The flammability of a coal-dust cloud is its ability to promote spreading
flames away from the source of ignition. Sinclair, 1
Removal from atmosphere of mill or from transfer points where dust is
thrown up. Partially closed ventilating systems are used, which
incorporate bag filters, Cottrells, cyclones, washing chambers, and spray
towers. Pryor, 3
a. A device used on a roof bolting machine while in operation for
separating solid particles from air and accumulating them in a form
convenient for handling.
b. Device used to collect dust produced in percussion rock drilling, this
device has an exhauster operated with compressed air from the available
air system. Air laden with dust and cutting is drawn from the boreholes
through the bit holes, the hollow drill steel, the adapter, and the
suction hose into a filter. The filtered air is excavated with the spent
compressed air through an exhaust port, and dust and cuttings settle in a
removable storage tank.
The binding of coal dust on roadway surfaces to prevent it becoming
airborne by any disturbance. One method is to spread calcium chloride over
the dust so that it absorbs water and forms a pasty cake that does not
rise into suspension when workers travel on the roadway.
See also:stone dust
A portable apparatus (as the Koltze tube, an impinger, etc.) used to
measure dust concentration in a mine or mill, as a health precaution.
Pryor, 3
An explosion which consists of a sudden pressure rise caused by the very
rapid combustion of airborne dust. Ignition of suspensions of combustible
dusts can occur in the following ways: (1) initiation by flame or spark,
(2) propagation by a gas explosion or blasting, and (3) spontaneous
combustion. Little is known about the last-named mechanism, which is
relatively rare in mines. The most frequent causes of major coal mine
explosions in the United States today are electric arcs, open flames, and
explosives. See also:coal-dust explosion
The removal of solid particles suspended in gas or ambient air.
BS, 5
An appliance to collect or precipitate suspended dust. Dust extraction is
often necessary at coal-preparation plants, loading stations, and also
underground. The appliance may be a cyclone, fabric filter, spray tower,
scrubber, or an electrostatic separator. See also:dust precipitator;
dust trap. Nelson
The burning of coal dust in the laboratory of the furnace. Fay
In Great Britain, the arbitrary standards laid down by the National Coal
Board in 1949 as representing comparative dust-free conditions in coal
mines. These are as follows: stone dust, 450 particles/cm3 (size
range, 0.5 to 5.0 mu m); anthracite, 650 particles/cm3 (size
range, 1 to 5 mu m); and coal, 850 particles/cm3 (size range, 1
to 5 mu m). Nelson
Pieces of gold under 2 to 3 pennyweights (3.1 to 4.7 g); very fine gold.
A hopper placed underneath the scraper, rapping roller, or other belt
cleaner, to collect the dust and dirt as it is removed from the belt; any
tank or vessel to receive and retain dust. Nelson
a. Shortfall in expected weight of sands or finely ground materials due to
wind action or loss when transported in open trucks. Pryor, 3
b. In laboratory sampling, the loss of part of a sample undergoing test,
through leakage of particles into the atmosphere. Pryor, 4
Crude oils, heavy asphalt oils, tars, solutions of petroleum asphalt in
gas oils, liquid asphalt, and emulsions of oils and water, used for laying
dust on roads. Fay
A section of the mine entry from which dust has been removed as completely
as possible by scraping or sweeping, aided by a compressed-air blast.
Rice, 2
One who dumps the dust catcher or loads the dust at blast furnaces.
Fay
A dredge containing a suction head that is pulled over the underwater
ground much as a dustpan would be. About 8 in (20 cm) high, the dustpan
may be from 20 to 40 ft (3.6 to 7.1 m) long and is supplied with jets
along its face to stir up the bottom surface. Carson, 2
A plan kept with the book in which stone-dust samples are recorded. It
shows the sampling zones in each roadway, distinguished by color, letter,
number, or mark, and identified with that roadway. Nelson
A vertical iron plate, supporting the slag runner of an iron blast
furnace. Fay
On a large scale, sinter plant gas may be cleaned by precipitators with
very high efficiencies. The dust is precipitated in a dry state, suitable
for pelletizing and feeding back onto the sinter strand.
See also:thermal precipitator
A surface treatment, as with oil or calcium chloride solution, to prevent
or reduce the dustiness of coal in handling. BS, 5