BREAKING INVERSIONS IN OPEN PIT MINES USING INDUCED VENTILATION FACILITIES
In open pit mines, temperature inversions are the most hazardous effects from the viewpoint of pollution. In the periods of inversions, down-draught prevails and turbulence weakens, which results in air blanketing. Contaminants accumulate inside open pit mines at concentrations much higher than allowable maximums. In order to estimate preventability of inversion consequences through the change in the temperature gradient, it is required to calculate the required energy for transition of open pit air to adiabaticity. To this effect, we propose a method of assessing feasibility of breaking inversions under action of conditional natural factors. The method uses an energy-based approach. The method application shows that energy required for breaking inversions in Vostochny open pit mine (Ekibastuz) and the calculated energy for the same purpose in Korkino open pit mine exceed by a few orders of magnitude the kinetic energy of fan blasts. Aimed to determine breakability of inversions in open pit mines by fans, a laboratory-scale experiment was carried out. The scale effect was taken into account using similarity criteria. Inversions were simulated by voltage supply to ends of nichrome curls. Heating was maintained until stabilization of the gradient. Then, model fans tried to break inversion. The heating elements were energized during operation of the fans to simulate action of factors that conditioned inversion. The results proved inefficiency of breaking inversions with the induced ventilation facilities. The test results were checked using the data of weather stations at Sibai and Uchaly open pit mines operating powerful turbo-jet installations. The analysis confirmed their efficiency in polluted air removal although the value of inversions was independent of the fan operation and inversions were only broken due to natural factors (e.g., ground surface heating, wind strengthening, etc.). Thus, it is found that in deep open pit mines under inversions, induced ventilation fails to break inversion, and can only be used for removal and suppression of contaminants, or for air agitation intended to decrease their concentration.
For citation: Dragunskiy O. N. Breaking inversions in open pit mines using induced ventilation facilities. Gornyy informatsionno-analiticheskiy byulleten'. 2019;5:13-21. [In Russ]. DOI: 10.25018/0236-1493-2019-05-0-13-21
: Dragunskiy O. N.
O.N. Dragunskiy, Candidate of Technical Sciences, Assistant Professor,
Senior Researcher, Mining Institute, National University of Science
and Technology «MISiS», 119049, Moscow, Russia, e-mail: firstname.lastname@example.org.Key words
Open pit mine aerology, deep open peat mines, temperature, inversion breaking, energy, induced ventilation, physical simulation, similarity criteria, ecology, production efficiency.References
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