Factors impacting respirable dust entrainment and dilution in high-velocity air streams.
Chekan-GJ; Listak-JM; Colinet-JF
Trans Soc Min Metal Explor 2004 Jan; 316:186-192
In conjunction with steady increases in production levels, longwall operators have applied greater quantities of ventilating air to control respirable dust and methane gas. As a result, air velocities greater than 7.6 m/sec (1,500 fpm) have been measured on longwall faces. Operators have expressed concern over the potential entrainment of respirable dust at these high velocities, especially during shield advance as dust falls from the shield canopy directly into the airstream. Laboratory tests to simulate dust liberation by shield movement were conducted at NIOSH's Pittsburgh Research Laboratory in a wind tunnel designed to study dust entrainment in high-velocity airstreams. Dust was introduced into the tunnel to determine dust concentration as it relates to entrainment, dilution, air velocity, and particle adhesion. Airborne dust samples were obtained by isokinetic sampling using BGI cyclones to quantify respirable dust concentration at the various air velocities. Lab tests were conducted at velocities ranging from 2.0 to 10.1 m/sec (400 to 2,000 fpm), and significant differences in airborne respirable dust levels were measured. This research is being conducted to provide fundamental information on the entrainment characteristics of respirable dust at high air velocities, which will subsequently lead to solutions for shield dust control. A discussion of the test procedures and results is presented.
Respirable-dust; Longwall-mining; Ventilation; Coal-mining; Mining-equipment
NIOSH Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
Research Tools and Approaches: Control Technology and Personal Protective Equipment
Transactions of the Society for Mining, Metallurgy, and Exploration