A layout consisting of six or more plows, 220 lb (100 kg) each, 20 yd
(18.3 m) apart on one rope or chain, feeding onto an armored conveyor; the
load on the conveyor is well distributed. A driving unit is arranged at
both ends of the face and operated alternately to impart a to-and-fro
movement to the plows. The minimum workable seam thickness is 20 in (50.8
cm) at gradients from 0 degrees to 20 degrees ; maximum length of face is
about 190 yd (174 m). See also:Gusto multiplow
The constant, used in stadia work, by which the staff intercept is
multiplied to determine the distance between the staff and the theodolite.
The value is generally taken as 100. See also:tachymeter
Hammond
A winding system based on the principles of the Koepe winder. The drive to
the winding ropes is the frictional resistance between the ropes and the
driving sheaves. Multirope friction winders are usually tower mounted,
with either cages or skips, and provided with a counterweight. The sheaves
are from about 6 to 12 ft (1.8 to 3.7 m) in diameter with a direct coupled
or geared drive. Four ropes are favored and these operate in parallel and
share the total suspended load. The system was introduced partly because
of the difficulty of winding heavy loads from deep shafts with a single
large-diameter winding rope. Modern winding ropes have become large and
heavy, being 2-1/4 in (5.72 cm) in diameter locked coil, weighing 16.5 st
(15 t) for a 1,000-yd (915-m) shaft; therefore, the introduction of the
friction winder, with its counterweight, and using four smaller ropes side
by side in place of one. Such ropes need be only 1-1/4 in (3.2 cm) in
diameter to give equivalent breaking strain. See also:Koepe winder
Nelson
The firing of a number of shots simultaneously.
See also:M
multishot gyroscopic instrument
A borehole surveying instrument that can take a number of readings during
its descent and ascent in the borehole. It comprises gyroscopic and
photographic recording units; direction and inclination indicators; a
timing clock, and other accessories. A movie film enables numerous records
to be taken throughout the depth of the borehole.
See also:gelatin borehole tube
A remote sensing device that is capable of recording data in the
ultraviolet, visible, and infrared portions of the spectrum.
Syn:shuttle multispectral infrared radiometer
See also:thematic mapper
A fan having two or more impellers working in series. BS, 8
A flexible, nonspinning rope; composed of concentric layers of strands of
relatively fine wires, alternate layers of strands being wound in opposite
directions over a hemp core. See also:multiple-strand rope
Sinclair, 5
A heavy roller with pneumatic tires used to consolidate embankments.
Hammond
The process of preservation of plant tissues under the influence of
arrested decay. Tomkeieff
Corn. Any fusible metal.
A drillers' term for pyrite. See also:pyrite
The concentration of explosive effect (i.e. jetting) which occurs at a
cavity at the end of an explosive charge; this effect is the basis of the
design and performance of shaped charges.
Contraction of mu-meson. An elementary particle with 207 times the mass of
an electron. It may have a single positive or negative charge.
Lyman
An etching reagent developed for use in the investigation of the structure
of iron-carbon-chromium alloys. It consists of a solution of 10 g
potassium ferricyanide, 10 g potassium hydroxide, and 100 mL water.
Osborne
A schistose rock composed of piedmontite and quartz. See also:ollenite
AGI
An isometric mineral, PbCu6 O8 (Cl,Br)2 ; rare;
secondary; forms minute black octahedra.
A flotation process that is not strictly of the same class as others, but
still makes use of the principle of selective oiling of sulfide particles.
The crushed ore is fed into an agitator and mixed with 4% to 5% of its
weight of a paste made of one part of oil or thin tar with three or four
parts of magnetic oxide of iron. This oxide must be ground to an
impalpable powder. These ingredients, with enough water to make a pulp,
are agitated for 5 to 20 min. The paste preferentially adheres to the
sulfides because of the oil. The ore is then fed over magnets, and oxide
of iron, with the mineral adhering to it, is pulled out. The oil and
magnetite are then recovered. Liddell
A cutter loader which is essentiaily a conversion unit for Anderton
shearer machines and designed to produce a reasonable percentage of large
coal. The top and bottom of the seam are cut by rotating drums of small
diameter while shearing the back of the cut with a narrow-kerf jib and
chain. Nelson
A term applied in Minnesota to rusty-colored outcropping rocks, such as
gabbros and quartzites, that resemble brown sugar. Etymol: Spanish, brown
sugar. AGI