a. A small excavation or hole made to improve ventilation by communication
with other workings or with the surface. See also:cundy
b. A venthole in the upper end of the inner tube of a double-tube core
barrel to allow air and/or water entrapped by the advancing core to
escape. Long
c. A void, cavity, or flaw in a casting or bit crown. Long
The rate at which energy is consumed, in horsepower or kilowatt units, in
moving air between two points.
Abbrev. for air horsepower.
Operation in which air is blown through molten copper in a wire bar or
anode furnace. Sulfur is removed as SO, and impurities are slagged off.
Pryor, 3
a. The airway or airways through which fresh air is brought into a mine.
b. A device for supplying a compressor with clean air at the lowest
possible temperature.
A machine in which the feed is stratified by means of pulsating currents
of air and from which the stratified products are separately removed.
BS, 5
a. Removing or cutting away loose material by means of compressed air,
using an air lance; airblasting. Henderson
b. In founding, a cleaning operation, as cleaning sand from molds and
castings, using an air lance; airblasting. Henderson
c. Opening passages for molten materials.
a. The short-circuiting of air from intake to return airways (through
doors, stoppings, wastes, and old workings) without doing useful work in
flowing around the faces. The total air leakage is usually within the
range of 35% to 53% of that passing through the surface fan.
Nelson
b. The air that escapes from compressed-air lines by leakage from joints,
valves, hoses, etc.
a. A cylinder operated by compressed air, used for keeping a rock drill
pressed into the hole being drilled. Hammond
b. A device, incorporating a pneumatic cylinder, providing support and
thrust for a jackhammer. BS, 12
An appliance to eliminate much of the labor when drilling with handheld
machines. It consists of a steel cylinder and air-operated piston, the rod
of which extends through the top end of the cylinder and supports the
drilling machine. The air leg and machine can be operated by one worker.
Syn:pneumatic drill leg
Eng. A level or airway (return airway) of former workings used in
subsequent deeper mining operations for ventilation.
An apparatus used for pumping water from wells either temporarily or for a
permanent water supply; for moving corrosive liquids such as sufuric acid;
for unwatering flooded mines; for elevating mill tailings, sands, and
slimes in cyanide plants; and for handling the feed to ball mills. In
operation, compressed air enters the eduction pipe and mixes with the
water. As the water and air rise, the air expands and is practically at
atmospheric pressure at the top of the discharge pipe. The efficiency of
the air lift is calculated on the basis of the foot-pounds of work done in
lifting the water, divided by the isothermal work required to compress the
air. Lewis
Dredge in which solids suspended in a fluid are lifted. By injecting air
into a submerged pipe beneath the water surface, the density of the fluid
column inside the pipe can be lessened, forcing the fluid column to rise
in the tubular pipe. Syn:airlift sampler
See:air-lift dredge
See:line oiler
An atmosphere-supplying respirator in which the respirable-gas supply is
not designed to be carried by the wearer (formerly called supplied-air
respirator). ANSI
a. A casing at the top of an upcast shaft to minimize surface air leakage
to the fan. It consists of a large double casing enveloping the whole of
the upcast-shaft top and extending into the headgear. Some are fitted with
power-operated doors and allow high-speed winding with little leakage. A
modern light-alloy structure raised through spring-loaded attachments by
the top of the cage on ascending has proved efficient.
Syn:shaft casing
b. A system of doors arranged to allow the passage of workers or vehicles
without permitting appreciable airflow. BS, 8
A worker who constructs brattices. Syn:brattice worker
A mat made of porous material, usually canvas, and used to subdivide and
distribute air in certain pneumatic-type flotation machines. Hess
A portable compressed-air appliance, which may be used as a blower or
exhauster. It converts the compressed air into a large induced volume of
moving air. The compressed air is fed through a side inlet and is expanded
at a high velocity through an annular orifice. It is useful for emergency
ventilation in workings where auxiliary fans cannot be installed.
Syn:injector; static air mover. See also:auxiliary ventilation
Nelson
A small, compressed-air drum haulage or hoist used for lifting, dragging,
or skidding work in mines. With capacities ranging from 660 to 4,400 lb
(300 to 2,000 kg), these winches have powerful piston motors and are
capable of continuous operation. They are easy to move from job to job and
are used for shaft sinking and moving wagon drills at quarry and opencast
operations. Nelson