A theory that strata movements caused by underground excavations were
limited by a kind of dome that had for its base the area of excavation,
and that the movements diminished as they extended upward from the center
of the area. See also:harmless depth theory; normal theory.
Nelson
An isometric mineral, Cu3 As; forms reniform and botryoidal masses
and disseminated grains. See also:white copper
A field term to denote, in accordance with an arbitrary scale established
for use in describing banded coal, a frequency of occurrence of vitrain
bands comprising more than 60% of the total coal layer.
CF:abundant vitrain; moderate vitrain; sparse vitrain. AGI
An explosive consisting of 70% ammonium nitrate, 25% trinitrotoluol, and
5% nitroglycerin. Hackh
A possible mineral species in the chlorite group.
In anthracite and bituminous coal mining, a general term for the attendant
of a small auxiliary engine, powered by steam or compressed air, used to
drive pumps to drain sumps (pits in which excess water is collected) or
supply water to boilers, or to operate a hoist for a shallow shaft. Also
called donkey runner. DOT
A small auxiliary hoisting drum and engine operated by steam, by
compressed air, and sometimes by an electric motor or an
internal-combustion engine. Long
Any of several kinds of combined pump and steam engine. It may be operated
independently of the engine; used to supply water to a boiler, drain
sumps, etc.
See:donkey engineer
An exploding charge producing an impulse that impinges upon an explosive
acceptor charge. Meyer
a. The essential treatment plant of a small dredge set on a pontoon. There
is usually a hopper into which the dragline dumps its spoil and which may
have a grizzly arrangement, according to the nature of the gravel. A water
supply washes the contents of the hopper into a revolving screen, feeding
the fines over riffled tables and rejecting the stones and oversize by
means of a stacker. This treatment plant or washing unit can be floated in
the excavation dug by a dragline and is the ideal unit to install when
small-scale operations are to be carried out below water level or where it
is not necessary to use dry opencast paddock methods. Harrison
b. Any one of a large number of unscientific devices with which it is
claimed water, mineral, and oil deposits can be located. AGI
c. A popular term for any of various kinds of geophysical prospecting
equipment.
a. Scot. A mine or roadway driven to the dip, usually the main road.
See also:slope
b. Som. An underground inclined plane.
A hinged or sliding frame or piece of wood, metal, stone or other
material, generally rectangular, used for closing or opening an entrance
or exit. Doors are placed in air passages of mines to prevent the
ventilating current from taking a short cut to the upcast shaft, and to
direct the current to the working face. See also:air door;
ventilation doors. Standard, 2
See:trapper
Scot. The roof or top of the workings at a shaft.
One whose duty it is to open and close a mine door before and after the
passage of a train of mine cars; a trapper. Zern
See:door tender
A soil-sampling tube or barrel equipped with an auger-type cutting shoe
and made to be rotated to obtain samples of sand, gravel, and other
granular material. The body of the sampler is essentially a tube in which
a small opening or window is machined and equipped with a covering, which
can be latched shut while the sample is being taken. When the sampler is
removed from the ground, the latch is released and the sample removed
through the door or window. Syn:window-type sample
a. Individual, dry, nonexplosive ingredients that comprise a portion of an
explosive formulation.
b. Absorbent material, as sawdust, infusorial earth, mica, etc., used in
certain manufacturing processes, as in making dynamite.
Webster 2nd
c. Heavy grease or other material used to protect or lubricate drill rods
and/or open gears, chain and sprockets, etc. Also called gunk; rod dope;
rod grease. Long
d. To apply a lubricant to drill rods, rod couplings, open gears, etc.
Long
e. To doctor a drill diamond. See also:doctor
f. A rubberlike compound applied to granite surfaces before inscriptions
are cut in the granite. AIME, 1
g. A viscous liquid put on pipe threads to make a tight joint.
Nichols, 1
h. Slang for mold lubricant. ASTM
A self-contained electronic system that makes use of Doppler's principle
of frequency shift of waves emanating from a moving source. In this
system, a pulsed or continuous wave is sent diagonally downward fore and
aft, forward and backward, and the frequencies are compared in order to
obtain the true ground speed. The heading is obtained from a special
magnetic compass and is maintained by a directional gyro used as an
integrating device. The distance thus determined has a precision better
than one part in a thousand, which is sufficient for most geophysical
surveys. Dobrin
a. A black gelatinous matter in peat and soft brown coal consisting of
humic acids or their salts; has a detrimental effect on briquettes and
coke. Syn:torf-dopplerit; trof-dopplerit; Weichbraunkohlen-dopplerit;
peat gel; brown-coal gel.
b. A gel in peat composed of ulmins derived from plant carbohydrates by
bacterial destruction of proteins.
c. An asphalt found in New Zealand and parts of Siberia.