The taking of air samples to assess their degree of dustiness, either on a
mass basis or on particle count in a known volume of air. Numerous
instruments have been developed for this purpose. Dust sampling is also
necessary to assess the efficiency of stone dusting.
See also:sampling instrument; konimeter; size selector;
thermal precipitator; tyndallometer.
A portable instrument for collecting dust samples so that corrective
measures can be taken for dust control and the prevention of respiratory
diseases. Dust-laden air is impinged in sampling flasks by manual,
compressed air, or electrical suction devices. Dust counts are made from
the collected air at laboratories with microscopes and counting cells.
Best, 1
The prevention or reduction of the dispersion of dust into the air, for
example, by water sprays. BS, 5
A coal-cutter jib designed to conduct water through ducts, or other
arrangement, to the back of the kerf, to suppress dust and reduce the
gas-ignition hazard. See also:whale-type jib
A person employed in coal mines to apply measures to allay coal dust on
mine roadways and along the coal faces. The worker also may be in charge
of dust suppression in rock drivages. See also:rock dust
Nelson
With this system, dust can be suppressed before it becomes airborne. A
series of nozzles discharge a chemical compound in a fine spray to
materially reduce the amount of water or other liquids necessary to
saturate fly ash and eliminate dust. The compound also aids in the
diffusion of the liquid dust suppressant, allowing it to penetrate deeper
into the material. This system can be used at any point in the handling of
bulk materials, wherever dust is a hazard. Best, 1
An appliance for the dry collection of dust during drilling in rock. The
rock chippings, dust, and air are sucked from the borehole through a
rubber hose to a drum-type container with filters. The drum is discharged
and the filters renewed periodically. In some of the newer types, the dust
is extracted through the hollow drill rods.
See also:C
Nelson
Chemical compounds that aid in the control of dry dusts such as coal and
silica to help prevent explosions and respiratory injury to workers. These
compounds are of two types. One type is used in a dry state and controls
dust by absorbing moisture from the air. The second type is an agent for
increasing the wetting effectiveness of water by breaking the surface
tension and permitting the water-compound mixture to thoroughly cover the
treated area. Best, 1
A haulage term for flying switch. Fay
A sink-float process used principally for coal cleaning. The process uses
a water suspension of loess (a natural claylike material) in special
trough-type separators provided with a clean coal weir and a reject drag
conveyor. Kirk
A type of wire cloth weave; a weave in which the first shute wire crosses
over the first and second warp wires, under the third and fourth warp
wires, and the second shute wire crosses under the first warp wire, over
the second and third warp wires, under the fourth and fifth, etc.
Henderson
A monoclinic mineral, VO(OH)2 ; forms minute pale-brown scales as
an alteration of montroseite in sandstone on the Colorado Plateau.
The amount of gravel that can be moved by a water cannon, or giant, in a
24-h day by a specified flow of water. The duty of giants varies
considerably with local conditions, such as the height of the gravel
banks, the nature of the gravel bedrock, head of water obtainable, size of
jet, etc. Griffith
The number of cubic yards of gravel that can be broken down and sent
through the sluice by 1 miner's inch of water for 24 h. It depends upon
the height of the bank, the character of the gravel and the bedrock, the
grade of the bedrock, the type of sluice, and the pressure of the water.
In well-rounded gravel without large stones, the duty of the miner's inch
is from 4.5 to 6 yd3 (3.3 to 4.6 m3 ) of gravel for 24
h. Under less favorable conditions, the duty may range from 2.8 to 4.6 yd
3 (2.1 to 3.5 m3 ) for 24 h. See also:miner's inch
Lewis
An opaque, dark-brown variety of retinite containing about 0.5% sulfur in
lignite at Dux, Bohemia, Czech Republic; is similar to muckite,
walchowite, and neudorfite.
A portable ball hardness tester in which the load is applied by means of a
vise or lever. It carries a special lens for measuring the impression's
diameter and from which the Brinell hardness value can be read directly.
Osborne
Sintering machine in which feed moves continuously on articulated grates
pulled along by chains in belt-conveyor fashion. Controlled combustion on
these grates causes the minerals to sinter. Pryor, 3
Blast roasting in which air currents are drawn downward through the ore
mass. Bennett
A multihearthed circular furnace, through which horizontal rabbles revolve
and move the feed across each hearth, so that it falls peripherally to the
one below and then works inward to central discharge for next hearth
below. Rising heat and air provide the roasting conditions.
Pryor, 3
An orthorhombic mineral, Ag3 Sb ; metallic silver-white, commonly
tarnished; sp gr, 9.74; in veins with galena, native silver, and silver
sulfosalts; an ore of silver.
Minerals artificially dyed to improve their color or to imitate a more
valuable stone; they usually fade or discolor and may include chalcedony,
turquoise, jadeite, opal, serpentine, and alabaster.