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

weak ground
 * Roof and walls of underground excavations that are in danger of collapse unless suitably supported.

wearing strip
 * A strip of metal applied to any particular device to take the wear of moving parts or objects. In conveyor work, it refers to the strip that is sometimes applied to the chain conveyor troughs and on which the drag chain rides.

wear plate
 * Sections of hardened steel plates of various thicknesses (as desired) which are welded (or bolted) in areas of severe wear, such as the insides of feeders, crushers, transfer chutes, or any other area where mined material passes, creating abrasion, and threatens wearing of these areas.

wear rib
 * Hard metal ridge applied to the outside surface of bottom-hole equipment and built up as close as practicable to the set-outside-diameter size of a reaming shell, which serves as a wear pad.

weather
 * a. To undergo changes, such as discoloration, softening, crumbling, or pitting of rock surfaces; brought about by exposure to the atmosphere and its agents.

b. To undergo or endure the action of the elements; to wear away, disintegrate, discolor, or deteriorate under atmospheric influences.

weather door
 * A door in a mine level whose purpose it is to regulate ventilation currents. A trapdoor.

weathered layer
 * a. In seismic work, a zone extending from the surface to a limited depth, usually characterized by a low velocity of transmission, which abruptly changes to a higher velocity in the underlying bedrock. The name is erroneous, and the zone is more properly called the low-velocity layer.

b. In seismology, the zone of the Earth that is immediately below the surface, characterized by low seismic-wave velocities.

weathered rock
 * Rock, the character of which has been changed by exposure to decaying conditions found in the zone of weathering.

weathering
 * a. The destructive processes by which earthy and rocky materials on exposure to atmospheric agents at or near the Earth's surface are changed in color, texture, composition, firmness, or form, with little or no transport of the loosened or altered material; specif. the physical disintegration and chemical decomposition of rock that produce an in-situ mantle of waste and prepare sediments for transportation. Most weathering occurs at the surface, but it may take place at considerable depths, as in well-jointed rocks that permit easy penetration of atmospheric oxygen and circulating surface waters.

b. Exposing ore to the atmosphere for long periods in order that a part, at least of the sulfide content, may become oxidized and washed away by the rain. c. See: seasoning.

weathering correction
 * In seismic exploration, a correction applied to reflection and refraction data for variations in travel time produced by irregularities in a low-velocity or weathered layer near the surface. Syn: low-velocity-layer correction.

weathering index
 * A measure of the weathering characteristics of coal, according to a standard laboratory procedure. Syn: slacking index.

weathering map
 * In seismic work, a map on which the low-velocity layer, or weathered layer, is plotted and contoured to show areal variations.

weathering of coal
 * The slow disintegration of coal into fires in surface stockpiles under the action of the weather, particularly frost after a wet period. See also: spontaneous combustion.

weathering of roadways
 * The disintegration or scaling of exposed surfaces of mine roadways, particularly in the case of clay or shale rocks. Gunite has been used for roadway protection against weathering. See also: guniting.

weathering shot
 * In seismic exploration, the detonation of a small explosive charge in the weathering or low-velocity layer to determine its velocity characteristics and thickness.

web
 * The slice or thickness of coal taken by a cutter loader when cutting along the face. The thickness of a web varies from a few inches with plow-type machines to up to about 6 ft (1.8 m) with the A.B. Meco-Moore. The term web tends to be restricted to thin or medium slices of coal. See also: buttock.

weber
 * Magnetic flux equivalent in the meter-kilogram-second (mks) system of the maxwell in the centimeter-gram-second (cgs) system. One weber equals 10 (super 8) maxwells. Abbrev., wb.

weberite
 * An orthorhombic mineral, Na (sub 2) MgAlF (sub 7) ; pale gray; forms grains in cryolite; in Greenland.

Weber process
 * A method of manufacturing pig iron in which the ore is mixed with a proportionate amount of coal sufficient to smelt it; after adding a binder the mixture is briquetted by means of a roller press into ovoids, which are subjected to low temperature carbonization between 550 degrees C and 600 degrees C, followed by smelting in a low shaft furnace.

weddellite
 * A tetragonal mineral, Ca(C (sub 2) O (sub 4) ).2H (sub 2) O ; in mud at the bottom of the Weddell Sea, Antarctica; also as urinary calculi. CF: whewellite.

wedge
 * a. A wedge-shaped piece of wood used to tighten timber sets against the roof and sides. See also: lag; lid.

b. A tapered piece of material used to initiate the deflection of a borehole. See also: deflecting wedge; Hall-Rowe wedge. c. Tapered piece of core that tends to bind and block a core barrel. d. A piece of mica that, on splitting, yields pieces thicker at one end than at the other. e. The shape of a stratum, vein, or intrusive body that thins out; specif. a wedge-shaped sedimentary body, or prism. See also: prism.

wedge-and-sleeve bolt
 * A bolt designed for use in roof bolting. It consists of a rod 1-3/4 in (4.45 cm) in diameter with one end threaded and the other end shaped to form a solid wedge. A loose split sleeve with an outside diameter of 1-1/2 in (3.81 cm) is fitted over the wedge. Anchorage is provided when the bolt is pulled downward in a hole and the sleeve is held by a thrust tube. Split by the wedge head of the bolt, the sleeve expands until it grips the sides of the hole. See also: bolt; slot-and-wedge bolt.

wedge bit
 * A tapered-nose noncoring bit, used to ream out a borehole alongside a steel deflecting wedge in hole-deflection operations. Also called: bullnose bit; wedge reaming bit. Syn: wedging bit.

wedge capping
 * A winding rope capping consisting of two tapered iron wedges that encircle the rope, the end of which is prevented from unravelling by casting onto it a small block of white metal. The wedges are contained by a steel bow, over which four or five wrought-iron hoops are driven. The greater the pull on the rope, the more the wedges grip it as they are drawn into the encircling hoops.

wedge clinometer
 * An end clinometer the bottom end of which is shaped to match the wedge-guide pin on the drive wedge; hence the two can be fastened together with copper shear rivets. When a drive wedge is driven into a wooden plug in a borehole the copper rivets break; after the clinometer has been removed from the borehole, the relation of the bearing and inclination readings to the flat face of the projection on the bottom of the clinometer case can be used to orient and place the deflection wedge in a manner so as to direct the deflected hole to follow the desired course. CF: plain clinometer; line clinometer.

wedge core lifter
 * A core-gripping device consisting of a series of three or more serrated-face, tapered wedges contained in slotted and tapered recesses cut into the inner surface of a lifter case or sleeve. The case is threaded to the inner tube of a core barrel. As the core enters the inner tube, it lifts the wedges up along the case taper. When the barrel is raised, the wedges are pulled tight, gripping the core.

wedge cut
 * a. A cut in which the central holes are positioned to cause the breakout of a wedge-shaped section of strata when fired.

b. A drill-hole pattern with the cut holes converging to form a V or wedge. The other holes are drilled to break to the opening made by the cut holes. See also: V-cut. c. A type of geometry for blasting pattern often used in drifting work. It can be adopted for all strata conditions. A wedge cut consists of pairs of holes, usually drilled horizontally, that meet or finish close together at the back of the cut so that a wedge-shaped section of the rock face will be removed on blasting. The holes should be drilled at an angle of approx. 60 degrees to the face line. Accordingly, the depth of pull that can be obtained with this type of cut is governed by the width of the drift, as this determines the maximum length of drill steel that can be used. Typically, the pull ranges from 5 ft (1.5 m) in a 12-ft-wide (3.7-m-wide) drift up to 6-1/2 ft (1.8 m) in a 15-ft-wide (4.6-m-wide) drift.

wedge guide
 * One of several implements used collectively to arrest a cage or skip in the event of an overwind using a multirope friction winder. Frictional forces, which gradually increase by virtue of the wedging action of the guides, are relied upon to bring the cage to rest and hold it in a stationary position with the aid of jack catches. See also: detaching hook.

wedge off
 * To deviate or change the course of a borehole by using a deflecting wedge. See also: bypass.

wedge-out
 * The edge or line of pinch-out of a lensing or truncated rock formation.

wedge out
 * See: thin out.

wedge pilot
 * That part of the bottom end of a Hall-Rowe deflecting wedge that matches the guide pin on the upper end of the Hall-Rowe drive wedge and by means of which the deflecting wedge can be oriented to direct the deflected borehole in the intended direction.

wedge reaming bit
 * A tapered or bullnose rotary bit used to restart drilling after a deflection wedge has been fitted into a borehole. See also: wedging reamer; wedge bit.

wedge roaster
 * Multiple-hearth vertical furnace. Rabbles rotating on each circular horizontal hearth work the continuously fed material across alternately to the periphery and then, on the next hearth below, toward the center, so that it gravitates through either a central or a peripheral opening and is at the same time exposed to rising heat or air blown through rabble arms.

wedge rock
 * An expression used on the Comstock lode to designate rock better than waste but too poor to be classed as "pay ore" or even "second-class ore." It became a custom to throw a wooden wedge onto a car containing very low grade ore, hence the term wedge rock. Syn: pin. CF: tag.

wedge rose bit
 * A serrated-face, hardened-metal, noncoring, cone-shaped bit used primarily to mill off part of the stabilizing or rose ring on the top end of a Hall-Rowe deflecting wedge.

wedge-set
 * A diamond bit with wedge-shaped configurations in the crown that are inset with diamonds.

wedge shot
 * See: wedge cut.

wedge socket fitting
 * A wire rope attachment in which the rope lies in a too-small groove between a wedge and housing, so that pull on the rope tightens the wedge.

wedge theory
 * The analysis formulated by Coulomb in 1776 of the force tending to overturn a retaining wall. Its basis is the weight of the wedge of earth that will slide forward if the wall fails.

wedge-wire deck
 * A screen deck comprising wires of wedge-shaped cross section spaced from each other at a fixed dimension; the underflow thus passes through an aperture of increasing cross section. Also called wedge-wire sieve (undesirable usage).

wedge-wire screen
 * A screen designed to reduce or eliminate clogging of material. It consists of wedge-shaped parallel wires with their wide edge upward. This type of screen is used for dewatering coal on vibrating, shaking, or stationary screens.

wedging
 * a. A method used in quarrying to obtain large, regular blocks of building stone, such as syenite, granite, marble, and sandstone. In this method, a row of holes is drilled, either by hand or by pneumatic drill, close to each other to create a longitudinal crevice. A gently sloping steel wedge is driven into this crevice. Usually several wedges are driven, and the block of stone can be detached without shattering.

b. The act of changing the course of a borehole by using a deflecting wedge. Syn: whipstocking. c. The lodging of two or more wedge-shaped pieces of core inside a core barrel and therefore blocking it. d. The material, moss, or wood used to render a shaft lining tight. e. The splitting, breaking, or forcing apart of a rock as if by a wedge, such as by the growth of salt or mineral crystal in interstices; specif. frost wedging.

wedging and blocking
 * See: blocking and wedging.

wedging bit
 * See: wedge bit.

wedging crib
 * In a circular mine shaft, a steel ring made of segments wedged securely to rock walls for use as a foundation for masonry lining. Also called: wedging ring; wedging curb.

wedging curb
 * See: curb.

wedging down
 * Breaking down coal at the face with hammers and wedges instead of by blasting.

wedging reamer
 * A reaming bit used to ream down alongside and pass the deflection wedge when deviating a borehole. Also called wedge bit; wedge reaming bit.

wedging shot
 * An opening shot. A center cut.

weeksite
 * An orthorhombic mineral, K (sub 2) (UO (sub 2) ) (sub 2) Si (sub 6) O (sub 15) .4H (sub 2) O ; resembles uranophane; in the Thomas range, Juab County, UT. Syn: gastunite.

weeks manometer
 * An inclined water gage.

weeper
 * A small feeder of water.

weeping rock
 * A porous rock from which water oozes.

Weg rescue apparatus
 * Oxygen supply fed automatically to a rescue worker through a valve controlled by the worker's breathing action, forming part of a portable outfit.

wegscheiderite
 * A triclinic mineral, Na (sub 5) (CO (sub 3) )(HCO (sub 3) ) (sub 3) ; forms fibrous aggregates of tiny acicular to bladed crystals; Green River formation, WY.

wehrlite
 * a. A mixture of pilsenite and hessite.

b. A peridotite composed chiefly of olivine and clinopyroxene with accessory opaque oxides common.

weibullite
 * An orthorhombic mineral, Pb (sub 6) Bi (sub 8) (S,Se) (sub 18) (?) ; differs from galenobismutite in possessing two distinct cleavages; steel-gray.

Weichbraunkohlen-dopplerit
 * See: dopplerite.

weigh batcher
 * Batching plant in which all ingredients for a concrete mix are measured by weight.

weigher-and-crusher man
 * Person who weighs zinc ore and other materials to be sintered, and crushes sintered ore preparatory to further reduction.

weighing feeder
 * A device that handles the feed continuously over a belt that is balanced to weigh a stream of ore.

weighing-in-motion system
 * An electronic system which weighs individually loaded coal wagons as they roll over a rail scale, feeding the information into a totalizing printer, which automatically prints out gross and net weights. It employs hermetically sealed load cells which accurately convert physical weight into electrical impulses. See also: weightometer. Syn: electronic weighing.

weigh larry
 * A traveling hopper for receiving, weighing or measuring, and distributing bulk materials. Usually fitted with a scale, either manually operated or of the automatic recording type. Weigh larries may be suspended between overhead tracks or carried on rails mounted below them. They may be hand-pushed or power-propelled, and some designs provide a riding platform or cab for the operator. A remote-control device for operating the bunker or bin gates is usually mounted on the larry chassis.

weight
 * a. Roof movement, esp. when it can be seen or heard.

b. Fracturing and lowering of the roof strata at the face as a result of mining operations. See also: crush.

weight batching
 * Weighing and combining the correct proportion of cement and aggregate in a concrete mix.

weight break
 * Cracks developing from the upper or tension side of a stratum caused by bending moment over a coal seam. Such breaks are induced in the nether roof in consequence of the moment exercised by the weight of the roof-stratum overhanging the face, cantilever fashion. The weight break differs from a shear plane in the more ragged and uneven character of the fracture and in hanging over the waste instead of over the unmined coal seam. Also called first break.

weight dropping
 * A seismic technique by which energy can be sent downward into the ground without the necessity of drilling shotholes. This technique involves lifting a weight, then permitting it to fall and strike the ground. The waves from the impact are then recorded. In areas where drilling is difficult, otherwise undesirable, or unduly expensive, this technique may be highly advantageous.

weighted average
 * Value calculated from a number of samples, each of which has been assigned an importance in accord with its position and general trustworthiness. In this connection a sample which was cross-checked by others would be more reliable than one which was isolated, particularly if the latter showed abnormal values or was for any other reason suspect. The cross-checked sample is sometimes called a weighted sample in mineral valuation of a deposit.

weighted average depth
 * A method of comparing the average depth of mine workings. It is based on the average depth from which the output is obtained, weighted for the tonnage produced.

weighted flowsheet
 * A materials flowsheet including a statement of the capacity in tons per hour at principal points in the plant.

weight indicator
 * An apparatus for recording and indicating the tension on a drilling line of a diamond or rotary drill. See also: tension drilling.

weighting
 * The occurrence of fracturing of the upper roof, with consequent rapid increase of the weight carried on the timber and packs supporting the roof; distinct from the fracturing of the nether roof.

weightometer
 * An appliance for the continuous weighing of coal or other material in transit on a belt conveyor. See also: weighing-in-motion system.

weight pit
 * The pit below the shaft station where heavy weights are attached to the guide ropes to keep them taut. Roughly, the weight needed is 1 st for each 1,000 ft (1.97 t per 1,000 m) of rope.

weight strength
 * The strength of an explosive per unit weight, expressed as a percentage of the value for blasting gelatin as a standard. See also: absolute weight strength.

Weinig flotation cell
 * Square type of machine in which air is blown down to join pulp entering the cell below a mechanically driven impeller.

weir
 * a. A small dam in a stream, designed to raise the water level or to divert its flow through a desired channel.

b. A notch in a levee, dam, embankment, or other barrier across or bordering a stream, through which the flow of water is regulated.

weir head
 * The depth of water in a measuring weir as measured from the bottom of the notch to the surface of the water upstream of the weir. The velocity of approach is not included.

weir table
 * A device to estimate the quantity of water that flows during a given time over a weir of a given width at different heights of water.

Weisbach triangle
 * a. A configuration used in the surveying of a mine shaft.

b. The highly attenuated triangle formed by the plan position of two shaft plumblines and one observation station.

weissite
 * An isometric(?) mineral, Cu (sub 5) Te (sub 3) ; bluish-black; at Vulcan, CO.

weiss quadrilateral
 * The quadrilateral formed by the plane position of two shaft plumblines and two observation stations.

welded dike
 * A term applied to pegmatitic and aplitic dikes, the boundaries of which have been obliterated by continued growth of the minerals of the granite into which the dikes have been injected.

welded tuff
 * A glass-rich pyroclastic rock that has been indurated by the welding together of its glass shards under the combined action of the heat retained by particles, the weight of overlying material, and hot gases. It is generally composed of silicic pyroclasts and appears banded or streaky. Syn: tuff lava. CF: ignimbrite.

weldment
 * A base or frame made of pieces welded together, as contrasted with a one-piece casting or a bolted or riveted assembly.

Weldon mud
 * See: Weldon process.

Weldon process
 * A process used formerly for the recovery of manganese dioxide in making chlorine from hydrochloric acid in a stoneware still, by adding lime to the still liquor and oxidizing with air to precipitate a mud containing calcium manganite and yielding chlorine when recirculated and treated with hydrochloric acid.

well
 * a. A borehole or shaft sunk into the ground for the following purposes: obtaining water, oil, gas, or mineral solutions from an underground source; introducing water, gas, or chemical reagent solutions under pressure into an underground formation; or removing the leachate from such an operation. See also: borehole mining.

b. A slot in the front of a hydraulic dredge hull in which the digging ladder pivots. c. A hollow cylinder of reinforced concrete, steel, timber, or masonry built in a hole as a support for a bridge or building. d. Commonly used as a syn. for borehole or drill hole, esp. by individuals associated with the petroleum-drilling industry. e. A wall around a tree trunk that protects it from fill. f. An artificial excavation (pit, hole, tunnel), generally cylindrical in form and commonly walled in, sunk (drilled, dug, driven, bored, or jetted) into the ground to such a depth as to penetrate water-yielding rock or soil and to allow the water to flow or to be pumped to the surface; a water well, originally applied to natural springs or pools, esp. mineral spas. See also: artesian well; deep well. g. The crucible of a furnace or a cavity in the lower part of some furnaces to receive falling metal. h. The small dark nonreflecting area in the center of a fashioned stone, esp. in a colorless diamond cut too thick. i. A vertical opening through the hull of a ship in which drill pipe or mining machinery is lowered to the seafloor, rather than being lowered over the side of the ship. Also called: moonpool.

well-conditioned triangle
 * A triangle that is equilateral or nearly so. In such a triangle any error in the measurement of an angle will be reduced to a minimum.

well core
 * A sample of rock penetrated in a well or other borehole obtained by use of a hollow bit that cuts a circular channel around a central column or core.

well cuttings
 * Rock chips cut by a bit in the process of well drilling and removed from the hole by pumping or bailing. Well cuttings collected at closely spaced intervals provide a record of the strata penetrated.

well-drill hole
 * Hole drilled by means of an apparatus known as a well drill, or similar to that, and used in groups for blasting on a comparatively large scale. Such holes are usually 5 in or 6 in (12.7 cm or 15.2 cm) in diameter and from 30 to 150 ft (9.1 to 45.7 m) deep.

wellglass fitting
 * A transparent lighting device used as a main lighting device in mines. Its distribution characteristics are simple, since there is no control of light other than that provided by the interior of the upper part of the fitting, which absorbs a large proportion of the upward flux component from the lamp and reflects the remainder. It is usually to be found spaced at intervals of 20 to 50 ft (6.1 to 15.2 m), 6 to 7 ft (1.83 to 2.13 m) high, along the centerline of roads 12 to 14 ft (3.66 to 4.27 m) wide. In general, the most noticeable effect of such a layout is glare.

wellhole
 * a. A large-diameter (about 6 in or 15 cm) vertical hole used in quarries and opencast pits for heavy explosive charges.

b. Change room.

wellhole blast
 * A method of quarry blasting in which the explosive charges are placed in rows of vertical holes. The loading ratio varies from about 3 st of rock per pound (6 t/kg) of explosive up to about 7 st (14 t/kg) under favorable conditions. Deck loading is usually employed, and a powerful gelatinous explosive is loaded at the bottom of the holes.

wellhole blasting
 * This type of blasting is virtually benching on a large scale. The depth and burden of the holes are much greater, and in consequence, the hole diameter must also be increased to ensure sufficient concentration of the explosive charge. Wellhole blasting is used in limestones esp. if the beds are horizontal and well-defined. It is not often used in highly abrasive igneous rocks because of the cost of drilling.

Wellington formula
 * The Engineering News formula for calculating the load-bearing capacity of driven piles.

well log
 * A graphic record of the measured or computed physical characteristics of the rock section encountered in a well, plotted as a continuous function of depth. Measurements are made by a sonde as it is withdrawn from the borehole by a wire line. Several measurements are usually made simultaneously, and the resulting curves are displayed side by side on a common depth scale. Both the full display and the individual curves are called logs. Well logs are commonly referred to by generic type, such as resistivity log and radioactivity log, or by specific curve type, such as sonic log and gamma-ray log. See also: borehole log; sample log; driller's log. Syn: borehole survey; geophysical log; wire-line log.

well logging
 * a. A widely used geophysical technique that involves probing of the Earth with instruments lowered into boreholes, their readings being recorded at the surface. Among rock properties currently being logged are electrical resistivity, self-potential, gamma-ray generation (both natural and in response to neutron bombardment), density, magnetic susceptibility, and acoustic velocity.

b. In deep bores, measurement of resistivity of the formations drilled through. Electrodes are plunged into the drilling mud at controlled spacings. See also: electric log. c. The lowering of sensors into a borehole and recording of physical information as a function of depth. Numerous types of geophysical logs can be recorded, the more common being rate of penetration, temperature, gamma-ray, electric, and caliper (for hole diameter).

well point
 * A hollow vertical tube, rod, or pipe terminating in a perforated pointed shoe and fitted with a fine-mesh wire screen; connected with others in parallel to a drainage pump; driven into or beside an excavation to remove underground water, to lower the water level and thereby minimize flooding during construction, or to improve stability.

well-point pump
 * A centrifugal pump that can handle considerable quantities of air; used for removing underground water to dry up an excavation.

well seismometer
 * Special type of seismometer that is used when recording in a borehole.

well shooting
 * In seismic work, a method or methods of logging a well so that average velocities, continuous velocities, or interval velocities are obtained by lowering geophones into the hole. Shots are usually fired from surface shot holes, but may be fired in the well itself, or perforating-gun detonations may be used. In continuous logging, a sound source is lowered in the hole together with recording geophones.

well-sorted
 * As used by geologists, it applies to material composed of grains of approx. uniform size. As used by engineers, it applies to material containing approx. equal amounts of several grain sizes.

well tube
 * A tube or tubing used to line wells.

well-tube filter
 * A strainer on a driven well tube to keep out grit.

well-tube point
 * A point at the end of a perforated tube used for sinking wells.

well-velocity survey
 * Method of determining the velocity distribution by recording in a borehole.

Welshman
 * A heavy steel ring, about 3 in or 4 in (7.6 cm or 10.2 cm) inside diameter, used in withdrawing a bar stuck or frozen in a skull or iron. The ring is placed on the bar, a wedge inserted, and the bar backed out by sledging on the wedge.

Welsh notch
 * A form of joint between the tubing used to line a collar (or a crossbar) and the arms (or uprights) of a timber set; developed in the Welsh coal mines. A Welsh notch is designed to be equally effective in resisting side and roof pressure.

wem
 * See: whim.

wenkite
 * A hexagonal mineral, Ba (sub 4) Ca (sub 6) (Si, Al) (sub 20) O (sub 39) )(OH) (sub 2) (SO (sub 4) ) (sub 3) .nH (sub 2) O (?) ; cancrinite group.

Wentworth grade scale
 * An extended version of the Udden grade scale, adopted by Chester K. Wentworth (1891-1969), U.S. geologist, who modified the size limits for the common grade terms but retained the geometric interval or constant ratio of 1/2. The scale ranges from clay particles (diameter less than 1/256 mm) to boulders (diameter greater than 256 mm). It is the grade scale generally used by North American sedimentologists. See also: Udden grade scale; phi grade scale; grade scale.

Wentworth scale
 * A logarithmic grade scale for size classification of sediment particles, starting at 1 mm and using the ratio 1/2 in one direction (and 2 in the other), providing diameter limits to the size classes of 1,-1/2,-1/4, etc., and 1, 2, 4, etc. Syn: grade scale. See also: Udden grade scale.

Wenzel's law
 * Applies to the dissolution of a solid in a liquid. The rate of dissolution is proportional to the surface area of the solid exposed to the action of the solvent.

wernerian
 * Of or relating to Abraham G. Werner (1749-1817), German mineralogist and geologist, who classified minerals according to their external characteristics, advocated the theory of neptunism, and postulated a worldwide age sequence of rocks based on their lithology. Also, said of one who is a great, but dogmatic, teacher of geology. n. An adherent of wernerian beliefs; a neptunist.

wernerite
 * A common scapolite. A mineral of the scapolite group, intermediate in composition between meionite and marialite. Syn: scapolite.

Wesco coal powder
 * Nongelatinous permissible explosive; used in coal mines.

weslienite
 * See: romeite.

Westfalia pillar plow
 * A plow designed for the extraction of coal pillars and for short, rapidly advancing development faces. The plow is guided along a panzer conveyor, but the pulling forces are not transmitted to the conveyor structure. The plow is automatically advanced at each end of its short run, giving a rapid face advance. This requires the use of self-advancing supports in conjunction with hydraulic anchorages.

Westfalia plow
 * See: hard-coal plow.

Westfalia tandem plow
 * A plow designed for use in a seam with sticky coal. It consists essentially of two shortened plow bases connected by a heavy tension spring and carrying two adjustable booms fitted with cutting bits and connected at the apex to a cutterhead, which plows at roof level or at any lower level that will bring down the top coal.

westfalite
 * A blasting explosive composed of ammonium nitrate and resin.

Weston photronic cell
 * This consists of a small box containing an iron disk thinly coated with the rare element selenium. When electromagnetic radiation in the form of light waves falls on this surface it sets up a potential difference between the iron and the selenium, which in turn causes a minute electric current to flow through the sensitive microammeter connected between them. The magnitude of this current is proportional to the intensity of the light, and it can be used as a measure. For use with miners' hand lamps the cell is mounted in a box, the microammeter being housed in the top or side. The lamp to be tested is placed in the box on a turntable, and the candlepower is read off directly since the instrument is already calibrated.

Westphal balance
 * In mineral analysis, a balance used to determine the specific gravity of heavy liquids which are in turn used to determine the specific gravity of mineral grains by a sink-float method. It is a modification of a Walker steelyard (beam) balance. Also called: Mohr balance. CF: Jolly balance; Walker balance.

West's solution
 * A liquid consisting of eight parts of white phosphorous and eight parts of sulfur to one part of methylene iodide. Useful in obtaining the refractive index by the Becke method. Refractive index, 2.05.

weta material
 * A refractory suitable instead of porcelain and quartz glass. Powdered silicon carbide mixed with silicates and certain metals; resists acids, alkalis, and temperature shock; is not easily broken.

wet analysis
 * A method of estimating the effective diameters of particles smaller than 0.06 mm by mixing a sample in a measured volume of water and checking its density at intervals with a sensitive hydrometer. A test may take several days.

wet- and dry-bulb thermometer
 * See: hygrometer; wet-bulb thermometer.

wet-and-dry screening
 * In sizing analysis of fine material, preliminary screening by washing a weighed sample on a 200-mesh screen, perhaps with use of a dispersing agent, such as sodium silicate. Removal of the minus fraction (which is settled and later brought into account) is followed by drying of the on-size and by standard sizing analysis. Screen action is thus rendered more efficient.

wet assay
 * Any type of assay procedure that involves liquid, generally aqueous, as a means of separation. CF: dry assay. See also: volumetric analysis.

wet blasting
 * Shot firing in wet holes. Special explosives are available for wet conditions, and the detonator wires must be well insulated to prevent short-circuiting and misfires.

wet-bulb temperature
 * a. The temperature of the air as measured by a wet-bulb thermometer; it is lower than the dry-bulb temperature (for all cases except when the air is saturated)--ininversely proportion to the humidity.

b. The lowest temperature which can be produced in a given air by the evaporation of moisture into that air. c. Temperature at which water evaporating into air can bring the air to saturation adiabatically at that temperature--a measure of the evaporating capacity of air. Indicated by a thermometer with a wetted wick. Measured in degrees C.

wet-bulb thermometer
 * An instrument that measures the evaporating capacity of air.

wet cleaning
 * A coal-cleaning method that involves the use of washers plus the equipment necessary to dewater and heat-dry the coal. This method is generally used when cleaning the coarser sizes of coal. It is a more expensive method than air cleaning and creates the additional problem of water pollution. Coal can, however, be cleaned more accurately by this method than by air cleaning. See also: froth flotation; washery.

wet clutch
 * A clutch that operates in an oil bath.

wet criticality
 * Reactor criticality achieved with a coolant.

wet cutting
 * A method of dust prevention in which water is delivered onto a moving cutter chain, through water pipes, and is carried into the cut where it is intimately mixed with the cuttings. This method is successful in seams up to 4 ft (1.22 m) thick.

wet cyclone
 * See: cyclone.

wet drilling
 * In rock drilling for blasting purposes, injection of water through a hollow drill shank to the bottom of a hole, to allay dust and danger of pneumoconiosis.

wet gold-silver ore
 * Lead ore with high silver content. During smelting, the lead trickles through the mass and collects gold and/or silver, which are later recovered.

wet grinding
 * a. Any milling operation carried on in water or a liquid.

b. The practice of applying a coolant to the work and the wheel to facilitate the grinding process. c. Comminution of ore in aqueous suspension; typically practiced in the ball milling of finely crushed rock. See also: grinding.

Wetherill's furnace
 * A furnace with a perforated iron bottom, under which a blast is introduced, and upon which zinc ore (red oxide) is reduced. A muffle furnace for roasting zinc ores.

Wetherill's magnetic separator
 * An apparatus for separating magnetic minerals from nonmagnetic minerals. It consists of two flat belts, the upper of which is the wider, run parallel to each other and over long magnets set obliquely to the belts. Consequently, magnetic particles are drawn up against the upper belt, and as they pass beyond the influence of the magnets, fall from the edge past the other belt into a bin. Another form operates by belts moving across the line of travel of the main belt.

Wetherill vacuum casting process
 * In this process, a mold, arranged for bottom feeding, is placed inside a vacuum bell; the bottom of the mold is connected by a tube to a ladle containing the molten metal, which is sucked into the mold cavity when a vacuum is formed.

Wethey furnace
 * A multiple-deck, horizontal furnace for calcining sulfide ores. It resembles the Keller furnace.

wet metallurgy
 * See: hydrometallurgy.

wet method
 * process, etc. See also: wet process.

wet milling
 * Comminution of ores and materials in the presence of a liquid in a suitable mill, either by rods, balls, or pebbles, or autogenously, by the material itself. See also: dry milling.

wet-milling plant
 * A mill in which a wet process is employed.

wet-mill man
 * See: wet-pan operator.

wet mining
 * a. A system of mining in which water is sprayed into the air at all points where dust is liable to be formed, and no attempt is made to prevent the air from picking up moisture. It therefore soon becomes saturated and remains so throughout the ventilation circuit.

b. Mining for salt and other water soluble minerals as brine rather than in the dry state.

wet mixer
 * See: clay maker.

wet-pan charger
 * Person who adds water to mixture, in addition to clay, shale, or brick, in grinding pans in order to make it plastic. May be designated according to clay ground in pans, such as silica-wet-pan charger. Syn: wet-pan feeder.

wet-pan feeder
 * See: wet-pan charger.

wet-pan operator
 * Person who tends and supervises loading of wet pans used for grinding and tempering clay, performing essentially the same duties as described under dry-pan operator. Syn: clay temperer; wet-mill man.

wet-plant operator
 * Person who works as a member of a crew performing any one or a combination of duties concerned with extracting cadmium, lead sulfate, and zinc oxide from dust recovered in Cottrell precipitators.

wet process
 * A metallurgical process in which the valuable contents of an ore are dissolved by acid or other solvents; a leaching or lixiviation process. Opposite of dry process. See also: wet method.

wet puddling
 * The ordinary process of puddling in which a furnace is lined with material rich in oxide of iron.

wet rot
 * a. Timber decay set up when mine props have not been treated with zinc sulfate, etc., and are exposed to alternations of moisture and drying out.

b. Timber decay caused by alternating wet and dry periods.

wet screening
 * The addition of water to a screen to increase its capacity and improve its sizing efficiency. Water may be introduced either by adding it to the feed stock or by spraying it over the material on the screen deck. The latter method is also used in rinsing or washing ores, etc., to recover minerals.

wet separation
 * A term used in connection with coal washing or other processes using fluid. See also: coal-preparation plant; washery.

wet sieve analysis
 * An American Society for Testing and Materials standard method of test, recommended for determining the grain sizing of materials in which slaking would occur.

wet sphere device
 * An instrument for assessing climatic conditions in mines, such as wet- and dry-bulb temperatures, air velocity, barometric pressure, and radiation. The field of usefulness of the instrument is limited to mines where the workers are normally sweating freely and wear few clothes.

wettability
 * The ability of a liquid to form a coherent film on a surface, owing to the dominance of molecular attraction between the liquid and the surface over the cohesive force of the liquid itself.

wettable sulfur
 * Sulfur treated so that it is easily dispersed in water.

wetted perimeter
 * The total length of surface in a channel or pipe that is in actual contact with water. See also: hydraulic mean depth.

wetterdynamite
 * Originally, only guhr dynamites to which were added salts containing water of crystallization, such as Glauber's salts, ammonium oxalate, etc., with the view of making them available in mines containing combustible gases.

wetting
 * A phenomenon involving a solid and a liquid in such intimate contact that the adhesive force between the two phases is greater than the cohesive force within the liquid. Thus, a solid that is wetted, on being removed from the liquid bath, will have a thin continuous layer of liquid adhering to it. Foreign substances, such as grease, may prevent wetting. Addition agents, such as detergents, may induce wetting by lowering the surface tension of the liquid. CF: water break.

wetting agent
 * a. A reagent to reduce the interfacial tension between a solid and a liquid, so facilitating the spreading of the liquid over the solid surface.

b. A chemical promoting adhesion of a liquid (usually water) to a solid surface. c. See: plasticizer. d. Substance that lowers the surface tension of water and thus enables the water to mix more readily with other substances and so facilitates the spread of the liquid over a solid surface.

wetting coal dust
 * The spraying of mine roadways with water or treatment with a wetting agent in order to (1) increase the difficulty of raising the dust deposit into the air to take part in an explosion, and (2) reduce the flammability of the dust raised in an explosion.

wetting effect
 * a. When surface-active agents cause water to displace air at the surface of a solid-water-air system, the surface tension of the solid-water phase has been lowered in comparison with that of the solid-air phase, by adsorption of the wetting agent (adhesional wetting). For a small particle, wetting can be separated into three stages (adhesion, immersion, spread). Wetting is a preliminary step in deflocculation.

b. A condition in which the surface tension of the solid-water phase is lowered in comparison with surface tension in the solid-air phase.

wet unit weight
 * The weight (solids plus water) per unit of total volume of soil mass, irrespective of the degree of saturation. Syn: mass unit weight. See also: unit weight.

whaler
 * A horizontal beam in a bracing structure.

whale-type jib
 * A coal-cutter jib that enables water to be taken, during cutting, to the back of the cut for dust suppression and prevention of gas ignition from frictional sparking. With an undercutting jib, it consists of a feed water pipe and four or five distributor pipes terminating in jets all arranged in the top plate of the jib. See also: undercut ignition; dust-suppression jib.

wheal
 * Corn. A mine.

Wheatstone-bridge-type instrument
 * An instrument that makes use of electrically heated filaments that burn methane and measure the heat output by resistance pyrometry. One or more filaments form the arms of a Wheatstone bridge circuit, the out-of-balance current being a function of the methane percentage.

wheelbase
 * The distance between the contact points on the front and back wheels of any vehicle and the surface upon which the vehicle travels.

wheel brae
 * A flat or landing on the top of an incline.

wheel conveyor
 * A series of wheels supported in a frame over which objects are moved manually or flow by gravity. See also: el conveyor; gravity conveyor; gravity wheel conveyor; portable conveyor.

wheel ditcher
 * a. A wheel equipped with digging buckets, carried and controlled by a tractor unit.

b. A machine that digs trenches by rotation of a wheel fitted with toothed buckets.

wheel dresser
 * A tool for cleaning, resharpening, and truing the cutting faces of grinding wheels.

wheeled tractor
 * A tractor, fitted with large rubber-tired wheels, which can travel comparatively fast over rough ground. See also: tractor.

wheeler
 * See: pusher.

wheelerite
 * a. A yellowish resin, found in the Cretaceous beds of northern New Mexico, filling the fissures of the lignite, or interstratified in thin layers. It is soluble in ether.

b. A yellowish variety of retinite that is soluble in ether and fills fissures in, or is thinly interbedded with, lignite beds in northern New Mexico.

wheel excavator
 * A large-capacity machine for excavating loose deposits, particularly at opencast coalpits. It consists of a large digging wheel that rotates on a horizontal axle and carries large buckets on its rim.

wheelman
 * See: rollerman.

wheel ore
 * See: bournonite.

wheel pit
 * A pit in which the lower part of a flywheel runs.

wheelrace
 * The place in which a water wheel is set.

wheel runner
 * See: incline man.

wheel scraper
 * A scraper mounted on an axle supported by a pair of wheels. It affords an easy means of conveying a loaded scraper to a dumping ground. See also: bowl scraper.

wherk
 * Eng. A small unexpected turning in the stone, side, or ore, often accompanied by a small joint; Derbyshire.

wherryite
 * A monoclinic mineral, Pb (sub 4) Cu(CO (sub 3) )(SO (sub 4) ) (sub 2) (Cl,OH,O) (sub 3) ; pale green; finely granular; related to caledonite; at the Mammoth Mine, AZ.

whetstone
 * Any hard fine grained rock, commonly siliceous, that is suitable for sharpening implements such as razors, knives, and other blades; e.g., novaculite.

Whetwell stove
 * A firebrick hot-blast stove on a regenerative system.

whewellite
 * A monoclinic mineral, Ca(C (sub 2) O (sub 4) ).H (sub 2) O ; soft; in coal seams, incrustations on marble; also in human urinary tracts. Syn: oxacalcite. CF: weddellite.

which-earth
 * Eng. A whitish earth found at Thame, Waterperry, and Adwell; mixed with straw, and used for sidewalls and ceilings; a natural mixture of lime and sand, flakes in water (like gypsum) without any heat.

whim
 * a. A large capstan or vertical drum turned by horsepower or steam power. Used to raise coal, water, etc., from a mine. Also called: whimsey; whim gin; horse gin.

b. Drum on which a hoisting rope is coiled. Also spelled wem.

whim driver
 * A laborer who drives a draft animal at the surface of a mine to supply power to a whim (large drum on which a cable is wound) used to hoist ore, coal, or rock in a shallow shaft. Becoming obsolete.

whim gin
 * See: whim; horse gear.

whim shaft
 * A shaft through which coal, ore, water, etc., are raised from a mine by means of a whim.

whin
 * a. Igneous rock. When parallel to the bedding planes, it is called a whinsill; when cutting across the strata, a whin dike.

b. A hard, compact rock. c. Whinstone or whinrock. In Nova Scotia, miners apply this term to a thick-bedded rock composed of grains of quartz with argillaceous or feldspathic matter that resembles graywacke. d. A whim or winch. e. See: dolerite.

whin float
 * a. Scot. A horizontal sill or lava flow of igneous rock.

b. Scot. A kind of greenstone, basalt, or trap, occurring in coal measures.

whinny
 * Resembling or abounding in whinstone.

whinstone
 * A colloquial British term for dolerite, basalt, and other dark fine-grained igneous rocks. The term is derived from the Whin Sill in northern England. CF: trap.

whintin
 * Cumb. Spotted schist. CF: calamanco; linsey.

whip
 * a. A rope that passes over a pulley and is pulled by a horse to hoist ore. Modern form occasionally seen has a car or lorry working backward and forward for shallow pitting. Called whip-and-derry when used with a derrick or gin.

b. One who operates such a hoisting apparatus. c. See: rod slap.

whip-and-derry
 * See: whip.

whip gin
 * A gin block for use as a whip, as in hoisting.

whip out
 * The enlargement of a portion of a borehole caused by the eccentric rotation and slap of the drill rods.

whipper
 * Person who raises coal, merchandise, etc., with a whip, as from a ship's hold.

whipping
 * a. The thrashing about of a moving rope, such as a hoisting cable in a mine shaft. Syn: surging.

b. Hoisting ore, coal, or other material by means of a whip.

whipping hoist
 * A hoist worked with a whip, esp. if by steam power.

whipstock
 * Wedge-shaped device used to deflect and guide a drill bit away from vertical; procedure of deflecting a hole. CF: arc cutter. See also: deflection wedge.

whipstocking
 * A term commonly used by petroleum-field drillers to designate the act or process referred to by diamond drillers as deflecting a borehole. See also: wedging.

whipstock point
 * The point within a borehole at which a deflection or change in course is desired.

whirling hygrometer
 * In mining, a hygrometer used to obtain wet-bulb temperatures. The hygrometer is spun round and round at a speed of about 200 rpm, for at least 1 min, and then read as quickly as possible. See also: Storrow whirling hygrometer.

whirlstone
 * Eng. Usually applied to sandstone (not a freestone) in the Carboniferous Limestone Series of Cumberland. Sometimes applied to a dolomite, limestone, or shale.

whistler
 * See: squealer.

white
 * The color of the mixture of electromagnetic radiation visible to the normal human eye. White is commonly, but incorrectly, applied to colorless minerals and gemstones.

white agate
 * See: chalcedony.

white alkali
 * An older term for accumulation of salts with high levels of sodium that may develop as a crust. CF: black alkali.

white antimony
 * See: valentinite; valentite.

white arsenic
 * Commercially called arsenic. Arsenic trioxide, As (sub 2) O (sub 3) ; the most important compound of arsenic. Obtained from the roasting of arsenical ores. See also: arsenic trioxide.

white Bengal fire
 * A very brilliant light produced by burning pure metallic arsenic.

white cast iron
 * Cast iron that gives a white fracture because the carbon is in combined form. See also: iron.

white clay
 * See: kaolin.

white coal
 * a. See: tasmanite.

b. Water power: a French designation (houille blanche).

white cobalt
 * A name frequently applied to smaltite and cobaltite. See also: cobaltite; smaltite.

white copper
 * A white alloy of copper; paktong. Usually German silver. Syn: domeykite.

white copperas
 * See: coquimbite; goslarite.

white copper ore
 * See: kyrosite.

white-countered gutta percha
 * A safety fuse in which the powder is enclosed in a thin tube of gutta percha, which in turn is enveloped in a waterproof textile covering. Abbreviated W.C.G.P.

white damp
 * Carbon monoxide, CO. A gas that may be present in the afterdamp of a gas- or coal-dust explosion, or in the gases given off by a mine fire; also one of the gases produced by blasting. It is an important constituent of illuminating gas, supports combustion, and is very poisonous because it is absorbed by the hemoglobin of the blood to the exclusion of oxygen. See also: damp.

white feldspar
 * See: albite.

white flat
 * Small, pale, rough nodule in hard shale in Shropshire.

white garnet
 * a. See: leucite.

b. A translucent variety of grossular resembling white jade in appearance.

white gold
 * Gold alloyed with nickel or palladium to give it a white color.

white gunpowder
 * A mixture of 2 parts potassium chlorate, 1 part potassium ferrocyanide, and 1 part sugar. Syn: white powder.

white heat
 * A common division of the color scale, generally given as about 2,800 degrees F (1,540 degrees C).

white horse
 * A term used by quarrymen to denote a light-colored gneiss, aplite, or pegmatite.

white-hot
 * A state in which a material is heated to full incandescence so as to emit all the rays in the visible spectrum in such proportion as to appear dazzling white.

White-Howell furnace
 * A revolving, cylindrical furnace for calcining calamine.

white iron
 * An extremely hard cast iron, resulting when a casting is chilled in a metallic mold. See also: gray iron.

white iron ore
 * An early name for siderite. See also: siderite.

white iron pyrites
 * See: marcasite.

white latten
 * An alloy of copper, zinc, and tin in thin sheets.

white lead
 * Basic lead carbonate or lead hydroxycarbonate.

white lead ore
 * a. See: cerussite.

b. A decomposition product of sphalerite. See also: white vitriol. Syn: lead carbonate.

White Lias
 * The Upper Rhaetic, as opposed to the overlying Blue Lias.

white limestone
 * The principal limestone division of the Great Oolite Series.

white metal
 * a. A general term covering a group of white-colored metals with relatively low melting points (lead, antimony, bismuth, tin, cadmium, and zinc). Includes the alloys based on these metals.

b. A copper matte of about 77% copper obtained from smelting sulfide copper ores. c. Usually a tin-base alloy (more that 50% tin); used for lining bearings and winding rope cappels.

white-metal cappel
 * A cappel in which the end of the winding rope (separated into a brush) is embedded in a plug of white metal inside a socket. See also: capping.

white-metal capping
 * A winding rope capping formed by opening out the wires of the rope for a length equal to that of the socket, cleaning them thoroughly of all grease, cutting out the hemp core, and finally drawing them into the warmed socket and running in the white metal, which is an alloy of lead, antimony, and tin.

white mica
 * See: muscovite.

white mineral press
 * A machine for briquetting flue dust.

white mundic
 * See: arsenopyrite.

white nickel
 * See: rammelsbergite; nickel-skutterudite.

white nickel ore
 * See: chloanthite.

white olivine
 * The mineral forsterite, Mg (sub 2) SiO (sub 4).

white opal
 * Precious opal of any light color, as distinguished from black opal; e.g., a pale blue-white gem variety of opal.

white ore
 * See: cerussite.

white powder
 * See: white gunpowder.

white pyrite
 * See: marcasite; arsenopyrite.

white salt
 * a. Salt dried and calcined; decrepitated salt.

b. Salt refined and prepared mainly for household use. Also, vacuum pan salt used for salting skins; distinguished from rock salt.

white sand
 * Sand that is usually quartzitic and pure enough to resist heat and slags; used for the final layer in Siemen's steel furnaces.

white schorl
 * See: albite.

white smoker
 * A plume of hydrothermal fluid issuing from the crest of an oceanic ridge; e.g., the East Pacific Rise at the mouth of the Gulf of California. The fluid is clouded by white precipitates, mostly barite and silica. It issues at rates of tens of cm/second and at temperatures of 100 to 350 degrees C (Macdonald et al., 1980). CF: black smoker.

white tellurium
 * See: sylvanite; krennerite.

white tin
 * Metallic tin after smelting, in contradistinction to black tin or cassiterite.

white tombac
 * A variety of brass made white by the addition of arsenic.

white vitriol
 * The mineral goslarite, ZnSO (sub 4) .7H (sub 2) O . Also called: salt of vitrol; zinc vitrol.

whiting substitute
 * A finely ground calcium carbonate, about 98% pure, contaminated by magnesia, silica, iron, or alumina. This material should not be confused with chalk whiting or precipitated chalk.

Whiting system
 * A system in which two parallel, grooved sheaves are coupled. These sheaves are driven directly from a hoisting engine. One sheave is set at a slight angle to the vertical so that the rope will pass freely from one sheave to the other. The hoisting rope passes around the drive sheaves and then to a takeup sheave, which is mounted on a horizontally movable carriage to take up slack or to change the hoist from one level to another. A tail rope is used in this system, although it may not be absolutely necessary.

whitlockite
 * A trigonal mineral, Ca (sub 9) (Mg,Fe)H(PO (sub 4) ) (sub 7) ; colorless; forms rhombohedra; at North Groton, NH. Syn: merrillite.

Whitney stress diagram
 * Diagram showing the stress distribution in a reinforced concrete beam in accordance with the theory of ultimate load.

Whitwell stove
 * A firebrick, hot-blast stove on a regenerative system.

whizzer mill
 * See: Jeffrey crusher.

whole body counter
 * A device used to identify and to measure the radiation in the body (body burden) of humans and animals. Uses heavy shielding to keep out background radiation, ultrasensitive scintillation detectors, and electronic equipment.

whole-circle bearing
 * A bearing that defines the direction of a survey line by its horizontal angle measured clockwise from true north.

whole diamond
 * A diamond (as mined), the shape of which has not been modified artificially. Syn: whole stone.

whole stone
 * See: whole diamond.

whole-stone bit
 * A bit, the crown of which is either surface set or impregnated with whole diamonds, as opposed to an impregnated or surface-set bit in which the inset diamonds are fragmented diamonds.