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Horizontal air-blocking shelf reduces dust leakage from surface drill shroud.

Authors
Potts-JD; Reed-WR
Source
Trans Soc Min Metal Explor 2008 Dec; 324:55-60
NIOSHTIC No.
20034905
Abstract
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 51-mm (2-in.) gap between the shroud and ground. The shelf was 152-mm (6-in.) wide and was 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.
Keywords
Mining-industry; Mining-equipment; Engineering-controls; Control-technology; Dust-control; Dust-control-equipment; Dusts
CODEN
TMENAE
Publication Date
20081201
Document Type
Journal Article
Editors
Yernberg-W
Fiscal Year
2009
NTIS Accession No.
NTIS Price
ISSN
1075-8623
NIOSH Division
PRL
Source Name
Transactions of the Society for Mining, Metallurgy, and Exploration
State
PA
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