The effect of temperature in underground mines is related to the geothermal gradients of rocks overlying the mining excavation. This may exceed the standards of comfort for human beings to work in an underground environment thus causing thermal discomforts and associated risk. In order to evaluate the influence of high ventilation temperatures on mine workers a mathematical model has been developed based upon the concept of heat transfer from the rock mass to the air flow in the underground environment. This model has been validated in the Noves Corvo underground copper mine, Portugal., Vidal F. Navarro Torres, C. Dinis Da Gama and Raghu N. Singh., and Obsahuje bibliografii
The research in question deals with problems of determining seismic P- and S-wave velocities for purposes of computing the elastic constants of a rock massif. This experimental study indicates various ways of measurement and its processing for different geological conditions. The experimental measurements were carried out on the surface of the studied rock massif, on the walls in workings, as well as on the surface in a quarry. The question of seismic pick-ups, geophones or piezo-electric transducers and the number of components required to identify P- and S-waves, is discussed. This is considered in connection with the choice and properties of the impact or piezo-electric seismic source. The result is a number of generalizing recommendations with respect to the measuring technique, inclusive of its use for determining the directional dependence of the elastic moduli., Roman Živor, Jan Vilhelm, Vladimír Rudajev and Tomáš Lokajíček., and Obsahuje bibliografii
The technique of assessing the failure of rigid overlying strata is applicable to deep mining with thick coal seams (a thickness of more than 1 m in the Ostrava-Karvina Coalfield), and in one case to longwall mining with controlled caving. The assessment of failure of rigid overlying strata makes it possible to distinguish whether the rigid overlying strata of rocks has been deformed or whether a strutting arch has been formed over the goaf below which is an area that is free from stress. Good knowledge of the mining, technical and geological conditions of a given site is a prerequisite for successful evaluation. There are advantages to utilising surface measurements for interpreting the effects of changes in rock mass, especially in areas of high overlying strata. The practical importance of failure assessment of overlying strata consists in determining the size of the mined-out area where the deformation of the rigid overlying strata occurred, which is dependent on the character of the rock mass. This paper is set in the context of the expected width of the goaf during deformation of rigid overlying strata within parameters that describe the mining and geological conditions of the locality. Changes in the area of the goaf, based the results of tensometric measurements, will also be placed in context., Eva Jiránková, Lubomír Staš, Vlastimil Kajzar and Hana Doležalová., and Obsahuje bibliografii
The aim of this paper is to show time-de pendent baseline variation between GPS stations situated in South-East Poland. This study was based on daily data analysis of selected GPS stations: WROC, GOPE, MOPI, KRAW and KATO. The start date o f the analysis is linked at every station with the beginning of its operation and the closing date of the operation is in 2006. The multiresolution signal decomposition method has been used to analyze the periodic terms of the time series of the above. The estimated trends enable further coordinate analysis as well as determination of site displacements at the study area., Mariusz Figurski, Krzysztof Kroszczyński, Paweł Kamiński and Marcin Gałuszkiewicz., and Obsahuje bibliografické odkazy