Controlled recirculation of section air in a trona mine.
Cecala-AB; Timko-RJ; Pritchard-CJ
Proc 4th US Mine Ventilation Symp Soc Min Metall & Exploration Wilton Company 1989; :484-490
As mine ventilation systems become more complex, it is increasingly difficult to supply fresh air to the working face. A high percentage of the fresh air entering a mine never reaches the working face because it short-circuits through stoppings and doors, exiting the mine without being utilized. When ventilation limits are reached, the only option presently available to most U.S. mines is to sink a new shaft--an extremely expensive undertaking that many companies cannot afford. Reusing or recirculating a percentage of ventilating airflow may make it possible for some mines to remain operational while maintaining a safe environment for workers. The U.S. Bureau of Mines performed such a study at a Trona mine in Granger, Wyoming. A vane axial fan was used to recirculate approximately 9.4 M3/s (20,000 cfm), 25 pct of the total ventilating airflow, back to the working face area of a three-entry continuous miner section. This study involved two evaluations: the first when the face was 305 m (1,000 ft) from the recirculation fan, the second when the face was 610 m (2,000 ft) from the fan. The evaluation consisted of monitoring the mine atmosphere for respirable dust, methane (CH4), carbon monoxide (CO), and nitric oxide (NO) at various locations in the intake and return entries. Several shifts were monitored, with and without the recirculation system in operation. With the recirculation system in operation, there was an increase in measured respirable dust concentrations in the intake along with a slight increase in the mine temperature (1.67 Deg c).
Mining-industry; Ventilation; Ventilation-equipment; Ventilation-systems; Air-flow; Air-quality-monitoring; Respirable-dust
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Proc 4th US Mine Ventilation Symp; Soc Min, Metall, & Exploration, Wilton, Company