The aim of this paper is to present the results of an investigation of induced seismic events which occurred during mining in the coalfields of Plants Paskov and Staříč of the Paskov Mine which belong to the southern part of the Ostrava-Karviná coal mines. Some results obtained in the time period January 1992 - December 2002 have already been published, and therefore, are mentioned here only briefly. The paper is based on new results of seismological observations at the OKC, KLOK, STEB seismic stations operated by the Institute of Geonics AS CR and stations of the Green Gas DPB, a.s., Paskov. A total of 26 seismic events were monitored from January 2008 to February 2012, most of them were localized into the area under study. As for the energy span of individual events according to the energetic classification of the Geophysical Centre of the Green Gas DPB, a.s., Paskov, all seismic events in Table 1 were estimated within the limits E(J) <5.0 ×102 ÷ 2.0 × 104>., Karel Holub, Jana Rušajová and Josef Holečko., and Obsahuje bibliografii
The paper presents the results of experimental examination of the weathering grade of granite rock mass in the medieval Jeroným Mine (Czech Republic). This mine is declared as a cultural heritage site of the Czech Republic therefore, non-destructive methods for determination of the Schmidt hammer rebound value and the ultrasonic pulse velocity were used to minimize negative impact on the historical workings during in situ exploration. Weathering grade of selected parts of the rockmass in underground spaces was classified visually according to the assumed classification (Hencher and Martin, 1982 in Vahed et al., 2009) and the above mentioned measurements were performed in these parts. Results show that the rebound value and the ultrasonic pulse velocity are decreasing with increasing weathering grade for all investigated parts. Therefore this result is possible to use as a supplementary method for evaluation of weathering grade of rock massif in this mine., Markéta Lednická and Zdeněk Kaláb., and Obsahuje bibliografické odkazy
The oldest mine cavities of the Jeroným Mine were already mined out more than 400 years ago. That is why it is necessary to determine the stability of individual parts of underground spaces. The assessment of stability of mine cavities is based on the long-term monitoring of chosen parameters. A distributed measurement network has been operated here using several different types of sensors. A laser distance meter that is used for measuring the height of a large chamber is one of these sensors. The results obtained from this monitoring are presented. Even if no apparent correlation seems to be visible between Earth’s tides and LDM variations, some features of recorded data, like dynamical frequency crossover in the power spectrum, could be due to the tidal cycles of the Earth., Zdeněk Kaláb, Markéta Lednická, Jaromír Knejzlík and Luciano Telesca., and Obsahuje bibliografii
The past five centuries of the Idrija Mercury Mine’s operation have had consequences on the environment, which have directly influenced the deformations developing in the wider exploration area. During the many years of mercury ore exploitation, the cross-stope mining method with backfilling from bottom to top was used. This has strongly transformed the stress-strain field in the surrounding rocks and caused long-term deformation processes that are still in progress. This is because the deformations have a small time gradient and thus bigger breaks or faster sliding terrain above old mine workings are not expected. The surface movements are bigger in the area built of Permian-Carboniferous, low-bearing-capacity rocks, which in the past was destroyed by major tectonic movements in the rock structure. Mine closure works, which included grouting and hardening of destroyed underground areas, as well as filling parts of the mine and backfilling empty spaces (i.e., mine roadways, blind shafts), are finished. The efficiency of mine shutdown works is constantly being verified by means of geotechnical and other measurements and observations, and will continue in the future., Jakob Likar., and Obsahuje bibliografii
The problem of bumps occurrence in deep mines during the long wall mining appears to be one of the most serious one in the design of engineering of mining. The bumps are caused for various reasons, but basically it is an aftermath of the accumulated energy, which is released under some unfavorable conditions. In this paper the influence of given dislocations and their slope in a coal seam are studied based. The numerical tool is the free hexagon method. This method belongs to a set of discrete element methods and enables us to define and calculate stresses in a natural way along the interfacial boundaries of adjacent particles (elements). Since the bumps are affected by a possible slip along the dislocations, dynamical response has to be taken into account. The velocity of excavation of the mine is considered by successive change of values of Eshelby’s forces on the face of the wall., Petr Pavel Procházka, Jiřina Trčková and Tat Seng Lok., and Obsahuje bibliografii
The medieval Jeroným Mine is a mine working in which places of various degrees of rock mass disintegration are there. Time-lapse recording, which has been performed in the Jeroným Mine since the year 2009, was induced by a necessity of documenting both areas of flaking-off and caved areas owing to an increased rate of occurrence of flaking-off phenomena in mine workings - rooms K3 and K4 of this mine. The methodology of recording, which uses as a basis repeated recording in time in the framework of geotechnical measurements carried out quarterly, is based on the principle of maintenance of not only parameters of images themselves, but also of location of a photo device used for documentation provision. This process is followed by the creation of information sheets of areas of flaking-off and caved areas and their classification. The method of recording was used owing to a high degree of disintegration of the rock mass in selected mine workings, a possibility of extension of caved areas and also the high rate of occurrence of subsidence phenomena occurring above those workings and even sporadically reaching the mine workings. Time-lapse recording is thus performed primarily in mine workings with reduced stability, situated very close to the surface. With regard to the principle of this method, results will be known only in further years., Radovan Kukutsch, Petr Žůrek and Martin Stolárik., and Obsahuje bibliografii
Combination of numerical models of deformations and repeated geodetic measurement results provide reliable information on the state of the rock mass in a mining area and support planning and control of the mining operation. The paper describes the concept of integrated monitoring and analysis of rock mass deformation in the Kvannevann iron ore mine (Norway) using sub-level caving (SLC) method. Geodetic control network developed for periodic measurements of surface subsidence and a source of geometrical data for numerical modelling of deformations using finite element method (FEM) has been characterised. Focus is given to the results of initial numeric al analyses with FEM of rock mass deformations due to SLC mining. The results of the modelling provided information on possible extent of deformation zones on the mining ground surface once mining with new method commences., Jan Blachowski and Steinar Ellefmo., and Obsahuje bibliografické odkazy
Permeability refers to the ability of coal to transmit gas when a pressure or concentration gradient exists across it. The permeability of coal is dependent upon factors that include effective stress, gas pressure, water content, disturbance associated with drilling and matrix swelling/shrinkage due to adsorption/desorption. A programme of laboratory tests were conducted on coal samples from the Bulli seam for evaluating the permeability and drainability of coal. Two different types of permeability apparatus were used in this study. The methods of permeability testing of coal under different triaxial conditions are discussed. Permeability testing of the Bulli seam coal with N2 is described. The laboratory test results were found to be in agreement with the calculated permeability values, Naj Aziz, Ting Ren, Jan Nemcik and Lei Zhang., and Obsahuje bibliografii
The purpose of this work was to detect groundwater pollution and to identify the conditions of soil and groundwater near the coal waste disposal "Panewniki" Halemba-Wirek Coal Mine using geoelectrical measurements. The firs t applied method was the VLF (Very Low Frequency) technique. This method, using military signals, allowed to perform the in-phase and the quadrature maps. Data were collected from four study areas located near the coal waste dump. Observed anomalies on both maps for each area showed places with different conductivity al lowed to detect the contaminated and uncontaminated zones. The VLF survey indicated that the contamination occurs in the eastern part of study area and is characterized by positive values of both measured electrical fields (the in-phase and the quadrature components). After preliminary contaminated zones were recognized using VLF met hod, an electrical imaging meth od was applied. Two electrical imaging profiles were carried out near the waste dump. The measurements a llowed to create the geoele ctrical model of surrounding area and to investigate the leachate plume. The electrical imaging showed that the greatest pollution occur in the area immediately adjacent to the coal waste what is confirmed by VL F survey. Based on the geological and ge ophysical knowledge from archives and on present researches, the contaminated aquifer with electrical resistivity of 5 to 15 Ω m deposited at depths of 3 to 7 m was found., Arlena Kowalska, Marta Kondracka and Maciej Jan Mendecki., and Obsahuje bibliografické odkazy