Thermal regimes of spontaneous firing coal washing waste sites

Abstract

Spontaneous firing is a typical phenomenon at coal washing waste dumps containing argillites, siltstones, sandstones, and coal. The study of the spatial and temporal variability of the heat temperature field on the sites of spontaneous firing a topical issue for further modeling and forecasting. At the area of the rocky dump spontaneous firingof the coal washing plant "Chervonogradska" of the JSC "Lviv Coal Company" (Ukraine), temperature measurements were performed at depths 0.5 m, 1.0 m, 1.5 m, 2.0 m, and 2.5 m along three profiles distanced 8 m, 15 m and 28 m from the edge of the dump. The measurements were taken twice at two-week intervals. The temperature measurements were carried out directly at the measuring points by a thermometer with a thermocouple and remotely in the infrared range using a FLUKE TiS40 thermal imager and a partial pyrometer "Smotrych - 4PM1".The temperature measurements were used to construct horizon maps and sections. The regularities of temperature variations in the vertical and horizontal directions were explained. The temperature gradients were calculated, and they reach 14.5 °C/m. The dependences of the temperature gradients variation on the depth and the absolute temperature values in the thickness of the heap were validated statistically. The harmfulness of water supply into the thickness of burning rock dumps leading to the intense spread of heating along the laterals was justified theoretically and confirmed experimentally.