A trace on the ground motion record representing the component of motion
in a vertical plane and in the direction of the seismic wave travel
direction.
(k g i ' DICTIONARY TERMS:vesicle A cavity of variable shape in a lava, forme
[\B]vesicle[\N]
Said of the texture of a rock, esp. a lava, characterized by abundant
vesicles formed as a result of the expansion of gases during the fluid
stage of the lava. CF:cellular; scoriaceous. AGI
a. Original spelling of vesuvianite. See also:leucite
b. A mixture of calcite and hydromagnesite. Hey, 1
A mineral, Ca10 Mg2 Al4 (SiO4 )5 (Si
2 O7 )2 (OH)4 . Tetragonal. Common in
contact-metamorphosed limestones. A massive light green variety is known
as californite. Syn:idocrase
A jadelike variety of vesuvianite (idocrase). Also called californite.
English
A monoclinic mineral, (Cu,Zn)3 (PO4 )(OH)3 .2H (sub
2) O ; greenish-blue. Formerly called arakawaite.
A mechanical sampling device that automatically selects one twenty-fifth
or one sixty-fourth of the ore passing through. Fay
A V-shaped flume, supported by trestlework and used by miners for bringing
down timber and wood from the mountains, at the same time using the water
for mining purposes. Fay
A vibrating ore screen in which the feed is from a saucer-shaped
distributer onto a conical surface kept in vibration by a ratchet motion.
Liddell
To have a swinging or oscillating motion; to move or swing back and forth,
such as a pendulum does; to have a period of vibration; to fluctuate; to
vacillate; to sound, such as a voice vibrates in an ear; to throb.
AGI
a. A trough or tube flexibly supported and vibrated at relatively high
frequency and small amplitude to convey bulk material or objects.
See also:oscillating conveyor
b. A metal trough mounted on flexible supports and free to move in a
vertical plane. It is vibrated at an angle of about 30 degrees to the
horizontal. The material being conveyed moves in a series of gentle
pitches and catches that blend to produce continuous, uniform flow. There
is no tumbling or sliding of the material to cause wear of the trough.
There are two basic types of vibrating conveyors: (1) the natural
frequency types (those supported by heavy-duty stiff coil or leaf
springs), and (2) forced vibration types (those supported by rocker arms
or rods pivoted at the trough and at the base connections). Materials can
be moved downward, horizontally, or up to 10 degrees slopes. It can convey
coal, limestone, sand, coke, granite, gravel, etc.
See also:shaker conveyor
A sediment coring tube designed to vibrate in such a way as to overcome
the resistance of compacted ocean floor sediments, sands, and gravel.
Hunt
A stoker developed in Germany and used increasingly in that country and in
the United States. The hearth consists of a rigid water-cooled matrix.
Coal is fed on to this at one end and is moved across it by the vibrating
motion to discharge as ash at the other end. The vibrations, with an
amplitude of about 1/8 in (3 mm) and in progress for about 5 s every 2 min
give a satisfactory feed rate. The rate of feed is controlled by altering
the duration of the vibrations. See also:stoker; underfeed stoker.
Nelson
This type table is used at the Kimberly Mines in South Africa for
concentrating the -3.33- to +0.59-mm fraction of pan concentrate and other
material of +0.59-mm size. Efficiency is 99%, and the ratio of
concentration 50,000:1.
Bar grizzlies mounted on eccentrics so that the entire assembly is given a
forward and backward movement at a speed of some 100 strokes a minute.
This is the type of grizzly now generally used ahead of a primary crusher.
Pit and Quarry
A loading stage or structure with a double vibrating action that causes
the coal or minerals to settle down in a mine car while being loaded. This
settlement increases the car-carrying capacity and reduces spillage during
transit. Syn:tram vibrator
a. A commercial screen in which the cloth, wire, or bar deck is vibrated
by solenoid or by magnetostriction, or mechanically by eccentrics or
unbalanced spinning weights. Pryor, 3
b. A screen oscillated either by mechanical or electrical means. The
amplitude of movement of the vibrating screen is smaller than that of the
jigging screen and its speed of oscillation is higher. BS, 5
c. A screen that is vibrated to separate and move pieces resting on it.
Nichols, 1
d. Machines of this type consist of one or more slightly inclined
screening surfaces mounted in a robust frame. To increase the capacity and
prevent blinding of holes, the screening surfaces are caused to vibrate.
This may be done by mounting the screen on powerful springs and causing it
to bear down on the underside of the frame. An alternative method used in
the Hummer screen is to stretch the wire screen to a high tension and
mount an electromagnet actuated by an alternating current at some
convenient point on the frame. The magnet works against the springs on
which the screen is mounted, and in this way very rapid vibration can be
secured and blinding greatly reduced. Miall
Wire-mesh screens that are vibrated and heated electrically to increase
efficiency. See also:screens
This consists of a thin steel wire stretched between knife edges, one
being free to move longitudinally. The wire is maintained vibrating at its
natural frequency by an electrical method. The knife edges are held firmly
against the girder under test, a change of strain in the girder varying
tension in the wire and hence its natural frequency. This gage is used in
conjunction with a reference instrument of fixed frequency; electrical
impulses from both instruments are superimposed to produce beats having a
frequency equal to the difference between the frequencies of the two
instruments. Changes in the frequency of the test gage caused by
variations in strain result in identical changes in the beat frequency.
The joint output from these two instruments is applied to the plates of a
cathode-ray tube, leading to an oscillation of the electron beam with a
frequency equal to that of the higher of the two applied frequencies, with
an amplitude that increases and decreases with the same frequency as that
of the beats. Hammond
a. The act of vibrating; oscillation. Vibrations may be free or forced;
longitudinal, transverse, torsional, or dilatational; also classified
according to kind, such as acoustical, electrical, flexural, etc.
AGI
b. The undesirable oscillatory movements of a drill string. Long
Drilling in which a frequency of vibration in the range of 100 to 20,000
Hz is used to fracture rock. Ultrasonic drilling is one of the better
known methods of vibration drilling. Min. Miner. Eng., 1