A percussive drill for prospecting through superficial deposits. The drill
is given a short stroke, 10 to 20 cm, and rotated by hand. Water is pumped
down through the hollow steel rods and escapes through openings in the
chopping bit. Casing is used, and the drilling rate is from 6 to 12 m per
shift. Nelson
A water pump that develops very high discharge pressure.
Nichols, 1
a. An engineering structure (such as a breakwater, groin, seawall, or
small pier) extending out from the shore into a body of water, designed to
direct and confine the current or tide, to protect a harbor, or to prevent
shoaling of a navigable passage by littoral materials. Jetties are often
built in pairs on either side of a harbor entrance or at the mouth of a
river. AGI
b. A British term for a landing wharf or pier used as a berthing place for
vessels. AGI
a. Corn. Miner's expression for a rich section of ore. Pryor, 3
b. Aust. A very rich patch of gold in either a reef or an alluvial
formation.
Ancient slabs of tin found in Cornwall, England; so called from the belief
that they were made by Jewish merchants and miners from Asia Minor before
the present era of mining. Hess
The lifting arm of a crane or derrick having a pulley at its outer end
over which the hoisting rope passes. See also:front-end equipment
Hammond
The operation of gradually working the jib of a shortwall coal cutter into
the cutting position in the coal seam. Jibbing-in is the first operation
before starting the cutting run across the face. Syn:sumping-in
Nelson
A crane having a swinging boom or jib. Crispin
In conveyor systems, the delivery end when a jib is fitted to deliver the
load in advance of and remote from the drive. Nelson
A person whose work is to make recesses for the cutting disk at the end of
coal-cutting machine faces. CTD
The process of starting a cut by swinging the jib of the coal cutter
(while the chain is cutting) from the front of the face to the full
cutting position. See:sump
a. A device that separates coal or ore from foreign matter, by means of
their difference in specific gravity, in a pulsating water medium. Also
spelled gig. See also:Baum jig; Bendelari jig; conset jig; Denver jig;
Harz jig; hutch; jigger; jig washer; Pan-American jig; stripping a jig.
b. A link or coupling connecting mine wagons.
The agent used in a jig that consists of the heavy fractions in the coal
that behave in some respects like a dense fluid. The pulsation of the
water or the motion of the screen keeps the bed open or in suspension
during part of the cycle so that heavy minerals entering the jig can
settle into the bed. Lighter materials cannot penetrate the jig bed and
therefore are forced to remain in the upper part of the jig and eventually
discharge over the top. Other agents in use are lead shot, iron punchings,
iron shot, pyrite, and magnetite. Newton, 1
Self-acting inclined track used to lower filled coal tubs and raise empty
ones. Pryor, 3
Hardened-steel bushing inserted in the face of a jig to serve as a guide
for drills. Crispin
S. Staff. A chain hooked to the back of a skip and running around a post
to prevent its too rapid descent on an inclined plane. CF:snub
Fay
N. Staff. See:crossgate
a. See:pan conveyor; shaker conveyor; jigging conveyor.
b. Scot. An apparatus for attaching hutches to a haulage rope. Fay
c. A mechanism that operates with quick up-and-down motion; a jolting
device. See also:jig
d. A machine for dressing small ore in which a sieve is dipped or moved
about under water.
e. Leic. A coupling hook used between coal cars. Standard, 2
f. Person that concentrates ore by jigging. Webster 3rd
Eng. Dressed or partly dressed ore obtained from jigging.
a. The separation of the heavy fractions of an ore from the light
fractions by means of a jig.
b. Up-and-down motion of a mass of particles in water by means of pulsion.
Pryor, 4
c. See:skimping
A series of steel troughs suspended from roof of stope or laid on rollers
on its floor and given reciprocating motion mechanically to move mineral.
Syn:jigger; pan conveyor. Pryor, 3