Seismic and rock burst hazards still currently appear to be important in most hard coal mines in Poland. Recently, there has been a significant increase in seismic activity in the Silesian rock mass, in comparison to previous years. In the period 2001-2010, hard coal mines experienced 33 rock bursts. The causes of rock burst occurrences are here presented, based on an analysis of the rock bursts that occurred in Polish hard coal mines. The scale of the rock burst hazard has been characterized with respect to the mining and geological conditions of the existing exploitation. The most essential of the factors influencing the status of rock burst hazard is considered to be the depth of the interval, ranging from 550 m to 1150 m. The basic factors that cause rock burst to occur are as follows: seismogenic strata, edges and remnants, goafs, faults, pillars and excessive panelling. The consequences of rock bursts are damaged and/or destroyed roadways. On this basis, the areas (ranges) of safe zones were selected as being those safe from rock burst hazard in roadways, according to the assessment conducted to establish different degrees of the risk., Renata Patyńska., and Obsahuje bibliografii
In 1965 the PD-1 mapping borehole was drilled in the classical location in Březno u Loun in the Ohře facies region. It was examined by many authors with various results. In 2006 the re vision of these results was pe rformed in archival samples. Carbonate content and insoluble residue minerals were determined. The gathered data were compared with similarly examined boreholes in the Bohemian Cretaceous Basin. The correlation showed that in the western and eastern Poohří region the profiles with different stratigraphy level were compared. After the elimination of this discrepancy the actual stratigraphy of the Poohří region can be easily compared with the other regions of the basin. The Č. Zahálka's statement of the equivalency of the sediment filling of the Ohře facies region and the Jizera formation in the Kokořín region is correct. This fact was validated by the Pd-1 borehole profile, where, due to a tectonic coupling, yet unknown, missing part of the youngest sediments of the Teplice and Březno formations (the real zone Xd) was conserved., Zdeněk Štaffen., and Obsahuje bibliografické odkazy
The NKCA and KVCA small-aperture (~ 90 m) seismic arrays in western Bohemia represent the second deployment of this type in the Czech Republic. The arrays have a regular triangular geometric configuration with high gain three-component seismographs in each corner of the triangle. This allows very weak local earthquakes to be detected with a high degree of precision and, thereby, substantially enhances the results of the pre-existing local seismic network (WEBNET). This paper reports on the pilot measurement period. It summarises the final configuration of the arrays and compares the derived results. The measured data have been analysed using the DP/EP system developed by NORSAR. This incorporates several array techniques such as beamforming, f-k analysis, and the cross-correlation method. It has been shown that during the study period, the levels of seismic activity recorded by the seismic arrays were up to fifteen times greater than the levels recorded by the pre-existing seismic network., Jaroslav Štrunc and Milan Brož., and Obsahuje bibliografii
Combustion of coal with limestone (a) and co-combustion of coal with limestone with wood, sewage sludge, soap and PTP (b) were performed in CFB. Inorganic matter composition and properties of all input materials were characterized. For this, chemical and coal petrography analyses of solid samples as well as their leaching tests, unburned carbon, and other properties were determined. There are not striking differences in composition of bottom and fly ashes from combustion/co-combustion data. In fly ash samples higher concentrations of Hg (about 2 ppm), As (about 800 ppm) and chlorine (about 400 ppm) are present than they are in bottom ash (0.002 ppm Hg, 250 ppm As, and 220 ppm Cl). Also relating concentrations of above elements determined in emissions are very similar for combustion/co-combustion regimes (about 0.010 mg.m-3 Hg, 0.027 mg.m-3 As and 24 mg.m-3 Cl). Content of unburned carbon in BA is below 2 wt.% and in FA below 0.6 wt.% in all combustion/co-combustion data. In FA samples the concentration of Hg, As, Se, etc. increases with increasing unburned carbon content, i.e. with decreasing grain size of FA. No significant differences in composition of emissions, bottom and fly ashes as well as in composition of water leachates were found from the combustion regimes I, II, III and IV., Martin Stach, Zdeněk Klika, Martina Nováčková and Václav Roubíček., and Obsahuje bibliografii
The reactivity of a char depends very on the parent coal. Much information about correlation between properties of coal and reactivity of chars is lost by using only standard methods for a large dataset evaluation. In this research a set of 8 coals has been investigated by thermal analysis and reactivity of obtained chars was analyzed as a function of properties of parent coal properties using Canonical correlation analysis. The reactivity of chars was determined by thermogravimetric analysis of nonisothermal combustion in oxygen. It can be stated that methods of multivariate data analysis are useful tools for the interpretation of coal chars reactivity data., Mariusz Minkina, Elwira Zajusz-Zubek and Andrzej Mianowski., and Obsahuje bibliografii
The paper discusses a problem of salt structures recent vertical movements that are observed by geodetic surveys on the example of salt dome in Inowroclaw. Presented survey results were carried by several years with use of precise levelling and GPS survey techniques. The new surveys were involved in 2002 that are carried on established network points and benchmarks of former existed country levelling network. Comp arative analysis of obtained displacement results derived by different methods is discussed as well. The effects of the an alysis are conclusions providing the usefulness of GPS techniques in the presented research. Other conclusions derived from carried observation deal with feat ures of determined vertical displacements., Zbigniew Szczerbowski., and Obsahuje bibliografické odkazy
This paper combines morphostructural analysis and geophysical methods in order to link the faults monitored inside Strašín Cave with faults and lineaments in the vicinity of the cave. The studied site is situated in SW Bohemia, at the foothills of the Bohemian Forest Mts. Main goal is to combine the morphostructural, morphometrical and geophysical methods in order to identify the fault system, monitored inside the cave. This will allow relevant interpretation of the observed movements in the frame of the local tectonic environment. The results show that the monitored faults are observable in the geophysical profiles and, using our knowledge of the structural setting, we have been able to link them with mapped tectonic structures in the vicinity of the cave. Thus, it has been demonstrated that even where outcrops are absent, the faults can be traced and that the monitored faults are significant enough to yield relevant data on tectonic movements. In addition, the combined resistivity and gravimetry profiles reveal a possible new, presently unknown, cave located 20 m below the surface about 200 m northnortheast of Strašín Cave., Filip Hartvich and Jan Valenta., and Obsahuje bibliografii
When using the PPP method, it is recommended to take into account the tropospheric influences for obtaining reliable estimates. Global Navigation Satellite System (GNSS) observations taken at low elevation suffer more strongly from atmospheric, antenna phase center variation and multipath effects, hence the observations are noisier than those at higher elevation angle, but they are essential to decorrelate the estimated station height and tropospheric zenith delay (ZTD). To relate the ZTD in the direction of an observation, the so-called mapping function (MF) are used. In this article the influence of different mapping function was studieds such as: Niell mapping function (NMF), Global Mapping Function (GMF) in conjunction with the Global Pressure and Temperature 2-GPT2, Vienna Mapping Function 1 and no mapping function. The MF were used at different elevation cutoff angles - 50 , 70, 100 and 150. The impact was analyzed: a) on the postfit residuals of the ionospheric free combination for phase (LC) and for pseudorange (PC), b) daily variability for North, East and Up component; c) evaluation of coordinates repeatability and how they are affected by the changes of the cutoff elevation angle and mapping function. The analyzed data was taken from 4 EUREF stations for a period of one month - October 2015. By using the VMF1 mapping function, the lowest value was obtained for the postfit residuals of the LC combination for all the stations. The difference in daily variation between each individual solution for the horizontal component is at the level of ~0.3 ÷ 0.5 mm, with smaller effect on the East component compared to North, whereas the Up component is at the level of ~1.0 ÷ 1.5 mm. The standard deviation (SD) is used as a measure of station position repeatability and the results suggested that for high precision determination a cutoff elevation angle of 100 should be used., Sorin Nistor, Norbert-Szabolcs Suba and Aurelian-Stelian Buda., and Obsahuje bibliografii
In order to utilize the absolute gravity ( AG) measurements in terms of tectonic study it is necessary to reduce all disturbing environmental and instrumental effects. Many of those can be easily modelled and this step is done routinely during measurements (i.e. tide, polar motion, ocean tidal loading). Other remains in data and there is a lack of conventional models for them. Significant gravity variation is associated with changes of soil water at global scale. We study this effect for the Lower Silesia (South-western Poland) territory. Computed gravity changes can reach up to 2 μgal peak-to-peak amplitude with seasonal time scale. This effect is beyond of accuracy of modern ballistic gravimeter. Using real data collected with FG5 gravimeter we show here that neglecting of this phenomenon can lead to serious misinterpretation in term of secular gravity changes. This is emphasized especially when only sparse data of a few year time span is at our disposal. No attempt of modelling of local hydrology impact on effect was made, while in this study we concentrate on large scale water storage influence on measured gravity., Marcin Rajner, Tomasz Olszak, Jerzy Rogowski and Janusz Walo., and Obsahuje bibliografické odkazy
The earthquakes of magnitudes ML=5.0 and 5.3 in the Kaliningrad enclave of Russia on September 21, 2004 were unexpected in a very low-seismicity area. The earthquakes caused minor damage in the Kaliningrad enclave, in northern Poland and in southwestern Lithuania, and macroseismic intensities of 6-7 (EMS) close to the epicenters. The earthquakes were felt up to 800 km distance. The events have been located under the central-northern part of the Sambia Penninsula at 16 and 20 km depth. Their source mechanism has been found to be a right lateral strike slip on a direction parallel to the edge of the Fennoscandian Shield and the East European Craton. The possible cause of the earthquakes is discussed. With the glaciotectonic cause unlikely, it seems the earthquakes evidence tectonic patterns, possibly resulting from stress propagating all across Europe from the Mediterranean region. Historical information seems to evidence past seismic activity in the region, which together with the 2004 earthquakes show the need to reassess seismic hazard in the area., Paweł Wiejacz., and Obsahuje bibliografii