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Appendix:Dictionary of Mining, Mineral, and Related Terms/V/1

vacancy
 * A point defect in a crystal structure where an atom or ion is missing from its expected position. Syn: Schottky defect.

vacant land
 * As defined by its opposite, land is not vacant when occupied as a mining claim without discovery by one who is diligently prospecting it for minerals that it may contain.

Vacquier-Steenland method
 * A numerical method used in gravity interpretation for calculating the depth to the source of many typical total field anomalies. The method involves the computation of the curvature of the observed total intensity by superposition of a special grid over the intensity contours. The curvature is proportional to the second vertical derivative of the magnetic intensity.

vacuole
 * See: vesicle.

vacuum
 * A method of producing ventilation by exhausting air from a mine. See also: vacuum fan.

vacuum casting
 * a. The casting of metals in vacuum. Also called suction casting. See also: vacuum metallurgy.

b. Slip casting in which the slip is de-aired before casting.

vacuum common fine salt
 * VCF; evaporated salt made in vacuum pans; of ordinary purity and ordinary screen analysis.

vacuum concrete
 * Concrete poured into a framework that is fitted with a linen filter in the form of a vacuum mat. As a result of the process ensuing, the concrete attains its 28-day strength in 10 days and has a 25% higher crushing strength.

vacuum deposition
 * Condensation of thin metal coatings on the cool surface of work in a vacuum.

vacuum fan
 * A fan for creating suction or partial vacuum. An exhaust fan. See also: vacuum.

vacuum filter
 * a. A form of filter in which the air beneath the filtering material is exhausted to hasten the process.

b. One in which the pulp is drawn into contact with a porous septum by means of a moderately high vacuum. Solids are arrested and filtrate drawn through. In the drum and disc types, filtration is continuous. Vacuum is produced by means of a pump. See also: pulp.

vacuum filtration
 * a. The separation of solids from liquids by passing the mixture through a filter and where, on one side, a partial vacuum is created to increase the rate of filtration. It may be used to extract fine coal from the suspension or cyanide solution for reuse.

b. See also: filter.

vacuum lifting
 * Lifting by a crane fitted with a suction pad, employed for such items as precast concrete components, large panes of glass, and sheet steel.

vacuum metallurgy
 * The processing of metals at elevated temperatures, usually by induction heating in high vacuum. See also: vacuum casting.

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.

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.

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.

b. See: pulsometer. c. A pump for exhausting air or other gas from an enclosed space to a desired degree of vacuum. 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.

vadose water
 * Water of the zone of aeration. Syn: suspended water.

vaesite
 * An isometric mineral, NiS (sub 2) ; 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.

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).

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.

valence crystals
 * Crystals whose atoms are held in position by covalent bonds; e.g., diamond and silicon.

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 ft (super 3) (0.007 m (super 3) ) are weighed.

valentinite
 * An orthorhombic mineral, Sb (sub 2) O (sub 3) ; soft; dimorphous with senarmontite; an oxidation product of antimony ores. Syn: white antimony.

valentite
 * Antimony trioxide, Sb (sub 2) O (sub 2), in orthorhombic crystals. Syn: white antimony; antimony trioxide.

valleriite
 * A hexagonal mineral, 1.53[(Mg,Al)(OH) (sub 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.

valley brown ore
 * A local name for comparatively pure high-grade limonite or brown iron ore in Cambro-Ordovician limestones in the Shanendoah 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.

Val separator
 * A launder used for cleaning buckwheat, rice, and barley sizes of anthracite. It has three distinguishing features: (1) a mixing tank at the head end of the machine, (2) a baffle in the bottom of the machine next to the mixing tank to facilitate the stratification of the solids in specific gravity layers, and (3) the use of a screen and bed of slate in the free discharge boxes.

valuation
 * a. The act or process of valuing, or of estimating the value or worth; appraisal.

b. The value or estimated price set upon a thing.

value
 * The valuable constituents of an ore; their percentage in an orebody, or assay grade; their quantity in an orebody, or assay value. See also: assay grade; assay value; unit value.

valve tower
 * A tower built up within a reservoir to house the control valves of supply pipes drawing off water at different levels.

vamping
 * The debris of a stope, which forms a hard mass under the feet of a miner.

van
 * a. To separate, such as ore from veinstone, by washing it on the point of a shovel.

b. A shovel used in ore dressing.

vanadate
 * A salt or ester of vanadic acid; a compound containing the radical (VO (sub 4) ) (super 3-) (ortho) or (VO (sub 3) ) (super -) (meta). CF: arsenate; phosphate.

vanadic ocher
 * A native yellow vanadium oxide found near Lake Superior.

vanadinite
 * A hexagonal mineral, Pb (sub 5) (VO (sub 4) ) (sub 3) Cl ; apatite group; soft; varicolored; sp gr, 6.7 to 7.1; in oxidized zones of lead ore deposits; in New Mexico, Arizona, Africa, Scotland, and Russia. Syn: vanadite.

vanadite
 * See: descloizite; vanadinite.

vanadium
 * A gray or white, malleable, ductile, metallic element. Symbol, V. Found in about 65 different minerals, among which are carnotite, roscoelite, vanadinite, and patronite; also found in phosphate rock, certain iron ores, and some crude oils. About 80% of the vanadium now produced is used as a ferrovanadium or as a steel additive; also used in ceramics, as a catalyst, and in the production of a superconductive magnet.

vanadium minerals
 * Those most exploited for industrial use are patronite (MoS (sub 2) with vandium sulfide), roscoelite (vanadium mica), vanadinite, carnotite, and chlorovanadinite. Metal is silvery and whitish; melting point is 1,720 degrees C; used in high-speed steels and shock-resistant alloys, chemicals, ceramics, and textiles.

vanadium ore
 * Most vanadium is obtained from vanadium-bearing magnetite (1% to 2.2% V) in South Africa. Other sources include patronite, carnotite, roscoelite, vanadinite, descloizite, and volborthite.

vanadium-zirconium turquoise
 * See: zirconium-vanadium blue.

vanalite
 * A monoclinic mineral, NaAl (sub 8) V (sub 10) O (sub 38) .30H (sub 2) O ; forms bright-yellow incrustations on weathered shales; in northwest Kara-Tau, Kazakhstan.

Van Allen radiation zone
 * Powerful doughnut-shaped zone of radiation 1,000 to 3,000 miles above the Earth's surface and parallel with the Equator.

van Arkel and de Boer process
 * See: iodide process.

vandenbrandeite
 * A triclinic mineral, Cu(UO (sub 2) )(OH) (sub 4) ; radioactive; dark green to black; secondary; associated with kasolite, sklodowskite, malachite, goethite, chalcocite, chalcopyrite, uraninite, curite, uranophane, and cobalt wad; occurs at Karungwe, Katanga, Republic of the Congo. Also spelled vandenbrandite.

vandenbrandite
 * A very rare, strongly radioactive, triclinic, dark green to almost black mineral, Cu (super 2+) (UO (sub 2) )(OH) (sub 4) ; a secondary mineral found associated with kasolite, sklodowskite, malachite, geothite, chalcocite, chalcopyrite, and uraninite; also found associated with curite, uranophane and cobalt wad; from Karungwe, Katanga, Zaire. Also spelled vandenbrandeite.

vandendriesscheite
 * An orthorhombic mineral, Pb(UO (sub 2) ) (sub 4) (OH) (sub 9) .2H (sub 2) O ; radioactive; forms small, amber-orange pseudohexagonal crystals, commonly barrel shaped; at Katanga, Congo.

van der Kolk method
 * A test used in microscopy to determine the index of refraction of a mineral grain relative to that of an immersion liquid. When transmitted light is blocked, the grain acts as a lens and the ocular inverts the image of the obstacle, causing a shadow to appear on the same side as the obstacle when the grain has the higher refractive index, but on the opposite side when the grain has the lower index. Syn: oblique illumination method. CF: Becke test.

van der Waals bond
 * Weak forces in crystal structures caused by induced dipoles resulting from juxtaposition of molecules; e.g., the bonding between electrostatically neutral layers in the talc structure.

van Dorn sampler
 * This sediment sampler consists of a Plexiglas cylinder closed at each end by an ordinary rubber force cup. The two cups are connected by a length of surgical rubber tubing inside the cylinder, prestressed enough to permit the force cups to retain the sample in the cylinder. In the armed position, the two cups are pulled outside the cylinder, where they are restrained by a releasing mechanism attached to the outside wall. Two short loops of wire connect the cups to the releasing mechanism. The cups are released underwater by sending a messenger down the hydrographic wire. This sampler does not invert, which prevents use of reversing thermometers in conjunction with sampling.

Vandyke brown
 * a. A naturally occurring pigment derived from indefinite mixtures of iron oxide and organic matter. Obtained from bog earth and peat deposits, or from ochers containing bituminous matter.

b. Etymol: its use by the 17th-Century Flemish painter Van Dyck. Syn: ulmin brown.

vane
 * The target of a leveling staff; one of the sights of a compass or quadrant.

vane anemometer
 * a. A small windmill-type instrument used to measure air velocity and to infer air volume movement. The vane anemometer has been the primary instrument for airflow measurement since the early 1900's.

b. See also: anemometer. c. Consists of several light, flat vanes, usually eight in number, mounted on radial arms that are attached to a horizontal spindle. This rotor drives, through a suitable gear train, a counting mechanism that indicates the revolutions of the rotor. The indicating dial, usually graduated in feet of air, may be located either concentrically with the rotor, or in a plane at right angles to the plane of rotation. By observing the number of revolutions over a timed interval, the velocity of flow is found. The instrument is available in a number of forms to cover velocities ranging from 30 to 6,000 ft/min (9.1 to 1,830 m/min).

vane-axial fan
 * An airfoil (propeller) or disk fan within a cylinder and equipped with air-guide vanes either before or after the wheel; includes driving-mechanism supports for belt drive or direct connection.

vane shear test
 * An in-place shear test in which a rod with thin radial vanes at the end is forced into the soil and the resistance to rotation of the rod is determined.

vane shear tester
 * A device used in soil testing, consisting of flat blades affixed to the end of a rod. It is forced into the soil, and the torque required to shear the soil, in situ, is determined as a measure of the shear strength of the zone tested by rotating the device. Syn: vane tester.

vane test
 * An in-place test to measure the shear strength of fine-grained cohesive soils and other soft deposits. A rod with four flat radial blades, or vanes, projecting at 90 degrees intervals is forced into the soil and rotated; the torque required to rotate the rod is a measure of the material's shear strength.

vane tester
 * See: vane shear tester.

vanner grease belt
 * In ore dressing, smelting, and refining, used for separation of valuable mineral from the gangue (waste minerals) in an ore.

vanoxite
 * A mineral, V (sub 6) O (sub 13) .8H (sub 2) O(?) ; a mixed-valence oxide; weakly radioactive; black; in the Colorado Plateau area as a sandstone cement; also a massive wood replacement associated with carnotite, gypsum, hewettite, pintadoite, tyuyamunite, and pyrite. See also: kentsmithite.

vanthoffite
 * A monoclinic mineral, Na (sub 6) Mg(SO (sub 4) ) (sub 4) ; colorless; at Wilhelmshall, Stassfurt, Germany.

vanuralite
 * A monoclinic mineral, Al(UO (sub 2) ) (sub 2) (V (sub 2) O (sub 8) )(OH).8H (sub 2) O ; yellow; at Mounana, Gabon.

vapart mill
 * A centrifugal grinder for pulverizing ore, coal, and coke.

vapor
 * a. A substance in the gaseous state as distinguished from the liquid or solid state.

b. Foul air in a mine. CF: gas.

vapor barrier
 * A material intended to prevent the passage of water vapor through a building wall to prevent condensation within the wall.

vapor density
 * The relative density of a gas or vapor as compared with some specific standard (as hydrogen). Abbrev., v d.

vaporization
 * See: evaporation.

vapor pressure
 * The pressure at which a liquid and its vapors are in equilibrium at a definite temperature. If the vapor pressure reaches the prevailing atmospheric pressure, the liquid boils. Symbol, p.

vapor system
 * A steam-heating system operating at pressure very near that of the atmosphere.

vara
 * Any of various old Spanish units of length used in Latin America and the Southwestern United States, equal in different localities to between 31 in and 34 in (78.7 cm and 86.4 cm); e.g., a unit equal to 33.3333 in (84.666 cm) in Texas, to 33.372 in (84.764 cm) in California, to 33.00 in (83.82 cm) in Arizona and New Mexico, and to 32.9931 in and 32.9682 in (83.802 cm and 83.739 cm) (among others) in Mexico. For other values, see ASCE (1954).

V-arching
 * Rock failure above a tunnel due to ring stresses. These cause rock to crack across a weakness plane and fall. The final shape is a reentrant V rather than a rounded arching. Syn: arching to a weakness. See also: arching.

Varian nuclear magnetometer
 * This magnetometer is available in two models, one for airborne surveys and the other for use on the ground. Both measure the total magnetic field of the Earth rather than its components.

variation
 * The angle by which the compass needle deviates from the true north; subject to annual, diurnal, and secular changes. Called more properly declination of the needle. See also: declination.

variation compass
 * A compass of delicate construction for observing the variation of the magnetic needle.

variegated
 * Said of a sediment or sedimentary rock, such as red beds or sandstone, showing variations of color in irregular spots, streaks, blotches, stripes, or reticulate patterns.

variegated copper ore
 * Bornite, erubescite.

variegated ore
 * See: bornite.

varietal mineral
 * A mineral that is either present in considerable amounts in a rock or characteristic of the rock; a mineral that distinguishes one variety of rock from another. Syn: distinctive mineral.

variety
 * In mineralogy, a mineral showing differences in color, other physical properties, or minor variations in composition from the material considered typical of the species. An example is emerald, the green-colored gem beryl.

variogram
 * A plot of the variance (one-half the mean squared difference) of paired sample measurements as a function of the distance (and optionally of the direction) between samples. Typically, all possible sample pairs are examined, and grouped into classes (lags) of approx. equal distance and direction. Variograms provide a means of quantifying the commonly observed relationship that samples close together will tend to have more similar values than samples far apart.

variole
 * A pea-size spherule, usually composed of radiating crystals of plagioclase or pyroxene. This term is generally applied only to such spherical bodies in basic igneous rock, e.g., variolite. CF: spherulite.

variolite
 * A fine-grained igneous rock of basic composition containing varioles. Not recommended usage.

variolitic
 * Said of the texture of a rock, esp. a basic igneous rock, composed of pea-size spherical bodies (varioles) in a finer-grained groundmass. CF: spherulitic.

variometer
 * A geophysical device for measuring or recording variations in terrestrial magnetism; a variable inductance provided with a scale.

variscite
 * a. An orthorhombic mineral, AlPO (sub 4) .2H (sub 2) O ; dimorphous with metavariscite; waxy; forms nodular masses in cavities where phosphate water acts on aluminous rock. Variscite is a popular gem material for cabochons and various carved objects, commonly substituting for turquoise. Syn: lucinite; utahlite.

b. The mineral group mansfieldite, scorodite, strengite, and variscite. CF: amatrice.

varislope screen
 * A suspended multiple deck screen with increased slopes in the second and third deck. It is used principally for coal and other large feed materials and combines scalping and sizing operations. The oversize lump material is removed on the top deck, egg or range size on the second, and nut size on the bottom deck. See also: trislope screen; vibratory screen.

varlamoffite
 * A mineral that is perhaps a variety of cassiterite.

varulite
 * A monoclinic mineral, (Na,Ca) (sub 2) (Mn,Fe) (sub 3) (PO (sub 4) ) (sub 3) ; alluaudite group; forms dull olive-green granular masses; at Varutrask, Sweden.

varve
 * a. A sedimentary bed or lamina or sequence of laminae deposited in a body of still water within 1 yr's time; specif. a thin pair of graded glaciolacustrine layers seasonally deposited, usually by meltwater streams, in a glacial lake or other body of stillwater in front of a glacier. A glacial varve normally includes a lower summer layer consisting of relatively coarse-grained, light-colored sediment (usually sand or silt) produced by rapid melting of ice in the warmer months, which grades upward into a thinner winter layer, consisting of very fine-grained (clayey), often organic, dark sediment slowly deposited from suspension in quiet water while the streams were ice bound. Counting and correlation of varves have been used to measure the ages of Pleistocene glacial deposits.

b. Any cyclic sedimentary couplet, as in certain shales and evaporites.--Etymol: Swedish.

varve clay
 * See: varved clay.

varved clay
 * A distinctly laminated lacustrine sediment consisting of clay-rich varves; also the upper, fine-grained, winter layer of a glacial varve. Syn: varve clay.

varves
 * Clayey soil containing thin alternate layers of different particle sizes; often combine the undesirable properties of clay and silt; formed from seasonal deposits from glacial streams.

vashegyite
 * An orthorhombic mineral, Al (sub 4) (PO (sub 4) ) (sub 3) (OH) (sub 3) .13H (sub 2) O(?) ; at Vashegy, Hungary, and near Manhattan, NV.

vat
 * a. A vessel or tub in which ore is washed or subjected to chemical treatment, as cyanide vat and chlorination vat. Syn: tank.

b. Salt pit. c. A term used in the Southwestern United States for a dried and encrusted margin around a waterhole.

vaterite
 * A hexagonal mineral, CaCO (sub 3) ; trimorphous with calcite and aragonite; at Ballycraigy, Larne, Northern Ireland.

vaughanite
 * A pure, dense, homogeneous, dove-colored, fine-textured limestone that breaks with a smooth and more or less pronounced conchoidal fracture that contains relatively few fossils, and that typically has a white, chalky appearance on weathered surfaces. Named after T. Wayland Vaughan (1870-1952), U.S. paleontologist.

vauquelinite
 * A monoclinic mineral, Pb (sub 2) Cu(CrO (sub 4) )(PO (sub 4) )(OH) ; fibrous.

vauxite
 * A triclinic mineral, FeAl (sub 2) (PO (sub 4) ) (sub 2) (OH) (sub 2) .6H (sub 2) O ; less hydrous than metavauxite or paravauxite; blue.

V-bob
 * A strong frame shaped like an isosceles triangle, turning on a pivot at its apex and used as a bell crank to change the direction of a main pump rod. It is used with Cornish pumping engines.

V-box
 * Sloughing box, used to separate slime (as overflow) from faster-settling portion of solids in pulp.

V-bucket conveyor elevator
 * See: gravity-discharge conveyor elevator.

VCR
 * See: vertical crater retreat.

V-cut
 * a. In mining and tunneling, a cut where the material blasted out in plan is like the letter V; usually consists of six or eight holes drilled into the face, half of which form an acute angle with the other half.

b. In underground blasting, a type of cut employed in which the cut holes meet in a V to pull the cut to the bottom of the holes properly. A single pair of holes may do in one kind of rock, but in another, two or three sets of V-holes entirely across the face may be needed. Also See also: wedge cut. Syn: plow cut; vee cut.

veatchite
 * A triclinic and monoclinic mineral, Sr (sub 2) B (sub 11) O (sub 16) (OH) (sub 5) .H (sub 2) O ; trimorphous with p-veatchite and veatchite-A.

vector
 * a. An entity represented as a directed magnitude, such as velocity, which is defined as consisting of a speed and a direction. See also: scalar.

b. See: hard vector.

vee cut
 * See: wedge cut; V-cut.

vees
 * a. A layer of soft clay or earth on the sides of a fault or dike. Syn: veez.

b. The acute angle between the fault plane and a coal seam; e.g., working the coal to the vees of the fault.

vee table
 * A pneumatic table, of U.S. design, for the drycleaning of coal, an improved form of the S.J. table.

veez
 * See: vees.

vegasite
 * See: plumbojarosite.

vegetable jelly
 * Same as fundamental jelly, carbohumin, etc. Syn: jelly.

veil
 * a. A removable plate to cover a screen, the action of which is not desired.

b. An aggregate of minute bubbles creating a whitish or cloudlike appearance in quartz. c. A variously formed weblike or netlike film in a radiolarian; e.g., patagium.

vein
 * a. An epigenetic mineral filling of a fault or other fracture in a host rock, in tabular or sheetlike form, often with associated replacement of the host rock; a mineral deposit of this form and origin. CF: lode. See also: true vein.

b. A narrow waterway or channel in rock or earth. Also, a stream of water flowing in such a channel. c. A thin, sheetlike igneous intrusion into a fissure. Not recommended usage. d. A coal seam or a bed of slate or other rock. Not recommended usage. e. A zone or belt of mineralized rock lying within boundaries clearly separating it from neighboring rock. It includes all deposits of mineral matter found through a mineralized zone or belt coming from the same source, impressed with the same forms and appearing to have been created by the same processes. f. A mineral deposit, usually steeply inclined. Used to describe a body that is usually smaller and has better defined walls than a lode. g. A rock fissure filled by intruded mineral matter. Many valuable minerals are codeposited with gangue stuff in veins. Usually the formation is steep to vertical, unlike a bedded deposit in which values are sandwiched horizontally. Vein is typically long, deep, and relatively narrow. h. The term lode is commonly used synonymously for vein. i. The filling of a fissure or fault in a rock, particularly if deposited by aqueous solutions. When metalliferous, it is called by miners a lode; when filled with eruption material, a dike. A bed or shoot of ore parallel with the bedding. Also called blanket deposit. j. A comparatively thin sheet of igneous rock injected into a crevice in rock. When this intrusion is large, it is called a dike. k. An irregular, sinuous, igneous injection, or a tabular body of rock formed by deposition from solutions rich in water or other volatile substances. l. A mineral body, thin in relation to its other dimensions, which cuts across the bedding and in which the minerals are later than the country rock. m. Sometimes used for a bed; e.g., a coal seam or a bed of slate. n. A layer, seam, or narrow irregular body of material different from surrounding formations. See also: vein or lode claim.

veined gneiss
 * A composite gneiss with irregular layering. The term is generally used in the field and has no genetic implications (Dietrich, 1960). CF: venite; composite gneiss.

vein intersection
 * a. The depth in the borehole at which the hanging and/or footwall of a vein is encountered.

b. The place where two or more veins cross or meet.

vein material
 * See: veinstuff.

vein miner
 * A miner experienced in the winning and working of mineral veins. See also: metal mining.

vein or lode claim
 * The terms "vein or lode" and "vein or lode claim" are used indiscriminately and interchangeably, and it follows that the term "vein or lode" is intended to be synonymous with the term "vein or lode claims." See also: vein; lode; lode claim.

vein quartz
 * A rock composed chiefly of sutured quartz crystals of pegmatitic or hydrothermal origin and commonly of variable size.

veinstone
 * The valueless stone that occurs with the valuable minerals in lodes and veins. Also called lodestuff; matrix; vein mineral; veinstuff. Sometimes mistakenly called gangue.

veinstuff
 * a. All the minerals occurring in a vein. See also: lodestuff.

b. Gangue. Syn: vein material.

vein system
 * An assemblage of veins of a particular area, age, or fracture system, usually inclusive of more than one lode.

velardenite
 * See: gehlenite.

velikhovite
 * A variety of pyrobitumen having a shining conchoidal fracture and occurring in the form of veins. It is partly soluble in organic solvent; sp gr, 1.2. In many ways it is similar to grahamite. It is assumed that it represents a weathering product of albertite. From the South Urals, Russia.

velocities in pipes
 * Experience has proved that the following are allowable velocities in pipes: air, 30 to 50 ft/s (9.1 to 15.2 m/s); compressed air, 25 to 40 ft/s (7.6 to 12.2 m/s); steam, 160 to 250 ft/s (46.8 to 76.2 m/s); water, 5 to 10 ft/s (1.5 to 3.0 m/s).

velocity
 * a. In explosives, the speed (in meters or feet per second) at which the detonating wave passes through a column of explosives. A high-velocity explosive renders a shattering effect, whereas a low-velocity explosive has a pushing or heaving effect. Syn: high velocity.

b. Linear flow rate of air per unit time. Measured in meters per second. c. A vector quantity that indicates a time rate of motion.

velocity determination
 * The determination of velocities and average velocities within the earth by seismic measurements.

velocity discontinuity
 * An abrupt change in the velocity of propagation of seismic waves within the earth, as at an interface.

velocity distribution
 * Relationship between seismic wave velocity and depth.

velocity head
 * a. The constant difference of height of a liquid between a level surface in a tank and a uniformly flowing jet through an orifice.

b. The distance a body must fall under the force of gravity to acquire the velocity it possesses. See also: kinetic energy. c. The energy possessed per unit weight of a fluid owing to its velocity. If at a given point the velocity is v feet per second, the velocity head at this point, v (super 2) /2g, g being the acceleration due to gravity in feet per second squared. Also called kinetic head. Syn: velocity pressure.

velocity lag
 * See: distance lag.

velocity meter
 * A seismometer used to record the velocity of ground motions.

velocity of air current
 * The higher the velocity of the air current, the greater will be the resistance to airflow. The resistance is nearly proportional to the velocity squared.

velocity of approach
 * a. The average velocity of water in a channel at the point where the depth over a flow measuring weir is recorded.

b. The mean velocity in the conduit immediately upstream from a weir, dam, Venturi throat, orifice, or other structure.

velocity of detonation
 * a. The velocity with which the shock wave traverses an explosive charge on detonation.

b. The velocity of detonation of an explosive was previously determined by what is known as the Dautriche test. The basis of this test is that a length of Cordtex detonating fuse detonates at a uniform speed, and if the two ends of a length of Cordtex are detonated simultaneously, the detonation waves will meet at the middle of the length of fuse. Similarly, if the two ends are detonated at different times, the distance from the middle of the fuse to the point where the two detonation waves meet is directly proportional to the interval of time between the detonations of the two ends of the Cordtex fuse. Furthermore, if the distance can be measured, the interval of time between the detonation can be calculated, since the velocity of detonation of Cordtex is known. Syn: Dautriche test.

velocity of retreat
 * An average velocity of flow of a liquid just downstream of a measuring weir.

velocity pressure
 * a. The pressure equivalent of the air velocity at any particular point. This is always positive. b. The pressure exerted by a moving fluid in the direction of its motion. It is the difference between the total pressure and the static pressure.

c. In Mine ventilation, the pressure exerted by the kinetic energy of air movement. Syn: velocity head. d. The algebraic difference between the total head and the static pressure.

velocity profile
 * A linear arrangement of sensors used to record reflections over a large range of shot-to-geophone distances, which is used to determine seismic velocity from the time-distance relationship.

velocity ratio
 * The ratio of the distance through which the force applied to a machine moves, and the distance through which the load moves. See also: mechanical advantage.

velocity reducing collector
 * This type of collector is designed to remove very large dust particles. It is often used ahead of other collectors to reduce the dust load, and to remove the particles most likely to cause abrasion. The velocity reducing collector has no moving parts and, in most instances, can be installed in front of the induced draft fan, reducing the abrasion of the fan blades. This type of collector also can be used under many high-temperature conditions.

velometer
 * A small portable direct-reading instrument used to measure the velocity of air at a point.

velvet
 * Profit; easily earned money.

velvet copper ore
 * Cyanotrichite in bright blue velvetlike druses and spherical forms. Syn: lettsomite; cyanotrichite.

vend
 * Products sold by coal mine annually.

vendeennite
 * A variety of fossil resin from Vendee, France.

Venetian red
 * A high-grade ferric-oxide pigment of a purer red hue than either light red or Indian red. Obtained either native as a variety of hematite red or more often artificially, by calcining copperas in the presence of lime. The composition ranges from 15% to 40% ferric oxide and from 60% to 80% calcium sulfate. The 40% ferric oxide is the pure grade, and sp gr, 3.45.

venite
 * Migmatite of which the mobile portion(s) were formed by exudation (secretion) from the rock itself (Dietrich & Mehnert, 1961). CF: veined gneiss; composite gneiss. Not widely used.

vent
 * a. In explosives, a small passage made with a needle through stemming, for admitting a squib to enable the charge to be lighted.

b. A hole, extending up through the bearing at the top of the core-barrel inner tube, that allows water and air in the upper part of the inner tube to escape into the borehole or into the annular space between inner and outer barrels.

vent bag
 * An enclosed airway to direct airflow to a given area or location.

ventilating column
 * See: motive column.

ventilating current
 * A current of air traveling in mines.

ventilating fan
 * See: mine ventilating fan.

ventilating pressure
 * a. The total head in pascals or kilopascals required to overcome the friction of the air in mines and to provide some final or exit velocity to discharge the air to the atmosphere.

b. The total pressure exerted on the atmosphere by the mine fan to overcome the resistance of the mine to the passage of a required volume of air throughout the mine necessary for its ventilation. See also: mine total head; fan total head; total ventilating pressure.

ventilation
 * Mine workings are usually subdivided to form a number of separate ventilating districts. Each district is given a specified supply of fresh air and is free from contamination by the air of other districts. Accordingly, the main intake air is split into the different districts of the mine. Later, the return air from the districts reunite to restore the single main return air current at or near the upcast shaft. See also: compound ventilation; fan drift; regulator.

ventilation department
 * A department for the purpose of planning adequate and economic ventilation for all future projects and to provide frequent information on existing ventilation systems.

ventilation doors
 * A door constructed to restrict the flow of ventilation air while permitting the passage of personnel and equipment. See also: door; separation door.

ventilation ducts
 * Two kinds are available, flexible and rigid ducts. Flexible ducts generally consist of flexible tubes made from fabrics coated with rubber or polyvinyl chloride, a nonflammable substance. They are available in varying lengths. Flexible ducting is suited for face ventilation in a variety of mining methods. It is suited also to crooked workings of limited extent. It has a higher resistance and a greater tendency to leak than rigid ducting. Rigid ducts are made of steel or fiberglass in lengths suitable for underground transport. This type of duct does not have to be accurately aligned and is therefore used, in the smaller sizes, in subsidiary work, particularly in crooked headings. For main tunnels where leakage must be minimized, flanged joints are used with suitable gaskets.

ventilation efficiency
 * One measure of the efficiency of a mine ventilation system is the ratio of the total amount of air actually reaching the working faces to the total amount (volume in cubic feet per minute) of air handled by the fan. See also: overall ventilation efficiency; thermometric fan test; ventilation standards; volumetric efficiency.

ventilation mason
 * A worker who erects by rough masonry or cement work, partitions of stone, brick, or concrete blocks to control proper circulation of air through passageways outby working places.

ventilation plan
 * A plan or drawing, required by law, that shows the ventilation air currents in a mine and the means of controlling them.

ventilation planning
 * When a new mine is projected or a new seam is to be worked from an existing mine, plans are prepared to show the proposed ventilating system, including the quantities of air and pressures and the principal appliances to control and distribute the air. Investigations and calculations are made to select a fan of the necessary type and size for the ventilation required. All of this important work comes within the general term ventilation planning. See also: air requirements; pressure survey; ventilation survey.

ventilation pressure
 * a. The pressure or head producing ventilation in a mine and measured by the height of a column of water it will support. The instrument used for this purpose is a water gage.

b. Pressure producing the flow of air, measured by a water gage, or the difference in level between the two ends of the water column in a vertical U-shaped tube, one end of which is connected to the air under pressure--for example, in the passageway leading to the fan--the other end being to the atmosphere. In some cases, the ventilating pressure is reported as meters of water in the U-tube; in other cases, the head is given in pascals or kilopascals.

ventilation regulator
 * See: regulator.

ventilation standards
 * The standards prescribed by regulations to provide air underground of a certain degree of purity. See also: ventilation efficiency.

ventilation stopping
 * See: stopping.

ventilation survey
 * a. Systematic observation of air pressure, quantity and quality, throughout a mine or part of a mine, to allow a detailed analysis of the ventilation system. Syn: pressure-quantity survey.

b. To distribute the air in a mine efficiently and economically, ventilation surveys are conducted. They may be classified as qualitative, quantitative, and pressure surveys. Qualitative surveys determine the proportion of flammable or poisonous gas, or dust, in the air that is being circulated through the mine. In hot and humid mines, they determine the conditions of air temperature and humidity. Quantitative surveys determine the quantity of air being circulated through the mine workings for a variety of reasons. This is done by measuring the volume of air passing at different points in the circuit by means of an anemometer, to investigate the existing air distribution, particularly to the individual faces; the location of leakage; and the possibility of its reduction or elimination. Pressure surveys measure the pressure absorbed and the resistance of the roadways and faces included in the survey. This enables determination of the power required to circulate the air in the different sections of the circuit and that is expended in ventilating individual districts. The total power expended in ventilating the mine may then be summed and the cost estimated. See also: ventilation planning.

ventilation symbols
 * A set of standard letters, signs, or marks used on mine ventilation plans to represent certain appliances or constructions to direct and control the flow of air underground.

ventilation tubing
 * Sheet steel or canvas piping 12 to 24 in (0.3 to 0.6 m) in diameter for conducting air to or from a tunnel, hard heading face, or sinking pit. The tubing extends from an auxiliary fan to within a few yards of the face to be ventilated. See also: tubing; auxiliary ventilation.

ventilator
 * a. A mechanical apparatus for producing a current of air underground, as a blowing or exhaust fan.

b. A furnace for ventilating a mine by heating the upcast air. c. A device for providing fresh air to a room or other space by introducing outside air or by exhausting foul air.

vent pipe
 * See: vent tube.

vent tube
 * a. Hose or piping conducting air-ejected drill cuttings from the borehole collar to a point some distance from the drill.

b. An exhaust pipe or tube. c. Tubing suspended from a wire in a mine opening to supply fresh air to a working place. Syn: vent pipe.

ventubes
 * Tubes of steel, fiberglass, or coated fabric with thin walls that can be easily connected. They are used in mine ventilation to lead air wherever it is needed. Also called ventilation tubing.

Venturi
 * A contraction in a tube or duct to accelerate the flow and lower the static pressure. It is used for metering and other purposes.

Venturi blower
 * a. A device resembling a Venturi meter that directs a jet of compressed air for ventilating short headings. The device is commonly made at a mine, and one well-proved type is called the Modder Deep. These blowers are mainly used in conjunction with ventilation ducting for the ventilation of headings several hundred feet in length.

b. An apparatus to induce a flow of air or gas in a duct by means of a jet of compressed air or water from a small nozzle in the duct.

Venturi flume
 * a. A type of open flume with a contracted throat that causes a drop in the hydraulic gradeline; used for measuring flow.

b. A control flume that comprises a short constricted section followed by one expanding to normal width. See also: control.

Venturi meter
 * A trademark for a form of the Venturi tube arranged to measure the flow of a liquid in pipes. Small tubes are attached to the Venturi tube at the throat and at the point where the liquid enters the converging entrance. The difference in pressure heads is shown on some form of manometer and from this difference and a knowledge of the diameters of the tubes, the quantity of flow is determined.

Venturi tube
 * A closed conduit that is gradually contracted to a throat causing a reduction of pressure head by which the velocity through the throat may be determined. The contraction is generally followed, but not necessarily so, by gradual enlargement to original size. Piezometers connected to the pipe above the contracting section and at the throat indicate the drop in the pressure head, which is an index of flow.

vent wire
 * A wire used by founders to make a hole in a sand mold for the escape of air or gases.

venus hairstone
 * See: rutilated quartz.

Venus's hairstone
 * Quartz containing needle-shaped crystals of rutile. See also: Thetis hairstone; sagenitic quartz; sagenite.

verde antique
 * A dark-green rock composed essentially of serpentine (hydrous magnesium silicate) usually crisscrossed with white veinlets of marble. Found in California, Georgia, Maryland, Massachusetts, New York, and Virginia. Used as an ornamental stone. In commerce, it is often classed as a marble.

verdelite
 * A green variety of elbaite (tourmaline).

verde salt
 * See: thenardite.

Verdet's constant
 * The rotation of the plane of polarization per centimeter per unit magnetic field in the Faraday effect. The value of the constant varies with temperature and is approx. proportional to the square of the wavelength of the light.

verdite
 * A deep green, relatively soft metamorphic rock of green fuschite (chromian muscovite) and clay with scattered grains of rutile; occurs in Transvaal and Zimbabwe; is carved for ornamental use.

verdolite
 * Talcose-dolomitic breccia rock from New Jersey.

verifier
 * a. A tool used in deep boring for detaching and bringing to the surface portions of the wall of the borehole at any desired depth.

b. In gas testing, an apparatus by which the amount of gas required to produce a flame of a given size is measured; a gas verifier.

vermeil
 * a. An orange-red garnet. Syn: vermilion.

b. A reddish brown to orange-red gem variety of corundum. c. An orange-red spinel. Syn: vermeille.

vermeille
 * See: vermeil.

vermicular quartz
 * Quartz in wormlike intergrowths with feldspar. See also: myrmekite.

vermiculite
 * A monoclinic mineral, (Mg,Fe,Al) (sub 6) (Si,Al) (sub 8) O (sub 20) (OH) (sub 4) .8H (sub 2) O ; mica group; basal cleavage; soft; pearly; a hydrothermal or weathering alteration of biotite; expands 6 to 20 times by thermal exfoliation; occurs in clay sizes in soils and as crystals and megacrysts in ultramafic rocks; in Montana, North Carolina, South Carolina, Wyoming, Virginia, Colorado, and South Africa. Syn: lernilite.

vermilion
 * a. A red pigment used in enormous quantities. Usually made from mercuric sulfide, HgS, tinted with puranitraniline. Also spelled vermillion.

b. A bright-red pigment consisting of mercuric sulfide. Prepared synthetically (as by the reaction of mercury, sulfur, and sodium hydroxide), but formerly obtained from the mineral cinnabar. Color ranges from crimson when coarse grained to nearly orange when finely divided. Both spellings are correct. c. See: alpha mercuric sulfide; cinnabar; vermeil.

vermillion
 * In the Lake Superior region, the lowest of the stratified schists; the crystalline schists.

vernadskite
 * Antlerite in aggregates of minute crystals or as pseudomorphs after dolerphanite. See also: antlerite.

Verneuil process
 * A technique developed by Auguste V.L. Verneuil (1856-1913), French mineralogist and chemist, for the manufacture of large crystals of corundum and spinel in which powdered alumina with appropriate oxide dopants is melted in an oxyhydrogen flame to produce boules of synthetic gems. See also: boule.

vernier closure meter
 * An instrument used to measure strain.

vernier compass
 * A surveyor's compass with a vernier, used for measuring angles without the use of the magnetic needle by means of a compensating adjustment made for magnetic variation.

vernier-reading manometer
 * This series of manometers covers a range of pressures from 0.001-in (25.4 mu m) water gage to 40-in (1.02-m) water gage. Syn: micrometer-reading manometer.

verrankohle
 * Rolled fragments of brown coal found on the coast of Norway.

vertical
 * a. A term used to define a direction that is perpendicular to a horizontal, or level, plane.

b. Local usage for vertical fractures, esp. in the Black Hills, South Dakota. c. Said of deposits and coal seams with a dip of from 60 degrees to 90 degrees. d. In aerial photographic mapping, a vertical line through the exposure station or rear nodal point. e. Orientation of a plumb-bob on a string under the force of gravity.

vertical aerial photograph
 * A photograph taken from an aircraft for purposes of aerial mapping or aerial geophysical prospecting; special cameras and techniques are employed. See also: profile flying.

vertical angle
 * Angle of elevation or depression, measured from the true horizontal plane.

vertical auger drill
 * A mobile-type rotary drill used on opencast sites with no hard rock for drilling vertical blasting holes. It can drill a hole of 5 in or 6 in (12.7 cm or 15.2 cm) in diameter to depths of about 30 ft (9.1 m). Drilling is by means of a rotary cutting head with interchangeable cutting bits, the auger removing the cuttings from the hole. An overall speed of 30 ft/h (9.1 m/h) can be obtained. See also: horizontal auger.

vertical balance
 * An instrument for measuring variations in the vertical component of the terrestrial magnetic field, usually by balancing the torque on a magnet system by means of a counter gravitational torque acting on counterweights.

vertical chain conveyor
 * Opposed-shelf type that has two or more vertical elevating conveying units opposed to each other. Each unit consists of one or more endless chains whose adjacent facing runs operate in parallel paths. Thus, each pair of opposing shelves or brackets receive objects (usually dish trays) and deliver them to any number of elevations.

vertical circle
 * a. Graduated circle on theodolite or tacheometer, by use of which the slope of the collimation line through sighting telescope is measured in survey work.

b. Any great circle of the celestial sphere passing through the zenith.

vertical collimator
 * An instrument in which the telescope sights vertically (upward or downward); used chiefly for centering a theodolite on a tower exactly over a station mark on the ground. It may be used for any vertical sight.

vertical component
 * That part, or component, of a vector that is perpendicular to a horizontal or level plane.

vertical crater retreat
 * a. A blasting method employed in underground sublevel mining. Initially a vertical slot extending across the width of the stope is mined. The remaining portion of the stope is then blasted by section into the vertical slot following sublevel procedures.

b. A variation of the sublevel stoping method that uses basic crater blasting models. Blasting is carried out at the base of vertical boreholes, making horizontal cuts and advancing upwards. A spherical charge is placed at an optimal distance from the stope back so that a maximum volume of rock is broken in the shape of an inverted cone. Borehole spacing is determined so that overlapping fragmentation cones do not disturb adjacent explosive charges. Abbrev. VCR.

vertical crater retreat mining
 * A patented mining method in which large, parallel, vertical drillholes permit placement of nearly spherical explosive charges, such that horizontal slices of ore are then broken into an undercut; applicable to ore of only moderate strength.

vertical curve
 * a. The curve between two lengths of a straight roadway that possess different gradients. The curve provides a gradual change for haulages from one inclination to the other. The curve leading to the top or brow of an inclined plane would be convex and at the bottom would be concave.

b. The graduated curve connecting two lengths of a railway or road, which are at different slopes. c. The meeting of different gradients in a road or pipe.

vertical cut
 * See: shear cut.

vertical dip slip
 * See: vertical slip.

vertical drains
 * Usually column of sand used to vent water squeezed out of humus by weight of fill.

vertical exaggeration
 * a. A deliberate increase in the vertical scale of a relief model, plastic relief map, block diagram, or cross section, while retaining the horizontal scale, to make the model, map, diagram, or section more clearly perceptible.

b. The ratio expressing vertical exaggeration; e.g., if the horizontal scale is 1 in to 1 mi and the vertical scale is 1 in to 2,000 ft, the vertical exaggeration is 2.64. Abbrev: VE c. The apparent increase in the relief as seen in a stereoscopic image.

vertical excavation limited area
 * This method of excavation is used in loose or wet soils--unconsolidated formations--where the banks must be supported by shoring or sheathing. The material must, out of necessity, be lifted out vertically.

vertical fold
 * See: upright fold.

vertical gradient
 * The rate of change of a quantity in the direction of the vertical.

vertical gradiometer
 * An instrument for measuring the vertical gradient of gravity.

vertical guide idler
 * An idler roller of about 3 in (7.6 cm) in diameter so placed as to make contact with the edge of the belt conveyor should the latter run too much to one side. Although vertical guide rollers are effective, they cause edge wear on the belting and their use is not favored.

vertical intensity
 * The vertical component of the magnetic field; usually considered positive if downward, negative if upward. CF: horizontal intensity.

vertical line
 * One that is exactly upright, or it points straight up and down.

vertical load-bearing test
 * See: load-bearing test.

vertical mill
 * A rolling mill in which the rolls are oriented vertically.

vertical photograph
 * An aerial photograph made with the camera axis vertical (camera pointing straight down) or as nearly vertical as possible in an aircraft.

vertical pump
 * This pump is often of the single-acting bucket or ram type with single or double cylinders and either with or without a flywheel. Vertical pumps may be used where headroom is adequate but area restricted, although horizontal reciprocating pumps are more generally used.

vertical reciprocating conveyor
 * A power or gravity-actuated unit that receives objects on a carrier or car bed usually constructed of a power or roller conveyor. The object is then elevated or lowered to other elevations.

vertical sand drain
 * a. A boring through clay or silty soil that is filled with sand or gravel to facilitate drainage of liquid from the soil.

b. See: perched water table.

vertical screw conveyor
 * A screw conveyor that conveys in a substantially vertical path. See also: screw conveyor.

vertical seismograph
 * An instrument that registers the vertical component of ground motion.

vertical separation
 * In a fault, the distance measured vertically between two parts of a displaced marker such as a bed. CF: horizontal separation.

vertical shaft
 * A shaft sunk at an angle of 90 degrees with the horizon or directly downward toward the center of the Earth.

vertical shear
 * Reference is to a beam, assumed for convenience to be horizontal and to be loaded and supported by forces, all of which lie in a vertical plane. The vertical shear at any section of the beam is the vertical component of all forces that act on the beam to the left of the section. The vertical shear is positive when upward and negative when downward.

vertical shift
 * In a fault, the vertical component of the shift. See also: shift.

vertical slip
 * In a fault, the vertical component of the net slip; it equals the vertical component of the dip slip. CF: horizontal slip. Syn: vertical dip slip.

vertical takeup
 * A mechanism in which the takeup or the movable pulley travels in a vertical plane.

vertical theory
 * The earliest view of subsidence in which it was supposed that the lines of break (limiting lines) were more or less vertical. Pillars left for support were accordingly formed immediately under the object to be protected, the question of dip being disregarded.

vesicle
 * 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 A cavity of variable shape in a lava, formed by the entrapment of a gas bubble during solidification of the lava. Syn: vacuole.

vesicular
 * 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.

vesuvian
 * a. Original spelling of vesuvianite. See also: leucite.

b. A mixture of calcite and hydromagnesite.

vesuvianite
 * A mineral, Ca (sub 10) Mg (sub 2) Al (sub 4) (SiO (sub 4) ) (sub 5) (Si (sub 2) O (sub 7) ) (sub 2) (OH) (sub 4) . Tetragonal. Common in contact-metamorphosed limestones. A massive light green variety is known as californite. Syn: idocrase.

vesuvian jade
 * A jadelike variety of vesuvianite (idocrase). Also called californite.

veszelyite
 * A monoclinic mineral, (Cu,Zn) (sub 3) (PO (sub 4) )(OH) (sub 3) .2H (sub 2) O ; greenish-blue. Formerly called arakawaite.

Vezin's sampler
 * A mechanical sampling device that automatically selects one twenty-fifth or one sixty-fourth of the ore passing through.

V-flume
 * 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.


text:
Appendix:Dictionary of Mining, Mineral, and Related Terms/V/2

vibracone
 * 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.

vibrate
 * 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.

vibrating conveyor
 * 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.

vibrating coring tube
 * A sediment coring tube designed to vibrate in such a way as to overcome the resistance of compacted ocean floor sediments, sands, and gravel.

vibrating grate
 * 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.

vibrating grease table
 * 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.

vibrating grizzlies
 * 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.

vibrating platform
 * 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.

vibrating screen
 * 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.

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. c. A screen that is vibrated to separate and move pieces resting on it. 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.

vibrating screens (heated)
 * Wire-mesh screens that are vibrated and heated electrically to increase efficiency. See also: screens.

vibrating wire strain gage
 * 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.

vibration
 * 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.

b. The undesirable oscillatory movements of a drill string.

vibration drilling
 * 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.

vibration gravimeter
 * A device that measures gravity by observation of the period of transverse vibration of a thin wire tensioned by the weight of a known mass; useful for observation at sea.

vibration meter
 * A seismometer that is used for measuring vibrations of structures from other than seismic causes.

vibration method of roof testing
 * A person's fingertips are placed against the roof, and then the roof is struck a sharp heavy blow. Such a blow usually sets up easily felt vibrations in an unsound roof.

vibration of foundations
 * The foundations of machinery installed in a building should be so designed that the frequency of the machine is two times the natural frequency of the combined system of machines and foundations.

vibration test
 * An approximate grading test for coarse-grained soils. A flat paper-covered board is inclined at a slope of 1:24. The dry and powdered sample of soil is spread in a thin layer across the top of the board. The board is tapped sharply and repeatedly. The soil will travel down the board, the largest particles traveling faster and further than the smaller ones. Dependent on the degree in which the soil spreads out, a grading can be allotted to the soil.

vibrator
 * a. A mechanism imparting vibration to screens, concrete consolidators, and shaking tables.

b. A tool that vibrates at 3,000 to 10,000 cycles per minute. It can be inserted into wet concrete or attached to formwork to compact the concrete. c. A device for attachment to bins or chutes to produce vibration and thus assist in gravity flow of contained material.

vibratory screen
 * A sizing screen similar to the shaking screen, but the reciprocating movement imparted to it is of greater frequency and much smaller amplitude--1,000 rpm and 1/4 in (6.4 mm) being typical. High-frequency vibration is more effective than the slow movement of the shaker in preventing blinding of holes, and the screening is more effective. It may contain one, two, or three screen decks with water sprays for washing products when screening. Five products ranging from plus 3/4 in (19.1 mm) to minus 1/8 in (3.2 mm) are possible from a double-deck screen. In general, the screen is inclined at from 12 degrees to 14 degrees for the coarser sizes and 17 degrees to 21 degrees for the finer sizes with counterflow operation. See also: pool washing screen; varislope screen.

Vibrex grease table
 * A device to concentrate and separate diamonds from gangue material. It is based on the principle that short, sharp vibrations in rapid succession transmitted to a greased surface cause diamonds to become imbedded in the grease, while water washes away other materials.

Vibroflotation
 * The trade name for a geotechnical process that uses vibration to compact clean sands and gravels. The vibration is combined with a water jet to give a high degree of compaction.

vibrograph
 * An instrument for recording the ground vibrations caused by heavy quarry blasts. The relationship between the amount of vibration, the distance from the blast, and the weight of explosive fired may be expressed thus: A = (KE)/D, where A = maximum amplitude in thousandths of an inch; K = constant depending on the quarry site; E = weight of explosive in pounds; and D = distance in feet. The constant K can be determined by firing a specimen blast of a given size at a given distance and measuring the amplitude of the record obtained. Amplitudes in excess of 0.04 in (1 mm) may give rise to damage. A movement of 0.008 in (0.2 mm) can be felt, and if used an excessive number of times may give rise to complaints of nuisance and damage. Short-delay blasting methods with small diameter holes reduce vibration hazards. See also: falling-pin seismometer; seismograph.

vicinal face
 * a. One of the facets modifying normal crystal faces; they usually lie nearly in the plane of the face they modify.

b. One of the crystal faces with complex Miller indices in apparent violation of the Bravais law requiring high densities of lattice points parallel to prominent faces. Vicinal faces are small and diverge from major faces by very small angles. Syn: vicinal form.

vicinal form
 * See: vicinal face.

Vickers' diamond hardness tester
 * A small impression machine, capable of testing very hard metals, finished components, and very thin sheets. The diamond is similar to that used in the diamond pyramid hardness test. The duration of application of the load is controlled automatically, being always applied and removed in exactly the same manner. This machine may also be used with a ball indenter for the Brinell hardness test.

Vickers hardness test
 * A test of resistance to deformation of metals or minerals in which a pyramid-shaped diamond is forced into a polished surface of the specimen to be tested under various static loads. The result is a function of the average length of the diagonals of the resulting indentation. CF: Tukon hardness test; Brinell hardness test.

victualic coupling
 * A development in which a groove is cut around each end of a pipe instead of the usual threads. Two ends of pipe are then lined up and a rubber ring is fitted around the joint. A pair of semicircular bands, forming a sleeve, are placed around the ring and are drawn together with two bolts. These have a ridge on both edges that fits into the groove of the pipe. As they are tightened, the rubber ring is compressed, making a watertight joint, while the ridges fitting in the grooves make it strong mechanically. Victualic pipe is faster to lay because in large sizes it does not have to be aligned perfectly and screwed in.

victualic joint
 * A proprietary pipe joint that allows the pipes to move through several degrees after fixing but yet to remain watertight. This joint is designed to allow about 12 degrees of movement without causing leakage. The pipes have specially shouldered ends that are contained by a circumferential rubber washer held by a special circumferential-type flange. The water has access to the inner part of the washer, on which it exerts pressure and thereby seals the joint.

Vielle-Montagne furnace
 * A mechanical roasting furnace similar to the Ross and Welter type.

Vienna turquoise
 * An amorphous turquoise imitation once manufactured in Austria, Czechoslovakia, France, and England. Having approx. the same chemical composition, hardness, density, and fracture, it is more difficult to detect than the various blue-stained minerals since used as turquoise substitutes.

vierendeel girder
 * An open-frame N-truss without diagonal members, with rigid joints between the top and bottom chords and the verticals. Known also as open-frame girder.

viese
 * Scot. The line of fracture of a fault or the soft earth in a fissure or on the sides of a fault. Also spelled vise.

vignite
 * A magnetic iron ore.

vigorite
 * An explosive resembling dynamite No. 2 and consisting of nitroglycerin with a more or less explosive dope.

Vigorite No. 5
 * Permissible explosive; used in mines. Also called L.F. Vigorite No. 5.

villamaninite
 * An isometric mineral, (Cu,Ni,Co,Fe)(S,Se) (sub 2) ; pyrite group; forms small iron-black cubo-octahedra and radiating nodular masses; at Villamin, Spain.

Villela's reagent
 * An etching reagent consisting of 95 ml of ethyl alcohol, 5 ml of hydrochloric acid, and 1 g of picric acid.

villiaumite
 * An isometric mineral, NaF ; soft; deep carmine; forms small crystals and grains in nepheline syenite; in Islands of Los, Guinea.

vinney
 * Copper ore, with a green efflorescence like verdigris.

vinogradovite
 * A monoclinic mineral, (Na,Ca,K) (sub 4) Ti (sub 4) AlSi (sub 6) O (sub 23) (OH).2H (sub 2) O ; white to colorless; forms crystals and spherical aggregates in nepheline syenite in the Kola Peninsula, Russia.

vinyl acetal resins
 * Prepared from polyvinyl acetate. Properties are toughness, adhesiveness, imperviousness to moisture, and stability toward light and heat. Used as an interlayer in safety glass and as a bonding resin.

violaite
 * A highly pleochroic variety of clinopyroxene found in the Caucasus Mountains, Russia.

violan
 * A violet variety of diopside found at St. Marcel, Piemont, Italy.

violite
 * See: copiapite.

virgate
 * To branch in diverging lines.

virgation
 * a. A divergent, branchlike pattern of fault distribution. The term is used in Russian literature.

b. A fold pattern in which the axial surfaces diverge or fan out from a central bundle. c. A sheaflike pattern, as shown on a map, of mountain ranges diverging from a common center. Ant: syntaxis.

virgin
 * a. Unworked or untouched; said of areas where there has been no mining.

b. An unexploited area or rock formation in which boreholes have not been drilled. c. See: primary metal.

virgin clay
 * Fresh clay, as distinguished from that which has been fired.

virgin coal
 * An area of coal that is in place (in situ) and unimpaired by mining activities.

virgin metal
 * Pure metal obtained directly from ore. See also: primary metal.

viridine
 * A green manganese-rich variety of andalusite.

viridite
 * a. A ferruginous chlorite in chloritic iron ore.

b. A general term formerly applied to indeterminable and obscure green alteration products occurring in scales and threads in the groundmass of porphyritic rocks.

virtual value
 * The calibration of alternating current instruments is based upon what is called the virtual value, and this corresponds to the direct-current value, which would produce the same heating effect in a given resistance. The peak value of alternating voltage or current is 1.4 times greater than the virtual value.

viscometer
 * An instrument used to measure the viscosity. Syn: viscosimeter.

viscosimeter
 * See: viscometer.

viscosity
 * The property of a fluid to offer internal resistance to flow; its internal friction. Specif., the ratio of the shear stress to the rate of shear strain.

viscosity coefficient
 * A numerical factor that measures the internal resistance of a fluid to flow; it equals the shearing force in dynes per square centimeter transmitted from one fluid to another that is 1 cm away, and generated by the difference in fluid velocities of 1 cm/s in the two planes. The greater the resistance to flow, the larger the coefficient. Syn: absolute viscosity; dynamic viscosity.

viscountess
 * Building slate 18 in by 10 in (45.7 cm by 25.4 cm).

viscous
 * a. Adhesive or sticky, having a ropy or glutinous consistency.

b. Imperfectly fluid; designating a substance that, like tar or wax, will change its form under the influence of a deforming force, but not instantly, as more perfect fluids do.

viscous damping
 * Viscous damping is the dissipation of energy that occurs when a particle in a vibrating system is resisted by a force the magnitude of which is a constant, independent of displacement and velocity, and the direction of which is opposite to the direction of the velocity of the particle.

viscous flow
 * A type of fluid flow in which there is a continuous steady motion of the particles; the motion at a fixed point always remains constant. Also called streamline flow; laminar flow; steady flow.

viscous resistance
 * The effect of surface friction between a particle and a liquid when the particle moves through the liquid. CF: turbulent resistance.

Visean
 * Upper Lower Carboniferous.

viseite
 * An isometric mineral, Ca (sub 10) Al (sub 24) (SiO (sub 4) ) (sub 6) (PO (sub 4) ) (sub 7) O (sub 22) F (sub 3) .72H (sub 2) O(?) ; white; forms wartlike masses; at Vise, Belgium.

visibility meters
 * The general principle of such meters is to observe a portion of the visual field against its background and then to bring about a condition such that the observed difference in brightness reaches a threshold value so that it is only just discernible. The instruments differ in their means by which this end is achieved. The threshold may be produced quite simply by interposing a light-absorbing medium, such as an optical wedge, in the field of view. Other methods include reducing the contrast between the object and its background by superimposing a veiling brightness over the observed field.

visible light
 * a. The light of the visible spectrum.

b. Electromagnetic radiation, with wavelength range approx. 4,000 to 7,000 Aa, which a normal human eye can detect. CF: invisible light; ultraviolet; infrared.

visible spectrum
 * That portion of the electromagnetic spectrum in which the waves normally produce, upon the human eye, color sensations of red, orange, yellow, green, blue, violet, or their intermediate hues, or of white light if the rays are combined. Distinguished from radio, infrared, ultraviolet, gamma, and X-rays.

Vissac jig
 * An air-operated pulsator jig in which air is alternately compressed and allowed to expand to produce pulsation. This jig has been used principally on sized bituminous coal.

visual indicator
 * A device by which the winding or haulage engineman can see on a dial or panel the position of the cages in a shaft or the journey on the haulage plane. See also: depth indicator.

Vitasul
 * A trade name for a chemical additive that eliminates or reduces considerably the danger of diesel locomotive fumes underground. Tests have established that the chemical, added to diesel fuel, reduces the carbon-monoxide danger from diesel locomotive exhausts to negligible proportions.

vitiated air
 * Air that has been rendered impure by the breath of workers and horses, or by being mixed with the various gases given off in mines. It is frequently called return air.

vitrain
 * a. Designation of macroscopically recognizable, very bright bands of coals. Very bright bands or lenses, usually a few millimeters (3 to 5) in width; thick bands are rare. Clean to the touch. In many coals, the vitrain is permeated with numerous fine cracks at right angles to stratification and consequently breaks cubically, with conchoidal surfaces. In other coals, the vitrain is crossed by only occasional perpendicular cracks. In the macroscopic description of seams, only the bands of vitrain having a thickness of several millimeters are usually noted. Examination with the microscope shows vitrain to consist of microlithotypes very rich in vitrinite. After clarain, vitrain is the most widely distributed and common macroscopic constituent of humic coals. Occurs in lenticular bands, each derived from a single piece of original vegetable growth. When it constitutes 30% to 60% of total seam, it is termed abundant; more than 60%, dominant; between 15% and 30%, moderate; below 15%, sparse.

b. A coal lithotype characterized macroscopically by brilliant, vitreous luster, black color, and cubic cleavage with conchoidal fracture. Vitrain bands or lenticles are amorphous, usually 3 to 5 mm thick, and their characteristic microlithotype is vitrite. CF: clarain; durain; fusain; vitrite. Syn: pure coal.

vitreous
 * a. In minerals, a luster typical of that of quartz or calcite. CF: adamantine; pearly; resinous.

b. That degree of vitrification evidenced by low water absorption. See also: impermeable; nonvitreous; semivitreous. c. Amorphous. d. Noncrystalline, such as volcanic glass. e. Consisting of or resembling glass.

vitreous copper
 * See: chalcocite.

vitreous copper ore
 * See: chalcocite.

vitreous fusion
 * Gradual fusion; having no sharp melting point.

vitreous silica
 * Silica glass.

vitreous silver
 * See: argentite.

vitric
 * Said of pyroclastic material that is characteristically glassy; i.e., contains more than 75% glass.

vitrics
 * a. Fused siliceous compounds, such as glasses and enamels, as distinguished from ceramics, or fused aluminous compounds.

b. The art or history of glass production.

vitric tuff
 * A tuff that consists predominantly of volcanic glass fragments. CF: crystal tuff; crystal-vitric tuff.

vitrifacture
 * The manufacture of vitreous or vitrified wares, as glass.

vitrifiable
 * Of or pertaining to a substance that can be vitrified.

vitrification
 * An act, or instance, or the process of vitrifying or making glassy; the condition of being vitrified; a vitrified body.

vitrification spalling
 * That resulting directly or indirectly from the permanent physical changes caused by vitrification.

vitrified
 * a. That characteristic of a clay product resulting when the temperature in a kiln is sufficient to fuse all the grains and close all the pores of the clay, making the mass impervious.

b. Converted into glass.

vitrified brick
 * A very hard paving brick burned to the point of vitrification and toughened by annealing.

vitriform
 * Having the form or the appearance of glass; glassy.

vitrify
 * To change into glass or into a glassy substance by heat and fusion. To make vitreous; esp. to produce (as in a ceramic ware) enough glassy phase or close crystallization by high-temperature firing to make nonporous. To undergo vitrification or vitrifaction; to become vitreous.

vitrifying
 * A stage in the heating of a clay when some of the ingredients have melted and have partially or completely closed the pores, as in stoneware and porcelain. The completion of this stage occurs at the point of maximum shrinkage without loss of shape. See also: baking; squotting.

vitrinertite
 * A coal microlithotype that contains a combination of vitrinite and inertinite totalling at least 95%, and containing more of each than of exinite. It generally occurs in high-ranking bituminous coals.

vitrinite
 * A group name comprising collinite and telinite. Differentiation between collinite and telinite depends in part on the method of observation. The distinction is more easily made in thin section or after etching a polished surface. Often there is uncertainty of distinction by reflected light, and in such cases, it is proper to use the general term vitrinite. See also: collinite; telinite.

vitrinization
 * The process in coalification that results in the formation of vitrain. See also: coalification. CF: incorporation; fusinization.

vitrinoid
 * Vitrain and similar material in coal.

vitriol
 * A sulfate of any of various metals (such as copper, iron, or zinc,); esp. a hydrate (as the heptahydrate) of such a sulfate having a glassy appearance or luster.

vitriol ocher
 * See: glockerite.

vitrite
 * A coal microlithotype group that contains vitrinite macerals totalling at least 95%. CF: liptite; vitrain.

vitro-
 * Prefix meaning glassy.

vitroclarain
 * A rock-type coal consisting of vitrinite (collinite or telinite) and other macerals, mainly exinite, and in which the other macerals exceed vitrinite in quantity. CF: clarovitrain.

vitroclastic
 * Pertaining to a pyroclastic rock structure characterized by fragmented bits of glass; also, said of a rock having such a structure.

vitrodurain
 * Durain in which much vitrain is present. Judged obsolete by the Heerlen Congress of 1935. CF: durovitrain.

vitrofusain
 * A coal constituent transitional between vitrain and fusain, and showing plant cell structure. The cell walls are soaked with vitrain, where the cell cavities are empty. It is not a mixture but a transition. Accepted by the Heerlen Congress of 1935 to designate material transitional between vitrain and fusain with fusain being predominant. CF: fusovitrain.

vitrophyre
 * Any porphyritic igneous rock having a glassy groundmass. Adj: vitrophyric. CF: felsophyre; granophyre. Syn: glass porphyry.

vitrophyric
 * Said of a porphyritic igneous rock having large phenocrysts in a glassy groundmass.

vivianite
 * a. A monoclinic mineral, 2[Fe (sub 3) (PO (sub 4) ) (sub 2) .8H (sub 2) O]; colorless where fresh; turning blue on oxidation; soft; a secondary mineral found in ore deposits and pegmatites, in clays associated with bone and other organic remains, and in anaerobic lake sediments. Syn: blue iron earth; blue ocher; Prussian blue.

b. The mineral group annabergite, baricite, hoernesite, koettigite, parasymplesite, and vivianite.

vlasovite
 * A monoclinic and triclinic mineral, Na (sub 2) ZrSi (sub 4) O (sub 11) ; forms colorless crystals in the contact zone of the Lovozero massif, Kola Peninsula, Russia. It is related to narsarsukite.

V-method of roasting
 * The introduction of a supplementary roast heap between each two regular heaps, so that, if left untouched, there would be a continuous and unbroken roast heap the entire length of the roast yard.

vogesite
 * A lamprophyre composed of hornblende phenocrysts in a groundmass of alkali feldspar and hornblende. Clinopyroxene, olivine, and plagioclase feldspar also may be present. Vogesite contains less biotite than minette. The name, given by Rosenbusch in 1887, is for the Vosges Mountains, France.

vogle
 * See: vug.

voglianite
 * a. A soft, green, basic uranium sulfate, found in nodules or as earthy coatings.

b. Validity of species is doubtful. All existing specimens, upon examination, have proved to be cuprosklodowskite. c. A variety of zippeite(?).

voglite
 * A monoclinic mineral, Ca (sub 2) Cu(UO (sub 2) )(CO (sub 3) ) (sub 4) .6H (sub 2) O(?) ; strongly radioactive; emerald to grass green; an alteration product of uraninite associated with liebigite.

void
 * a. A general term for pore space or other openings in rock. In addition to pore space, the term includes vesicles, solution cavities, or any primary or secondary openings. Syn: pore; interstice.

b. That portion of a borehole from which the core could not be recovered.

void ratio
 * The ratio of the volume of void space to the volume of solid substance in any material consisting of voids and solid material, such as a soil sample, sediment, or sedimentary rock. Symbol e. Syn: voids ratio.

voids ratio
 * See: void ratio.

vol
 * See: vole.

volatile
 * Readily vaporizable.

volatile combustibles
 * See: volatile matter.

volatile fluxes
 * The volatile constituents of a magma.

volatile matter
 * In coal, those substances, other than moisture, that are given off as gas and vapor during combustion. Standardized laboratory methods are used in analysis. Syn: volatiles; volatile combustibles.

volatile ratio
 * In coal, the ratio of the volatile matter to the sum of the volatile matter and the fixed carbon.

volatiles
 * The volatile constituents (or rest magma) remaining after the less volatile ores have crystallized as igneous rocks. Syn: volatile matter.

volborthite
 * A monoclinic mineral, Cu (sub 3) V (sub 2) O (sub 7) (OH) (sub 2) .2H (sub 2) O ; radioactive; has one perfect cleavage; dark olive to yellow-green; a secondary mineral with carnotite in sandstone. Syn: uzbekite.

volcanic
 * Characteristic of, pertaining to, situated in or upon, formed in, or derived from volcanoes. See also: extrusive.

volcanic ash
 * See: ash.

volcanic breccia
 * a. A pyroclastic rock that consists of angular volcanic fragments that are larger than 64 mm in diameter and that may or may not have a matrix.

b. A rock that is composed of accidental or nonvolcanic fragments in a volcanic matrix. Syn: alloclastic breccia; lava breccia.

volcanic clay
 * See: bentonite.

volcanic conglomerate
 * A water-deposited conglomerate containing more than 50% volcanic material, esp. coarse pyroclastics.

volcanic dust
 * See: ash.

volcanic earthquake
 * A seismic disturbance that is due to the direct action of volcanic force, or one whose origin lies under or near a volcano, whether active, dormant, or extinct.

volcanic focus
 * The subterranean seat or center of volcanism of a region or of a volcano.

volcanic glass
 * A natural glass produced by the cooling of molten lava, or a liquid fraction of it, too rapidly to permit crystallization. Examples are obsidian, pitchstone, tachylyte, and the glassy mesostasis of many extrusive rocks. CF: glass.

volcanicity
 * See: volcanism.

volcanic ore deposits
 * The major group of ore deposits of magmatic origin, designated as young by European mineralogists, which have been formed under near-surface conditions and very often in Tertiary or younger volcanic rocks. In a strict sense, deposits formed in relation to surface eruptions.

volcanic plain
 * Surface formed by extensive lava or ash flows that cover topographic irregularities.

volcanic rift zone
 * See: rift zone.

volcanic rock
 * a. A generally finely crystalline or glassy igneous rock resulting from volcanic action at or near the Earth's surface, either ejected explosively or extruded as lava; e.g., basalt. The term includes near-surface intrusions that form a part of the volcanic structure. Syn: volcanite.

b. A general term to include the effusive rocks and associated high-level intrusive rocks; they are dominantly basic.

volcanics
 * A general collective term for extrusive igneous and pyroclastic material and rocks.

volcanic water
 * Water in, or derived from, magma at the Earth's surface or at a relatively shallow level; juvenile water of volcanic origin.

volcanism
 * The processes by which magma and its associated gases rise in the crust and are extruded onto the Earth's surface and into the atmosphere. Also spelled vulcanism. Syn: volcanicity.

volcanite
 * An obsolete term variously used to denote a volcanic rock and selenian sulfur.

volcano
 * a. A vent in the surface of the Earth through which magma and associated gases and ash erupt; also, the form or structure, usually conical, that is produced by the ejected material.

b. Any eruption of material; e.g., mud, that resembles a magmatic volcano. Obsolete var; vulcano. Pl: volcanoes. Etymol: the Roman deity of fire, Vulcan.

volchonskoite
 * See: volkonskoite.

vole
 * The place where tin ore is stored to be dried before being put into a smelting furnace. Syn: vol.

voler reductol
 * A lubricant for enclosed gear units; composed of high-quality mineral oil with a suspension of superfine colloidal graphite and silicone foam inhibitor.

volgerite
 * A discredited term equal to stibiconite.

volkonskoite
 * A monoclinic mineral, Ca (sub 0.3) (Cr,Mg,Fe) (sub 2) (Si,Al) (sub 4) O (sub 10) (OH) (sub 2) .4H (sub 2) O ; smectite group. Also spelled volchonskoite.

volley
 * The act of exploding blasts in sections. A round of holes fired at any one time.

volt
 * The practical meter-kilogram-second (mks) unit of electrical potential difference and electromotive force (emf) that equals the difference of potential between two points in a conducting wire carrying a constant current of 1 A when the power dissipated between these two points equals 1 W. It equals the potential difference across a resistance of 1 Omega when 1 A of current is flowing through it; the standard in the United States.

voltage
 * Electromotive force.

voltaite
 * An isometric mineral, K (sub 2) Fe (sub 9) (SO (sub 4) ) (sub 12) .18H (sub 2) O ; has both ferric and ferrous iron.

Volta's list
 * A list or series of metals, such that any one will be at a higher electrical potential when put in contact with any of those that follow, and at a lower potential if in contact with any metal before it in the series.

voltmeter
 * An instrument for determining voltage.

voltzite
 * Wurtzite mixed with an organometallic zinc compound.

volume defect
 * A crystal structure deviating from ideality by having two or more chemical species in one or more crystal sites. CF: crystal defect; disorder.

volume susceptibility
 * See: susceptibility.

volumetric
 * Chemical analysis based upon the reaction of a volume of standard solution with the material being analyzed.

volumetric analysis
 * Quantitative chemical analysis in which known weight of sample is dissolved and reacted with a standard chemical solution of strength proportional to its normality or hydrogen equivalent. Completion of reaction (end point) is judged by change of color, incipient precipitation, or effect on an indicator. See also: dry assay; wet assay.

volumetric efficiency
 * a. The ratio of the total quantity of air passing along the faces to the quantity flowing in the fan drift. See also: overall ventilation efficiency; surface air leakage.

b. The ratio of the volume of air discharged to the displacement for a fan or compressor. c. The volume of water that enters a pump cylinder for each piston stroke divided by the volume swept by the piston (piston area times stroke).

volumetric shrinkage
 * The decrease in volume, expressed as a percentage of the soil mass when dried, of a soil mass when the water content is reduced from a given percentage to the shrinkage limit. Also called volumetric change.

volute
 * a. A spiral casing to a mine fan to provide an area of passage, which gradually increases in proportion to the increasing area of discharge from the fan. See also: evase.

b. A spiral casing for a centrifugal pump or a fan designed so that speed will be converted to pressure without shock.

volute pumps
 * This type of centrifugal pump is the most commonly used. The impellers may be open, closed or semienclosed, single suction, double suction, or nonclogging. They discharge into casings that are progressively expanding spiral designs of one or more stages (multistage). The casings housing the rotating elements may be vertically or horizontally split, and a few designs have casings divided on an angle from the horizontal. Pumps in this class usually have a specific speed below 4,000 rpm with single-suction impellers and a specific speed of 5,000 rpm with double-suction impellers.

von Neumann spike
 * The pressure peak leading the detonation wave prior to the establishment of the C-J state.

vonsenite
 * An orthorhombic mineral, Fe (sub 3) BO (sub 5) ; ludwigite group; contains both ferrous and ferric iron with ferrous iron replaced by magnesium toward ludwigite; black; forms coarse granular masses; at Riverside, CA.

von Sterneck-Askania pendulum
 * A device for measuring the vertical component of gravity, characterized by the use of four pendulums in a single case.

von Wolff's classification
 * A quantitative chemical-mineralogic classification of igneous rocks proposed in 1922 by F. von Wolff.

vooga hole
 * See: vug.

Vooys process
 * A coal-cleaning process using a heavy suspension, consisting of clay and finely ground barite (-150 or #MG200 mesh) in water. A coal containing as little as 3.3% to 3.4% ash is steadily produced, with a yield practically equal to the theoretical float-and-sink yield.

vorobievite
 * A white or rose-colored variety of beryl from the Ural Mountains, Russia, and Madagascar. Syn: morganite. Also spelled vorobyevite.

vortex finder
 * Tube projecting into central vortex of hydrocyclone or dense medium cyclone through which the classified fines or lighter specific gravity fraction of pulp leaves the system.

vraibite
 * An orthorhombic mineral, Tl (sub 4) Hg (sub 3) Sb (sub 2) As (sub 8) S (sub 20) ; forms gray-black crystals or thin red splinters; commonly intergrown with realgar and orpiment; occurs at Salonika, Macedonia, Greece.

vug
 * A small cavity in a rock, usually lined with crystals of a different mineral composition than the enclosing rock. Adj: vuggy. CF: druse; miarolitic cavity; geode. Syn: bug hole; vogle; vooga hole. See also: cavity; vuggy porosity; loch. Etymol: Cornish vooga, cavern or cavity.

vugg
 * A misspelling of vug.

vuggy
 * Pertaining to a vug or having numerous vugs. Syn: vugular.

vuggy lode
 * A lode or vein in which vugs or drusy cavities are of frequent occurrence.

vuggy porosity
 * Porosity due to vugs in calcareous rock. The term vugular is used by some writers but condemned by others. See also: vug.

vugh-arching
 * When a pocket of rock in the periphery of an excavation is weaker than the remainder, it may fail under the ring stress. Fragments split away or fall out until all the weak rock is removed, forming an artificial vugh. This is called vugh-arching.

vug hole
 * See: vug.

vugular
 * See: vuggy.

vulcan coal powder
 * Explosive; used in mines.

vulcanism
 * Volcanism.

vulcanite
 * a. An orthorhombic mineral, CuTe ; with rickardite and native tellurium, it forms coatings on rocks; occurs at the Good Hope Mine, Vulcan, CO.

b. A dark-colored, hard variety of vulcanized India rubber that differs from the softer rubber in having been vulcanized at a high temperature; ebonite. It takes a high polish, and is used for making combs, ornaments, etc., and in electrical work because of its fine insulating properties.

vulcanites
 * A general name for igneous rocks of fine grain size, normally occurring as lava flows, and thus in direct contrast with plutonites.

vulcanized rubber
 * A rubber that has been heated with sulfur to change its properties.

vulcanizing machine
 * Consists essentially of two heavy metal plattens that are placed one on each side of the previously prepared joint and clamped firmly together. Each platten is heated, and this combined application of heat and pressure over a period completes the joint. These machines are used to vulcanize the belt joints of conveyors.

vulcan powder
 * High explosive composed of 30% nitroglycerin, 52.5% sodium nitrate, 10.5% charcoal, and 7% sulfur.

vulpinite
 * A scaly, granular variety of anhydrite; may be admixed with silica; cut and polished for ornamental purposes.

V-vat
 * a. A funnel box; also, having a groove or grooves of a triangular section.

b. See: spitzkasten.

vysotskite
 * A tetragonal mineral, (Pd,Ni)S ; isomorphous with braggite; in minute grains or prisms; at Norilsk, Russia.

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