Usually implies direct evidence derived from shafts, wells, and borings,
or obtained by geophysical methods. Also called subsurface geology.
Challinor
A method used in large deposits with a very strong roof. In this method, a
deposit is divided by levels and on every level chutes are raised to the
next one. Mining starts from the mouth of the chutes in such a way as to
develop a funnel-shaped excavation (mill, glory) with slopes so steep that
the broken ore falls into the chutes and thus to the cars on the lower
level. A sufficiently strong pillar is left for protection at the higher
level. Syn:underground milling
The transportation of coal or minerals from the working face to the shaft
bottom. Haulage usually implies trams, tubs, or mine cars drawn by horses,
locomotives, electric or compressed-air haulage engines. Conveyors are not
generally regarded as a haulage method. See also:gravity haulage;
haulage; locomotive haulage; main transport; subsidiary transport.
Nelson
See:underhand stoping; underground glory-hole method.
Sectional conveyor, usually of the troughed belt type, capable of being
lengthened or shortened as mining operations advance or retreat, as
contrasted to an above-ground conveyor having a fixed length for
reasonably permanent installation. According to location in the mine or
usage, underground conveyors may be known as face, room, gathering, main
haulage, or intermediate haulage conveyors. See also:belt conveyor;
conveyor; haulage conveyor; flight conveyor; mother conveyor.
Syn:main conveyor; entry conveyor.
Natural or manmade excavation under the surface of the Earth.
Obert
See:measuring chute
A shaft sunk from an adit, tunnel, or working level, through which mining
operations are conducted. The upper end terminates underground. A winze or
raise becomes an underground shaft when equipped and used for hoisting and
the conduct of other mining operations. CF:winze
a. An enlargement of an entry, drift, or level at a shaft at which cages
stop to receive and discharge cars, workers, and material. Fay
b. An underground station is any location where stationary electric
equipment is installed for the utilization of electricity. This includes
pump rooms, compressor rooms, hoist rooms, battery-charging rooms, etc.
c. Excavation housing special equipment. Pryor, 3
Distinctive features of underground surveying are that stations are
usually in the roof instead of the floor; the object to be sighted and the
crosshairs of the telescope must be illuminated; distances are usually
measured on the slope; either the transit tripod has adjustable legs or a
trivet is used; and often an auxiliary telescope is attached to the
transit, either at one end of the horizontal axis or above the main
telescope, with the line of sight of the auxiliary telescope parallel to
that of the main telescope. Horizontal and vertical distances are computed
from slope distances and vertical angles. The transit is set up at one
station, being centered by plumb, and the vertical distance from the
station to the horizontal axis of the transit is measured. A plumb bob is
hung at the next station, with a point on the plumbline marked by some
form of clamping target. The vertical angle to the point so marked is
measured, and the distance from horizontal axis to the target is taped.
Urquhart
A flameproof, air-filled transformer of a size up to 300 kV.A, which can
be used inby near the face in safety-lamp mines. A nitrogen-filled
transformer for mining use is the latest trend. Nelson
The transporting of ore, rock, people, materials, and supplies through
shafts and haulageways, including the loading of ore or rock into cars and
carrying it to the surface. Jackson, 3
See:ground water; subsurface water.
An underground room prepared at an accessible spot in an underground mine
in which repairs can be made on the mining equipment used underground.
Underground mining technique based on underhand stoping and cut-and-fill
stoping with a single advancing face. See also:underhand stoping;
cut-and-fill stoping.
A stope made by working downward from a level.
The working of a block of ore from an upper to a lower level; mining
downward. The method is particularly suitable for narrow, highly inclined
deposits. Syn:horizontal-cut underhand; underbreaking;
underground milling. CF:overhand stoping
See also:underhand longwall
Picking or drilling downward. Fay
a. To cut away or mine out the lower portion of a coal seam or a part of
the underclay so as to win or get the overlying coal. Craigie
b. To mine out a portion of the bottom of a seam, by pick or powder, thus
leaving the top unsupported and ready to be blown down by shots, broken
down by wedges, or mined with a pick or bar. In England, the terms jad,
hole, undercut, kirve, and bench are synonymous. See also:undermine;
undercut. Fay
The extension of a vein or ore deposit beneath the surface; also, the
inclination of a vein or ore deposit from the vertical; i.e., hade.
Syn:underlie