Appendix:Dictionary of Mining, Mineral, and Related Terms/S/9

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A fibrous talc. From the German spath.

spaced loading

a. Loading so that cartridges or groups of cartridges are separated by open spacers that do not prevent the concussion from one charge from reaching the next.

b. See: deck loading.

space frame

A three-dimensional frame that is stable against wind pressure without being braced against any other structure.

space group

In crystallography, any one of 230 independent combinations of the 14 essentially different kinds of three-dimensional periodicity (Bravais lattices) with other symmetry operations (point groups, screws, glides). CF: plane group; Bravais lattice; point group; screw; glide.

space lattice

a. A three-dimensional regularly repeating set of points so arranged as to determine sets of equally spaced parallel planes in various directions forming polyhedral cells (as in a honeycomb). Specif., a set of such points occupied by the atoms of a crystal.

b. The pattern formed by the spatial distribution of atoms or radicals in a crystal. See also: crystal pattern; lattice. c. Any one of 14 infinite three-dimensional arrays of points such that each point is in an identical point environment. Syn: Bravais lattice. CF: net.


a. A piece of metal wire twisted at each end so as to form at one end a guard to keep the explosive in a shothole in place and at the other end another guard to hold the tamping in its place, thus providing an open space between explosive and tamping. When this is provided, the charge constitutes a cushion shot.

b. Piece of wood doweling which is interposed between charges to extend the column of explosive. c. A marker block. Also called spacer block. d. The tapered section of a pug joining the barrel to the die; in this section beyond the shaft carrying the screw or blades, the clay is compounded before it issues through the die.


The distance between adjacent shotholes in a direction parallel to the quarry or other face.

Spackman System

See: coal constituent classification.


a. A means of marking an underground survey station that consists of a flat spike in which is drilled a hole for the threading of a plumbline.

b. See: spud.

spade drill

See: flat drill.

spade-end wedge

A type of deflecting wedge in boreholes. See also: deflecting wedge.


Corn. A worker in the tin mines. Also called spalliard.


A term used in South Wales for a train of personnel carriages, for use on the main slants at the beginning and end of each shift. The seats are so arranged that they are horizontal when the carriage is on the inclined slant. See also: man-riding car; man-riding conductor.


a. A relatively thin, commonly curved and sharp-edged piece of rock produced by exfoliation.

b. To break off in layers parallel to a surface. c. To break ore. Pieces of ore thus broken are called spalls. Also spelled: spawl.


Eng. A pickman; a working miner. A laborer in tinworks. Also spelled spallier.


The chipping, fracturing, or fragmentation, and the upward and outward heaving, of rock caused by the action of a shock wave at a free surface or by release of pressure. Syn: exfoliation.

spalling floor

A place for breaking ore with a 4- to 5-lb (1.8- to 2.3-kg) sledge hammer.


a. The horizontal distance between the side supports or solid abutments along sides of a roadway. See also: abutment; pressure arch.

b. The horizontal distance between the supports of a bridge, arch, beam, or similar structural member. See also: clear span; effective span.

spangle gold

Aust. Smooth, flat scales of gold.


A trigonal mineral, Cu (sub 6) Al(SO (sub 4) )(OH) (sub 12) Cl.3H (sub 2) O ; soft; vitreous; dark green; in Cochise County, AZ.

Spanish chalk

A variety of steatite in Aragon, Spain.

Spanish emerald

Emerald of the finest quality (presumably from South America).

Spanish lazulite

Iolite, a variety of cordierite.

Spanish topaz

a. Any orange, orange-brown, or orange-red variety of quartz resembling the color of topaz; e.g., heat-treated amethyst. CF: topaz; Madeira topaz.

b. A wine-colored or brownish red citrine from Spain.


See: gypsum.


a. A term loosely applied to any transparent or translucent light-colored mineral that is readily cleavable having a vitreous luster; e.g., Iceland spar (calcite), fluorspar (flourite), feldspar, heavy spar (barite).

b. Applied locally by miners to small clay veins found in coal seams. c. Corn. Quartz. d. See: Iceland spar.

sparable ore

A nonmetallic tin ore occurring in small granules.


A collective term for the late Percambrian fragmental rocks of Scandinavia, esp. the feldspathic sandstones of the Swedish Jotnian, consisting mainly of coarse arkoses and subarkoses, together with polygenetic conglomerates and graywackes. Etymol: Greek sparagma, fragment, thing torn, piece.


N. of Eng. A wedge from 6 to 8 in (15 to 20 cm) long for driving behind plates when adjusting them to the circle of the shaft. Also called spear wedge.

spare face

See: standby face.


a. A descriptive term for the crystalline transparent or translucent interstitial component of limestone, consisting of clean, relatively coarse-grained calcite or aragonite that either accumulated during deposition or was introduced later as a cement. It is more coarsely crystalline than micrite, the grains having diameters that exceed 10 mu m.

b. A limestone in which the sparite cement is more abundant than the micrite matrix.

spark absorber

See: absorber.

spark chamber

An instrument for detecting and measuring nuclear radiation; analogous to the cloud chamber. It consists of numerous electrically charged metal plates mounted in a parallel array, the spaces between the plates being occupied by inert gas. Ionizing radiation causes sparks to jump between the plates along its path through the chamber. See also: bubble chamber; cloud chamber.


A marine seismic source that employs an electrical spark discharge to form the outgoing signal and produces a trace in the recorder showing the subbottom strata.

sparkle metal

A matte containing about 74% copper.

spark test

Identification of type of iron alloy by appearance of sparks emitted when rubbed on grindstone.


a. Pertaining to, resembling, or consisting of "spar"; e.g., sparry vein or sparry luster. Like spathic; as in feldspathic. See also: spar.

b. Pertaining to "sparite" esp. in allusion to the relative clarity, both in thin section and hand specimen, of the calcite cement; abounding with sparite, such as a sparry rock.

sparry iron

See: siderite.

sparry lode

A lode filled with spar, e.g., fluorspar, calcspar, or heavy spar.

sparse vitrain

A field term to denote, in accordance with an arbitrary scale established for use in describing banded coal, a frequency of occurrence of vitrain bands comprising less than 15% of the total coal layer. CF: abundant vitrain; dominant vitrain; moderate vitrain.


A variety of calcite containing some manganese.


A former name for zincite.


a. Corn. In mining, to fine for disobedience of orders.

b. A variation of spall.


Resembling spar, esp. in regard to having good cleavage. Syn: spathose.

spathic iron

A native ferrous carbonite, also called siderite, containing 48% iron and usually traces of manganese. It is the best native ore for making steel tools by the direct method formerly used. See also: siderite.

spathic iron ore

See: siderite.


Widely distributed crystallization of sparry carbonates, such as calcite and dolomite; development of relatively large sparry crystals that have good cleavage.


See: spathic.

spathose iron

Carbonate of iron, FeCO (sub 3) . See also: siderite.


See: spall.

spawl beater

See: sledger.

SP curve

See: spontaneous potential curve.


a. One of several types of fishing tools designed to be driven and wedged inside of bits, rods, etc., lost in a borehole. CF: fishing tap.

b. A rodlike fishing tool having a barbed-hook end, used to recover rope, wire line, and other materials from a borehole. c. Eng. A wooden pump rod cut into lengths of about 40 ft (12 m) , and, for heavy work, often measuring 16 in (40.6 cm) square. Wrought iron spears are also used.


a. The point of convergence of two cross faces set off in the form of the letter V.

b. A conical head on a wire-line core barrel, engaged by the dogs on the overshot assembly for the purpose of removing the inner tube of the core barrel from a borehole.

spear pyrite

A marcasite in twin crystals resembling the head of a spear. See: marcasite.


See: special rounds.

special flexible rope

A wire rope composed of 6 strands of 37 wires each.

special rounds

Sometimes used to designate a very high quality or grade of drill diamonds.

specialty steel

A steel containing alloys that provide special properties, such as resistance to corrosion or to heavy load. Also called alloy steel.


A mineral distinguished from others by its unique chemical and physical properties; it may have varieties.


Word used with a special meaning in mineral dressing, where minerals of the same species often exhibit differences in their reactions. "Specific to" warns the observer that the process in hand is empirical in some ways, designed to apply to one specific orebody.

specific adhesion

The chemical bond between glued or cemented surfaces as distinct from any form of mechanical bond.

specific adsorption

Selective adsorbing action.

specific damping capacity

A measure of the vibrational energy absorbed by the rock and may be considered to be a measure of the internal friction. It is determined by the sharpness of resonance that is evident when a specimen is vibrated through a range of frequencies centered on the fundamental longitudinal resonant frequency. Damping of the dry type (coulomb damping) is commonly assumed to be independent of the velocity, and thus independent of the frequency, and is somewhat sensitive to moisture content. Syn: coulomb damping.

specific extraction of rock broken

Quantity of broken rock (ore) in volume or weight per foot drilled or fired per quantity of explosive.

specific gravity

a. The ratio between the weight of a unit volume of a substance and that of some other standard substance, under standard conditions of temperature and pressure. For solids and liquids, the specific gravity is based upon water as the standard. The true specific gravity of a body is based on the volume of solid material, excluding all pores. The bulk or volume specific gravity is based upon the volume as a whole--i.e., the solid material with all included pores. The apparent specific gravity is based upon the volume of the solid material plus the volume of the sealed pores. See also: apparent specific gravity.

b. Ratio of densities of a gas and air, based on dry air = 1. c. The weight of a substance compared with the weight of an equal volume of pure water at 4 degrees C. Specific gravity is numerically equal to density given in grams per cubic centimeter or milliliter. CF: density.

specific-gravity hydrometer

A hydrometer indicating the specific gravity or relation of the weight of a given liquid per unit volume to the weight of a given unit volume of water. See also: hydrometer; Marsh funnel.

specific gravity of soil grains

This is measured in a calibrated glass bottle with special precautions against the inclusion of air. Such testing is applied in many soil problem computations. See also: pycnometer.

specific heat

a. Heat required to raise the temperature of a unit weight of air 1 degrees F (0.56 degrees C). Usually, the specific heat at constant pressure is used in air conditioning. For ordinary concrete and steel it is 0.22 Btu/lb/ degrees F and 0.12 Btu/lb/ degrees F (0.92 kJ/kg/ degrees C and 0.50 kJ/kg/ degrees C), respectively.

b. The ratio of the amount of heat required to raise a unit weight of a material 1 degree to the amount of heat required to raise the same unit weight of water 1 degree. c. The heat in calories required to raise the temperature of 1 g of a substance 1 degrees C.

specific humidity

a. The mass of moisture per unit mass of dry air.

b. Absolute humidity, or weight of water vapor contained per unit weight of dry air. CF: relative humidity. See also: humidity.

specific mineral

See: essential mineral.

specific population

Number of particles in unit volume of pulp.

specific resistance

See: resistivity.

specific retention

The ratio of the volume of water that a given body of rock or soil will hold against the pull of gravity to the volume of the body itself. It is usually expressed as a percentage. CF: field capacity.

specific speed

a. A factor by which the performance of any particular design of impeller for a centrifugal pump or water turbine can be computed. It is the speed in revolutions per minute at which a geometrically similar impeller of suitable diameter will rotate to deliver 1 gal/min (3.785 L/min) at 1 ft (30.5 cm) head in the case of a pump. In a water turbine, the specific speed is that at which a geometrically similar runner of suitable diameter will turn to develop 1 hp (746 W) under a head of 1 ft (30.5 cm).

b. The particular speed at which a fan achieves its maximum efficiency.

specific surface

a. The surface area per unit of volume of soil particles.

b. The ratio of the total surface of a substance (as an adsorbent) to its volume; surface area (as of a finely divided powder) per unit mass.

specific volume

a. Volume of one gram at specified temperature.

b. Volume per unit weight of dry air. Not equal to the reciprocal of density, which is based on unit volume of mixture. Measured in cubic feet per pound (cubic meters per kilogram).

specific weight of sediment

The dry weight per unit volume of the sediment in place. See also: dry density.

specific yield

The ratio of the volume of water that a given mass of saturated rock or soil will yield by gravity to the volume of that mass. This ratio is stated as a percentage. CF: effective porosity.


a. A sample, as of a fossil, rock, or ore. Among miners, it is often restricted to selected or handsome samples, such as fine pieces of ore, crystals, or fragments of quartz showing visible gold. CF: hand specimen.

b. A small mass of coal, rock, or, mineral, or soil, which gives, roughly, an idea of the kind and quality of the deposit from which it was derived. In the case of ore in particular, the specimen should admit of the identification of the various minerals present. A specimen cannot be viewed as a sample.

specimen boss

An employee whose duty is to watch carefully, in all parts of the mine, for the appearance of high-grade mineral, and when it is likely that such spots will be opened up, should be the first person at the face after the blast to prevent high-grading (the theft of valuable samples).

specimen hunting

Another name for high-grading.


In mineral dressing, unusually rich pieces of ore or characteristic constituents thereof in coarsely crystalline form--not representative samples.


A small piece of alluvial gold weighing up to 1 oz or 2 oz (28 g or 56 g).


An early name for talc or steatite. Etymol: German "Speckstein", "bacon stone," alluding to its greasy feel.


A two-handled frame for carrying well-boring tools.

spectacle stone

An early popular name for selenite, alluding to its transparency.

spectral gamma-ray log

Record of the radiation spectrum and relative intensities of gamma rays emitted by strata penetrated in drilling. Because of their different energies the relative amounts of radioactivity contributed by different elements can be determined. CF: gamma-ray well log. See also: radioactivity log.


An optical instrument similar to, but more versatile than, the simple spectroscope. Scales are provided for reading angles. A wavelength spectrometer is one designed or equipped in a manner to measure the wavelengths at which absorption bands occur in an absorption spectrum.


An instrument to detect very slight differences in color of solutions of different chemicals and thus measure the quantity of the chemical present. It consists of a light source, an optical prism for providing monochromatic light; i.e., light of a single wavelength only, and a device for measuring the intensity of the light beam after it has passed through the solution. Traces of aluminum in steel may be determined in this way. Also called spekker.


a. A band of light showing in orderly succession the rainbow colors or isolated bands or colors corresponding to different wavelengths, as seen through a spectroscope or photographed in a spectrograph. The visible spectrum is only a small region in the vast spectrum of electromagnetic waves, which extend from the longest radio waves to the minutely short waves (gamma rays) emitted by radioactive elements. See also: emission spectrum; continuous spectrum; absorption spectrum.

b. An array of visible light ordered according to its constituent wavelengths (colors) by being sent through a prism or diffraction grating. c. An array of intensity values ordered according to any physical parameter, e.g. energy spectrum, mass spectrum, velocity spectrum. d. Amplitude and phase response as a function of frequency for the components of a wavetrain, such as given by Fourier analysis, or as used to specify filter-response characteristics. Pl: "spectra." Adj: "spectral."

spectrum colors

The hues or wavelengths into which white light is separated upon passing through a transparent prism, six of which are readily distinguished by the normal human eye: red, orange, yellow, green, blue, and violet. See also: visible spectrum. By extension, any small range of wavelengths outside the visible range.


Mirrorlike, as specular iron ore, which is a hard variety of hematite. See also: specularite.

specular hematite

See: specularite.

specular iron

Variety of hematite, Fe (sub 2) O (sub 3) , black, lustrous, metallic gleam. Mohs hardness, 5.5 to 6.5. May be micaceous in form. Contains 70% iron; sp gr, 4.9 to 5.3. See also: specularite; hematite.

specular iron ore

A variety of hematite with brilliant black color and metallic luster. See: hematite.


A black or gray variety of hematite with splendant metallic luster, often showing iridescence; occurs in micaceous or foliated masses or in tabular or disklike crystals. Syn: specular hematite; gray hematite. See also: hematite; specular iron; iron glance.

specular schist

Metamorphosed oxide-facies iron formation characterized by a high percentage of strongly aligned flakes of specular hematite. CF: itabirite.

specular stone


speculative resources

Undiscovered resources that may occur either in known types of deposits in favorable geologic settings where mineral discoveries have not been made, or in types of deposits as yet unrecognized for their economic potential. If exploration confirms their existence and reveals enough information about their quantity, grade, and quality, they will be reclassified as identified resources.


The length of belt, chain, cable, or other linkage which passes a fixed point within a given time. It is usually expressed in terms of feet per minute. In the case of the rolling chain conveyor, the load is moved at a rate double the chain speed. In screw conveyors, the speed is expressed in terms of revolutions per minute and the speed at which the material is conveyed is dependent upon speed, pitch of the screw, type of flight, angle of inclination, nature of material, etc.

speedy moisture tester

A calcium carbide method for the quick determination of moisture. A pressure gage is calibrated to give direct values of moisture content percent of soil samples.


Metallic arsenides and antimonides smelted from cobalt and lead ores.


See: smaltite.


One who scientifically investigates caverns.


The scientific study or exploration of caverns and related features.


A secondary mineral deposit formed in caves.


A rest period for crews at furnace, stock house, etc., or a period of work in drilling the taphole; a change or turn.


Subjecting the heated bloom to the action of rolls having regularly shaped projections on their working surface, then subjecting the bloom while still hot to the action of smooth-faced rolls. The surface working is said to give a dense texture to pipe made from the bloom, adapting it to resist corrosion.


Zinc of under 99.6% purity.

Spence automatic desulfurizer

An improved maletra furnace provided with automatic rakes.

Spence furnace

A furnace of the muffle or reverberatory type, the ore being supported on shelves and stirred mechanically.


a. A monoclinic mineral, Zn (sub 4) (PO (sub 4) ) (sub 2) (OH) (sub 2) .3H (sub 2) O ; pearly white.

b. The synthetic material (Fe,Mn) (sub 3) (C,Si).


See: tritomite.


a. To break ground; to continue working.

b. To exhaust by mining; to dig out; used in the phrase, to spend ground.

spent fuel

Nuclear-reactor fuel that has been irradiated to the extent that it can no longer effectively sustain a chain reaction. Fuel becomes spent when its fissionable isotopes have been partially consumed and fission-product poisons have accumulated in it. Syn: depleted fuel.

spent shot

A blasthole that has been fired, but has not done its work.


A calcarenite that contains ooliths and fossil debris (such as bryozoan and foraminiferal fragments) and that has a quartz content not exceeding 10%. Type locality: Spergen Hill, situated a few miles southeast of Salem, Indiana, where the Salem Limestone (formerly the Spergen Limestone) is found. Syn: Bedford Limestone.


An isometric mineral, PtAs (sub 2) ; pyrite group; tin white; sp gr, 10.6; (super ) occurs with heavy-metal ores, also in placers.

Sperry process

A process for manufacturing white lead in which softened and desilverized lead anodes, preferably containing some bismuth, are placed in the Sperry cells. Direct current dissolves the lead from the anodes, and carbon dioxide is used to precipitate white lead (basic lead carbonate) from the solution. The Sperry process slime, which contains the impurities from the anodes, is washed, dried, and melted to an impure bismuth bullion, which goes to the bismuth refinery.


An isometric mineral, Mn (sub 3) Al (sub 2) (SiO (sub 4) ) (sub 3) ; garnet group with Mn replaced by Fe and Mg; crystallizes as dodecahedra and trapezohedra; in skarns and granite pegmatites; may be of gem quality. Also spelled spessartite. CF: emildine. Syn: manganese-aluminum garnet.


A "lamprophyre" composed of phenocrysts of green hornblende or clinopyroxene in a ground mass of sodic plagioclase, with accessory olivine, biotite, apatite, and opaque oxides. Named for Spessart, Germany. Syn: spessartine.


The cauliflowerlike blowout or outcrop of a lode that extends beyond the limits of the defined vein deeper down.


A trigonal mineral, CoCO (sub 3) ; calcite group; forms peach-blossom red spherical masses. Also spelled spherocobaltite. Syn: cobaltocalcite.


See: spherulitic.


Alternate spelling of spherosiderite.

sphagnum peat

Peat composed mainly of bog moss. It is characterized by an open texture, is lightweight, has a high absorbing power, good isolating properties, a clean appearance, and freedom from black dust.


a. An isometric mineral, ZnS , with Zn replaced by Fe with minor Mn, As, and Cd; trimorphous with wurtzite and matraite; perfect dodecahedral cleavage; resinous to adamantine; occurs with galena in veins and irregular replacement in limestone; a source of zinc. Syn: blende; zinc blende; jack; blackjack; steel jack; false galena; pseudogalena; mock ore; mock lead. See also: beta zinc sulfide.

b. The mineral group coloradoite, hawleyite, metacinnabar, sphalerite, stilleite, and tiemannite.


See: titanite.


An open crystal form of two nonparallel faces which intersect two or three crystallographic axes. CF: dome; disphenoid.


A wedgelike igneous intrusion, partly concordant and partly discordant.


See: manganite.


A fernlike tree of the coal forest characterized by round-lobed pinnules that are contracted at the base. See also: Neuropteris.

sphere ore

See: cockade ore.


A general term applied to rocks made up of spherules. It includes such textures as oolitic, pisolitic, spherulitic, variolitic, orbicular, etc.

spherical dam

A brick or concrete seal or stopping built into a roadway to close off an area against water. The convex surface is from the water side of the roadway. The construction is built well into the ground and all crevices cemented.

spherical model

A function frequently used when fitting mathematical models to experimental variograms, often in combination with a nugget model.

spherical wave

A seismic wave propagated from a point source whose front surfaces are concentric spheres.

spherical wave front

Spherical surface that a given portion of a seismic impulse (in an isotropic medium) occupies at any particular time.

spherical weathering

See: spheroidal weathering.


a. The preferred spelling for sphaerite.

b. Spherical grains, including ovulite with concentric structure and spherulite with radial structure.


See: sphaerocobaltite.


A homogeneous spherulite formed of minute crystals branching outward from the center. See also: spherulite.


In general, any figure differing but little from a sphere. In geodesy, a mathematical figure closely approaching the geoid in form and size, and used as a surface of reference for geodetic surveys.


a. Having the shape of a spheroid.

b. Composed of spherulites. c. Said of the texture of a rock composed of numerous spherulites.

spheroidal jointing

See: spheroidal parting.

spheroidal parting

A series of concentric and spheroidal or ellipsoidal cracks produced about compact nuclei in fine-grained, homogeneous rocks. CF: exfoliation; spheroidal weathering. Syn: spheroidal jointing.

spheroidal structure

See: orbicular structure.

spheroidal weathering

A form of chemical weathering in which concentric or spherical shells of decayed rock (ranging in diameter from 2 cm to 2 m) are successively loosened and separated from a block of rock by water penetrating the bounding joints or other fractures and attacking the block from all sides. It is similar to the larger-scale exfoliation produced usually by mechanical weathering. See also: spheroidal parting. Syn: onion-skin weathering; concentric weathering; spherical weathering. CF: exfoliation.


A variety of siderite occurring in globular concretionary aggregates of bladelike crystals radiating from a center, generally in a clayey matrix (such as those in or below underclays associated with coal measures). It appears to be the result of weathering of water-logged sediments in which iron, leached out of surface soil, is redeposited in a lower zone characterized by reducing conditions. Also spelled sphaerosiderite.


a. A rounded or spherical mass of acicular crystals, commonly of feldspar, radiating from a central point. Spherulites may range in size from microscopic to several centimeters in diameter. Also spelled: sphaerolite.

b. Any more or less spherical body or coarsely crystalline aggregate with a radial internal structure arranged around one or more centers, varying in size from microscopic grains to objects many centimeters in diameter, formed in a sedimentary rock in the place where it is now found; e.g., a minute particle of chalcedony in certain limestones, or a large carbonate concretion or nodule in shale. CF: spherite; variole. c. A small (0.5 to 5 mm in diameter), spherical or spheroidal particle composed of a thin, dense calcareous outer layer with a sparry calcite core. It can originate by recrystallization or by biologic processes.


Said of the texture of a rock composed of numerous spherulites; also, said of a rock containing spherulites. CF: variolitic; radiated. Syn: globular; sphaerolitic.


a. A ring inserted at the joints of the suspension column of a borehole pump. Radial vanes from the ring support a central sleeve, which acts as a steady bearing from the pump shaft.

b. The bowl part of a spider and slips. Also called bowl. See also: spider and slips. c. See: drum horn. d. Assembly of radiating tie rods on the top of a furnace.

spider and slips

A gripping device used to grip and hold rods or casing while coupling or uncoupling them as they are being run into or pulled from a borehole. Also called bowl and slips. See also: spider.

spider gear

A differential gear that rotates on its shaft in a rotating case.

spiderweb rock

A local term in Ohio for sandstone beds that show crossbedding on a small scale, which is complicated by intricate interlacing of fine-bedding planes. Frequently seen in sawed stones, esp. where the lamination is slightly oblique or irregular. It is very like the grain of wood that shows in a planed board.


An alloy containing 10% to 25% manganese. Is used in steelmaking as a deoxidizing agent and to raise the manganese content of the steel. Also called spiegel and psiegel iron.

spigot product

In ore dressing, the material discharged at the bottom of the hydraulic classifier.

spike amygdule

A cylindrical amygdule whose longer axis is at right angles to the bedding.

spike driver

In bituminous coal mining, one who drives a team of two or more draft animals in tandem for hauling wagons or cars of coal. Also called spike-team driver.

spike team

a. A team consisting of three draft animals, two of which are at the pole while the third pads.

b. Three mules, two abreast and one in the lead, used in a mine to haul coal cars.

spike-team driver

See: spike driver.


A term used in the United States for the operation of adding ferromanganese, silicomanganese, or other deoxidizing agent, to an open hearth bath for the immediate stoppage of all oxidizing reactions.


a. A large timber driven into the ground, used as a foundation; a pile.

b. A plank driven ahead of a tunnel face for roof support. Also called forepole. c. A temporary lagging driven ahead on levels in loose ground. See also: spill. d. A short piece of plank sharpened flatways and used for driving into watery strata as sheet piling to assist in checking the flow.


An ironstone miner who excavates and sets timber supports in roadways through wastes and disturbed ground.

Spilhaus-Miller sea sampler

An instrument resembling the bathythermograph and operating in a similar fashion, with the additional ability of obtaining water samples at discrete depths within the limit of operation. Basically, a bathythermograph to which 12 small seawater sampling bottles are attached, it performs the same functions as a cast of Nansen bottles and reversing thermometers to limited depths, but with less accuracy. It is useful for studies of shallow water areas, bays, and estuaries, where rapidity of sampling is of greater importance than the degree of accuracy of temperatures.


a. Forepoling over timber and steel supports in weak, loose beds. See also: spilling.

b. Driving timbers ahead of an advancing tunnel through treacherous, loose, watery ground.


An altered basalt, characteristically amygdaloidal or vesicular, in which the feldspar has been albitized and is typically accompanied by chlorite, calcite, epidote, chalcedony, prehnite, or other low-temperature hydrous crystallization products characteristic of a greenstone. Spilite often occurs as submarine lava flows and exhibits pillow structure. Adj: spilitic. The name was given by Brongniart in 1827.

spilitic suite

A group of altered extrusive and minor intrusive basaltic rocks that characteristically have a high albite content. The group is named for its type member, spilite.


Albitization of a basalt to form a spilite.


Any of the thick laths or poles driven ahead of the main timbering to support the roof or sides in advancing a level in loose ground, or to support the sides of a shaft when sinking through a stratum of loose ground. Syn: spile. See also: forepole.


Ore, pulp, circulating liquor inadvertently discharged from flow line and requiring appropriate means of recovery or removal. Syn: spillage.


See: spilla.

spillage conveyor

A small, short conveyor to lift coal out of a spillage pit and deliver it into a mine car or onto the main conveyor. It is usually a chain conveyor run either continuously or intermittently.

spillage pit

An opening below the loading point of a trunk or gate conveyor, to receive spillage. If the output is small, the pit may be emptied by hand once or twice in a shift, but if big tonnages are loaded, a spillage conveyor is installed.


(sharp-edged thick boards or steel rods) ahead and around timber or steel frames.

spill pit

See: runoff pit.

spill trough

A trough to retrieve melted brass that may be spilled in pouring from a crucible into a flask.


A rock representing an early stage in the formation of adinol or spotted slate. CF: adinole.


a. Shaft of a machine tool on which a cutter or grinding wheel may be mounted.

b. Metal shaft to which a mounted wheel is cemented. c. In founding, a rod or pipe used in forming a core.

spindle conveyor

A chain-on-end conveyor in which the chain pins are extended in a vertical plane, usually of enlarged diameter in that portion above the chain, on which special revolvable fixtures can be rotated, for the purpose of spraying or drying. Outboard rollers or sliding shoes support the chain and product.

spindle speed

a. Same as bit rotational speed.

b. The number of times the drive rod of a gear-feed-drill swivel head must turn to advance the attached drill string 1 in (2.54 cm).

spindle stage

A graduated horizontal rotation axis attached to a microscope stage for observation and measurement of optical properties of small crystals. CF: goniometer; universal stage.


a. An isometric mineral, MgAl (sub 2) O (sub 4) ; crystallizes as octahedra; colorless to pale tints; Mohs hardness, 7.5 to 8; in high-temperature metamorphic rocks, contact metamorphosed limestones, serpentinites, and ultramafic rocks; may be of gem quality.

b. The spinel series gahnite, galaxite, hercynite, and spinel. c. The mineral group brunogeierite, chromite, cochromite, coulsonite, cuprospinel, franklinite, gahnite, galaxite, hercynite, jacobsite, magnesiochromite, magnesioferrite, magnetite, manganochromite, nichromite, ringwoodite, spinel, trevorite, ulvoespinel, and vuorelainenite. d. Minerals with the spinel structure, such as the linnaeite group. e. A synthetic crystal with spinel structure that is used as a gemstone, a refractory, or for instrument bearings; e.g., ferrospinel. Also spelled spinelle; spinell; spinelite. See also: magnesium aluminate.

spinel emery

A mixture of spinel, corundum, and magnetite, the corundum being present in variable proportions. It is a heavy, black, fine-grained aggregate. Dark gray crystals of corundum appear in the best varieties.


See: spinel.


A medium- to coarse-grained hypidiomorphic-granular titaniferous magnetite-rich igneous rock with spinel from a few percent to 20%.

spinifex texture

Interpenetrating lacy elongate olivine crystals in komatiite, commonly considered to have been formed by quenching. Their disposition resembles the intermesh of an Australian grass for which the texture is named.

spinning cable

A flexible wire or plant-fiber cable or rope used as a spinning chain. See also: spinning chain.

spinning chain

Link chain wrapped several times around drill rod, casing, or pipe and used on the drum to spin up or spin out such equipment when it is being pulled or run into a borehole. A rope or flexible wire cable may be used in lieu of a chain.

spinning fiber

Asbestos suitable for the spinning of asbestos fabrics.

spinning rope

A plant-fiber rope used for the same purpose as a spinning chain. See also: spinning chain.

spin out

To unscrew lengths of drill rod casing, or pipe by mechanical means, using a spinning chain, rope, or cable in conjunction with power derived from the cathead or other rotating device.

S-P interval

In earthquake seismology, the time interval between the first arrivals of transverse (S) and longitudinal (P) waves, which is proportional to the distance from the earthquake source.


Screen coated with zinc sulfide or other fluorescing substance, on which scintillations are observable when bombarded by radioactive rays.

spin up

To screw lengths of drill rod, casing, or pipe together by mechanical means by using a spinning chain, cable, or rope in conjunction with power derived from the cathead or other rotating device.


a. A spiral coal chute that mechanically separates the slate from the coal. The lighter, irregularly-shaped coal falls over the edge of the spiral while the flatter and heavier slate adheres somewhat to the chute surface and is carried down to a special pocket.

b. The Humphrey's spiral is successfully used in recovering chromite from chrome; sands, rutile, ilmenite, and zircon from beach sands (Florida): and tantalum minerals and lepidolite from crushed ores. Also used in concentrating some iron ores and coal. See also: Humphrey's spiral.

spiralarm methanometer

An instrument that depends on the heat output of burning methane for its action. There are two varieties: those having a controlled flame burning within them and those in which combustion of the methane occurs on electrically heated filaments. A combustible gas alarm making use of the flame principle is the Naylor Spiralarm.

spiral classifier

See: Akins' classifier.

spiral cleaner

A device for removing dirt from a conveyor belt.

spiral coal cleaner

A spiral chute in which the plate is inclined towards the center of the spiral. The stone tends to flow down centrally, the coal tends to slide off around the outside of the spiral. They are seldom used as coal cleaners.

spiral concentrator

A sluice formed in five or six tight spirals, in which centrifugal force aids the separating effect of sluice action. See also: Humphrey's spiral.

spiral conveyor

See: screw conveyor.

spiral core

A piece of core the outside surface of which is rifled. See also: rifle.

spiral curve

a. A curve of gradually increasing radius that allows an easy transition between a circular arc and a straight on a road or railway.

b. In railroad or highway surveying, a curve of progessively decreasing (or increasing) radius used in joining a tangent with a simple circular curve or in joining two circular curves of different radii. Syn: transition curve.

spiral grooving

See: rifling.

spiral gummer

A screw device, attached to a longwall coal cutter, for removing the holings and depositing them either in the track of the machine or at the side clear of the face. It is designed in two types: end discharge and side discharge.

spiral hole

A borehole that follows a corkscrewlike course. CF: rifle.


a. Rifling.

b. A drill hole twisting into a spiral around its intended centerline.

spiral level

A section of convex glass tube containing fluid and an air bubble. When level, the air bubble centers itself on an etched line on the tube.

spiral system

In open pit mining, a haul road arranged spirally along the perimeter walls of the pit so that gradient of road is more or less uniform from the bottom to the top of the pit.

spiral track

A track layout for rail or road transport from large opencast pits. The track is arranged spirally along the steep rise from the coal or ore benches so that the gradient is moderate throughout.

Spiral Vane Disk Cutter

Trade name for a cutter loader incorporating a special variety of shearer head. The Mark II model consists of section plates welded together to form a composite whole spiral. The disk is made in different sizes to give cutting diameters of from 31 to 72 in (79 to 183 cm) with a maximum web depth of 30 in (76 cm). A single spiral is used for softer coals and a double spiral for hard coals. A plow attached to the machine throws the coal onto the conveyor.

spiral worm

A device to withdraw broken rods from a borehole. It is lowered down the hole and the screw is turned around until it grips the broken rod below the joint. See also: wad hook; wad coil.


A kind of fuse. The tube carrying a train to the charge in a blasthole. Also called reed or rush, because these, as well as spires of grass, are used for the purpose. See also: reed.

Spirelmo smoke helmet

A helmet in which the crown and frontpiece are blocked out of rawhide, and the front shield is fitted with two mica windows in hinged aluminum frames. It has a twin-tubed air feed on each side of the helmet and a valve for the escape of excess and vitiated air. Air is supplied through an armored hose from double-acting bellows or a blower worked by a second person at the fresh air base. Airtightness is obtained by means of a soft leather apron secured in position about the neck and shoulders. Illumination is provided by portable electric lamps, and communication with the wearer by an approved type of mine telephone.

spirit of copper

Acetic acid obtained by distilling copper acetate.

spirits of niter

a. Nitric acid.

b. A solution of ethyl nitrite in alcohol.

spirits of sulfur

Sulfurous acid.

spirits of verdigris

Acetic acid.

spirits of vinegar

Dilute acetic acid.

spirits of wine

Ethyl alcohol.

spirits of wood

Methyl alcohol.


A monoclinic mineral, (Mn,Zn) (sub 2) Te (sub 3) O (sub 8) ; red to purple.

spitted fuse

Slow-burning fuse that has been cut open at the lighting end for ease of ignition. A small quantity of the plastic explosive used in the hole is sometimes inserted in the cut.


a. Lighting the fuse for a blast.

b. An action of or appearance on the surface of slowly cooled, large masses of melted silver or platinum, in which the crust is forcibly perforated by jets of oxygen, often carrying with them drops of molten metal. Also called sprouting.

spitting rock

A rock mass under stress that ejects small fragments with considerable velocity on breaking.


A series of hopper-shaped or pointed boxes for separating mineral-bearing slimes according to fineness, in which the width of each box is double that of its predecessor, while the lengths increase by arithmetical progression. As used in flotation, it is the froth-separating compartment of mechanical-agitation-type flotation machines. Also called spitz. See also: funnel box.


Hydraulic classifiers shaped like the spitzkasten, but having provision for pressure water to flow upward from near the apex, thus improving efficiency of separation.


a. A plate lined with firebrick and placed over the iron trough next to the taphole to keep down flame that blows from the taphole during a cast.

b. A water spray system for the protection of the metal structure immediately above the tapping hole during the tapping of a blast furnace.

splash man

A laborer who shovels charcoal over the surface of molten copper being poured from a reverberatory furnace into a tilting ladle to prevent excess oxidation of metal.


One of a series of divergent small faults at the extremities of a major fault. Splays are typically associated with rifts.

splay faulting

Minor faulting that diverges from a longer dislocation at an acute angle.


Applied to the degree of luster of a mineral, reflecting with brilliancy and giving well-defined images, such as hematite or cassiterite.


a. A joint made in a broken haulage rope. Splicing is a skilled job and the rope ends are unlaid for a length on each side of the break and reformed to a definite pattern.

b. Generally used to designate an insulated reconnection of wires of an electric cable after it has been cut. c. To unite two ropes by interweaving the strands.

splice box

An enclosed connector permitting short sections of cable to be connected together to obtain a portable cable of the required length.


Said of a vein that pinches out and is overlapped by another parallel vein.

splint coal

A miner's term long used in Eastern United States and Scotland for certain hard dull coals with a distinctive type of fracture. Splint coals are irregular and blocky, with an uneven rough fracture, grayish black in color and of granular texture. Splint coals are banded coals. Coals containing more than 5% of anthraxylon and more than 30% of opaque attritus determined by microscopic examination are classed as splint coal. The content of anthraxylon and opaque matter is determined perpendicular to the bedding across the entire thin section (2 to 3 cm in width). The opaque attrital portion of the splint coal may be intercalated with fine, hairlike streaks of anthraxylon. It occurs mainly as bands and benches in otherwise bright-banded coal and is wide-spread in bituminous coal seams. Corresponds either to duroclarite or, more frequently, to clarodurite according to the ratio of vitrinite and inertinite. May also correspond to vitrinertite.

splintery fracture

The property shown by certain minerals or rocks of breaking or fracturing into elongated fragments like splinters of wood.


a. To divide the air current into separate circuits to ventilate more than one section of the mine. CF: air split.

b. The workings ventilated by that branch. c. A bench separated by a considerable interval from the other benches of a coal bed. d. The upper or lower portion of a divided coal seam. e. To divide a pillar or post by driving one or more roads through it. f. A layer of coal which has separated from its parent seam. See also: split seam; ventilation; splitting. g. The process of dividing a core lengthwise, dividing a granular material into several representative parts for sending samples to several interested parties or reducing either core storage space or the quantity of material retained as a sample. h. The division of a bed of coal into two or more horizontal sections by intervening rock strata.

split-barrel sampler

A drive-type soil sampler with a split barrel; also a swivel-type double-tube core barrel, the inner tube of which is split. Syn: split-tube sampler.

split brilliant

A brilliant split apart at the base of its pyramidal forms, so as to make two gems.

split bushing

A bushing made in two pieces, for ease of insertion and removal.

split check

A system of leasing practiced at Cripple Creek, Colorado, whereby the miners and company divide the profits.

split coal

Coalbed separated by clay, shale, or sandstone parting that thickens so that both benches cannot be mined together.

split core

A core that has been split lengthwise into halves or quarters.

split core barrel

A type of core barrel which can be opened longitudinally to remove the core.

split inner-tube core barrel

A double-tube core barrel with the inner tube split lengthwise.

split lagging

Drum lagging made in two pieces to allow changing it without dismantling the drum.

split-ring core lifter

A hardened steel having an open slit, an outside taper, an inside or outside serrated surface. In its expanded state, it allows the core to pass through it freely, but when the drill string is lifted, the outside taper surface slides downward into the bevel of the bit or reaming shell, causing the ring to contract and grip tightly the core which it surrounds. Also called core catcher; core gripper; core lifter; ring lifter; split-ring lifter; spring lifter.

split-ring lifter

See: split-ring core lifter.

split rock

A rock possessing tabular structure, or which cleaves easily in the lines of lamination, and is consequently suitable for flagging and curbstones.


In mine ventilation, airways connected in parallel.

split seam

A coal seam that has separated into two or more layers which may, or may not, rejoin some distance away. Syn: coal split. See also: multiple splitting.

split shovel

A device for sampling fine ore, consisting of a fork in which the prongs are separate scoops, each scoop being the same width as the open spaces between.

split spread

A type of seismic spread in which the shot point is at the center of the arrangement of geophones. It is commonly used for continuous profiling and for dip shooting. Syn: straddle spread; symmetric spread.

split sprocket

A two-piece sprocket that can be assembled on a shaft without removing the shaft bearings.

split system

a. A system of ventilation in which air is split along the airways or at the face. See also: natural splitting; controlled splitting.

b. Historically, a combination of warm air heating and radiator heating. Also used for other combinations, such as hot water steam, steam warm air, etc.

split the air

See: split.


a. Parting of a coalbed into two or more benches separated by other rocks.

b. In mine ventilation, the practice of connecting airways in parallel by dividing the total air flow among them. c. Abrasion of a rock fragment resulting in the production of two or three subequal parts or grains. d. The property or tendency of a stratified rock of separating along a plane or surface of parting. e. The sampling of a large mass of loose material (e.g., a sediment) by dividing it into two or more parts; e.g., quartering.

splitting knife

A knife used for splitting leather or for diamond cleaving.

splitting method

A method of mining pillars seldom followed. A room is first driven through the pillars, splitting them into smaller blocks. The pockets are turned at right angles and are driven into the blocks. This method is really gouging the pillars and is wasteful.

splitting of air

See: ventilation; splitting.

splitting shot

Arkansas. A shot put into a large mass of coal detached by a previous blast. See also: block hole.

split-tube barrel

See: soil sampler; split-barrel sampler.

split-tube sampler

See: soil sampler; split-barrel sampler. CF: solid-barrel sampler.


A monoclinic mineral, LiAlSi (sub 2) O (sub 6) ; pyroxene group; prismatic cleavage; in granite pegmatites in crystals up to scores of meters long (called logs); a source of lithium; may be of gem quality (lavender kunzite, green hiddenite). Formerly called triphane. Syn: lithia amethyst; lithia emerald.


Overburden, nonore, or other waste material removed in mining, quarrying, dredging, or excavating. See also: waste.

spoil bank

a. A term common in surface mining to designate the accumulation of overburden.

b. Underground refuse piled outside. c. That part of a mine from which coal has been removed and the space more or less filled up with waste. d. To leave coal and other minerals that are not marketable in a mine. See also: spoil heap.

spoil dam

An earthen dike forming a depression in which returns from a borehole can be collected and retained.

spoil heap

a. The pile of dirt produced by mining operations and stacked at the surface of a mine either in conical heaps or in layered deposits. Syn: dump; tip.

b. A pile of refuse material from an excavation or mining operation; e.g., a pile of dirt removed from, and stacked at the surface of, a mine in a conical heap or in layered deposits, such as a tip heap from a coal mine. See also: spoil bank.

spoil-heap fire

The spontaneous heating and burning of small coal, carbonaceous shale, and perhaps iron pyrites in spoil heaps.

spoil pile

See: waste dump.

spoil pool

The reservoir formed by a spoil dam in which the returns from a borehole collect and are retained. CF: sludge pit; sump.


a. See: cuttings.

b. The debris or waste material from a mine.


a. A form of metal characterized by a porous condition, which is the result of the decomposition or reduction of a compound without fusion. The term is applied to forms of iron, the platinum-group metals, titanium, and zirconium. Metal has appearance of a sponge due to high porosity.

b. Hafnium produced by the Kroll process.

sponge iron powder

Ground and sized sponge iron, which may have been purified or annealed or both.

sponge metal

A form of metal characterized by a porous condition, which is the result of the decomposition or reduction of a compound without fusion. Metal has the appearance of a sponge due to high porosity.


Said of a vesicular rock structure with thin partitions between the vesicles, thus resembling a sponge.

spongy iron

See: reduced iron.


Used to describe the driving potential that causes electric currents to circulate in boreholes. These currents are not in any way deliberately induced by the well-logging equipment. Also called self-potential; SP curve. See also: spontaneous potential curve.

spontaneous combustion

a. The heating and slow combustion of coal and coaly material initiated by the absorption of oxygen. The two main factors involved are (1) a coal of a suitable chemical and physical nature; and (2) sufficient broken coal and air leaking through it to supply the oxygen needed. The heat generated is retained with consequent rise in temperature. See also: gob fire; hydrogen sulfide; open fire; weathering of coal.

b. The outbreak of fire in combustible material that occurs without the direct application of a flame or a spark. It is usually caused by slow oxidation processes (such as atmospheric oxidation or bacterial fermentation) under conditions that do not permit the dissipation of heat. c. Ignition that can occur when certain materials such as tung oil are stored in bulk, resulting from the generation of heat, which cannot be readily dissipated; often heat is generated by microbial action. Also known as spontaneous ignition.

spontaneous polarization

a. Electrochemical reactions of certain orebodies causing spontaneous electrical potentials.

b. See: self-potential method; spontaneous potential method.

spontaneous potential curve

The electric log curve that records changes in natural potential along an uncased borehole. Small voltages are developed between mud filtrate and formation water of an invaded bed, and also across the shale-to-mud interface. These electrochemical components are augmented by an electrokinetic potential (streaming potential) developed when mud filtrate moves toward a formation region of lower fluid pressure through the mud cake. Where formation waters are less resistive (more saline) than drilling-mud filtrate, the spontaneous-potential curve deflects to the left from the shale baseline. First used about 1932, the curve was added to the resistivity log to make up the basic electric log of well-logging practive. Syn: SP curve; self-potential curve.

spontaneous-potential method

See: self-potential method.

spontaneous potential method

An electrical method in which a potential field caused by spontaneous electrochemical phenomena is measured. Syn: self-potential method; spontaneous polarization.


a. Cast iron distance piece placed between timbers.

b. To wind rope or cable on a hoist drum. c. The drum of a hoist. d. The movable part of a slide-type hydraulic valve. e. To wind in a winch cable.

spool-type roller conveyor

A type of roller conveyor in which the rolls are of conical or tapered shape with a diameter at the ends of roll larger than at the center.


A tool for cleaning dust or sludge from quarry blasting holes. Syn: scraper. See also: pneumatic blowpipe.


In bituminous coal mining, a laborer who scoops drillings out of boreholes in which explosives are to be charged for blasting down coal, using a slender iron rod with a cup-shaped projection bent at right angles to the handle.


Many mineral raw materials, such as petroleum, cementation water (water containing dissolved copper or iron sulfates or other metal compounds), or brine are extracted by pumping through boreholes. In spooning, a long spoon (a hollow cylinder with a bottom equipped with a clap valve, or ball valve, and open above) is attached to a cable that is let down into the boreholes where the cylinder fills with the liquid; this is emptied out after the cylinder is raised.

spoon proof

Test-ladle specimen taken during various stages of melting and fining.

spoon sampler

A rotating soil sampler, fitted with an auger-type cutting shoe.


Part of the reproduction organs of many coal measures' plants. There are two kinds, namely, megaspores (female) and microspores (male). They are found in most coal seams, particularly the dull layers. Megaspores vary from 1 to 5 mm in size, and microspores (or pollen grains) from about 0.01 to 0.1 mm.

spore coal

a. Coal in which the attritus contains a large amount of spore matter along with transparent attritus. See also: cannel coal.

b. Coal formed out of the spores of lycopods.


A maceral of the exinite group consisting of spore exines generally much flattened parallel to stratification. CF: cutinite. See also: resinite.

sporinite coal

This type of coal consists of more than 50% of spores (microspores and megaspores). Other structured components uniformly distributed through the coal are cuticles, resin bodies, and gelified and fusinized tissues. Hand specimens of low rank sporinite coal are brownish, with matt or granular surfaces. The coal may have high or low ash and occurs in seams of different geological, age but is particularly common as bands of limited thickness in seams of the Lower Carboniferous. Sporinite coal naturally admixed with medium rank gelitocollinite coals is used for coking.


A colloidal form of aluminum hydroxide, Al (sub 2) O (sub 3) .H (sub 2) O , occurring as one of the constituents of bauxite. Also called cliachite; alumogel. Syn: diasporogelite.


a. To mark the site at which a borehole is to be drilled, a piece of equipment placed, or a structure built.

b. To set a drill or piece of machinery at a preselected site. c. An inclusion in a diamond. d. To direct to the exact loading or dumping place.


The use of one or just a few roof bolts at spot locations.

spot cooler

Low capacity, semiportable refrigeration unit of 150,000 to 500,000 Btu/h (44 to 146.5 kW) cooling capacity that is used in cooling sites of limited extent, such as an underground enginehouse or the face of a development end. The refrigerant used is nontoxic, and an electric or compressed-air drive is applied to a reciprocating compressor.

spot level

The reduced level of any survey point.

spot log

A log or marker placed to show a truck driver the spot to stop to be loaded.

spotted schist

See: spotted slate.

spotted slate

A slaty or schistose argillaceous rock whose spotted appearance is the result of incipient growth of porphyroblasts in response to contact metamorphism of low to medium intensity. CF: desmosite; spilosite; adinole. See also: fleckschiefer; fruchtschiefer; garbenschiefer; maculose. Syn: spotted schist; knotted schist; knotted slate.


a. In truck usage, the person who directs the driver into loading or dumping position.

b. In a pile driver, the horizontal connection between the machinery deck and the lead (pile guide). c. See: car pincher.

spot tests

Simple and speedy qualitative tests used to identify minerals species when prospecting, valuing a deposit, or testing mill products.

spotting hoist

A small haulage engine used for bringing mine cars into the correct position under a loading chute, feeder or other point. See also: pickrose hoist.

spotty ore

Ore in which the valuable material is concentrated irregularly as small particles; e.g., coarse gold in low-grade rocks.

spout delivery pump

A pump, similar to a diaphragm pump, that is not capable of delivering water above its own height. See also: force pump.


Person who directs the pouring of slag from a ladle through a spout into a reverberatory furnace used for smelting.


a. A short wooden prop set in a slanting position for supporting the coal during the operation of holding.

b. To chock or stop, as a vehicle or wheel, by a sprag; prop. See also: spur. c. The horizontal member of a square act of timbers running parallel to the axis of a heading. d. See: rod spear; stell.


In anthracite and bituminous coal mining, a laborer who rides trains of cars and controls their free movement down gently sloping inclines by throwing switches and by poking sprags (short, stout, metal or wooden rods) between the wheel spokes to stop them.


The act of checking a mine car with a sprag.

sprag road

A mine road having such a sharp grade that sprags are needed to control the descent of a car; hence, two-, three-, or four-sprag road. See also: sprag.


In a hydrocyclone, the discharge from the apex in spray form, showing that the cyclone is not overloaded.

spraying machine

A machine that applies a spray under pressure on mine timber supports to preserve and fireproof them. It may also be used for limewashing and water spraying of dust. The machine is mounted on wheels and operated by compressed air.

spraying screen

A screen used for the removal, by spraying, of fine solids present among or adhering to larger particles.


Appliances to damp deposits of dust in tunnels and workings before and after shotfiring and loading operations. Water sprays are also used along dusty roadways. Various types of mist projectors and atomizers are used and effect considerable improvement, but the dust trapped consists chiefly of the coarser particles. In many dusty mines, a water pipe system extends throughout the workings and sprays are employed at all loading and other dusty points. Sprays are also used to suppress dust at coal and ore processing plants. See also: whale-type jib.

spray water

See: rinsing water.


a. The area covered at a given thickness by a given quantity of such materials as chippings or road binder.

b. The surface in proportion to the depth of a stone. c. The surface or width at the girdle in proportion to the depth of a cut stone, such as a diamond. d. The layout of geophone groups from which data from a single shot are recorded simultaneously. Syn: seismometer spread; seismic spread.


a. A horizontal timber below the cap of a set, to stiffen the legs and to support the brattice when there are two air courses in the same gangway.

b. A piece of timber stretched across a shaft as a temporary support of the walls. c. A tool used in sharpening machine drill bits. d. A strut in a tunnel or heading timber sets. e. A machine which spreads dumped material with its blades.

spreader chains

Chains joining the end of the tail chain to ends of the spreader.

spreader operator

See: tripper man.

spread recorder

An instrument used in bridge testing to measure any outward spread of an abutment under load. See also: rotation recorder.


a. To enlarge the bottom of a drill hole by small charges of a high explosive in order to make room for the full charge; to chamber a drill hole. See also: camouflet.

b. To chamber. See also: chamber. c. A general name for any natural discharge of hot or cold pure or mineralized water.

spring auxillary cylinder

A heavy tension spring, enclosed in a cylinder, which is connected to the panline of certain types of shaker conveyors to keep the conveyor in tension. It is attached to the conveyor by a driving chain and to a prop by a fixing chain. Keeping the conveyor in tension, it is claimed, will save the conveyor connections and increase the output.

spring constant

Force that produces a unit elongation of the spring used in geophysical instruments.

spring core lifter

See: core lifter.

spring dart

a. A tool used to retrieve lost boring gear.

b. A device to withdraw the steel casing from a borehole when finished. The casing is cut into convenient lengths and then the spring dart is lowered to bring up each length separately. The dart springs open immediately when it meets a cut or recess in the casing, which length it then grips and lifts to the surface.


a. A quarry blasting method in which a succession of charges is fired in a borehole to open up a chamber.

b. Enlarging the bottom of a drill hole by exploding a small charge in it. c. In certain types of rock, large quantities of stone can be blasted down by the method known as springing the shothole. The technique requires that the rock contains well-defined bedding or jointing planes, such as are found in most sedimentary and some igneous rocks, particularly granite. The principle of springing is to drill a borehole with a heavy burden and then explode a succession of gradually increasing charges of black powder so that the bedding planes or joints are opened up to permit the placing of a large final charge. Syn: bullying; overspringing.

springing a hole

See: springing.

spring lifter

See: core lifter.

spring line

The meeting of the roof arch and the sides of a tunnel.


Held in contact or engagement by springs.

spring-roll crusher

A crushing machine similar to the double-roll crusher with the difference that springs are fixed to the bearings of one roll.

spring rolls

Crushing rolls used in ore breaking. Two parallel cylinders, mounted horizontally, are held apart by shims, and pressed together by powerful springs. Crushable rocks falling between them are drawn down as the cylinders revolve, but unbreakable material causes the springs to yield and let it pass without damage.

spring washer

A washer consisting of a steel ring cut through and bent into helical form, which prevents a nut from unscrewing.


An act of spraying water into the atmosphere and on coal surfaces to allay coal dust.


A gear that meshes with a chain or crawler track.

sprocket gear

A gear that meshes with a roller or silent chain.

sprue hole

A pouring hole in a mold; a gate.


a. To break ground with a drilling rig at the start of well-drilling operations. Syn: spud-in. See also: spad.

b. To bore, as the first 50 ft (15 m) of an oil well, by the use of a bull wheel. c. To commence drilling operations by making a hole. d. To begin the drilling of a borehole with a spud or diamond-point bit. e. An offset type of fishing tool used to clear a space around tools stuck in a borehole. f. A cabletool drill bit. g. An anchorage during dredging provided by a steel post underneath a dredger that can be lowered by a toothed rack or by ropes until it is secured in the seabed, riverbed, or dredge pond.

spud bit

a. A mud or diamond-point bit used to drill through overburden or soil down to bedrock.

b. A broad, dull, chisel-face drilling tool for working in earth down to rock with a churn or cabletool drill.


A term applied to a borehole that has been started and the hole has reached bedrock and/or the standpipe has been set.


a. A churn drill, churn-drill operator, or the special bit used to begin a borehole by rotary, diamond, or churn drills.

b. A colloquialism for a small drilling-rig.

spudder drill

See: churn drill.


a. The operation, in rope drilling, of boring through the subsoil at the start of a hole.

b. In diamond and/or rotary drilling, a general term applied to drilling through overburden with a fishtail bit, drag bit, or diamond-point bit. c. Sinking a conductor, standpipe, or casing with a churn- or cable-type drill rig.

spudding bit

a. A broad dull drilling tool for working in earth down to the rock.

b. A heavy chisel bit used in percussive drilling to drill through subsoil. c. See: spud bit. d. The bit used to start the hole. When the hole is deep enough, regular drilling tools are substituted.

spudding boreholes

The working of a cable drill up and down on a short length of rope, when passing through the superficial deposits down to bedrock. This section of hole is cased.

spudding drill

A drill that makes a hole by lifting and dropping a chisel bit. Syn: churn drill.

spudding driller

In petroleum production industry, one who uses a lightweight, portable drilling rig (spudder) for the drilling of shallow wells, or a regular cable drilling rig to drill the first few feet of a well. Also called spudder or spud driller. Syn: spud driller.

spudding drum

In a churn drill, the winch that controls the drilling line.

spudding tool

Tool used to begin a borehole in earthy materials with a diamond or rotary drill; also, a drilling tool used by a cable tool or churn drill.

spud drill

See: churn drill.

spud driller

See: spudding driller.


See: spud.


On a dredge, steel tubes pointed at the bottom and provided with lifting tackle at the top that are used to hold and to move the dredge.

spud setter

A mine surveyor. See also: spud.

spud well

On a dredge, a pair of guide collars for a spud.


a. A brace or prop. See also: sprag.

b. A small vein branching from a main one. c. A rock ridge projecting from a sidewall after inadequate blasting. d. A relatively short and small vein of quartz that cuts across the bedding, in contrast to a saddle reef that more or less follows the bedding.

spur-end facet

See: triangular facet.


A monoclinic mineral, Ca (sub 5) (SiO (sub 4) ) (sub 2) (CO (sub 3) ) ; dimorphous with paraspurrite; forms light gray granular masses resembling limestone; at Velardena, Durango, Mexico; Scawt Hill, Ireland; Luna County, NM; and Crestmore, CA.


Forest of Dean. A disintegrated stone.

spur track

In railroading, a short sidetrack connecting with the main track at one end only.

spur valley

A short branch valley.