A stonecutter's ax with a flat face and a pointed peen.
Webster 3rd
A kind of vermiculite from West Chester, Chester County, PA. Fay
A variety of monoclinic pyroxene, commonly augite or diopside, containing
manganese and zinc; forms large, coarse crystals having rounded edges and
uneven faces; at Franklin, NJ.
Crusher used to break softish materials; e.g., limestone and coal.
See also:swing-hammer crusher
A plunger-type jig with the plunger beneath the screen. May be either
single or multiple compartments. Its distinguishing features are (1) the
stroke is produced with a cam operated by a lever and rocker-arm
mechanism, (2) the weight of the column of water above the plunger is
balanced by means of compressed air, (3) automatic operation is obtained
by means of a submerged float that measures the specific gravity of the
mass of coal, refuse, and water at the peak of the pulsion stroke, (4)
refuse is withdrawn through a star gate extending the full width of the
overflow lip, and (5) the slope of the screen plate is readily adjustable
by means of heavy screws at the feed end. It is widely used on bituminous
coal on sizes ranging up to a maximum of 6 in (15 cm). Mitchell
An arrangement to keep a continuous miner in full operation at all times.
It consists of a series of short conveyors, each mounted on driven wheels
and coupled into a train to run alongside the heading or room conveyor.
Nelson
A cone for coal washing; similar to the Callow and Caldecott cones.
See also:cone classifier
A simple type of crusher for coal, with a drum to which are bolted toothed
segments designed to grip the coal, forcing it down into the crushing
opening.
A crusher enclosed in an iron casing in which a revolving shaft carries
swinging arms having a free arc movement of 120 degrees . The rotation of
the driving shaft causes the arms to swing out and strike the coal, ore,
or other material, which, when sufficiently fine, passes through the
grated bottom. Liddell
Jeffrey-Traylor vibrating feeder
A feed chute vibrated electromagnetically in a direction oblique to its
surface. Rate of movement of material depends on amplitude and frequency
of vibration.
Jeffrey-Traylor vibrating screen
An electric vibrating screen operated by action on an oscillating armature
and a stationary coil. Gaudin, 1
See:carbohumin; vegetable jelly.
a. A drivage at right angles to the main cleat. Mason
b. Eng. A road driven bordways in a pillar of coal. A jud driven bordways
along a pillar of coal with goaf or an old bord on one side is called a
"loose end jenkin." SMRB
c. N. of Eng. A variation of "junking." Fay
A ferroan variety of antigorite.
A series of tables esp. compiled for mining work that includes tables of
density, vapor pressure, and absolute humidity. Roberts, 1
S. Afr. Part of the Jeppestown Series forming the footwall of the Main
Reef on the Central and East Rand. Beerman
See:shaking table
An employee in a mine whose duty it is to clean up falls or refuse, or to
make a miner's working place safe. See also:wasteman
A highly siliceous clay brick, semisilica brick. AISI
Beds of decomposed gypsum. Standard, 2
a. A hard black variety of cannel coal or brown coal, compact in texture,
having a rough fracture and dull luster that takes a good polish and is
thus used in the jewelry trade. Syn:black amber
b. A sudden and forceful rush or gush of fluid through a narrow or
restricted opening; e.g., a stream of water or air used to flush cuttings
from a borehole. AGI
c. A black variety of marble.
d. Jet piercing, a thermal method of drilling large-diameter blast holes
in hard cherty iron formation (taconite); formerly used mainly on the
Mesabi Range in Minnesota, but also on the Marquette Range in Michigan.
The rotating drill head is fed a mixture of kerosene and oxygen, ignited
to direct a high-temperature flame against the rock, causing the rock to
spall into fine particles by thermal expansion. Method has been almost
totally replaced by rotary drills using tricone bits.
See also:jet hole