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vacuum method

In flotation, a method in which the pulp, saturated with air at
atmospheric pressure, is allowed to rise to a height above the normal
hydrostatic level of the pulp. In the course of this ascent, the dissolved
gases precipitate from solution and form a vast number of very tiny
bubbles that attach themselves selectively to the hydrophobic solids.
Gaudin, 2

vacuum method of testing sand

A method of carrying out a triaxial test on a sand sample by maintaining a
partial vacuum in the rubber bag containing the sample. Hammond

vacuum pump

a. A centrifugal or reciprocating pump that extracts steam or air from a
chamber or pipe to create a partial vacuum. A vacuum pump, hand or power
operated, is part of a pump station equipment where gravity flow is
absent. Nelson
b. See:pulsometer
c. A pump for exhausting air or other gas from an enclosed space to a
desired degree of vacuum. Webster 3rd
d. A pump in which water is forced up a pipe by the difference of pressure
between the atmosphere and a partial vacuum. CF:air pump

vacuum system

A two-pipe, steam-heating system equipped with vacuum pumps to permit
maintenance of pressure below atmospheric within the radiators.
Strock, 2

vadose water

Water of the zone of aeration. Syn:suspended water

vaesite

An isometric mineral, NiS2 ; pyrite group.

vake

Soft, compact, mixed claylike material with a flat, even fracture, found
most often in volcanic terrains. Not recommended. See:wacke

valaite

A pitch-black resin of unknown composition. Found in thin crusts on
dolomite and calcite in the Coal Measures of Moravia, Czechoslovakia.
Tomkeieff

Valantin conveyor cutter

A cutter chain on an armored flexible conveyor that cuts its own stable
holes; pushed by pulsating rams; height, 18 in (45.7 cm); minimum workable
seam, 20 in (50.8 cm); on gradients 0 degrees to 20 degrees ; maximum
length of face, 45 yd (40 m). Nelson

valence

The degree of combining power of an element or a radical.

valence bond

Linkage of pairs of electrons so as to unite their atoms as a molecule.
When an element has more than one valence, its commonest combination is
called the principal valence. Pryor, 3

valence crystals

Crystals whose atoms are held in position by covalent bonds; e.g., diamond
and silicon. Newton, 1

valencianite

A variety of adularia in a silver mine at Valencia, Guanajuato, Mexico.

Valentine scale

Pocket-sized beam scale of Chinese origin used in valuation of alluvial
tin gravels. The beam is so calibrated as to read in catties per cubic
yard when concentrates from washing of 1/4 ft3 (0.007 m3
) are weighed. Pryor, 3

valentinite

An orthorhombic mineral, Sb2 O3 ; soft; dimorphous with
senarmontite; an oxidation product of antimony ores.
Syn:white antimony

valentite

Antimony trioxide, Sb2 O2 , in orthorhombic crystals.
Syn:white antimony; antimony trioxide.

valleriite

A hexagonal mineral, 1.53[(Mg,Al)(OH)2 ].[(Fe,Cu)S] ; an irrational
but discrete interlayer complex of hydroxide and sulfide layers; massive;
soft; resembles pyrrhotite in color.

vallevarite

A light-colored monzonitic igneous rock composed chiefly of andesine,
microcline, and antiperthite, with small quantities of clinopyroxene,
biotite, and apatite. The name, given by Gavelin in 1915, is for
Vallevara, Sweden. Obsolete. AGI

valley brown ore

A local name for comparatively pure high-grade limonite or brown iron ore
in Cambro-Ordovician limestones in the Shenandoah Valley of Virginia.
See also:mountain brown ore

valley fill

A fill structure consisting of any material other than coal waste and
organic material that is placed in a valley where side slopes of the
existing valley measured at the deepest point are greater than 20 degrees
, or the average slope of the profile of the valley from the toe of the
fill to the top of the fill is greater than 10 degrees .

Vallum diamond

Rock crystal (quartz) from the Tanjore District, India.