Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

Dispersal of Coal and Rock Dust Deposits.

Authors
Singer-JM; Cook-EB; Grumer-J
Source
NTIS: PB 211 004 :32 pages
Link
NIOSHTIC No.
10000144
Abstract
The objective of this investigation was to determine minimum air velocities and entrainment rates for coal and rock dust dispersion in wind tunnel experiments under conditions that simulate dispersion from surfaces in coal mines where airflows are induced by weak gas explosions. Dust deposits were bed- or ridge-shaped; particle sizes were 6 to 80 microns (cohesive deposits) or 100 to 150 microns (free- flowing deposits); and wind tunnels were 7.62 Cm wide by 5.08 Cm high by 300 cm long, and 2.4 M wide by 1.5 M high by 215 m long. The investigation showed that minimum air velocities (directed at midheight) of separate, layered, or mixed piles of coal dust and rock dust were within the range 5 to 30 m/sec, independent of size of wind tunnel. This finding considerably facilitates scaling of data to mine-size passageways. Free-flowing deposits dispersed relatively slowly by single-particle detachment; cohesive dusts dispersed faster by the breaking and lifting of large clumps along weak failure flames; particle dispersion occurred in flight. Layered or mixed deposits of coal and rock dust did not disperse selectively. Semi-empirical expressions were derived relating minimum air velocities and dispersion rates to dust-pile geometry, cohesion, porosity, and bulk density.
Publication Date
19720101
Document Type
IH; Report of Investigations
Fiscal Year
1972
NTIS Accession No.
PB-211004
NTIS Price
A04
Identifying No.
RI-7642
NIOSH Division
PRC;
Source Name
NTIS: PB 211 004
TOP