The array of monochromatic X-ray diffractions produced by a mineral
powder. CF:crystallogram
Ratio of the volume of voids between particles, plus the volume of pores,
to the volume occupied by the powder, including voids and pores.
Pryor, 3
A tetragonal mineral, CaMoO4 ; forms a series with scheelite as
tungsten replaces molybdenum; a minor source of molybdenum in Idaho,
Michigan, Nevada, and California, and Siberia, Russia.
A wood treatment consisting of impregnating the wood with a saccharin
solution. It hardens the wood, and renders it fireproof to some extent.
Liddell
a. Any form of energy available for doing any kind of work; e.g., steam
power and water power. Specif., mechanical energy, as distinguished from
work done by hand. Standard, 2
b. Used loosely to indicate the electric current in a wire. Fay
c. Rate of doing work. The foot-pound-second (fps) unit of power is the
horsepower (hp), which is a rate of working equal to 550 ft.lbf/s (745.7
W). The electrical power unit, the watt, equals 107
cm-gram-second (cgs) units; i.e., 107 erg/s or 1 J/s. CTD
The part of a lever between the fulcrum and the point where force is
applied. Nichols, 2
See:pedestrian-controlled dumper
One or more winches mounted on a tractor and used to manipulate parts of
bulldozers, scrapers, or other machines. Nichols, 2
A high-speed tractor-mounted winch with one to three drums; used chiefly
for operating bulldozers, scrapers, and rooters. Nichols, 1
A machine consisting of: (1) a bottomless scraper bucket; (2) a two-drum
hoist; (3) two long cables that attach to the front and rear of the
scraper; (4) a movable tail block; (5) a short, guyed mast located behind
a ground hopper or other delivery point; and (6) two sheave blocks mounted
on the mast to guide the operating cables to the hoist. The tail block is
shifted manually from time to time, swinging the scraper in a wide arc
until all the material within the operating radius has been taken out.
Pit and Quarry
A mechanically operated auger for exploring and testing deposits that are
not very hard. The drilling rig may be mounted on a lorry or on continuous
tracks when greater depths may be reached. Nelson
In fully mechanized coal mining, a system of pit props connected to a
flexible armored conveyor by means of hydraulic rams. Pryor, 3
a. The ratio of the mean actual power in an alternating-current circuit
measured in watts to the apparent power measured in volt-amperes; equal to
the cosine of the phase difference between electromotive force and
current. Webster 3rd
b. The ratio of the total watts input to the total root-mean-square
volt-ampere input to a rectifier or rectifier unit. Coal Age, 1
c. A clause frequently found in electric power contracts, which sets forth
that if a customer permits the average power factor of the load used to
fall below a specified value, a penalty charge will be made. Power factor
is often defined as the ratio of actual power to apparent power and is
usually expressed as a percentage. Kentucky
Meter that indicates the relation of the phase between the line current
and the line voltage, which actually is the same as the power factor of
the load. Coal Age, 3
Power-operated machine used mainly for removing dirt and fines from
material to be crushed. There are three main types--the live-roll grizzly,
the vibrating-bar grizzly, and the bar grizzly feeder.
See also:static grizzly
a. In general, an electrically operated hydraulic pump, placed at the gate
end, to supply power to face equipment; e.g., self-advancing supports. The
system forms a closed circuit with the oil returning to a reservoir
containing about 212 gal (800 L) of oil. The pump can supply 2-1/2 gal
(9.5 L) of oil per unit at 2,000 psi (13.8 MPa), which allows a setting
load of about 9 st (8 t) per prop. See also:hydraulic power
Nelson b. A unit that converts AC or DC current to AC or DC voltages suitable for
the operation of electronic equipment. NCB
A manually operated compacting machine, weighing about 200 lb (91 kg),
raised by an intrinsic internal combustion mechanism and allowed to fall
by gravity. See also:mechanical rammer
A sequence control system that is suitable for a group of conveyors in
tandem. The trunk conveyor contactor is first closed; after a delay of
from 3 to 15 s, sufficient for its motor to come up to speed, power is
switched on to the contactor of the second conveyor; finally, after a
similar delay, power is switched on to the third conveyor or conveyors.
All power comes through the number 1 conveyor contactor so that, if this
conveyor is stopped, all other conveyors in tandem stop as well.
See also:sequence starting
An excavating and loading machine consisting of a digging bucket at the
end of an arm suspended from a boom, which extends cranelike from the part
of the machine that houses the powerplant. When digging, the bucket moves
forward and upward so that the machine does not usually excavate below the
level at which it stands. See also:shovel loader
Power shovels are used for mining coal, iron ore, phosphate deposits, and
copper ore. The shovels may be used either for mining or for stripping and
removing the overburden, or for both types of work, although at some coal
mines the shovels used for stripping are considerably larger than those
used for other mining. Lewis