idea to analyse stress changes in coal and help to minimise rock bursts in the multi-layered hard rock ground. Using the proposed primary Key and the sub-Key strata units the model predicts the formation and instability of the overlying strata that leads to abrupt dynamic changes to the surrounding rock stress. The data obtained from the vertical stress monitoring in the 38 m wide coal pillar located adjacent to the longwall face indicates that the Key strata layers have a significant influence on ground behaviour. Sudden dynamically driven unloading of strata was caused by the first caving of the sub-Key strata while reloading of the vertical stress occurred when the goaf overhang of the sub-Key strata failed. Based on this findings several measures were recommended to minimise the undesirable dynamic occurrences including pre-split of the hard Key strata by blasting and using the energy consumption yielding reinforcement to support the damage prone gate road areas. Use of the numerical modelling simulations was suggested to improve the key theory accuracy.

Przejdź do artykułu

Abstrakt

The major downside of blasting works is blast vibrations. Extensive research has been done on the subject and many predictors, estimating Peak Particle Velocity (PPV), were published till date. However, they are either site specific or global (unified model regardless of geology) and can give more of a guideline than exact data to use. Moreover, the model itself among other factors highly depends on positioning of vibration monitoring instruments. When fitting of experimental data with best fit curve and 95% confidence line, the equation is valid only for the scaled distance (SD) range used for fitting. Extrapolation outside of this range gives erroneous results. Therefore, using the specific prediction model, to predetermine optimal positioning of vibration monitoring instruments has been verified to be crucial. The results show that vibration monitoring instruments positioned at a predetermined distance from the source of the blast give more reliable data for further calculations than those positioned outside of a calculated range. This paper gives recommendation for vibration monitoring instruments positioning during test blast on any new site, to optimize charge weight per delay for future blasting works without increasing possibility of damaging surrounding structures.

Przejdź do artykułu

Abstrakt

Dynamic Mine disasters can be induced by the instability and failure of a composite structure of rock and coal layers during coal mining. Coal seam contains many native defects, severely affecting the instability and failure of the compound structure. In this study, the effects of coal persistent joint on the strength and failure characteristics of coal-rock composite samples were evaluated using PFC2D software. The results show that with the increase of included angle α between the loading direction and joint plane direction, the uniaxial compressive stress (UCS) and peak strain of composite samples first decrease and then gradually increase. The elastic moduli of composite samples do not change obviously with α. The peak strain at α of 45° is the lowest, and the UCS at α of 30° is the smallest. This is inconsistent with theoretical analysis of lowest UCS at α of 45°. This is because that the local stress concentration caused by the motion inconformity of composite samples may increase the average axial stress of upper wall in PFC2D software. Moreover, the coal persistent joint promotes the transformation from the unstable crack expansion to the macro-instability of composite samples, especially at α of 30° and 45°. The majority of failures for composite samples occur within the coal, and no obvious damage is observed in rock. Their failure modes are shear failure crossing or along the coal persistent joint. The failure of composite sample at α of 30° is a mixed failure, including the shear failure along the persistent joint in coal and tensile failure of rock induced by the propagation of coal persistent joint.

Przejdź do artykułu

Abstrakt

Increasing environmental pressure against waste disposal, particularly fine waste surface storage and concern about mining damages have resulted in an increase in the popularity of a fly ash, tailing and binding agent mixture used as compaction grout of roof fall rocks in a gob area of longwalls. Backfilling of voids forming as a result of exploitation with the fall of roof with mixtures containing fine-grained industrial wastes is a common practice in coal mines. It is aimed at achieving numerous technological and ecological advantages as well as at controlling mining hazards. Research on hydraulic transport of fine-grained slurry conducted to date focused mainly on issues related to the analysis of the conditions related to pipeline transportation. The processes concerning the propagation of mixtures within the gob, on the other hand, remain largely unknown. The process of flow of fine-grained slurry through the caving is subject to a series of factors related, among other things, with the properties of the applied wastes and mixtures, the characteristics of the gob as well as the variability of these properties during the flow through the gob and in time. Due to the lack of sufficient knowledge pertaining to the changes taking place in the gob and in the slurry while it penetrates the gobs, no methods allowing for the design and optimization of the gob grouting process have been established so far. The paper presents the selected results of laboratory tests regarding the flow of ash and water mixtures in a model of a gob, pertaining to two selected types of fly ash produced in hard coal combustion, particularly concerning the impact of the type of the ash and the density of the slurry on the effectiveness of the gob grouting process.

Przejdź do artykułu

Redakcja

Editor-in-Chief

Prof. Antoni Tajduś, AGH University of Science and Technology, Krakow

Associate Editor

Prof. Jakub Siemek, AGH University of Science and Technology, Krakow, Poland

Section Editors

Dr Katarzyna Cyran, AGH University of Science and Technology, Poland

Prof. Wacław Dziurzyński, Strata Mechanics Research Institute, Polish Academy of Sciences, Krakow, Poland

Associate prof. Jerzy Krawczyk, Strata Mechanics Research Institute, Polish Academy of Sciences

Associate prof. Krzysztof Tajduś, Strata Mechanics Research Institute, Polish Academy of Sciences, Poland

Editorial board

Prof. Piotr Czaja, AGH University of Science and Technology, Krakow, Poland

Prof. Józef Dubiński, Central Mining Institute, Katowice, Poland

Prof. Stanisław Nagy, Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

Prof. Stanisław Prusek, Central Mining Institute, Katowice

Prof. Tadeusz Słomka, AGH University of Science and Technology, Krakow

Prof. Ryszard Tadeusiewicz, AGH University of Science and Technology, Krakow

Prof. Wacław Trutwin, Strata Mechanics Research Institute, Polish Academy of Sciences, Krakow

Prof. Andrew K. Wojtanowicz, Louisiana State University, Baton Rouge, USA

Chairman of International Advisory Board

Prof. Marek Cała, AGH University of Science and Technology, Krakow, Poland

Members of International Advisory Board

Prof. Leandro R. Alejano, Universidad de Vigo, Spain

Prof. Kashy Aminian, West Virginia University, USA

Prof. Timothy Carr, West Virginia University, USA

Prof. Eleonora Widzyk-Capehart, University of Chile, Chile

Prof. Pedro Riesgo Fernández, University of Oviedo, Spain

Prof. Mihaly Dobróka, University of Miskolc, Hungary

Prof. Sevket Durucan, Imperial College London, United Kingdom

Prof. Aidarkhan Kaltayev, al-Frabi Kazakh State University, Almaty Kazachstan

Prof. Evgeny I. Križanivskij, National Oil and Gas University of Ukraine, Ivanofrankovsk, Ukraine

Prof. Ian Lowndes, University of Nottingham, Nottingham, United Kingdom

Prof. Henryk Marcak, AGH University of Science and Technology, Krakow

Prof. Marian Marschalko, VŠB-Technical University of Ostrava,Czech Republic

Prof. Stefan Miska, University of Tulsa, Tulsa, USA

Prof. Pierpaolo Oreste, Politecnico di Torino, Italy

Prof. Durga Charan Panigrahi, Indian School of Mines, Dhanbad, India

Prof. Tadeusz Patzek, The University of Texas at Austin, USA

Prof. Lucjan Pawłowski, University of Technology, Lublin

Prof. Genadyi G. Pivnyak, National Mining University of Ukraine, Dniepropetrovsk, Ukraine

Prof. Pekka Särkkä, Helsinki University of Technology Helsinki, Finland

Prof. Anton Sroka, Strata Mechanics Research Institute of the Polish Academy of Sciences, Krakow

Prof. Stanisław Stryczek, AGH University of Science and Technology, Krakow

Prof. Vlad Ulmanu, University Petroleum-Gas of Ploiesti, Romania

Prof. Jann Rune Ursin, University of Stavanger, Norway

Prof. Jan Wachowicz, Central Mining Institute, Katowice

Prof. Yaroslavl Vasyuchkov, Russian Academy of Natural Sciences, Moscow, Russia

Prof. Isik Yilmaz, Cumhuriyet University Sivas, Turkey

Kontakt

Mrs. Marta Bitner

Instytut Mechaniki Górotworu PAN

ul. Reymonta 27, 30-059 Kraków

Phone: +48 12 637 62 00 w. 58

Email: ams@img-pan.krakow.pl

Instrukcje dla autorów

General information

It is essential for us that authors write and prepare their manuscripts according to the instructions and specifications listed below. Therefore, authors are strongly encouraged to read these instructions carefully before preparing a manuscript for submission.

Archives of Mining Sciences (AMS) is concerned with original research, new developments and case studies in all fields of mining sciences which include:

- mining technologies,

- stability of mine workings,

- rock mechanics,

- geotechnical engineering and tunnelling,

- mineral processing,

- mining and engineering geology,

- mining geophysics,

- mining geodesy

- ventilation systems,

- environmental protection in mining,

- economical aspects in mining,

- mining machine science.

Papers are welcomed on all relevant topics and especially on theoretical developments, analytical methods, numerical methods, rock testing, site investigation, and case studies.

AMS publishes research and review articles, technical notes.

Papers suitable for publication in AMS are those which:

- contain original work - the main result is not published elsewhere neither by the authors nor somebody else, and is not currently under consideration for publication in any other journal,

- are focused on the core aims and scope of the journal,

- are clearly and correctly written in English.

Authors are required to contribute to the cost of publication – publication charge 1000 PLN or 250 Euro. There is no submission charge.

Electronic submission:

All submissions must be made electronically via Editorial System https://www.editorialsystem.com/editor/amsc/articles/list/?qt=NEW

Language

The papers should be written in English.

Length of paper

The research and review articles may not exceed 16 typewritten pages, technical notes -10 pages, format A4 including figures and tables.

Format

The initial submission should be sent as Microsoft World (Arial, 12 points, line spacing - 1,5) or pdf file with all drawings, pictures and tables placed in the text.

After acceptance the text (in Microsoft Word), figures and tables should be sent as separate files.

Layout of the manuscript

First and last name(s) of the author(s), title of the article, abstract, keywords, methodology and introduction to the topics, results, conclusions, acknowledgements and references. The subtitles should conform to the decimal system of numbering.

Abstracts

The abstract should briefly summarize the most important results reported in the paper (up to 200 words).

Keywords.4-6 keywords

Formulae

Formulae should be prepared with Microsoft Equation, written clearly with distinct notation of upper and lower indices and parentheses, maintaining an uniform numbering.

Tables

Tables should be prepared as separate file in Microsoft World format.

Figures

If possible, the figures should be prepared with a vector graphics software (cdr, wmf, al or dxf formats) or as eps, jpg, bmp (figures width no greater than 13.5 cm). Use Arial font for the comments on drawings in size 6-10 points. The photographs should be converted to high resolution scans in *.jpg or *.tiff format. Figures should be submitted as separate files.

References

A bibliography without numbering, arranged alphabetically according to the author’s last name, should include all positions referring in the text. In case of more than one article from the same year, the articles should be differentiated as follows: 1985a, 1985b, etc. The following order is required: last name and initials of all co-authors, year, title, type of publications, (journal, conference material, collection of monograph articles, unpublished texts) with the page numbers used.

Quoting references

Name(s) of the author(s) should be provided in parentheses. e.g.: (Brandt, 1993), (Crosdale & Beamish, 1994). (Dziurzynski et al., 1990) in the case of one, two or more than two authors, respectively. If the name(s) of the author(s) is included in the text, then the reference should be cited as follows e.g.: „According to Brandt (1993)...”

Example of bibliography.

Brandt, J., 1993. Neuere Erkentnisse auf dem Gebiet der Gasausbruchprognose. Glückauf Forschungshefte 54, 5, 228-233.

Crosdale, P. J., Beamish, B.B., 1994. Methane sorption studies at South Bulli (NSW) & Central (QLD) collieries using a high-pressure microbalance. 28 Newcastle Symposium on „Advances in the study of Sydney Basin”, Newcastle, NSW, Australia, 15-17 April, 118-125.

Dziurzynski, W., Trutwin W., Tracz J., 1990. Symulacja komputerowa przepływu powietrza i gazów powyrzutowych w sieci wentylacyjnej kopalni. J. Litwiniszyn (Ed.), Górotwór jako ośrodek wielofazowy; Wyrzuty skalno-gazowe. Wydawnictwo AGH, Kraków, Vol. II, 743-758.

Lama R. D., Bodziony, J., 1996. Outbursts of gas, coal and rock in underground mines. Publisher Lama & Associates, 130 Brokers Road, Mt. Pleasant, NSW 2519, Australia.

Nekrasovski, Ya. E., 1951. Razrabotka plastov podverzhennykh vnezapnym vybrosam ugla i gaza. Ugletekhizdat, Moskva.

Ta strona wykorzystuje pliki 'cookies'. Więcej informacji