See:fresh water
a. A space in a seam from which the coal has been eroded and its place
filled with clay or sand. Syn:horseback
b. A local enlargement or thickening in a vein or ore deposit, as opposed
to a pinch.
c. The tendency of soils, on being removed from their natural, compacted
beds, to increase in volume owing to an increase in void ratio; i.e., the
space between soil particle increases. Carson, 1
d. A low dome or quaquaversal anticline of considerable areal extent.
e. Waves caused by the wind but no longer being activated.
Schieferdecker
f. Long and generally symmetrical waves, period approx. 10 s, produced by
storm and wind remote from the point of observation. These are gravity
waves and contribute to the mixing processes in the surface layer and thus
to its sound transmission properties. Hy
g. In geology, a large-scale submarine topographic feature rising above
the surrounding surface and having nearly equal length and width.
Hy
A rod coupling having a considerably larger outside diameter than the
drill rods to which it is threaded, such as BW rod outside diameter with
AW rod threads. Syn:oversize coupling
a. A soil or rock that expands when wetted. Long
b. Soil or rock that flows into mine workings as a result of pressure.
A numerical expression to indicate the relative swelling properties of a
sample when heated under standardized conditions. Nelson
When a shaft is sunk through a thick, dry deposit of shale, the absorption
of water may cause the shale to swell and damage the shaft lining. Again,
when shale is exposed to weathering, the lamina tends to separate and the
material swells. When wet, the disintegrated mass still further swells and
eventually becomes a plastic clayey deposit. Nelson
a. The pressure that heated and softened coal exerts when it is obstructed
from free swelling.
b. The pressure exerted by a contained clay when absorbing water in a
confined space.
A depression in a mine road from which the road rises both ways.
Mason
See:floatstone
a. A variety of marble that gives off a fetid odor when broken or rubbed.
Also called stinkstone. See also:bituminous limestone
b. See:fetid calcite
c. See:anthraconite
a. In power-shovel nomenclature, the rotation of the superstructure on the
vertical shaft in the mounting. Carson, 1
b. In revolving shovels, to rotate the shovel on its base.
Nichols, 1
c. See:swing radius
d. In churn drills, to operate a string of tools. Nichols, 1
The distance in degrees that a shovel must swing between digging and
dumping points. Nichols, 2
See:slabbing cut
a. A rock breaker in which crushing force is generated by hammers loosely
mounted on a rapidly revolving shaft. Rock entering the crushing chamber
is hit and rebounds against liner plates of walls or against other rock,
until small enough to escape through a grid. Pryor, 3
b. A machine in which size reduction is effected by elements loosely
pivoted to disks fitted on a rotating horizontal shaft mounted in a
surrounding casing. Also called pulverizer; swing-hammer mill; swing
hammer. See also:Jeffrey crusher
A simple method of regulating the flow of lump ore in a chute. It consists
of several heavy pivoted hammers that allow fine ore to pass through, but
check the passage of lumps. Nelson
The adjustment of the boundaries of a mining claim to more nearly conform
to the strike of the vein. A reasonable time is allowed the discoverer to
explore the vein or lode to find out its strike and make the adjustment.
This controller is made up of three fixed electrodes consisting of groups
of parallel plates of noncorroding alloy fixed at the bottom of curved
troughs of insulating material of uniform width and varying depth. The
trough is deep at the end, corresponding to full speed and minimum
resistance; it is shallow at the maximum-resistance starting position. The
moving electrodes, of similar construction, are joined to form the star
point of the rotor and are moved toward or away from the fixed electrodes,
giving a wide range of resistance. Sinclair, 5
An instrument of the steady deflection type where speed is read off
directly from the scale of the instrument. This is most useful for
measuring low speeds, since it permits a spot reading. This instrument
does not integrate and is used extensively in work connected with the
ventilation of building interiors and to a fair extent underground.
Roberts, 1
An amalgamated copper plate hung in a sluice to catch float gold.
Fay
This instrument consists essentially of a damped, pivoted vane that is
deflected when placed in an airstream. As the weight of the vane is
constant, the angle of inclination will be dependent upon the rate of
change of momentum of the impinging airstream. The instrument gives a
direct reading and can be calibrated for use over a wide range of
velocities, from 20 to 2,000 ft/min (6.1 to 609.6 m/min). In underground
airways, it can be used without attachments. Its main use is the
measurement of air velocity in ducts and the rate of air discharge from
ventilating grills. Roberts, 1
A crane with one horizontal boom on which there is a counterweight. It can#WORD ®43¯ ®53¯ tower crane ®23743¯ ®23744¯
swing through a full circle. See also:tower crane