The aim of this paper is an analysis of the variability of the methane content in coal seams in the area of the Dębieńsko Mine and it’s relation to the geological structure of this coal deposit, and also the possibilities of a methane hazard in the areas of future coal mining and methane utilization as a fuel. The Dębieńsko coal deposit is located in the western part of the Upper Silesian Coal Basin (USCB), on the boundary between folded and disjunctive tectonic zones. Coal exploitation in this area ended in 2000, but interest in this deposit is currently high due to plans to initiate coking coal mining. The area of the Dębieńsko mine is relatively well prospected because of the deep drillings (up to 2000 m in depth) carried out within it. The methane conditions of the deposit are varied, the methane content increases with depth according to northern pattern of methane distribution in the USCB, in which the high-methane zone occurs under the several hundred meters zone of natural outgassing of the coal seams. This zone is divided into two smaller methane sub-zones, the first (shallower) at a depth of 1000 m and the second (deeper) at 1700–1900 m. A sub-zone of lower methane content occurs between these two high-methane sub-zones. The most important reasons for this methane distribution are temperature and pressure facilitating the gas adsorption in coal seams, and also the presence of impermeable siltstones and shalestones as well as the maceral composition and coal rank of coal seams. The methane content also changes laterally in accordance with the tectonics of the area. The so called Knurów and Leszczyna Anticline with found increased methane content in coal seams in relation to neighboring areas as well as Orlova Overthrust together with the system of latitudinal faults of brittle tectonic regime which are possible pathways for methane migration play a special role here. These structures can be taken into account as a potential source of methane hazard in a future coal mine, they can also be promising structures for methane prospection as a fuel.
The new legislative provisions, regulating the trade in solid fuels in our country, draw attention to the need to develop and improve methods and methods of managing hard coal sludge. The aim of the work was to show whether filtration parameters (mainly the permeability coefficient) of hard coal sludge are sufficient for construction of insulating layers in landfills at the stage of their closing and what is the demand for material in the case of such a procedure. The analysis was carried out for landfills for municipal waste in the Opolskie, Śląskie and Małopolskie provinces. For hard coal sludge, the permeability coefficient values are in the range of 10–8–10–11 m/s, with the average value of 3.16 × 10–9 m/s. It can be concluded that this material generally meets the criteria of tightness for horizontal and often vertical flows. When compaction, increasing load or mixing with fly ash from hard coal combustion and clays, the achieved permeability coefficient often lowers its values. Based on the analysis, it can be assumed that hard coal sludge can be used to build mineral insulating barriers. At the end of 2016, 50 municipal landfills were open in the Opolskie, Śląskie and Małopolskie Provinces. Only 36 of them have obtained the status of a regional installation, close to 1/3 of the municipal landfill are within the Major Groundwater Basin (MGB) range. The remaining storage sites will be designated for closure. Assuming the necessity to close all currently active municipal waste landfills, the demand for hard coal sludge amounts to a total of 1,779,000 m3 which, given the assumptions, gives a mass of 2,704,080 Mg. The total amount of hard coal sludge production is very high in Poland. Only two basic mining groups annually produce a total of about 1,500,000 Mg of coal sludge. The construction of insulating layers in landfills of inert, hazardous and non-hazardous and inert wastes is an interesting solution. Such an application is prospective, but it will not solve the problem related to the production and management of this waste material as a whole. It is important to look for further solutions.
Weak mysterianism defines the situation in philosophy of mind in which we can neither formulate a solvable problem of consciousness nor prove that it is unsolvable. To develop the issue the author starts with a description of the theories and concepts described as mysterious. General mysterianism is a position in the philosophy of mind, according to which we are admittedly able to indicate scientific issues but cannot formulate them as scientific problems and thus solve them. These issues are called ‘mysteries’ by Noam Chomsky. The article presents several argumentation strategies typical for mysterian theories – evolutionary closure, autonomy of consciousness, and methodological mysterianism of William Seager. Each is subject to criticism, which shows that the mysterian argumentation is non-conclusive. It turns out, therefore, that the problem of mysteriousness is that indicating the possibility of mysteries in science does not entail a proof that we are dealing with specific mysteries (first and foremost the mystery of the mind).
The paper discusses thermodynamic phenomena accompanying the flow of gas in a slotted seal. The analysis of the gas flow has been described based on an irreversible adiabatic transformation. A model based on the equation of total enthalpy balance has been proposed. The iterative process of the model aims at obtaining such a gas temperature distribution that will fulfill the continuity equation. The model allows for dissipation of the kinetic energy into friction heat by making use of the Blasius equation to determine the friction coefficient. Within the works, experimental research has been performed of the gas flow in a slotted seal of slot height 2 mm. Based on the experimental data, the equation of local friction coefficient was modified with a correction parameter. This parameter was described with the function of pressure ratio to obtain a mass flow of the value from the experiment. The reason for taking up of this problem is the absence of high accuracy models for calculating the gas flow in slotted seals. The proposed model allows an accurate determination of the mass flow in a slotted seal based on the geometry and gas initial and final parameters.
The present work deals with continuum mechanical considerations for deformable and rigid solids as well as for fluids. A common finite element framework is used to approximate all systems under considerations. In particular, we present a standard displacement based formulation for the deformable solids and make use of this framework for the transition of the solid to a rigid body in the limit of infinite stiffness. At last, we demonstrate how to immerse a discretized solid into a fluid for fluid-structure interaction problems.