Mining Publication: Horizontal Air Blocking Shelf Reduces Dust Leakage from Surface Drill Shroud
Original creation date: February 2009
Authors: JD Potts, WR Reed
NIOSHTIC2 Number: 20035145
2009 SME Annual Meeting and Exhibit, February 22-25, Denver, Colorado, preprint 09-041. Littleton, CO: Society for Mining, Metallurgy, and Exploration, Inc., 2009; :1-5
Installation of a horizontal air blocking shelf around the inside perimeter of the surface mining drill deck shroud is proposed to improve dust capture. Without the use of this shelf, a strong coanda effect airflow pattern results in dust leakage to the environment, especially at the shroud-to-ground interface. Bailing air exits the drill hole and travels along the drill steel to the underside of the table, where it fans out across the bottom of the drill table and continues down the sides of the shroud. This dust-laden bailing air then strikes the ground and fans out under gaps between the shroud and the ground. The proposed shelf prevents dust-laden air from striking the ground by redirecting it toward the center of the enclosure, where it can be captured. Laboratory tests demonstrated that the shelf reduced dust levels outside of the shroud by 81% under operating conditions consisting of a 1.9:1 collector to bailing airflow ratio, and a 5.1-cm (2-in) gap between the shroud and ground. The shelf was 15.2 cm (6 in) wide and located at a height equal to 2/3 the distance measured from the bottom of the shroud to the bottom of the drill table. The air blocking shelf was also capable of overcoming the adverse impact of vertical leakage along the shroud seams as long as this leakage was confined to an area below the horizontal plane defined by the shelf location.
NIOSHTIC2 Number: 20035145
2009 SME Annual Meeting and Exhibit, February 22-25, Denver, Colorado, preprint 09-041. Littleton, CO: Society for Mining, Metallurgy, and Exploration, Inc., 2009; :1-5
- Experimental Mine and Laboratory Dust Explosion Research at NIOSH
- Horizontal Air-Blocking Shelf Reduces Dust Leakage from Surface Drill Shroud
- Improved Drill Shroud Capture of Respirable Dust Utilizing Air Nozzles Underneath the Drill Deck
- Methane and Dust Control by Water Infusion: Pittsburgh Coalbed (Fairview, W. Va.)
- Neural Network Technology for Strata Strength Characterization
- A New Method to Clean Dust from Soiled Work Clothes
- Reducing Dust Exposure from Contaminated Work Clothing with a Stand-Alone Cleaning System
- Technology News 447 - Dust Collector Discharge Shroud Reduces Dust Exposure to Drill Operators at Surface Coal Mines
- Technology News 485 - Improved Cab Air Inlet Location Reduces Dust Levels and Air Filter Loading Rates
- Wearing Hearing Protection Properly: A 3-D Training Aid for Drillers