a. A light, mobile, and fast-cutting drill in which the bit does not
reciprocate but remains against the rock in the bottom of the hole,
rebounding slightly at each blow. There are three types of hammer drills;
drifter, sinker, and stoper. Lewis
b. A development of the piston drill in which the drill steel is not
attached to the piston but remains in the hole, the piston delivering a
rapid succession of light hammer blows. The drill steel is frequently
hollow so that air or water may be driven through to cool the bit and
clean the hole. Rotation of the bit is automatic. Also known as
jackhammer. Barger
c. A percussive drill. BS, 12
d. A rock drill powered by compressed air that reciprocates a free piston,
causing it to strike the shank of the drill steel. When of light
construction, a hand hammer drill, otherwise supported on a tripod or bar.
Pryor, 3
a. A pulverizing unit consisting of a rotor, fitted with movable hammers,
that is revolved rapidly in a vertical plane within a closely fitting
steel casing. The hammers hit falling rock, which is fractured on impact,
or by collision with other rocks or with the casing. When sufficiently
reduced in size, the pulverized rock escapes through grids in the casing.
Syn:beater mill
b. Coal crusher in which the blow is induced with the aid of centrifugal
force. The coal is broken with the impact and usually dragged across grate
bars in the bottom of the unit. See also:ring crusher
A compressed-air-operated hand machine used by miners to break up the
harder rocks in a mine. It consists mainly of a pick and a hammer operated
by compressed air. The hammer driving the pick is set in a cylinder, where
the compressed air enters and presses the hammer, which in turn drives the
wedge-shaped edge of the pick into the rock in short sufficient shocks of
from 1,500 to 2,000 blows per minute. See also:poll pick
Stoces
A stone, the appearance of which suggested sand veined with gold, perhaps
mottled jasper. Webster 2nd
The intersection of two vein or fracture systems at an acute angle.
AGI
Measurement of height of mine haulage animals equivalent to 4 in (10.2
cm).
A screwlike tool much like a large carpenters' bit or a short cylindrical
container with cutting lips attached to a rod and operated by hand and
used to bore shallow holes and obtain samples of soil and other relatively
unconsolidated near-surface materials. CF:auger
The drilling of holes by hand for site investigations or for the
exploration of shallow mineral deposits. The hand drill is used for depths
of about 15 m and where the ground is loose or not too hard. CF:auger
Nelson
A flexible cable used principally in making electrical connections between
a mining machine and a truck carrying a reel of portable cable. Also
called head cable; butt cable.
The removal by hand of impurities from coal, or vice versa. BS, 5
See:cobbing
A historical method of drilling blastholes in rock by hammer and a
hand-held steel or bit. Single-jack drilling was done by one miner. In
double-jack drilling, one miner held the steel for one or two strikers
with hammers. Peele
A hand lamp, with battery and fitments similar to a cap lamp except that
it forms a self-contained unit. Nelson
a. Scot. Loading coal from face by hand. Pryor, 3
b. Eng. Loading coal from face by hand, but small coals are loaded
separately from large lumps. Pryor, 3
c. See:sublevel stoping
An iron barrow used in a foundry. Fay
The mechanism for opening the valves of a steam engine by hand in
starting. Standard, 2
Any hammer wielded by hand. A blacksmith's (or miner's) hammer used with
one hand as distinguished from a heavier hammer or sledge. Fay
An ordinary rock drill held in the hand and not mounted on a bar or
column. The air leg support is now widely used in tunnels and rock
drilling generally. Nelson
Manually operated moving-screen jig used to treat small batches of ore.
The jig box is fixed to a rocking beam and moved up and down in a tank of
water. Pryor, 3
A portable battery-operated lamp incorporating a tungsten filament light
source within a glass of the dome or well-glass type and providing maximum
illumination in the horizontal plane. BS, 13
A lead weight attached to a lead line of up to 100 fathoms (183 m), used
in hydrographic surveying. Hammond