Browse

Self-heating and autoignition are the precursors of spontaneous combustion. All coals can be self-heat in mines or in storage; but only if the conditions are favourable they may autoignite, when the coal interact with the oxygen in the air. This is first step in the spontaneous combustion. In storage, the temperature of a stockpile is determined by the type of coal, particle size, oxygen concentration of the air, balance of the heat of coal oxidation, moisture content of the coal etc. Coal naturally oxidizes over ...

Within the lignite deposits located in the Oltenia coal basin, frequent sand bands are emerging, carriers of signifi cant aquiferous horizons and complexes. The geological pattern induces an important variation of hydro-geological conditions along the deposit’s spreading, which in turn gives difficulties in mining technology selection. Determining the problem’s solution involves th e versions ranking from the strongest to the weakest, in relation to all the criteri a. Both maximum and minimum criteria can exis...