One of the possible ways of physic-chemical destruction (PCD) of coal was considered. It is established that condition of the realization of a principle possibility of spontaneous dispersion of coal is to reduce its surface energy by 40-60 J/m2. Laboratory experiments to study the PCD of coal in different liquids were conducted. According to the results, kinetic curves of swelling coal in them transition D-G stamps is presents. It was established that the most intensive physical and chemical destruction of the coal to a particle size from tenths to tens of millimeters occurs in solutions of methylamine and hydrochloric acid. The most severe swelling of the coal was noted in those environment as well. The intensity of swelling is not significantly associated with the characteristics of wetting. The influence of various effects on the PCD parameters of coal was studied by physical simulation. The total time the chemical destruction of coal on the treated area was calculated. It was proposed method PCD for coals occurring in the clay rocks of various stages of catagenesis.
The article discusses the features of fastening preparatory workings in difficult geological conditions, which are studied in three directions: improving concrete, arch and anchor fasteners with the consideration of the initial physical and mechanical properties of the rock mass; introduction of steel-polymer anchor; improvement of cast strips designs in combination with arch and anchor fasteners for reuse. Protection methods of mine workings and means of fastening often do not correspond to the peculiarities of the manifestation of rock pressure at the end sections of lavas and in zones of tectonic disturbances, as a result of which can become the main cause of the unsatisfactory state of the mine workings. Mathematical modeling of the rock massif stress-strain state has been carried out by the finite element method. Rigid and pliable cast strips, various technologies for erecting a cast strip, as well as a combination of cast strips with anchor and arch fasteners are modeled. The locations and sizes of rocks destruction zones, stresses in the rock mass for different options of fastening have been determined. The drawbacks of the existing technologies for the construction of cast strips are revealed and the factors for increasing their technical efficiency are established.
The causes of endogenous fires and methods to prevent coal spontaneous ignition were analyzed. Rational parameters of rock massif tamponage with different polymeric chemical compositions for stabilization of its stress-strain state and isolation of mine workings from methane penetration and fresh air leakage were investigated by the mine experimental methods. The dependences of the nominal pressure of injection of the chemical composition into the rock massif were established with taking into account coefficients of influence of rock type and stress concentration in the zones unloaded from rock pressure, in zones of geostatic pressure and in stress concentration zones. In order to control any accidental leaks of chemical composition through the main cracks, the stress-strain state of the rock massif in the mined area is taken into account for calculating the volume of substance to be injected. The parameters of methods for the rock massif cementation and tarring around the isolating bulkhead are substantiated. The method is developed for constructing a double isolating bulkhead in difficult mining and geological conditions to isolate the mined-out areas in the coal seams prone to spontaneous ignition.
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