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Evaluating ventilating air movement in underground limestone mines by monitoring respirable dust generated from production shots.
Chekan-GJ; Colinet-JF; Grau-RH
Mine ventilation: Proceedings of the 10th U.S./North American Mine Ventilation Symposium, Anchorage, Alaska, May 16-19, 2004. Leiden, Netherlands: Balkema, 2004 May; :221-232
Underground limestone mines typically have large entries ranging from 30 to 60 ft wide and 16 to 40 ft high. This may result in low-velocity airflow throughout the mine. Air velocities less than 25 fpm are common, and airflow in the entry can be stratified or readily affected by seasonal patterns of natural ventilation. In addition, limestone mines may have minimal or no mechanical ventilation and often do not have extensive stopping lines built to control air movement throughout the mine. As a result, it can be hard to measure air velocities and define airflow patterns by using conventional airflow-measuring equipment such as anemometers and smoke tubes. This paper describes a different approach for evaluating air movement and flow patterns throughout the mine by measuring respirable dust levels generated from production shots as the dust moves through the mine air circuit. Production shots generate a considerable volume of dust in a very short time and serve as a distinctive point source of dust that can be monitored. Typically, faces are shot on an off-shift with no mining activity, so dust levels from the shots are not influenced by dust generation from loading, hauling, and crushing operations. The respirable dust that becomes airborne after the shot can stay in the air even at very low velocities. This dust moves with the general airflow patterns in the mine. In this study, light-scattering instruments, which log dust concentrations in real time, were used to monitor the dust movement throughout two limestone mines. Studies were done using these instruments to determine if they may provide a viable means to assess overall mine ventilation patterns. Dust samplers were positioned throughout each mine to record respirable dust movement after production shots. Results show that this method can be used to quickly assess mine ventilation patterns. This sampling also identified how long it took for the ventilation in each mine to clear the dust after the shots. The sampling instrumentation, sampling technique, and results of the studies are discussed.
Ventilation; Underground-mining; Dust-exposure; Dusts; Stone-mines; Nonmetal-mining; Respirable-dust; Dust-samplers; Health-hazards; Occupational-health; Sampling; Sampling-methods; Ventilation-systems
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Mine ventilation: Proceedings of the 10th U.S./North American Mine Ventilation Symposium
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division