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

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a. To trim rough blocks of stone with a pick or broad chisel; used by quarrymen. See also: scabble.

b. A person who works at a mine contrary to union orders or during a strike. c. A defect consisting of a flat volume of metal jointed to a casting through a small area. It is usually set in a depression, a flat side being separated from the metal of the casting proper by a thin layer of sand. d. A fault in the base metal for vitreous enameling; the scab is a partially detached piece of metal (which may subsequently have been rolled into the metal surface) and is liable to cause faults in the applied enamel coating.


To dress (as stone) in any way short of fine tooling or rubbing. CF: scab.


In quarry industry, one who roughs stone slabs in blocks with a scabbling pick to produce a uniform rectangular shape and to reduce shipping weight.

scabbling hammer

A hammer with two pointed ends for picking the stone after the spalling hammer.


a. A deliquescent cubic mineral, MnCl (sub 2) .

b. A name applied to various minerals, including monticellite, a doubtful selenide of lead, and a brick-red powdery fluoride containing rare earths.


A name occasionally applied to a nugget, as of gold.

Scaife process

A modified Ugine-Sejournet process for hot extrusion of steel and other metals. The basic difference between the original Sejournet extrusion process and the Scaife modification is one of direction. In the Sejournet, the billet is forced forward through the die with the mandrel projecting through the die to maintain internal shape. In the modified process, the billet is forced into the closed die and the ram pressure squeezes it back over the mandrel. Both are based on the use of molten glass as a lubricant.


A quantity fully described by a number, such as a speed that has no associated direction. See also: vector.


a. The ratio between linear distance on a map, chart, globe, model, or photograph and the corresponding distance on the surface being mapped. It may be expressed in the form either of a direct or verbal statement using different units (e.g., 1/24,000 or 1:24,000, indicating that one unit on the map represents 24,000 identical units on the ground) or a graphic measure (such as a bar or line marked off in feet, miles, or kilometers).

b. Loose, thin fragments of rock, threatening to break or fall from the roof or wall of a mine. To remove such fragments. c. Crude paraffin wax, obtained by filtering the cooled heavy distillation from petroleum or shale. d. A fault, in glass or vitreous enamelware, in the form of an embedded particle of metal oxide or carbon. e. Newc. A small portion of air abstracted from the main current. Also called scale of air, and sometimes spelled skail. f. To regulate the air current in a roadway. g. Used among English miners for carbonaceous shale interbedded with thin layers of coal. h. The flakes and rubble that fall in after the ore has been removed.

scale cleaner

In bituminous coal mining, one who scales off loose pieces of slate from the roof and walls of haulageways, using a pick or a bar. Also called slate handler.

scale copper

Copper in very thin flakes.

scaled distance

A factor relating similar blast effects from various size charges of the same explosive at various distances; it is computed by dividing the distance of concern by an exponential root of the explosive quantity detonated per delay.

scale door

A door that has an air regulator. Syn: regulator door.


A closed crystal form, each face of which is a scalene triangle; trigonal scalenohedra have 12 such faces; tetragonal have 8. Adjective: scalenohedral. See: dogtooth spar.

scale of hardness

See: hardness scale.


a. An electronic instrument for counting radiation-induced pulses from Geiger counters and other radiation detectors.

b. A laborer who knocks the roasted lead ore off grates with a bar as it is dumped from conveyors into cars below, prior to melting, to separate and recover the lead. Lead ore is loaded on grates attached to a conveyor and carried through a furnace in which the sulfur is driven off by roasting.


For weighing materials in transit, these include the track scale (carload lots) in which the load is checked by manual operation of weights; platform scales; automatic dump hoppers; conveying weighers that continuously record or register the weight of a portion of passing conveyor belt.


In plant design, calculations of required capacities, machine sizes, etc., from data obtained in batch and pilot testing.


a. The plucking down of loose stones or coal adhering to the solid face after a shot or a round of shots has been fired.

b. Removal of loose rocks from the roof or walls. Also called ramming. CF: exfoliation.

scaling bar

A long metal bar flattened on one end and used to remove loose material from a mine roof or rib. See also: bar.

scaling furnace

A furnace or oven in which plates of iron are heated for the purpose of scaling them, as in the preparation of plates for tinning.

scaling of the face

In mining, consists of the removal of loose overhanging rock.


a. Eng. Loose ground; foliated ground is frequently called scally ground by miners. Also spelled scal. Probably a variation of scale.

b. Rock easily broken up because of its scaly structure.


a. Eng. To cut or break off the sides of a heading without holing or using powder.

b. Eng. To get or hew coal off the face. c. One of a mosaic of small shallow intersecting hollows formed on the surface of soluble rock by turbulent dissolution. They are steeper on the upstream side, and smaller sizes are formed by faster-flowing water. Syn: flute; solution ripple.


a. The process of removing oversize lumps on a continuous basis from a stream of bulk material.

b. Removing large pieces of mine waste from run-of-mine coal, usually when passing over a screen, on way to the preparation plant.

scalped anticline

See: breached anticline.


Heavy screen shielding fine screen for separating differently sized particles.


a. The removal, by screen or grizzly, of undesirable fine material from broken ore, stone, or gravel.

b. A milling term for the removal of a mineral during closed-circuit grinding of the ore.

scalping screen

A coarse primary screen or grizzly; usually a vibrating grizzly.


Said of the texture of a mineral, esp. a mica, in which small plates break or flake off from the surface like scales.


Eng. Applied to freestone in thin layers, mixed with mica.

scamy post

N. of Eng. Soft, short, jointy freestone, thinly laminated and much mixed with mica.


A silvery-white metallic element that develops a slightly yellowish or pinkish cast upon exposure to air. Symbol, Sc. It occurs as a principal component in the rare mineral thortveitite; or is extracted as a by-product from uranium mill tailings. It is of interest for use in space missiles.

scanning electroprobe X-ray microanalyzer

An instrument for metallurgical research. It can create visual images of the minutest particles in metals and alloys by use of X-ray beams. Magnification is up to 3,000 times, and particles smaller than a millionth of an inch can be examined in detail.


A gage by which slates are assorted in sizes.


a. The dimensions of a stone in length, breadth, and thickness.

b. Stones more than 6 ft (2 m) long. c. A piece of timber of thickness from 2 to 4 in (5 to 10 cm) and of width from 2 to 4-1/2 in (5 to 11 cm). d. Small timber, such as 2 in by 3 in (5.1 cm by 7.6 cm), 2 in by 4 in (5.1 cm by 10.2 cm), etc., used for studding.


a. A mineral group, Na (sub 4) Al (sub 3) Si (sub 9) O (sub 24) Cl (marialite), to Ca (sub 4) Al (sub 6) Si (sub 6) O (sub 24) (CO (sub 3) ,SO (sub 4) ) (meionite); a tetragonal isomorphous series; occurs in calcium-rich metamorphic rocks or igneous rocks as the product of alteration of plagioclase feldspar.

b. Any mineral of the scapolite group, intermediate in composition between marialite and meionite (Ma:Me from 2:1 to 1:3), containing 46% to 54% silica, and resembling feldspar when massive, but having a higher density and a fibrous appearance. Intermediate compositions were formerly called dipyre and mizzonite for Ma- and Me-rich samples, respectively. Syn: wernerite.


Introduction of, or replacement by, scapolite. Plagioclase is commonly so replaced. The replacement may involve introduction of chlorine.


In founding, an imperfect spot in a casting.


A hexagonal mineral, Al (sub 5) (OH) (sub 13) (CO (sub 3) ).5H (sub 2) O ; compact; fine-grained; in vertical fissures in sandstone at South Bay, Scarborough; in sandstone at Yorkshire, England. Also spelled scarbroeite. Syn: tucanite.


A projecting ledge of rock, left in a shaft as footing for a ladder or to support pitwork.


a. Lenticular pockets of clean coal in sandstone, usually found in the region of a washout. Also called coal scares.

b. N. of Eng. Thin laminae of pyrite in coal.


a. A lapped joint made by beveling, notching, or otherwise cutting away the sides of two timbers at the ends, and bolting or strapping them together so as to form one continuous piece, usually without increased thickness. Also called scarf joint.

b. A piece of metal shaped or beveled for a scarf weld.


In the iron and steel industry, one who tends rolls through which skelp (steel strips for making pipe or tube) or steel sheet is run to bevel edges prior to its being formed into tube.


a. Splicing timbers, so cut that when joined the resulting piece is not thicker at the joint than elsewhere.

b. Tapering the ends of two pieces to be joined to avoid an enlarged joint. c. Cutting surface areas of metal objects, ordinarily by using a gas torch. The operation permits surface defects to be cut from ingots, billets, or the edges of plate that is to be beveled for butt welding.

scarf joint

a. A butt joint in which the plane of the joint is inclined with respect to the main axis of the members.

b. See: scarf.


A machine with downward projecting teeth for breaking hard soil at quarries and opencast pits. It may be self-propelled or attached to another vehicle. See also: rooter.


To roughen up, as a road, for repairs.


a. A line of cliffs produced by faulting or by erosion. The term is an abbreviated form of escarpment, and the two terms commonly have the same meaning, although scarp is more often applied to cliffs formed by faulting. See also: fault scarp.

b. A relatively straight, clifflike face or slope of considerable linear extent, breaking the general continuity of the land by separating surfaces lying at different levels, as along the margin of a plateau or mesa. A scarp may be of any height. The term should not be used for a slope of highly irregular outline. CF: cuesta.


The formation of scars or scaurs in roasting pyrite for sulfuric acid manufacture.


Deviation of portions of a radiation beam by scattering centers in the medium through which the beam passes. In ultrasonics, it occurs by reflection, refraction, or diffraction at any acoustical discontinuity comparable in size with, or larger than, the wave length used; in radiography, the scatter occurs by the Compton, photoelectric, and pair-production processes.

scatter pile

In underground mining, ore left adjacent to a longwall face to stop flying ore from being lost when blasting. A secondary use is to confine ventilation.


To pick up surplus fluid and return it to a circulating system.


a. Any chemical that is added to a system or a mixture to consume, or to convert to an inactive form, small quantities of impurities or undesired materials.

b. In flotation, a rougher cell in which the tailings, before being rejected as waste, are subjected to a scavenging flotation treatment. Concentrating tables are also used as scavenger machines. c. In metallurgical operations, an active metal added to combine with oxygen and/or nitrogen in the molten metal and so cause removal of impurities into slag. d. Oxygen, iodine, or more complex materials that, when added to a mixture, combine with free radicals in the mixture and permit the measurement of these radicals.

scavenger cells

Secondary cells for the retreatment of tailings.

scavenger mining

The removal of coal so close to the surface as to undermine the topsoil, resulting in devastation above ground. Usually engaged in by an independent operator working an old mine on a lease from a major corporation.


In mineral processing, final stage in flotation of mineralized froth before discard of tailing. The cells are so worked as to remove for retreatment as much low-grade rising mineral as possible under the given working conditions.


A monoclinic mineral, Ca (sub 7) Si (sub 6) (CO (sub 3) )O (sub 18) .2H (sub 2) O ; forms bundles of thin, colorless, tabular crystals at Scawt Hill, County Antrim, Ireland.

scepter quartz

Quartz crystals resembling a scepter in shape.


A tetragonal mineral, FeSb (sub 2) O (sub 4) ; red to reddish-brown.


A trigonal mineral, Na (sub 21) (SO (sub 4) ) (sub 7) F (sub 6) Cl ; colorless; at Searles Lake, CA. CF: galeite.


A trigonal mineral, (Mn,Fe) (sub 16) Si (sub 12) As (sub 3) O (sub 36) (OH) (sub 17) ; dimorphous with nelenite; reddish-brown.


An isometric mineral, AgBiS (sub 2) ; a high-temperature polymorph of matildite and member of the halite group; not recognized as a valid mineral species; occurs as acicular crystals, granular, or massive. See also: matildite.

schaum earth

Same as aphrite.


A tetragonal mineral, CaWO (sub 4) , with molybdenum replacing tungsten toward powellite CaMoO (sub 4) ; prismatic cleavage; sp gr, 5.9 to 6.1; varicolored, fluoresces bright blue; in limestone and pneumatolitic veins near granite contacts, granite pegmatites; a source of tungsten.


A whitish, gray; yellow, green, or pale reddish; brittle; tasteless; inodorous hydrocarbon; melts at 44 degrees C; soluble in alcohol and ether; may be distilled without decomposition, boiling at 92 degrees C. Syn: xylocryptite.


A mineral, (Na,Ca)(Fe,Mn)Si (sub 2) O (sub 6) ; brown to black; a variety of manganoan aegirine.


a. Fossil resin found in brown coal.

b. A former name for phoenicochroite.


Showing principles of construction or operation, without accurate mechanical representation.


a. A very rare, weakly radioactive, orthorhombic(?), black mineral, (Ca,Y,Sb,Mn) (sub 2) (Ti,Ta,Nb,W) (sub 2) O (sub 6) (O,OH) , found at Torvelona, Norway, in pegmatite with plagioclase, tourmaline, bismuth, euxenite, thortveitite, monazite, alvite, beryl, garnet, and magnetite. Small amounts of uranium may be present.

b. A name for an incompletely described possible member of the betafite subgroup of the pyrochlore group.

Schicht mixed-flow fan

In this fan, the blades are mounted on the curved portion of a dish-shaped rotor and are designed to impart dynamic energy but no pressure or static energy to the air, the dynamic energy being converted to pressure in the diffuser. The fan is suitable for water gauges up to 20 in (50.8 cm) and there is an absence of noise. It is useful where the resistance of the mine is known and not liable to alter materially.

schiefer spar

A variety of calcite occurring in very thin plates or scales.


A phenomenon related to sheen; an almost metallic iridescent shimmer or play of color seen just below the surface in certain varieties of pyroxene, feldspar, etc. Etymol: German. See also: adularescence; schillerization.


Enstatite or bronzite peridotite with poikilitic pyroxenes. Orthorhombic pyroxenes possess the poikilitic texture to a peculiar degree, and esp. when more or less altered to bastite, the term schiller is esp. applied to them.


The development of poikilitic texture by the formation of inclusions and cavities along particular crystal planes, largely by solution somewhat as are etch figures.

schiller obsidian

Obsidian with schiller effect.

schiller spar

An altered enstatite or bronzite, having approx. the composition of serpentine. Syn: bastite. Also spelled schillerspar.


A strongly foliated crystalline rock, formed by dynamic metamorphism, that can be readily split into thin flakes or slabs due to the well developed parallelism of more than 50% of the minerals present, particularly those of lamellar or elongate prismatic habit, e.g., mica and hornblende. The mineral composition is not an essential factor in its definition unless specif. included in the rock name, e.g., quartz-muscovite schist. Varieties may also be based on general composition, e.g., calc-silicate schist, amphibole schist; or on texture, e.g., spotted schist. See also: magnesian schist; pelitic schist. CF: paraschist.


Said of a rock displaying schistosity.


The foliation in schist or other coarse-grained, crystalline rock due to the parallel, planar arrangement of mineral grains of the platy, prismatic, or ellipsoidal types, usually mica. It is considered by some to be a type of cleavage. Adj: schistose.


A light-red variety of manganoan pectolite. See: pectolite.


a. Tabular bodies, generally a few inches to tens of feet long, that occur in plutonic rocks. They have the same general mineralogy as the rocks, but because of differences in mineral ratios, they are darker or lighter; the boundaries with the plutonic rock tend to be transitional. Some schlieren are modified inclusions, others may be segregations of minerals. Etymol: German. Sing: schliere. Also spelled schliere. Adj: schlieric. CF: flow layer.

b. Regions of different density in fluid, esp. as shown by special apparatus. c. A method or apparatus for visualizing or photographing regions of varying density in a field of flow.

Schmidt apparatus

Apparatus used to determine the position of rest of a freely swinging shaft plumbline.

Schmidt-type magnetic field balance

This has been the most commonly used magnetic instrument for prospecting on land. It consists of a magnet pivoted near but not at its center of mass, so that the magnetic field of the earth creates a torque around the pivot that is opposed by the torque of the gravitational pull upon the center. The angle at which equilibrium is reached depends on the strength of the field. Readings are taken through an eyepiece by comparing a scale reflected from a mirror on the magnetic element with a fixed scale. The balance may be either the horizontal or vertical type.


A monoclinic mineral, Cu (sub 2) Pb (sub 2) (SeO (sub 3) )(SeO (sub 4) )(OH) (sub 4) ; light blue; at La Rioja, Argentina. Also spelled schmeiderite.

Schneider furnace

A distillation furnace for the reduction of zinc ores containing lead, with a recovery of the latter metal as well as the zinc.


A monoclinic mineral, Al (sub 2) (PO (sub 4) )(VO (sub 4) ).8H (sub 2) O ; yellow-orange.


The mineral group burtite, natanite, schoenfliesite, vismirnovite, and wickmanite.


An orthorhombic mineral, UO (sub 3) .2H (sub 2) O ; strongly radioactive; perfect cleavage; yellow; an alteration product of uraninite or ianthinite. Formerly called schoepite I. Syn: epiianthinite. See also: metaschoepite; paraschoepite.

Scholl's method

A method for determining the uranium in any of its ores in which the uranium is extracted with dilute nitric acid. This extract is then diluted, filtered, and treated with ferric chloride and sodium carbonate causing the vanadium iron and aluminum to precipitate. The uranium is then precipitated from the filtrate by boiling with caustic soda and purified by solution in nitric acid. Following precipitating with ammonia, the ammonium uranate is ignited to the oxide, and weighed. When this weight is multiplied by the factor 0.847, it gives the weight of uranium.


An orthorhombic mineral, CaZn (sub 2) (PO (sub 4) ) (sub 2) .2H (sub 2) O; dimorphous with parascholzite; colorless to white.

Schone's apparatus

An elutriator consisting of a tall glass vessel tapering toward the bottom, where water enters at a constant rate. Schone's formula is: V = 104.7 (S#MN1) (super 1.57) D (super 1.57) where V is the velocity of water (millimeter/second) required to carry away particles of diameter D and specific gravity, S.


a. A black variety of tourmaline.

b. A discontinued term for schorl.


An isometric mineral, Ca (sub 3) Ti (sub 2) (Fe (sub 2) Si)O (sub 12) , with Ti decreasing toward andradite in the garnet group.

schorl rock

A term used in Cornwall, England, for a granular rock composed essentially of aggregates of needlelike crystals of black tourmaline (schorl) associated with quartz, and resulting from the complete tourmalinization of granite.

Schottky defect

a. An atomic vacancy.

b. A point defect in a crystal structure where an atom is missing from a correct site. Syn: vacancy. CF: point defect; Frenkel defect. c. A defect in anionic crystal in which a single ion is removed from its interior lattice site and relocated in a lattice site at the surface of the crystal. d. A defect in anionic crystal consisting of the smallest number of positive-ion vacancies and negative-ion vacancies that leave the crystal electrically neutral.

Schramhobel cutter plow

See: cutter plow.


A tetragonal mineral, (Fe,Ni) (sub 3) P ; highly magnetic; contains small amounts of cobalt and traces of copper and tarnishes to brass yellow or brown. Schreibersite occurs in tables or plates as oriented inclusions in iron meteorites. Syn: rhabdite.


A triclinic mineral, NaCa (sub 3) (UO (sub 2) )(CO (sub 3) ) (sub 3) (SO (sub 4) )F.10H (sub 2) O; radioactive; soft; greenish-yellow color and fluorescence; an alteration product of uraninite; a source of uranium. Also spelled schroeckingerite. Syn: dakeite.


An opaline variety of allophane rich in aluminum. Material at the type locality is a mixture of glassy hyalophane and earthy variscite.


A name for interlayered Ni-rich vermiculites and chlorites.


A hexagonal mineral, Hg (sub 3) (SO (sub 4) )O (sub 2) ; yellow.


An orthorhombic mineral, PbCu(Nd,Gd,Sm,Y)(CO (sub 3) ) (sub 3) (OH).1.5H (sub 2) O ; light blue.


A monoclinic mineral, PbHAsO (sub 4) ; forms colorless thin crystalline plates; resembles selenite; at Tsumeb, Namibia.

Schulze elutriator

The original type of water elutriator; it has since been improved.

Schulze-Hardy rule

This states that the ion that causes a soluble to coagulate is opposite in sign to the electric charge of the colloidal particle; further, the coagulating power increases with the valency of the ion.

Schulz's theory

A mine subsidence theory that distinguishes between the manner of fracture of shale and sandstone, holding that the former rock breaks along vertical lines irrespective of the angle of dip, and that the latter has a vertical fracture over a rise face and a fracture at right angles to the bed over a dip face. The theory predicts vertical lines of break in either rock for a level seam, and is, indeed, a compromise between the vertical theory and that of the normal.

Schumann plot

Integral plot in graphic representation of sizing analysis.


See: shungite.


A mercurian variety of tetrahedrite. Also spelled schwazite.

scientific alexandrite

A synthetic corundum colored by vanadium oxide to resemble true alexandrite in some of its optical characters.

scientific emerald

A synthetic beryl glass colored by chromic oxide to resemble true emerald in color.


See: scintillation counter.


A very small light flash excited in certain natural or synthetic crystals by radioactive rays or particles; the basic phenomenon of the scintillation counter in which the photoelectric effect of the scintillation flashes is amplified and measured to give a measure of intensity of radioactivity.

scintillation counter

A sensitive instrument for the location of radioactive ore, such as uranium, radium, and thorium. It uses a transparent crystal that gives off a minute flash of light when struck by a gamma ray, and a photomultiplier tube that produces an electrical impulse when the light from the crystal strikes it. The scintillation counter has advantages over the Geiger counter as it is more sensitive, more compact, and can distinguish between types of radiation. The instrument responds to gamma rays emitted from the minerals mentioned and charts their intensity. It is used in aerial geophysical prospecting and the resulting maps are used as a guide for a more detailed ground investigation. See also: coal-sensing probe.

scintillation probe

An electronic logging device consisting of a scintillation-type gamma-ray detecting unit built into a container small enough to be lowered into a borehole.


An instrument for measuring radioactivity, based on emission of light by certain crystals under impact of gamma rays.

scissor fault

A fault of dislocation, in which two beds are thrown so as to cross each other. CF: hinge fault; rotational fault.


Scot. Liable to break off in thin fragments, as the roof of a mine working.


An instrument for determining the degree of hardness of a mineral by ascertaining the pressure on a moving diamond point necessary to effect a scratch.

scleroscope hardness test

A test to determine the hardness of metals by measuring the rebound from them of a standard diamond-tipped hammer dropped from a given height. See also: Shore hardness test; Shore scleroscope.


A maceral of coal within the inertinite group, consisting of the sclerotia of fungi or of fungal spores characterized by a round or oval form and varying size.


The dross of metals.


A monoclinic mineral, CaAl (sub 2) Si (sub 3) O (sub 10) .3H (sub 2) O ; zeolite group; pseudotetragonal; fibrous to acicular; can show wormlike motion if heated; in cavities in basalt and hydrothermal veins.


A protecting cover or screen; protection; shelter. A metal cover and holder combined for holding a miner's candle, esp. for hanging on wooden timbers.


High-grade tin requiring little or no dressing.


Firebricks of a certain standard size.


a. Diesel- or battery-powered equipment with a scoop attachment for cleaning up loose material, for loading mine cars or trucks, and hauling supplies.

b. A large-sized shovel with a scoopshaped blade. c. Coal miner's shovel; also sometimes used to refer to scraper. d. See: scraper bucket. e. A device that gathers ore at feed end of ball mill and delivers it into the feed trunnion.


In bituminous coal mining, a laborer who places the cable-drawn scoop of a scraper loader in position for it to scrape up coal (blasted from the working face) as it is dragged by the hoisting engine to a point where the coal is dumped into mine cars.


Similar to a front end loader; a low-profile loader articulating in the center with a large bucket in front (usually five tons or more) that transports ore in an underground mine. The operator sits at sideway controls facing the loader and drives it in either direction as required. Usually used for loading ore cars, shuttle cars, or hauling directly to an ore pocket.


A rodlike or stemlike crystallite that terminates in brushes or plumes.


a. A bill run up by a collier in bad times for the necessaries of life.

b. See: task. c. To mark with scratches or furrows; e.g., rocks in certain localities were scored by glacial drift.


a. A bomb-size pyroclast that is irregular in form and generally very vesicular. In less restricted usage, a vesicular cindery crust on the surface of andesitic or basaltic lava, the vesicular nature of which is due to the escape of volcanic gases before solidification; it is usually heavier, darker, and more crystalline than pumice. The adj. form, scoriaceous, is usually applied to pyroclastic ejecta. Cinder is sometimes used synonymously. CF: pumice.

b. A local term for melted or partly melted rock surrounding burned-out coal beds in the Western United States. See also: clinker.


Said of the texture of a coarsely vesicular pyroclastic rock (e.g., scoria), usually of andesitic or basaltic composition, and coarser than a pumiceous rock. The walls of the vesicles may be either smooth or jagged. Also, said of a rock exhibiting such texture. Syn: scoriform; scorious. CF: vesicular.


The separation of gold or silver by heating it to a high temperature with a large amount of granulated lead and a little borax, in a scorifier. The gold or silver dissolves in the molten lead, which sinks to the bottom of the vessel, while the impurities form a slag with the lead oxide that is produced.


A bone ash or fireclay crucible somewhat larger than a cupel; used in assaying and in the metallurgical treatment of precious metals.


See: scoriaceous.


See: scoriaceous.


An orthorhombic mineral, FeAsO (sub 4) .2H (sub 2) O ; variscite group; colorless or pale-green to brown; in gossans, oxidized zones of metal veins, and around hot springs; a minor source of arsenic.

Scortecci process

A process for direct reduction of iron pyrites that depends on the dissociation of pyrites in the absence of air, and in the presence of carbon, with the formation of iron and carbon disulfide.


A monoclinic mineral, (Fe,Mg)Al (sub 2) (PO (sub 4) ) (sub 2) (OH) (sub 2); lazulite group; forms a series with lazulite; light blue.


a. A wooden stop-block or iron catch placed across or between the rails of underground roadways, to keep the cars from running loose, or to hold them when standing upon an inclined plane.

b. Leic. The lower lift of coal that is wedged up in driving a heading. c. To dress, as stone, with a pick or picking tool.

scotch block

a. A wedge or block temporarily fitted to a running rail in order to hold (scotch) the wheel of a railway vehicle.

b. One form of gas port in an open-hearth steel furnace; the distinguishing feature is that it is monolithic, being made by ramming suitably graded refractory material around a metal template.


A method of dressing stones either with a pick or with pick-shaped chisels.

Scotch pebble

A rounded fragment of agate, carnelian, cairngorm, or other variety of quartz; found in gravels of parts of Scotland and used as a semiprecious stone.

Scotch pig

A very pure grade of pig iron.

Scotch topaz

Applied in the gem stone trade to yellow transparent quartzes resembling Brazilian topaz in color; used for ornamental purposes. See also: citrine. CF: topaz.


The erosion of the bed or bank of a river or of a seacoast by the action of flowing water and waves. See also: scour protection.

scour and fill

A process of alternate excavation and refilling of a channel, as by a stream or the tides; esp. such a process occurring in time of flood when the discharge and velocity of an aggrading stream are suddenly increased, causing the digging of new channels that become filled with sediment when the flood subsides. Syn: washout.

scouring cinder

A basic slag that attacks the lining of a shaft furnace.

scour protection

The protection of soil or other submerged material against scour, by the use of steel sheet pilings, revetment, riprap, or brushwood, or by combining any such methods as most suited to the site. See also: lining.


a. One who gathers information about the drilling rig of a rival company for the benefit of its employer. Also called snooper.

b. An engineer who makes a preliminary examination of promising oil and mining claims and prospects. c. One who goes into a potential area, esp. for oil or gas, to lease or option the land.

scout boring

Trial bores made to test formations of area being prospected.


In stoneworking, a quarryman whose function is to split off large portions of rock by means of a jump drill and wedges.

scout hole

A borehole penetrating only the uppermost part of an orebody with the intention of delineating its surface configuration. Also, a shallow hole drilled to scout for an indication of ore or to explore an area in a preliminary manner.

scout prospecting

Prospecting undertaken in new country in which the first step is to scout prospect rivers, streams, and creeks by washing gravel obtained from their beds.


Corn. A tin-bearing lode.


A former name for rhabdophane.


A device used to a limited extent to load solid blocks of coal. The scow proper is a flat steel plate that is moved underneath the undercut and blocks the coal by means of a hoist and a tail rope. The coal is then wedged down on the scow, and the solid block is hauled by means of the hoist and a headrope to a delivery point where it is transferred to cars.

scowl bowl

See: scowle.


Forest of Dean. Ancient ironstone quarry and mine workings. Syn: scowl bowl.


Hardpan; Isle of Man, U.K.


a. To search for and extract ore in a mine that is apparently worked out.

b. An Alabama term for a small soft-coal mine complete in itself.

scram drift

See: scram drive.

scram drive

a. Underground drive above the tramming level, along which ore is moved by scrapers (slushers) to a discharge chute.

b. See: scram drift.


a. Defective product not suitable for sale.

b. Discarded metallic material, from whatever source, which may be reclaimed through melting and refining. c. Som. Stone only fit for rough walling. d. See: diamond scrap.

scrap baler

In the iron and steel industry, one who presses, in a baling press, steel scrap into compact blocks, for remelting in the open-hearth furnace. Also called scrap builder; scrap pressman.

scrap bar

The uneven ends of the muck bars.

scrap-carbon process

Indian scrap-carbon process using 100% steel scrap in which petroleum coke replaces carbon and acid slag replaces silicon. The hearth is protected from erosion by spreading an easily fusible silica sand over the banks before charging, and manganese ore is used instead of iron ore for oxidizing the carbon.


a. A rod for cleaning out a shothole prior to charging with explosives. See also: stemmer; spoon.

b. A mechanical contrivance used at collieries to scrape the culm or slack along a trough to the place of deposit. c. A machine used in mines for loading cars and transporting ore or waste for short distances. There are two basic types of scraper: (1) the hoe or open type, which is particularly suitable for moving coarse, lumpy ore; and (2) the box or closed type, which is particularly suited for handling fine material, esp. on a loading slide. Syn: box scraper. d. A digging, hauling, and grading machine having a cutting edge, a carrying bowl, a movable front wall (apron), and a dumping or ejecting mechanism. Also called carrying scraper or pan. e. An apparatus used to take up coal from the floor of a mine, after it has been shot, and deposit it either in cars or in a conveyor. See: spoon. f. A rubber-tired device used to move earth in surface mining. g. See: carryall. h. See: poker man. i. The name applied to a bowl scraper or a multibucket excavator. Also known as a scraper excavator.

scraper and break detector

In Great Britain, every shot firer is provided with a scraper for cleaning out shotholes, and in safety lamp mines a break detector must also be provided. The two tools are combined in the scraper and break detector. It can clean out a shothole and detect breaks in the walls of 1/8 in (3 mm) or more in width. The firing of a shot in a hole traversed by a crack exceeding 1/8 in in width is forbidden.

scraper box plow

a. A layout of rope-drawn scraper boxes with knives on the face side. They are drawn to and fro, and pushed against the face by guides controlled by rams. A haulage of 250 hp (186 kW) must be installed in a semipermanent engineroom; it has a rope diameter of 1-1/4 in (3 cm) and a speed of 3 ft/s (1 m/s). No conveyor is required as the coal is scraped by boxes to the loading point. The maximum workable seam thickness is 20 in (51 cm) on gradients of 0 degrees to 30 degrees ; maximum length of face, 220 to 275 yd (200 to 250 m); and advance per shift, 6-1/2 to 8 ft (2.0 to 2.4 m).

b. See: Haarmann plow; Kema plow; Gusto scraper box.

scraper bucket

a. One of the excavating bowls or buckets that form part of a scraper.

b. In coal mines, the scraper bucket is a bottomless, three-sided box, with a hinged back. The hinge operates in a forward direction so that on the return journey on the coal face the back opens allowing the box to remain empty. On the loading journey, the coal closes the hinge and the material is drawn or scraped forward to the point of discharge. Syn: scoop. See also: scraper loader.

scraper chain conveyor

See: chain conveyor.

scraper conveyor

a. A mechanical device for conveying coal, rock, ashes, culm, etc., in a metal trough by means of scrapers attached to a rope or chain.

b. A conveyor consisting of chain-drawn scrapers or flights running in a trough through which they push the material to be transported. Also called drag-link conveyor; flight conveyor; chain conveyor.

scraper hoist

A power-driven hoist that operates a scraper to move material (rock or coal) to a loading point.

scraper loader

a. A machine used for loading coal or rock by pulling an open-bottomed scoop back and forth between the face and the loading point by means of ropes, sheaves, and a multiple drum hoist. The filled scoop is pulled on the bottom to an apron or ramp where the load is discharged onto a car or conveyor.

b. A combined scraper and transporting machine. Originally towed by a tractor, but now diesel-electric with a direct current motor in each wheel. c. A double-drum winch with two steel ropes. The loading capacity of a scraper loader ranges from 30 to 80 tons per hour depending on conditions. The loader is used for transporting and loading coal on longwall faces, for removing and loading stone in tunnels, and for stowing dirt on longwall faces. Syn: slusher. See also: loader.

scraper plow

One scraper box with picks, rope-drawn and unguided along the face. A 30-hp (22.4-kW) haulage advances with the face, which is made convex to eliminate the need for guides. Speed, 3 to 4 ft/s (approx. 1 m/s). Suitable seam conditions; thickness, 12 to 24 in (30 to 60 cm) at gradients of 0 degrees to 35 degrees (preferably 15 degrees to 25 degrees ); and maximum length of face, 65 yd (60 m). Syn: porte et gardin plow.

scraper ripper

Strip-mine equipment that breaks, loads, and hauls coal. Features include ripping teeth on the lip for breaking the coal and a flight conveyor for carrying the broken coal away from the lip. As the ripper teeth bite into and loosen the coal, the conveyor sweeps the loose coal upward and prevents buildup ahead of the lip.

scrap forgings

Forgings formed from wrought-iron scrap.

scrap hoist operator

In the iron and steel industry, one who operates a skip hoist to carry scrap material to the furnaces.

scrap mica

Mica that because of size, color, or quality is below specifications for sheet mica. Includes flake mica and the mica, except sheet, obtained from pegmatite mining as a sole product or as a byproduct, from the preparation of sheet mica, and from waste in fabricating sheet mica.

scrap picker

A person employed on the slag dump to pick out pieces of iron carried to the dump in slag ladles.

scrapping bottom coal

Lifting coal that has been left by an undercutting machine.

scrap sorter

In metallurgy, a laborer who sorts scrap metal and removes foreign matter preparatory to use in recasting.


A calcareous, earthy, or strong substance that separates from seawater in boiling it for salt. See: striation.

scratch pan

A pan in saltworks to receive the scratch.

screaming joint

A joint from which air leaks and makes a screaming noise. Compressed air escaping at a screaming joint or hole in an air hose can be the cause of a mine fire.


A sieve, screen, or strainer; a coal screen. See also: talus.

scree bars

Scot. Bars of which a scree is constructed. See also: scree.


a. A large sieve for grading or sizing coal, ore, rock, or aggregate. It consists of a suitably mounted surface of woven wire or of punched plate; it may be flat or cylindrical, horizontal or inclined, stationary, shaking, or vibratory, and either wet or dry operation. See also: Bradford breaker; shaking screen; stationary bar screen; vibratory screen.

b. A cloth brattice or curtain hung across a road in a mine to direct the ventilation. See also: brattice. c. A perforated sheet placed in the gating system of a mold to separate dirt from molten metal.

screen analysis

a. The size distribution of noncohering particles as determined by screening through a series of standard screens.

b. See: sieve analysis. c. The percentage of a sample retained on each size of a series of standard laboratory screens. d. Determination of the particle-size distribution of a soil, sediment, or ore by measuring the percentage of the particles that will pass through standard screens of various sizes. Syn: grading test.

screen box

A container in which diamond screens are inserted and in which the material (diamond particles) that passes through a sieve or screen collects and is retained.

screen chute

A discharge chute equipped with a screen section, either stationary or vibrating, to remove the finer portions of the material being handled from the major line of flow.

screen cloth

A woven medium suitable for use in a screen deck.

screen deck

A surface provided with apertures of specified size for carrying out the operation of screening.

screened coal

Coal that has passed over any kind of a screen and therefore consists of the marketable sizes.

screened lump lime

Lump lime after forking or screening to remove the finer portion. The portion removed is usually that which will pass a 1/2-in sieve.

screened trailing cable

A flexible cable provided with a protective screen or screens of tinned copper wire, or other conducting material, applied (1) to enclose each power core separately (individual screening), or (2) to enclose all the cores of the cable (collective screening).


a. The separation of solid materials of different sizes by causing one component to remain on a surface provided with apertures through which the other component passes.

b. Use of one or more screens (sieves) to separate particles into defined sizes. Also called sizing. See also: sieving.

screening machine

An apparatus having a shaking, oscillatory, or rotary motion, used for screening or sifting coal, stamped ores, and the like.


a. Fine coal that will pass through the smallest mesh screen normally loaded for commercial sale for industrial use.

b. The residue from a screening operation.

screenings crushing

A stage in bituminous coal crushing in which units for crushing screenings reduce secondary product to final small, commercial sizes, such as 1- to 3/8-in (2.5- to 1-cm) stoker coal or screenings.

screen iron ore

Accumulation of surface debris on the lower slopes of iron-bearing hills. The scree material may contain sufficient iron ore to make its mining an economic proposition as at Middleback Ranges of South Australia.

screen loading chute

A type of chute with a bar screen or grizzly bottom that permits fines to fall onto the conveyor belt first, providing a cushion for the large material that passes over the screen.

screen overflow

That portion of the feed material discharged from the screen deck without having passed through the apertures.

screen pipe

A perforated pipe lined with fine-mesh screen, set in portions of a borehole where the walls must be supported and the ingress of water or oil cannot be restricted. Also called well point.

screen plate

a. A metal plate with specific-sized openings used to control the fineness of grinding in dry pans and hammer mills.

b. A plate provided with apertures of specified size for use as a screen deck.

screen room

That part of a breaker where boys picked slate and bony.


Wire meshes with specific-sized openings for grading particles of various sizes. See also: vibrating screen.

screen size

A standard for determining the size of particles. The particles are passed through screens with openings of specified size. The size of the particles is determined by the size of the opening through which the particles will not pass.

screen sizing

Separating various-sized grain into portions, by a screen or sieve. Also called screening; sizing.

screen underflow

That portion of the feed material that has passed through the apertures in a screen deck.

scree plate

Scot. An iron plate at the foot of a screen on which screened coal is discharged.


a. The feed screw in the swivel head of a gear-feed diamond drill.

b. Syn. for an auger stem having helical webs. c. A combined symmetry operation involving rotation about an axis and a translation parallel to it. CF: space group. d. A crystal defect involving a dislocation about which layers of adatoms spiral during crystal growth. CF: Burgers vector.

screw bell

a. A device to withdraw broken rods from a borehole, when the fracture occurs below a joint. The screw bell is lowered to cut a thread on the end of the broken rod and thus secure a grip sufficient to withdraw it safely.

b. A fishing tool shaped like a bell, bell tap, or bell screw. c. See: bell screw; bell socket; bell tap.

screw conveyor

a. A conveyor screw revolving in a suitably shaped stationary trough, or casing fitted with hangers, trough ends, and other auxiliary accessories.

b. A conveyor in which a spiral blade presses material forward as it rotates in a suitable housing. Syn: tubular screw conveyor; spiral conveyor. See also: grit collector; vertical screw conveyor.

screw-down mechanism

That mechanism on a mill for lowering and raising the rolls to accommodate the distance between them to the requirements of the article being rolled.

screw elevators

Vertical screw elevators are used for handling pulverulent materials. A typical installation for delivering bulk cement into a plant consists of a screw feeder, which takes the cement from the bulk-cement car and feeds it to the screw elevator. Both these units are airtight and all joints are fitted with rubber gaskets that prevent the loss of cement and render the operation dustproof.

screw fan

See: axial-flow fan.


A system of gears, ratchets, and friction devices, or some combination of these parts, in the swivel head of a diamond drill, which controls the rate at which a bit is made to penetrate the rock formation being drilled. When controlled by a feed gear, the bit maintains the same penetration rate per revolution regardless of drill-stem revolutions per minute. Also called gear feed, mechanical feed.

screw feeder

An auger-type screw to transfer material from one piece of equipment to another.


See: jackscrew.

screw mixer

See: screw-type mixing conveyor.

screw pile

A wide helical blade fixed on a shaft and screwed into the ground by means of a winch or capstan.


See: hoisting plug.

screw shackle

A long cylindrical nut, threaded internally with a right-hand thread at one end and a left-hand thread at the other, used to connect and tighten together the ends of two rods forming a brace or tie.

screw-type mixing conveyor

A type of screw conveyor consisting of one or more conveyor screws, ribbon flight or cut flight, conveyor screws with or without auxiliary paddles. See also: blending conveyor; screw conveyor.


An instrument used by surveyors for marking posts, trees, etc.


a. Derb. Ironstone in irregular-shaped nodules.

b. Derb. A small subordinate vein. Also spelled skrin.


A helical projection on a drill rod or stem to remove cuttings from a hole.


S. Wales. Overlying strata loosened or broken by workings underneath. Probably a variation of scrunge, to squeeze.


a. Corn. A thin, sometimes calcareous or siliceous rock attached to the wall of a lode.

b. Corn. Loose ore at the point where a lode is disturbed by a cross vein.


a. Device in which coarse and sticky ore, clay, etc., is washed free of adherent material, or mildly disintegrated. The main forms are the wash-screen, wash trommel, log washer, and hydraulic jet or monitor. Scrubbers or scrubbing towers are also used to separate soluble gases with extracting liquids, or to remove dust from air by washing.

b. Device for separating environmentally noxious chemical substances from waste gas streams.


Eng. A provincial term for a variety of calciferous sandstone.


a. A mixture of tin oxide and iron-tin alloy formed as dross on a tin-coating bath.

b. See: scum.


See: self-contained self-rescuer.

scuffing grind

Tumbling of sands with sufficient violence to remove loosely adherent surface coatings without otherwise breaking down the particles to any great extent.


Incrustations of slag, dross, and metal on the contacting surfaces of vessels that treat or hold molten metals.


To break slate into slabs suitable for splitting. See also: hard way.


Fracturing the slate along the grain, e.g., across the cleavage.


a. Impure or extraneous matter that rises or collects at the surface of liquids, as vegetation on stagnant water, or dross on a bath of molten metal. Sometimes incorrectly used for the word froth in flotation.

b. A surface deposit sometimes formed on clay building bricks. The deposit may be of soluble salts present in the clay and carried to the surface of the bricks by water as it escapes during drying; it is then known as dryer scum. The deposit may also be formed during kiln firing, either from soluble salts in the clay or by reaction between the sulfur gases in the kiln atmosphere and minerals in the clay bricks; it is then known as kiln scum. Cf.: efflorescence. c. Undissolved batch constituents floating as a layer above the molten glass in a pot or tank furnace. d. Areas of poor gloss on a vitreous enamel; the fault may be due to action of furnace gases, to a nonuniform firing temperature, or to a film clay arising from faulty enamel suspension. e. The "clouds" appearing around decalcomania formed by varnish residue. f. A surface defect appearing as dull patches on otherwise bright surfaces of glazes, glass, or porcelain enamel.


Dev. A small vein.