Appendix:Dictionary of Mining, Mineral, and Related Terms/S/12

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subaeration cells

See: sub-A flotation cells.

subaeration method

In flotation, a method employing an impeller, of which the principal function is to keep the pulp in suspension, and a port for admission of air below the surface of the pulp, this port of entry being in the vicinity of the impeller.


Said of conditions and processes, such as erosion, that exist or operate in the open air on or immediately adjacent to the land surface; or of features and materials, such as eolian deposits, that are formed or situated on the land surface. The term is sometimes considered to include fluvial. CF: subaqueous; subterranean. See also: surficial.

sub-A flotation cells

Those in which air is supplied direct to a rotary agitator, mechanically driven, situated at depth in the flotation cell so that air is churned with ore pulp. Two types are (1) that in which air is drawn down by impeller; and (2) that in which low-pressure air is blown in. Syn: subaeration cells.


a. A group term applied to rocks of the tholeiitic and calc-alkaline series.

b. Said of an igneous rock that contains no alkali minerals other than feldspars. c. Used to describe an igneous rock of the Pacific suite.


Somewhat angular, free from sharp angles but not smoothly rounded; specif. said of a sedimentary particle showing definite effects of slight abrasion, retaining its original general form, and having faces that are virtually untouched and edges and corners that are rounded off to some extent.


Said of conditions and processes, or of features and deposits, that exist or are situated in or under water, esp. freshwater, as in a lake or stream. CF: subaerial.

subaqueous disposal

A mine waste management practice whereby mill tailings or mine waste rock are emplaced under a body of water to minimize sulfide oxidation and acid formation, and eliminate airborne particulate pollution. If a natural sedimentation basin is utilized, erosion hazards inherent to subaerial impoundments are eliminated.

subaqueous mining

Surface mining in which the material mined is removed from the bed of a natural body of water.


See: semiarid.


A sandstone that does not have enough feldspar to be classed as an arkose, or a sandstone that is intermediate in composition between arkose and pure quartz sandstone. CF: arkose.

subaudible noise

Noise the intensity of which is so low that it can only be detected by means of a microphone and suitable amplifying equipment. How these subaudible noises, or microseisms, originate has not definitely been established, but it is believed that they are produced by incipient cracking or intermovement between fragments of crystalline aggregates in the rock. It has been found that almost invariably a period of increased microseismic activity precedes any large-scale ground movement or failure.


a. A layer of material laid on the natural ground under a road base for purposes of strengthening. CF: subgrade.

b. The lowest part of a base.

subbituminous A coal

The rank of coal, within the subbituminous class of Classification D 388, such that, on the moist, mineral-matter-free basis, the gross calorific value of the coal in British thermal units per pound is equal to greater than 10,500 (24.42 MJ/kg) but less than 11,500 (26.75 MJ/kg) and the coal is nonagglomerating.

subbituminous B coal

The rank of coal, within the subbituminous class of Classification D 388, such that, on the moist, mineral-matter-free basis, the gross calorific value of the coal in British thermal units per pound is equal to greater than 9,500 (22.10 MJ/kg) but less than 10,500 (24.42 MJ/kg) and the coal is nonagglomerating.

subbituminous C coal

The rank of coal, within the subbituminous class of Classification D 388, such that, on the moist mineral-matter-free basis, the gross calorific value of the coal in British thermal units per pound is greater than 8,300 (19.31 MJ/kg) but less than 9,500 (22.10 MJ/kg), and the coal is nonagglomerating.

subbituminous coal

a. Black lignite or lignitic coal.

b. Coal of rank intermediate between lignite and bituminous. In the specifications adopted jointly by the American Society for Testing and Materials (D388-38) and the American Standards Association (M20.1-1938), subbituminous coals are those with calorific values in the range 8,300 to 13,000 Btu (19.3 to 30.2 MJ/kg), calculated on a moist, mineral-matter-free basis, which are both weathering and nonagglomerating according to criteria in the classification.


Partially or indistinctly conchoidal.


Cooling of a liquid refrigerant below the condensing temperature at constant pressure.

subcritical area of extraction

An area of goaf too small to cause full subsidence at the surface. See also: critical area of extraction.

subdeposit level

See: group level.

subdrift caving

See: sublevel caving.

subdrifting and caving

See: top slicing combined with ore caving.


See: underdrilling.


The process of one lithospheric plate descending beneath another. See also: obduction.

subduction zone

A long, narrow belt in which subduction takes place; e.g., along the Peru-Chile trench or in the volcanic arc belts of the western Pacific Ocean.

subeconomic resources

The part of identified resources that does not meet the economic criteria of reserves and marginal reserves.


A subvariety of provitrain in which the corky origin of the cellular structure is microscopically visible. CF: periblain; xylain.


a. A variety of provitrinite characteristic of suberain and consisting of corky tissue.

b. A maceral of brown coal and lignite derived from the suberin layer in corkified cell walls of some Mesozoic and younger plants. CF: periblinite; xylinite; telinite.


a. Said of a mature lithic wacke (or lithic graywacke) in which quartz grains and fragments of siliceous and argillaceous rocks predominate, and feldspars make up less than 10% of the rock and may be altogether lacking. Such rocks have also been called subgraywackes.

b. Said of a mature lithic arenite containing abundant quartz grains and fragments of the more stable rocks (such as cherts), and less than 10% feldspar grains.


A layer, stratum, or material immediately beneath some principal surface; specif. a layer of earth or rock that is graded to receive the foundation of an engineering structure. Often it is the soil or natural ground that is prepared and compacted to support, and that lies directly below, a road, pavement, building, airfield, or railway. CF: subbase.

subgrade surface

The surface of the earth or rock prepared to support a structure or a pavement system.


The most common type of sandstone, intermediate in composition between orthoquartzite and graywacke (Pettijohn, 1957). Composition is typically 30% to 65% quartz and chert, less than 15% clay matrix, more than 25% unstable materials such as feldspar grains and rock fragments, and voids or mineral cement exceeding the amount of clay matrix. The rock is lighter colored and better sorted, and has less matrix, than graywacke. CF: graywacke.


a. Said of a mineral grain that is bounded partly by its own rational faces and partly by surfaces formed against preexisting grains as a result of either crystallization or recrystallization.

b. Said of the shape of such a crystal, intermediate between euhedral and anhedral.

subhydrous macerals

Macerals having a low hydrogen content, such as fusinite.


An inclined shaft along the footwall of a reef on the Rand. It develops and extracts ore from areas below the main haulage level. See also: staple shaft.


One of the small crystals that often unite in parallel growths to build up larger crystals of the same general habit.


Said of a stratum situated immediately under a particular higher stratum or below an unconformity. Ant: superjacent. Syn: underlying.

subjective brightness

The subjective brightness of a surface is determined by two factors, the light flux radiated from the surface and the sensitivity of the eye under the conditions in which the surface is seen. The sensitivity of the eye is partly controlled by the contrasts presented over the visual field, but is mainly dependent on its adaptation brightness level.


a. A secondary level for working ore in top slicing and sublevel caving; a companion heading.

b. An intermediate level opened a short distance below the main level; or, in the caving system of mining, 15 to 20 ft (4.6 to 6.1 m) below the top of the orebody, preliminary to caving the ore between it and the level above. See also: sublevel stoping; caving system.

sublevel backstoping

See: sublevel stoping.

sublevel caving

a. A stoping method in which relatively thin blocks of ore are caused to cave by successively undermining small panels. The ore deposit is developed by a series of sublevels spaced at vertical intervals of 18 to 25 ft or 30 ft (5.5 to 7.6 m or 9.1 m) and occasionally more. Usually only one or two sublevels are developed at a time, beginning at the top of the orebody. The sublevels are developed by connecting the raises with a longitudinal subdrift from which timbered slice drifts are driven right and left opposite the raises to the ore boundaries or to the limits of the block. Usually alternate drifts are driven first, and caving back from them is begun and continued while the intermediate slices are being driven. The caving is begun at the ends of the slices by blasting out cuts and retreating in the same manner toward the raises. The broken and caved ore formerly was shoveled into cars and trammed to the raises, but in recent years it is dragged to the raises by power scrapers. Successively lower sublevels are developed and caved back until the entire block has been mined. This method is intermediate between block caving and top slicing, since part of the ore is mined as in top slicing and part is caved. See also: top slicing combined with ore caving.

b. Similar to top slicing from which it is thought to have been developed. The general plan of operations is to mine every other slice by driving crosscuts (slice drifts) from 18 to 36 ft (5.5 to 11.0 m) apart. The ore between the crosscuts as well as that in the slice above is then mined, thus causing the overlying material to cave. The method is applicable to irregular and steeply dipping orebodies that cannot be worked by top slicing. The present tendency is to sink vertical shafts in the footwall rather than inclined shafts as formerly done. Also called subdrift caving.

sublevel drive

A drive often made in a section, esp. in gently inclined deposits, that divides the deposit into narrower panels and zones. They are narrower, and the support and equipment for them is more simple than that required in level drives.

sublevel method

See: sublevel stoping.

sublevel slicing

See: top slicing combined with ore caving; sublevel stoping.

sublevel stoping

a. In this mining method, the ore is excavated in open stopes, retreating from one end of the stope toward the other. The orebody is developed first by a series of sublevel drifts above the main haulage level. The sublevels are connected by a starting raise at one end of the stope and by a passageway raise for entrance to them and the stope face at the other end. Chute raises connect the haulage level to the lowest sublevel, at which the tops of the chute raises are belled out to form mill holes. Beginning at the starting raise the ore is benched down from the sublevels; the broken ore falls into the mill holes, where it is drawn off through the chutes. The stope face is kept nearly vertical as it is benched backward toward the passageway raise.

b. A mining method involving overhand, underhand, and shrinkage stoping. Its characteristic feature is the use of sublevels. The sublevels are worked simultaneously, the lowest on a given block being farthest advanced and the subs above following one another at short intervals. The uppermost sublevel underneath the cover is partly caved. The caved cover follows down upon the caved ore. The broken ore is in part drawn from the level, and a part remains in the stope to give lateral support to the walls and to prevent admixture of cover and ore. The breaking faces are developed by crosscuts, which are extended from wall to wall from the end of the sublevel. The method can also be looked upon as a retreating method, the orebody being worked from the top down and the individual blocks upon a given level being worked from their ends to the center. Modifications of this method are chamber-and-pillar system; chambers without filling; combination of subslicing and stoping; drift stoping; filling system; Mitchell slicing system; pillar robbing; pillar robbing and hand filling; room-and-pillar system; square work and caving; square work, pillar robbing, and hand filling; sublevel back stoping; sublevel method; sublevel slicing system; substoping. c. A method of mining best adapted to steeply inclined deposits that have strong ore and strong walls. The ore is usually blocked out by two horizontal drifts separated vertically by 100 to 200 ft (30 to 61 m) and raises between the two horizontal drifts, the latter separated by comparable distances. Vertical pillars may be left between stopes on the same level, and horizontal ones to support the main haulage. After the main blocks of ore have been completely mined, it is common practice to rob the pillars, and the walls of the stope may collapse after the pillars have been robbed. d. Of lodes, open-stope mining in which ore is blasted and drawn through footwall openings to a gathering level in the country rock below. Used with strong containing walls and wide lodes. e. Of massive deposits, working simultaneously of a series of sublevels echeloned vertically, the lowest leading and the uppermost being partly caved as the covered rock descends. f. See: sublevel backstoping; substoping.


a. A coating or deposit formed in a glass tube or on charcoal as a result of heating certain minerals.

b. The product of sublimation. c. A solid deposit by a gas or vapor; commonly used in reference to material deposited by volcanic gases.


a. The process by which a solid substance vaporizes without passing through a liquid stage. CF: evaporation.

b. The process of ore deposition, as of sulfur or mercury, by vapors; the volatilization and transportation of minerals followed by their deposition at reduced temperatures and pressures. Sublimation deposits are generally associated with fumarolic activity.

sublimation theory

The theory that a vein was filled first with metallic vapors.


To cause to pass from the solid state to the vapor state by the action of heat and again to condense to solid form.

submarginal land

Generally means land not very good for farming. Tens of millions of tons of coal are removed each year by stripping the surface of this type land.

submarine blast

A charge of high explosives fired in boreholes drilled in the rock underwater for dislodging dangerous projections and deepening channels.

submarine canyon

An elongated, steep-walled cleft running across or partially across the Continental Shelf, the continental borderland and/or slope, the bottom of which grades continually downwards.

submarine drilling

Drilling from the surface of a body of water with a drill mounted on an anchored tower, platform, or barge.

submarine mines

Workings that follow the mineral under the sea. Syn: undersea workings.

submarine packing

Special heavy paper shells in which dynamite is packed in underwater blasting.

submarine throat

A throat with the fluid level below the bottom of a melter. See also: throat.

submerged unit weight

The weight of the solids in air minus the weight of water displaced by the solids per unit of volume of soil mass; the saturated unit weight minus the unit weight of water. See also: unit weight.


a. In an air lift, the distance below the water level, during pumping, at which the air picks up water.

b. A term that implies that part of a land area has become inundated by the sea but does not imply whether the sea rose over the land or the land sank beneath the sea.

submetallic luster

A luster between metallic luster and nonmetallic luster.


Said of the texture of an igneous rock in which the feldspar crystals are approx. the same size as the pyroxene and are only partially included by them. The term ophitic generally includes such textures.


a. S. Afr. Rock that would have been the outcrop on the surface, but is covered by other formations.

b. Area of intersection of a geologic feature with the surface of bedrock beneath the regolith.


In coal and coke sampling, part of the sample consisting of a number of increments spaced evenly over the unit.

subsequent ore deposit

See: epigenetic.


The sudden sinking or gradual downward settling of the Earth's surface with little or no horizontal motion. The movement is not restricted in rate, magnitude, or area involved. Subsidence may be caused by natural geologic processes, such as solution, thawing, compaction, slow crustal warping, or withdrawal of fluid lava from beneath a solid crust; or by human activity, such as subsurface mining or the pumping of oil or groundwater. See also: shift; cauldron subsidence; settlement. Syn: land subsidence; bottom subsidence.

subsidence area

The area affected by subsidence over areas where minerals or other substances have been removed. The area is larger than the mined-out area below.

subsidence basin

A shallow troughlike depression at the surface resulting from subsidence.

subsidence break

A fracture in the rocks overlying a coal seam or mineral deposit as a result of its removal by mining operations. The subsidence break usually extends from the face upward and backward over the unworked area.

subsidence factor

Full subsidence expressed as a fraction of the thickness of coal seam extracted. See also: maximum subsidence.

subsidiary fracture

Minor breaks sometimes developed in the rocks along a fault plane. They often indicate the general direction of movement and were caused by differential tension in the rocks contiguous to the main fault plane. See: tension fracture.

subsidiary survey

An underground survey made to determine the position of a faceline or goafline or some other specific feature.

subsidiary transport

The conveying or haulage of coal or mineral along the working faces and outward to a junction or loading point. See also: main transport; underground haulage.

subsieve analysis

In powder metallurgy, size distribution of particles all of which will pass through a 44-mu m (No. 325) standard sieve, as determined by specified methods.

subsieve material

In mineral dressing, material finer than 400 mesh that must be sized by elutriation in rising currents of water or air, by microscopic counts, or other methods.

subsieve sizes

Particle sizes too small for efficient grading on screens; usually minus 200-mesh material. They are examined by elutriation (beaker decantation, sedimentation, infrasizing in air, turbidimetry, permeability).


A basic silicate.


A term proposed by Clarke (1908) to replace basic. CF: persilicic; mediosilicic.


See: top slicing combined with ore caving.

subsoil drainage

The removal of subsoil water by open intercepting ditches and drain pipes. The distance between subsoil drains is a maximum in sandy soils and a minimum in clay. See also: catchwater drain.


The firing of small charges of dynamite 2 ft or 3 ft (0.6 m or 0.9 m) below the surface for breaking up impervious strata of soil, clay, etc., for aerating, draining, and moistening the soil.

subsoil plow

A one-tooth ripper designed for agricultural work. Also called pan breaker.


a. A subdivision of a stage; the rocks formed during a subage of geologic time.

b. In a microscope, a mechanism for holding polarizers or other attachments below the stage.


An electrical installation containing generating or power-conversion equipment and associated electric equipment and parts, such as switchboards, switches, wiring, fuses, circuit breakers, compensators, and transformers.


Any substance represented to be, or used to imitate, a gemstone; e.g., plastic, glass, doublet, synthetic ruby, or natural spinel; all could be substitutes for natural ruby.


A chemical defect wherein one ion replaces another in a crystal structure. Substitution may be partial; e.g., iron for zinc in sphalerite up to 30%, or complete; e.g., manganese and iron in the series rhodochrosite-siderite.


a. An open stope method of mining employed in wide orebodies with strong walls.

b. See: sublevel stoping.


a. A layer of metal underlying a coating, regardless of whether the layer is basis metal.

b. The true lattice of a crystal, as distinct from its discontinuity lattice, or surface.


a. That part of any structure that is below ground, more particularly the foundations. The latter may take many forms, according to the nature and bearing strength of the ground.

b. The lower portion of a structure upon which something else is built up.


a. The zone below the surface, in which geologic features, principally stratigraphic and structural, are interpreted on the basis of drill records and various kinds of geophysical evidence.

b. Rock and soil materials lying beneath the Earth's surface.--adj. Formed or occurring beneath a surface, esp. beneath the Earth's surface. CF: surficial. See also: subterranean. c. An underground workplace.

subsurface contour

See: structure contour.

subsurface correlation

Correlation of rock units and structures that do not appear at the surface, by means of well logs, mine maps, and geophysical data.

subsurface corrosion

Formation of isolated particles of corrosion products beneath the metal surface. This results from the preferential reaction of certain alloy constituents by inward diffusion of oxygen, nitrogen, and sulfur.

subsurface geology

Geology and correlation of rock formations, structures, and other features beneath the land or sea-floor surface as revealed or inferred by exploratory drilling, underground workings, and geophysical methods. CF: surface geology.

subsurface injection

See: subsurface waste disposal.

subsurface map

a. A map depicting geologic data or features below the Earth's surface; esp. a plan of mine workings, or a structure-contour map of a petroleum reservoir or an underground ore deposit, coal seam, or key bed.

b. A plane surface representation, generally in horizontal projection, of geologic data or features beneath the Earth's surface. There are many types of subsurface maps, such as structure contour maps, isopachous maps, and maps showing variations in lithology, or proportions of different types of lithology in rocks not exposed at the surface.

subsurface waste disposal

Waste disposal in which manufacturing wastes are deposited in porous underground rock formations. Disposal wells should be at least 200 ft (61 m) deeper than the deepest water-bearing formation, and they must be sealed with cement from top to bottom. Also called subsurface injection.

subsurface water

Water in the lithosphere in solid, liquid, or gaseous form. It includes all water beneath the land surface and beneath bodies of surface water. Syn: subterranean water; underground water; ground water.

subtense bar

A horizontal bar used in the subtense system of surveying by tacheometry. It is held at a distant point and its distance is calculated from its known length and the angle that it subtends at the observer's eye. See also: tachymeter.


See: subterrane.


The bedrock beneath a surficial deposit or below a given geologic formation. Syn: subterrain. Adj. subterranean.


Formed or occurring beneath the Earth's surface, or situated within the Earth. CF: subaerial. See also: subsurface. Syn: subterrestrial; subterrane.

subterranean stream

A body of subsurface water flowing through a cave or a group of communicating caves, as in a karstic region.

subterranean water

See: ground water; subsurface water.


See: subterranean.


See: semitranslucent.


Imperfectly or partially transparent; semitransparent.


Not quite vitreous.


See: hypabyssal.


Below weathering. Pertaining to the consolidated material-bedrock or high-velocity weathered layer or zone. This velocity is distinctly greater than that in the weathered zone.


a. An old name for amber, esp. amber mined in former East Prussia (Poland) or recovered from the Baltic Sea.

b. A light yellow, amber-colored variety of grossular garnet.


The shape of the bottom of a cutting edge or tooth that tends to pull it into the ground as it is moved.

sucked stone

Corn. A honeycombed or porous stone.

sucking pump

A suction pump.


a. Atmospheric pressure pushing against a partial vacuum.

b. The pull of a pump. c. Adhesion of a mass of mud to the underside of an object being lifted out of it.

suction anemometer

An anemometer that measures wind velocity by the degree of exhaustion caused by wind blowing through or across a tube.

suction bailer

See: sand pump.

suction basket

The strainer at the foot of the suction pipe of a pump or of a suction hose.

suction blast

See: backlash.

suction chamber

A suction chamber is designed to provide a trough of low pressure between the sealed area and the intake, so that air that would otherwise be drawn into the sealed area, through fissures and pores surrounding the seal, is drawn instead into the chamber. If the pressure within the sealed-off mine area is less than that outside, it is necessary to reduce the pressure within the chamber. This can be done by using an ejector or fan to draw air through a pipe in the outer wall of the chamber; a second pipe, fitted with a control valve, serves as an intake. Adjustment of the valve gives regulation of the chamber pressure within fine limits.

suction cutter

a. In dredging, use of pump fed by pipe with power-rotated cutting blades to lift spoil.

b. In alluvial dredging, use of power-rotated cutting shoe to detach minerals from deposit, followed by their delivery by suction and elevation through a centrifugal pump.

suction-cutter dredge

A dredge in which rotary blades dislodge the material to be excavated, which is then removed by suction, as in a sand-pump dredger.

suction dredge

a. A dredge that digs by means of powerful suction pumps, the semiliquid spoil thus raised being frequently conveyed away in a floating pipeline.

b. See: sand-pump dredger. c. A dredge in which the material is lifted by pumping through a suction pipe.

suction fan

A fan that sucks or draws the air toward it through airways or air pipes. The term generally used is exhaust fan.

suction head

The head or height to which water can be raised on the suction side of the pump by atmospheric pressure. See also: lift pump.

suction lift

In pump nomenclature, it exists when the liquid level is below the pump centerline and/or when a gage on the suction would show a vacuum.


An augite-bearing hypersthene basalt characterized by pillow structure and containing bytownite and magnetite. It differs from normal basalts in containing neither glass nor olivine and in having an equigranular texture (Johannsen, 1937). Its name, given by Coleman in 1914, is derived from the Sudbury District, ON, Canada. Not recommended usage.

sugar sand

A variety of sandstone that breaks up into granules resembling sugar.

sugar spar

Corn. Friable granular quartz. See also: sugary quartz.

sugar stone

a. Eng. An ironstone in Norfolk, so-named from its rich brown color.

b. Compact white to pink datolite from the Michigan copper district.

sugar-tube method

A dust-sampling technique that measures airborne dustiness on a mass basis. In the glass tube is placed a layer, 1-1/2 in (3.8 cm) deep, of sized granulated sugar weighing 100 g. By means of a suitable pump, air is drawn through the sugar tube at a rate of approx. 1 ft (super 3) /min (0.0283 m (super 3) /min). The dust is retained in the sugar tube, which is then stoppered and sent to the laboratory for analysis. The sugar is dissolved and the dust is caught on a filter paper that is incinerated to give the weight of dust.

sugary quartz

A granular and somewhat friable and massive variety of quartz. Syn: sugar spar.


a. A set of apparently comagmatic igneous rocks.

b. A collection of rock specimens from a single area, generally representing related igneous rocks. c. A collection of rock specimens of a single kind; e.g., granites from all over the world. d. In stratigraphy, the lithodemic unit next higher in rank to lithodeme. It comprises two or more associated lithodemes of the same class (e.g., plutonic, metamorphic). For cartographic and hierarchical purposes, suite is comparable to group. The name of a suite combines a geographic term, the term suite, and an adj. denoting the fundamental character of the suite; e.g., Idaho Springs Metamorphic Suite. e. A major group of Tertiary and younger igneous rocks thought by Harker (1909) to characterize regions around each of the world's great oceans. Because there is such a wide variety of tectonic environments and associated rock types in these regions, the terms are now seldom used. See also: Atlantic suite; Pacific suite; Mediterranean suite. CF: lithodeme.

suites (of igneous rocks)

See: consanguinity.

sulfate-bearing soils

On silts where the groundwater contains more than 0.1% of SO (sub 3) , or where a clay soil has more than 0.5% of this substance, the use of lime-free cement in all concrete work is essential to prevent the resulting chemical attack. High-alumina cement gives complete protection, but a sulfate-resisting cement to British Standard 12 may be used where conditions are less severe.

sulfate sulfur

The inorganic sulfur in coal other than the pyritic sulfur.

sulfate test

Sulfate in soil can be precipitated as barium sulfate and measured so as to indicate whether water or soil will have a harmful effect on concrete.

sulfating roast

A roast in which conditions in a furnace allow sulfur in feed to recombine with calcined products to form sulfates. Syn: sulfatizing roast.


The chemical reaction that takes place in many roasting operations in which metallic sulfates form instead of oxides.

sulfatizing roast

See: sulfating roast.

sulfhydryl-collector method

In flotation, a method for treatment of various oxygen ores where sulfhydryl collectors are used to float the base-metal minerals from associated minerals.

sulfide enrichment

Enrichment of a deposit by replacement of one sulfide by another of high value, as pyrite by chalcocite.

sulfide of iron

An iron ore with sulfur as its main impurity.

sulfide ore

Ore in which the sulfide minerals predominate. See also: mixed ore.

sulfide zone

a. That part of a sulfide deposit that has not been oxidized by near-surface waters. See also: oxidized zone; protore.

b. A generally manto-shaped deposit in which secondary sulfide enrichment has occurred as a part of ore-deposit oxidation. Syn: secondary sulfide zone.


In conditioning a flotation pulp, addition of soluble alkaline sulfides in aqueous solution to produce a sulfide-metal layer on an oxidized ore surface.

sulfidizing method

In flotation, a method for treatment of various oxide ores in which the desired base-metal minerals are sulfidized, then the ore is floated as if it were a sulfide ore. It is useful in treating lead carbonate ores, less useful if other lead minerals are present, and of limited utility in connection with copper and zinc ores.


A mineral in which sulfur and antimony are united chemically with a metal.


An ore mineral of any metal or metals with which sulfur and arsenic are united chemically.

sulfonic acid

A hydrophilic group. In the sulfate ester, an oxygen link is provided, forming the acid group of many commercial surface-active agents in which a little sulfonic acid and much long-chain sulfate ester are linked to fatty acids and oils. Examples of reagents used in mineral processing include Lissapol LS (sodium salt of oleic acid chloride and p-anisidine sulfonic acid); and Aerosol (sulfosuccinic acid diester).


Light green to yellow vaselinous variety of sulfur-containing bitumen.


Elements that occur preferentially in minerals free of oxygen (or fluorine or chlorine); i.e., mostly as sulfides, selenides, tellurides, arsenides, antimonides, intermetallic compounds, native elements, etc. This group includes some of the chalcophile and some of the siderophile elements as classified by Goldschmidt.

sulfur ball

a. An accumulation of sulfur in the form of iron pyrites sometimes found in coal seams, often hard enough to break the bits on cutting machines.

b. A concretionary form of the sulfide of iron occurring as both pyrite and marcasite. This material seems to crystallize or grow within the coal as a result of the action of waters bearing sulfuric acid acting upon compounds of iron. This iron is then taken into solution as iron sulfates and subsequently converted to sulfides that form into the sulfur ball.

sulfur dome

An inverted container, holding a high concentration of sulfur dioxide gas, used in die casting to cover a pot of molten magnesium to prevent burning.


Pac. The undecomposed metallic ores, usually sulfides. Chiefly applied to auriferous pyrites. Concentrate and sulfide are preferable. An old syn. for sulfide. Obsolete.

sulfur group

The group VI elements sulfur, selenium, tellurium, and oxygen.

sulfur mining

Thick sulfur-bearing deposits may be worked by a network of tunnels and general caving. The bed is extracted in a series of thick slices, horizontal if the dip is great, or parallel to the dip if it is moderate. See also: Frasch process.

sulfur ore

Pyrite, often roasted for its sulfur.


Mercapto thiol. -SH, the monovalent radical.


a. Mud and silt deposited from flowing water.

b. Scoria on molten metal in the ladle.

Sullivan angle compressor

A two-stage compressor in which the low-pressure cylinder is horizontal and the high-pressure cylinder is vertical. It is a compact compressor and is driven by a belt, or it can be directly connected to an electric motor or diesel engine.


An isometric mineral, Cu (sub 3) VS (sub 4) ; forms a series with arsenosulvanite; bronze yellow; at Burra Burra, South Australia; and Mercur, UT.

summary of reinforcement

A cutting list with details of reinforcing bars.

summer black oil

as a heavy tempering oil and for waterproofing cement.


a. An excavation made underground to collect water, from which it is pumped to the surface or to another sump nearer the surface. Sumps are placed at the bottom of a shaft, near the shaft on a level, or at some interior point.

b. An excavation smaller than and ahead of the regular work in driving a mine tunnel or sinking a mine shaft. c. A hole sunk in a drift to a depth of 2 to 3 yd (1.8 to 2.7 m). d. To undercut coal preliminary to placing a shortwall machine in position for cutting along the working face. Sometimes called a sumping cut. e. To test the load in depth. f. See: cut. g. To drill diagonally. h. See: jib in. i. A pit or basin in which the returns from a borehole are collected and stored and in which the cuttings settle before recirculating the cuttings-free drilling fluid. j. A cellar under a drill floor.

sump cleaner

In bituminous coal mining, one who shovels up accumulations of coal, rock, dirt, and refuse at the bottom of a shaft and loads it into buckets that are hoisted to the surface or an upper level for dumping.


a. A shothole drilled diagonally.

b. In bituminous coal mining, a person who oils and greases coal-cutting machines. Also called machine sumper.

sump fuse

A waterproof fuse for use in a sump.


a. Forcing the cutter bar of a coal cutter into or under the coal. Also called sumping cut.

b. A small square shaft, generally made in the airheadings when crossing faults, etc., or made to prove the thickness of coal, etc.

sumping bar

An angle iron about 8 ft (2.4 m) long with flanges about 4 in (10 cm) high, weighing about 75 lb (34 kg). Its function is to guide the cutter bar on an electric coal-cutting machine.

sumping cut

See: sump.


See: jibbing-in.


In metal mining, a person who installs sets of timbers to support the walls of a shaft, working with the shaft sinking crew and installing the timbers as the work advances.

sump shaft

The shaft in a mine at the bottom of which is the sump.

sump shot

A blast made in a shaft that is being sunk, to make a collecting place for water.

sump winze

A winze sunk in the bottom of the lowest level, to explore the lode below and ascertain whether the sinking of the main shaft is advisable.

sun bed

a. A sublithographic limestone or mudstone at the top of the White Lias, the upper surface of which bears polygonal cracks attributed to sun drying.

b. Alternatively a corruption of "sound" bed because, when dry, the rock rings when broken with a hammer. CF: guinea bed; ring stone.

sun cheek

The south side of a vein.

sun crack

See: mud crack.

Sunday stone

A calcareous deposit formed inside pipes carrying waste water from collieries. It is composed of alternating dark and light bands corresponding to the day and night shifts and a broader light band corresponding to Sunday.

Sundberg method

In electrical prospecting, an inductive method in which the current flows through an insulated copper cable connected to a source of alternating current and run along the surface in a rectangle 1 mile by 1/2 mile (1.6 km by 0.8 km) in dimensions. A series of transverse profiles are laid out perpendicular to and crossing the cable, and the magnetic part of the electromagnetic field is measured at discrete points along the profiles by special search coils consisting of several hundred turns of wire. The magnitude and direction of the induced field observed by the coils can be related to the inductive effect of the subsurface material directly below.


a. A monoclinic mineral, Pb (sub 10) (SO (sub 4) )Cl (sub 2) O (sub 8) ; forms plumose aggregates of adamantine crystals having one perfect cleavage; at Laangban, Sweden.

b. A name proposed for a hypothetical amphibole end-member composition, but never accepted by the IMA nor widely used by mineralogists.


See: andorite.

sun gear

The central gear in a planetary set.


Drilled or excavated downward.

sunken pit

See: dig-down pit.

sunk shaft

A shaft that is driven from the top downward (vertical or inclined).

sun opal

See: fire opal.


A name of a soft grade of paraffin wax with a low melting point. It can be burned in an ordinary miners' lamp with a nail (usually copper) in the wick and gives little smoke. Also called miners' sunshine.


a. An aventurine feldspar, generally a brilliant, translucent variety of oligoclase that emits a reddish or golden billowy reflection from minute scales or flakes of hematite spangled throughout and arrayed parallel to planes of repeated twinning. CF: goldstone; moonstone. Syn: heliolite.

b. A red-to-yellow variety of bytownite caused by minute inclusions of copper and found in basalt from Oregon. See also: aventurine.

sun vein

N. of Eng. Ore vein discovered on the south side of a hill. Sun is synonymous with south, so sun veins are south veins.

super airflow cleaner

In this cleaner, the coal is fed from a raw coal hopper by an oscillating plunger feeder ensuring uniform feed throughout the entire width of the machine deck. A rotating shutter in the inlet duct provides a pulsating air current, which is much more effective as a separating current than a uniform airstream. The coal and refuse stratify as they move toward the discharge end of the deck with the refuse falling to the bottom against the deck. The perforated deck has four refuse draws; normally the products of the first two draws are discharged as refuse and the third and fourth draws as middlings. The product of the third draw may be refuse or middlings, depending on the ash content of the feed. Generally, this cleaner is an effective machine for cleaning coal from 3/4 in (1.91 cm) to 1/4 in (0.64 cm) by 28 mesh if it contains less than 5% of surface moisture. It will not clean effectively below 20 mesh.


An alloy for very high-temperature service in which relatively high stresses (tensile, vibratory, and shock) are encountered and oxidation resistance is frequently required.

supercapacity bucket elevator

A type of continuous bucket elevator employing supercapacity elevator buckets. See also: supercapacity elevator bucket.

supercapacity elevator bucket

A type of continuous elevator bucket used with a pair of chains in which the back of the bucket at the bottom extends backward into space between the up and down runs to provide additional capacity without increase in length or projection. See also: supercapacity bucket elevator.


A blower that increases the intake pressure of an engine.


The abrupt and large increase in electrical conductivity exhibited by some materials at very low temperatures.

supercritical area of extraction

An area of goaf of sufficient extent to cause full subsidence at more than one point on the surface.


An instrument of limited sensitivity for measuring changes in the total intensity of the magnetic field.


The presence of a very large excess of coal dust in the air over that required for consumption of the oxygen.


The antiparallel alignment of unpaired d electrons of metal cations through coupling with p electrons of intervening anions to produce magnetic order. CF: ferrimagnetism; antiferromagnetism.


Pertaining to, or lying on or in, a surface or surface layer; e.g., superficial weathering of a rock, or a superficial structure formed in a sediment by surface creep. The term is used esp. in Great Britain; the syn. surficial is more generally applied in the United States.

superficial compaction

Compaction of soil in layers generally not greater than 6 in (15 cm) deep, by various methods, including the use of the frog rammer, vibration, sheepsfoot roller, pneumatic tired rollers, or similar machines. See also: compaction equipment.

superficial deposit

The most recent of geological formations; unconsolidated detrital material lying on or near the surface, generally unstratified. See: surface deposit.


Said of a mineral deposit or enrichment formed near the surface, commonly by descending solutions; also, said of those solutions and of that environment. CF: hypogene; mesogene.

supergene enrichment

A mineral deposition process in which near-surface oxidation produces acidic solutions that leach metals, carry them downward, and reprecipitate them, thus enriching sulfide minerals already present. Syn: enrichment; secondary enrichment. See also: oxidized zone.

superheated steam

Steam above a temperature of 100 degrees C; produced by heating water under a pressure greater than standard atmosphere.


a. A device that superheats, esp. steam or other gases; esp. a coil or other device through which steam from a boiler passes to be superheated.

b. A refractory lined chamber in a water-gas plant that ensures completion of the decomposition of the oil vapors begun in the carburetor.


In geology, to establish (a structural system) over, independently of, and eventually upon underlying structures; said of terranes, rivers, drainage systems, valleys, etc.; as, a superimposed valley.

superimposed halo

A dispersion pattern formed in the regolith by the movement of material in subsurface waters.


One who supervises the feeding and maintenance of glass-melting furnaces (tanks), and the operation of reheating ovens (lehrs) for fire-glazing glass articles. Directs unloading and storage of raw materials and crushing and washing of waste glass (cullet) used as ingredients in the manufacture of new glass.

superjacent pattern

A dispersion pattern developed more or less directly over the bedrock source.

superjacent roadway system

See: methane drainage.


X-ray diffractions, in addition to fundamental diffractions, which appear as an alloy inverts from disorder to perfect order of its constituent atoms at lattice sites; called superlattice diffractions and attributed to a superstructure of ordered atoms. Superlattice diffractions also appear where long-range order obtains in the stacking of silicate structural units, such as in phyllosilicates. See: superstructure; long-range order.


A mechanism that simulates rocking, bumping, and sluicing action used in panning and gives precise information as to the possibility of gravity treatment of sands. It is used in rapid assays and as a research aid.


Any of various commercial phosphate fertilizers obtained as white to gray granules or powders by acidulating ground insoluble phosphate rock, such as: (1) a product made by acidulating with sulfuric acid, consisting essentially of primary calcium phosphate, calcium sulfate, and smaller quantities of secondary calcium phosphate, and containing usually about 20% of available phosphoric acid; or (2) a product made by acidulating with phosphoric acid, consisting essentially of primary calcium phosphate and containing usually 40% to 50% of available phosphoric acid.


a. A principle stating that if a body is subjected to several stresses acting simultaneously, then each stress produces its own strain or strains, and these strains may be superimposed to give the complete state of strain of the solid. Similarly, two separate stress distributions in a body, due to the application of two separate stresses, may be superimposed to give the stress distribution due to the simultaneous application of these two stresses.

b. The order in which rocks are placed or accumulated in beds one above the other, the highest bed being the youngest.


See: overprint.


Using extra large pushers, or two or even three standard units in tandem, to increase the speed and size of loading.

supersaturated solution

A solution that contains more of the solute than is normally present when equilibrium is established between the saturated solution and undissolved solute.

super section

Two sets of mining equipment operating simultaneously and sharing a common dumping point on the same section, with each set being ventilated by a separate split on intake air.


A crystal structure resulting from large unit cells when an alloy inverts from disordered occupancy of lattice sites by "averaged" constituent atoms in small unit cells to individual atomic species occupying specific lattice sites and having long-range order; e.g., disordered Cu (sub 3) Au has a primitive cubic unit cell with averaged "Cu-Au atoms" at each corner, while ordered Cu (sub 3) Au has a face-centered cell with Au atoms its corners and Cu its face centers, the large face-centered unit cell containing eight of the small primitive unit cells. See: superlattice; long-range order.

supplementary twinning

Twinning by which a crystal simulates the symmetry of a crystal class with higher grade in the same system.

supplied-air respirator

An atmosphere-supplying device that provides the wearer with respirable air from a source that is outside of the contaminated area.

supply cager

In anthracite and bituminous coal mining, one who directs and assists the loading of mine supplies on a cage (elevator) at a mine having a separate shaft or shaft compartment for handling supplies.

supply-hoist engineer

See: supply-hoist operator.

supply-hoist operator

In anthracite and bituminous coal mining, one who operates the hoisting machinery that serves the shaft or shaft compartment of a mine in which mining supplies are lowered into the mine. Also called supply-hoist engineer.

supply motorman

In bituminous coal mining, a person who operates a mine locomotive to haul trips (trains) of cars, loaded with timbers, rails, explosives, and other supplies, into a mine.

supply pump

See: bank pump.


A general term for any timber, steel, concrete, brick, or stone structure erected to counteract the subsidence of the roof strata when undermined. See also: self-advancing supports; steel arch; steel support.

support roller

In a crawler machine, a roller that supports the slack upper part of the track.


Materials placed in stopes for the purpose of ground control, that is to arrest or regulate the closure of the walls.

suppressed weir

A measuring weir having its sides flush with the sides of the channel, so that there are no end contractions.

supratenuous fold

A pattern of fold in which there is thickening at the synclinal troughs and thinning at the anticlinal crests. It is formed by differential compaction on an uneven basement surface. CF: similar fold; parallel fold.


a. Any load including earth that is supported above the level of the top of a retaining wall. See also: relieving platform; active earth pressure.

b. The algebraic sum of the losses and gains of a cornet of gold during cupellation and solution.


a. The top of the ground. As used in the conveyance of coal in place, or in a conveyance of land reserving the minerals, includes not merely the surface within the boundary lines, without thickness, but includes whatever earth, soil, or land lies above the superincumbent upon the coal or mineral reserved.

b. See: cover; drift; mantle; overburden. c. In geology, usually refers to (1) the boundary surface between one bed or mass of rock and another immediately adjacent, such as a bedding surface, a fault surface, a surface of unconformity, a surface of igneous compact, or (2) an imaginary surface, such as the axial surface of a fold.

surface action

Any kind of action that affects a surface; e.g., action of smoke fumes, moisture, etc., on a painted surface.

surface-active agent

Chemical compound that modifies physical, electrical, or chemical characteristics of surface of solid, also surface tensions of solids or liquids. Used in froth flotation and in detergency. Characteristically, its heteropolar molecules are attracted to a specific type of surface in a mixture where one group forms polar monolayer attachments while the rest of the molecule points outward and changes the relations between the surface and the ambient phase. These relations may change lyophilic and aerophilic attraction, surface tension, intermiscellar grouping, emulsification, and froth foaming. Surface-active agents include cleaners (e.g., soaps); water repellants (e.g., greases); dispersants and emulsifiers (e.g., glue); and additives adsorbed at interfaces between liquids (usually aqueous) and external gas, liquid or solid phases, with resulting change in interfacial tension. Three electrochemical types are unionized molecule, anion, and cation. Important characteristics of surface-active agents are solubility in the medium and effects of specific adsorption at interfaces. Such agents either provide anchorage between phases or form a barrier, according to their flocculating or dispersing effect.

surface activity

The property possessed by certain solid substances to influence the surface tension of liquids. See also: depressant; flotation agent; surface tension.

surface air leakage

The amount of surface air entering a fan through the casing at the top of the upcast shaft, the airlock doors, and the fan-drift walls. The extent of leakage will depend on the fan-drift water-gage method of construction, the number and type of entrances, and whether the upcast shaft is used for winding. The surface leakage at airlocks may vary from about 25,000 ft (super 3) /min (708 m (super 3) /min) at 5-in (12.7-cm) water gage to about 55,000 ft (super 3) /min (1,557 m (super 3) /min) at 25-in (63.5-cm) fan-drift water gage. See also: volumetric efficiency.

surface area

Of a particle, area calculated from data obtained by a specified method, such as: (1) adsorption measurement, (2) calculation, (3) permeability measurement, (4) microscopic observation, or (5) close screening and averaging from study of a number of particles.

surface break

See: surface damage.

surface bunker

A large capacity hopper or standage room to store coal or mineral coming from the winding shaft. The provision tends to equalize the run of mine going to the preparation plant and smooth out any minor breakdowns in the plant.

surface charges

All expenses incurred on the surface of a mine that have to be charged against the mineral.

surface circuit

The mine car track layout from the shaft to the preparation plant and back to the shaft. The term includes all the equipment necessary to move and control the movement of cars, such as creepers, retarders, back shunts, traversers, and turntables.

surface clay

An unconsolidated, unstratified clay occurring on the surface.

surface conductance

The heat transmitted from (or to) a surface to (or from) the fluid in contact with the surface in a unit of time per unit of surface area per degree temperature difference between the surface and fluid. Measured in units of watts per square meter Kelvin.

surface damage

a. Any damage done to land surface during mine exploration or development operations. Syn: surface break.

b. Scot. Ground occupied and damaged by colliery operations; the compensation for such.

surface deposit

a. Orebody that is exposed and can be mined from the surface.

b. See: superficial deposit.

surface dressing

The covering of an existing surface with a coating of bituminous binder covered by a layer of chippings or fine aggregate.

surface drift

A drift (usually inclined) from the surface to the coal seam or orebody to be developed. See also: drift mining; slant.

surface drilling

Boreholes collared at the surface of the Earth, as opposed to holes collared in mine workings or underwater. See also: surface rig.

surface energy

Product of surface tension (dynes per centimeter) and surface area (centimeters), expressed in ergs. Work required to increase surface area by unit area.

surface factor

See: fineness factor.

surface geology

a. Geology and correlation of rock formations, structures, and other features as seen at the Earth's surface. CF: subsurface geology.

b. See: surficial geology.

surface leaching

A mining practice that represents an alternative to conventional ore beneficiation in that the mineral values are hydrometallurgically extracted rather than concentrated in solid form for further processing. See also: solution mining.

surface lift

A term used in the freezing method of shaft sinking. The surface around the shaft tends to heave owing to the formation of ice and the variation of temperatures. This uplift is sufficient to throw surface structures, such as winding towers, out of alignment. To enable corrections to be made, the tower bases may be mounted on grillages with facilities for jacking to keep the towers level.

surface lines

The boundary lines of a mining claim as indicated by the locator.

surface loss

Losses of air occurring in the restricted area around the tub and caused by the increased velocity along the walls of the airway, and from the friction and turbulent effects due to the surfaces of the tub. For an empty tub, a portion of the turbulent effect is due to eddying and shock within the tub.

surface mining

a. The mining in surface excavations. It includes placer mining, mining in open glory-hole or milling pits, mining and removing ore from opencuts by hand or with mechanical excavating and transportation equipment, and the removal of capping or overburden to uncover the ores.

b. Mining at or near the surface. This type of mining is generally done where the overburden can be removed without too much expense. c. The obtaining of coal from the outcroppings or by the removal of overburden from a seam of coal, as opposed to underground mining; or any mining at or near the surface. Also called strip mining; placer mining, opencast; opencut mining; open-pit mining.

surface plan

A map of the surface layout of a mine.

surface reinstatement

The restoration of the surface after opencast mining operations have been completed. The work may involve leveling the hill-and-dale formation, drainage, and relaying of the original topsoil, also known as resoiling.

surface rig

A drill rig designed specif. and used only for surface drilling operations. See also: surface drilling.

surface rights

a. The ownership of the surface of land only where mineral rights are reserved.

b. The right of a mineral owner or an oil and gas lessee to use so much of the surface of land as may be reasonably necessary for the conduct of operations under the lease. c. Those reserved to the owner of the land beneath which ore is being mined.

surface-set bit

A bit containing a single layer of diamonds set so that the diamonds protrude on the surface of the crown. Also called single-layer bit. CF: multilayer bit.

surface slope

The inclination of the water surface expressed as change of elevation per unit of slope length; the sine of the angle that the water surface makes with the horizontal. The tangent of that angle is ordinarily used; no appreciable error resulting except for the steeper slopes.

surface speed

See: peripheral speed.

surface string

A large diameter drivepipe sunk through the uppermost part of the overburden. CF: conductor; standpipe.

surface tension

a. In the flotation process, the contractile force at the surface of a liquid whereby resistance is offered to rupture. b. Interfacial tension between two phases, one of which is a gas.

c. A condition that exists at the free surface of a body (such as a liquid) by reason of intermolecular forces unsymmetrically disposed about the individual surface molecules and is manifested by properties resembling those of an elastic skin under tension. Specif., the force per unit length of any straight line on the surface that the surface layers on opposite sides of the line exert upon each other. See also: surface activity.

surface texture

The aggregate of the surface features of sedimentary particles, independent of size, shape, or roundness; e.g., polish, frosting, or striations.

surface thrust

See: erosion thrust.

surface water

Water that rests on the surface of the lithosphere.

surface-water drain

Any pipe laid in the ground for carrying away surface water. See also: separate system.

surface wave

An elastic wave in which the energy is confined to the surface or a narrow region just below the free surface of an extended solid. These waves readily follow the curvature of the part being inspected and are reflected only from sharp changes of direction at the surface.

surface working

See: surface mining.


Surface active agent, a substance that affects the properties of the surface of a liquid or solid by concentrating in the surface layer.


Gr. Brit. Afterdamp or chokedamp; or pressure exercised by a pent-up gas resulting in its escape with or without rupture of strata.


Pertaining to, or occurring on, a surface, esp. the surface of the Earth. CF: subsurface. See also: subaerial. Syn: superficial.

surficial creep

See: soil creep.

surficial geology

Geology of surficial deposits, including soils; the term is sometimes applied to the study of bedrock at or near the Earth's surface. See also: surface geology.

surf zone

The area between the outermost breaker and the limit of wave uprush. Syn: breaker zone.


a. To move sideways; to fleet.

b. The uneven rate of flow and regular variations in pressure caused by time lags between pressure strokes on a piston-type pump. c. In fluid flow, long-interval variations in velocity and pressure that are not necessarily periodic and may even be transient.

surge bin

a. In salt mining, a generally large bin above the crusher into which the mine-run salt is dumped prior to being discharged into the primary crusher. A feeder at the bottom of the surge bin facilitates transfer of the mine-run material to the crusher.

b. A compartment for temporary storage, which will allow converting a variable rate of supply into a steady flow of the same average amount.

surge bunker

A large-capacity storage hopper, installed near the pit bottom or at the input end of a processing plant to provide uniform feeding of material from bulk deliveries. Surge bunkers are generally required either on the surface or underground to act as a buffer between the shaft and the coal preparation plant and the working faces. See also: bunker; surge hopper.

surge hopper

A hopper (bunker) designed to receive a feed at fluctuating rate and to deliver it at some predetermined rate. Syn: surge bunker.

surge pipe

Open-topped standpipe to release pressure from surge.

surge pulley

The pulley used on a tension carriage in endless-rope haulage. See also: balanced direct-rope haulage.

surge tank

a. A standpipe or storage reservoir at the downstream end of a closed aqueduct or feeder pipe, as for a water wheel, to absorb sudden rises of pressure and to furnish water quickly during a drop in pressure.

b. An open tank to which the top of a surge pipe is connected so as to avoid loss of water during a pressure surge. c. In pumping of ore pulps, a relatively small tank that maintains a steady loading of the pump. When new pulp is in short supply, a float valve causes recirculation of part of the load, therefore avoiding settlement. Alternatively, a float may vary the speed of the pump, vary the rate of delivery to the tank, or divert the flow to a parallel system.

surveyor's compass

An instrument used in surveying for measuring horizontal angles. Syn: surveyor's dial. CF: circumferentor; semicircumferentor.

surveyor's cross

A simple instrument made of two bars forming a right-angled cross with sights at each end and used in setting out right angles in surveying.

surveyor's dial

See: surveyor's compass.

surveyor's level

A leveling instrument consisting of a telescope (with cross hairs) and a spirit level mounted on a tripod, revolving on a vertical axis, and having leveling screws that are used to adjust the instrument to the horizontal.

surveyor's measure

A system of measurement used in land surveying, having the surveyor's chain (one chain = 4 rods = 66 ft = 20.1 m = 100 links = 1/80 mile) as a unit. CF: Gunter's chain.

Surwell clinograph

Well-surveying device for large-diameter holes that determines the departure of the borehole from vertical. Uses a gyroscope and spherical level with a photographic record made on 16-mm moving-picture film, which includes a photograph of a small watch by which the depth is determined from correlation with a synchronized depth-time record made at surface.


A trigonal mineral, Pb (sub 4) (SO (sub 4) )(CO (sub 3) ) (sub 2) (OH) (sub 2) ; trimorphous with leadhillite and macphersonite; in the Susanna Mine, Leadhills, Scotland.


a. Property of a material that defines the extent to which it will be magnetized in a given external field.

b. The ratio of the electric polarization to the electric intensity in a polarized dielectric. The ratio of induced magnetization to the strength H of the magnetic field causing the magnetization. Syn: magnetic susceptibility; volume susceptibility.

suspect terrane

A terrane whose spatial and genetic relations with respect to adjacent terranes during their time of formation is unknown or uncertain. Inasmuch as most terranes fall into these categories, the term may be considered redundant. See also terrane.

suspended matter

Particles from the feed, of specific gravity equal or close to that of a separating medium, and which are therefore relatively difficult to remove from the bath.

suspended solids

Solids that can be separated from a liquid by filtration.

suspended tray conveyor

A vertical conveyor having one or more endless chains with suitable pendant trays, cars, or carriers that receive objects at one elevation and deliver them to another elevation. Syn: corner-fastened tray conveyor; corner-hung tray conveyor; suspended tray elevator; suspended tray lift.

suspended tray elevator

See: suspended tray conveyor.

suspended tray lift

See: suspended tray conveyor.

suspended tubbing

A permanent method of lining a circular shaft in which the tubbing (German type) is temporarily suspended from the next wedging curb above. Slurry is run in behind the tubbing by means of a funnel passing through the holes provided in the segments. No temporary supports are required. See also: tubbing.

suspended water

See: vadose water.


a. The condition of a mixture of solid particles and water or air in which the solid particles are individually supported, normally by means of an upwardly moving current and sometimes with the assistance of mechanical agitation.

b. A mode of sediment transport in which the upward currents in eddies of turbulent flow are capable of supporting the weight of sediment particles and keeping them indefinitely held in the surrounding fluid (such as silt in water or dust in air). c. The state of a substance in such a mode of transport; also, the substance itself. d. A method of rock bolting employed to secure loose fragments or sections of rock that may fall from a mine roof.

suspension current

See: turbidity current.

suspension dryer

See: flash coal dryer.

suspensoid particles

Small solid particles suspended in a liquid; they exhibit the Brownian movement and do not settle by themselves, but can be readily coagulated.


Material in suspension that is to be filtered out.


A white mineral: (Mn,Mg)BO (sub 2) (OH). It is isomorphous with szaibelyite.

Sutton, Steele, and Steele dry table

A concentrator of the Wilfley type in motion, but instead of using water, stratification is by means of rising currents of air. Heavy grains are pushed forward by the head motion, while lighter grains roll or flow down the slope toward the tailing side.

suture joint

See: stylolite.


A hexagonal mineral, Ca (sub 5) (AsO (sub 4) ) (sub 3) F ; apatite group.


A trigonal mineral, SrAl (sub 3) (PO (sub 4) )(SO (sub 4) )(OH) (sub 6) ; beudantite group; at Wermland and Skane, Sweden.


See: celadonite.


a. A pistonlike device provided with a rubber cap ring that is used to clean out debris inside a borehole or casing.

b. See: bailer; sand pump. c. In well drilling, to pull the drill string so rapidly that the drill mud is sucked up and overflows the collar of the borehole, thus leaving an undesirably empty borehole. d. Procedure for applying suction within the casing or tubing to draw fluid from a reservoir rock. e. A rod with flexible rubber suction cups working inside the pipe on a wire line. f. A hemp brush used in founding, esp. for holding water, moistening mold joints, spraying on edges, or spreading blacking on dry-sand molds.


a. Newc. A thin layer of stone or refuse coal at the bottom of the seam.

b. N. of Eng. Impure shaly coal or black shale.


a. A shallow, water-filled hollow produced by subsidence, resulting from underground mining.

b. A digger's roll of blankets, containing spare clothes, food, etc.

swage block

A large rectangular block of cast iron used by a blacksmith. It is pierced through with numerous holes, both round and square in section, for the reception of work that requires shouldering.

swallet hole

See: sinkhole.


Derb. A loose, broken, or porous place in a vein. It derives its name from the ease with which water sinks through the loose material.


As applied to a mining claim, to clear a narrow strip along the boundary line, where the location is on timberland.

swamp buggy

Any vehicle with very large, low-pressure tires enabling it to be used in swamps.

swamp ore

See: bog iron; bog iron ore.


a. In diamond grinding operations, a relatively dry dust derived either from grinding operations where no coolant or lubricant is applied to the grinding operation or where the coolant (kerosene, an aqueous solution, or an emulsion of oil and water) is sprayed on the wheel as a fine mist.

b. Fine metallic particles removed by a cutting or grinding tool; chippings and shavings from soft iron castings used as a reducing agent in various chemical syntheses. c. Scot. A tool for widening boreholes. d. An intimate mixture of grinding chips and fine particles of abrasive and bond resulting from a grinding operation.


See: dike swarm.


A monoclinic mineral, CaMg(UO (sub 2) )(CO (sub 3) ) (sub 3) .12H (sub 2) O ; radioactive; green; forms an efflorescence with gypsum, schroeckingerite, bayleyite, and andersonite.


Derb. A soft clay in the vein.

S wave

A body wave that travels through the interior of an elastic medium with particle motion perpendicular to the direction of propagation. Originally applied to earthquake seismology, where it was the second (hence: S) type of wave to arrive at a recording station. Syn: distortional wave; equivolumnar wave; rotational wave; secondary wave; shear wave. See also: transverse wave.


A sideways movement, such as sidesway, in a structural frame.

swaying of a bank

York. Undergoing disturbance due to weight of the roof. A settling of the mine roof.

sway rod

A diagonal brace designed to resist wind or other horizontal force acting on a structural framework.


a. Eng. To burn slowly.

b. To melt and run down; to waste away without feeding the flame. A candle is said to sweal when the grease runs down owing to its burning in a strong current of air or being improperly carried or fixed.


a. To gather surface moisture in beads as a result of condensation. The roof of a mine is said to sweat when drops of water are formed upon it, by condensation of steam formed by the heating of the waste or goaf.

b. To exude nitroglycerin; said of dynamite in which nitroglycerin separates from its adsorbent.


See: thawing.


a. The condensation of moisture and distillation products on the surface of a roast heap, forming a damp and sticky crust.

b. See: exudation.

sweating out

Bringing small globules of one of the low-melting constituents of an alloy to the surface during heat treatment, such as lead out of bronze.


A hexagonal mineral, NaBe (sub 4) SbO (sub 7) ; at Laangban, Sweden.

Swedish bit

See: chisel bit.

Swedish iron

An iron of highest quality owing to the freedom from phosporus and sulfur of the Swedish ore.

Swedish mining compass

A compass in which a magnetic needle is suspended on a jewel and a stirrup so that it can rotate about both a horizontal and a vertical axis.


a. Aust. That part of a branch that reunites with the main vein farther on.

b. In founding, a profile pattern, used esp. in forming molds for cylindrical or other symmetrical articles. c. A form or template used for shaping sand molds or cores by hand. d. A curved metal blade projecting from the central shaft of a pug mill to force clay through holes at the bottom.


See: sweeps.

sweeping table

Stationary circular buddle provided with rotating brushes that prevent formation of channels as pulp flows radially across.

sweep plates

Eng. Curved plates for barrowways at a turn. A turnsheet.


a. The dust of the workshops of jewelers, goldsmiths, silversmiths, and assayers and refiners of gold and silver. Also called sweeping.

b. Brushwood arms on round buddles that rotate slowly and break down channels as ore slime runs across the surface.


Valuable metal washed from sweeps.


a. Eng. Free from combustible gases or other gases, or from fire stink.

b. Applied to potable water and to oil and gas free of hydrogen sulfide. c. Said of crude oil or natural gas that contains few or no sulfur compounds. CF: sour.

sweetish astringent

Applied to those minerals that have the taste of alum.

sweet roast

See: dead roast.

sweet roasting

Complete roasting or until arsenic and sulfur fumes cease to form. See also: roasting.

sweet water

See: fresh water.


a. A space in a seam from which the coal has been eroded and its place filled with clay or sand. Syn: horseback.

b. A local enlargement or thickening in a vein or ore deposit, as opposed to a pinch. c. The tendency of soils, on being removed from their natural, compacted beds, to increase in volume owing to an increase in void ratio; i.e., the space between soil particle increases. d. A low dome or quaquaversal anticline of considerable areal extent. e. Waves caused by the wind but no longer being activated. f. Long and generally symmetrical waves, period approx. 10 s, produced by storm and wind remote from the point of observation. These are gravity waves and contribute to the mixing processes in the surface layer and thus to its sound transmission properties. g. In geology, a large-scale submarine topographic feature rising above the surrounding surface and having nearly equal length and width.

swelled coupling

A rod coupling having a considerably larger outside diameter than the drill rods to which it is threaded, such as BW rod outside diameter with AW rod threads. Syn: oversize coupling.

swelled ground

a. A soil or rock that expands when wetted.

b. Soil or rock that flows into mine workings as a result of pressure.

swelling number

A numerical expression to indicate the relative swelling properties of a sample when heated under standardized conditions.

swelling of shale

When a shaft is sunk through a thick, dry deposit of shale, the absorption of water may cause the shale to swell and damage the shaft lining. Again, when shale is exposed to weathering, the lamina tends to separate and the material swells. When wet, the disintegrated mass still further swells and eventually becomes a plastic clayey deposit.

swelling pressure

a. The pressure that heated and softened coal exerts when it is obstructed from free swelling.

b. The pressure exerted by a contained clay when absorbing water in a confined space.


A depression in a mine road from which the road rises both ways.

swimming stone

See: floatstone.


a. A variety of marble that gives off a fetid odor when broken or rubbed. Also called stinkstone. See also: bituminous limestone.

b. See: fetid calcite. c. See: anthraconite.


a. In power-shovel nomenclature, the rotation of the superstructure on the vertical shaft in the mounting.

b. In revolving shovels, to rotate the shovel on its base. c. See: swing radius. d. In churn drills, to operate a string of tools.

swing angle

The distance in degrees that a shovel must swing between digging and dumping points.

swing cut

See: slabbing cut.

swing-hammer crusher

a. A rock breaker in which crushing force is generated by hammers loosely mounted on a rapidly revolving shaft. Rock entering the crushing chamber is hit and rebounds against liner plates of walls or against other rock, until small enough to escape through a grid.

b. A machine in which size reduction is effected by elements loosely pivoted to disks fitted on a rotating horizontal shaft mounted in a surrounding casing. Also called pulverizer; swing-hammer mill; swing hammer. See also: Jeffrey crusher.

swing-hammer regulator

A simple method of regulating the flow of lump ore in a chute. It consists of several heavy pivoted hammers that allow fine ore to pass through, but check the passage of lumps.

swinging a claim

The adjustment of the boundaries of a mining claim to more nearly conform to the strike of the vein. A reasonable time is allowed the discoverer to explore the vein or lode to find out its strike and make the adjustment.

swinging-electrode controller

This controller is made up of three fixed electrodes consisting of groups of parallel plates of noncorroding alloy fixed at the bottom of curved troughs of insulating material of uniform width and varying depth. The trough is deep at the end, corresponding to full speed and minimum resistance; it is shallow at the maximum-resistance starting position. The moving electrodes, of similar construction, are joined to form the star point of the rotor and are moved toward or away from the fixed electrodes, giving a wide range of resistance.

swinging-gate anemometer

An instrument of the steady deflection type where speed is read off directly from the scale of the instrument. This is most useful for measuring low speeds, since it permits a spot reading. This instrument does not integrate and is used extensively in work connected with the ventilation of building interiors and to a fair extent underground.

swinging plate

An amalgamated copper plate hung in a sluice to catch float gold.

swinging-vane anemometer

This instrument consists essentially of a damped, pivoted vane that is deflected when placed in an airstream. As the weight of the vane is constant, the angle of inclination will be dependent upon the rate of change of momentum of the impinging airstream. The instrument gives a direct reading and can be calibrated for use over a wide range of velocities, from 20 to 2,000 ft/min (6.1 to 609.6 m/min). In underground airways, it can be used without attachments. Its main use is the measurement of air velocity in ducts and the rate of air discharge from ventilating grills.

swing-jib crane

A crane with one horizontal boom on which there is a counterweight. It can#WORD �43� �53� tower crane �23743� �23744� swing through a full circle. See also: tower crane.

swing loader

A tractor loader that digs in front and can swing the bucket to dump to the side of the tractor.

swing loose

Arkansas. To gradually loosen over a considerable area and sag; said of the rock over a mine working.

swing of a lathe

The largest diameter of work that can be carried between the centers of a lathe. In England, the swing refers to radius.

swing parting

Arkansas. A parting some distance from the mouth of an entry. The loaded cars are left by the gathering driver to be taken out by a swing driver.

swing radius

See: swing.

swing roller

In a revolving shovel, one of several tapered wheels that roll on a circular turntable and support the upper works.

swing shift

a. Workday from 4 p.m. to midnight.

b. Occasionally refers to the 12 midnight to 8 a.m. shift. c. Working arrangement in a three-shift continuously run plant that changes working hours at regular intervals. During swing the old morning shift becomes the new afternoon shift. The afternoon shift of the first period must work the morning shift of the next with only an 8-h break on the first day of change.

Swiss lapis

A fraudulent imitation of lapis lazuli (lazurite) obtained by staining pale-colored jasper or ironstone with ferrocyanide. Also known as German lapis. See also: false lapis.


a. A mine switch is a device for enabling a car or a trip of cars to pass from one track to another. The term switch is also frequently used in a loose sense to apply to the whole side track or turnout, and a car standing on a side track is frequently said to be standing on the switch. See also latches.

b. Eng. A mechanical device for opening and closing an electric circuit; a mechanism for shifting a moving body in another direction.


a. A zigzag arrangement of a roadway (or rail tracks) for surmounting the grade of a steep hill or the slope wall of a surface or open-pit mine. Common in mountainous mining districts.

b. A hairpin curve. c. See: shunt back.


This is a general term applied to switching, interrupting, controlling, metering, protective, and regulating devices, as well as assemblies of these devices with associated interconnections, accessories, and supporting structures. The term is used primarily in connection with generation, transmission, distribution, and conversion of electric power.

switch plate

An iron plate on tramroads in mines used to change the direction of movement. Syn: turnsheet.

switch point

A movable tongue or rail for diverting a train from one track to another.

switch throw

a. The arrangement of levers by means of which a switch is thrown for the straight track or the turnout.

b. The handle or lever by which a switch is operated.


A colloquial term used in the Wisconsin lead-mining region for an offshoot or branch of a main lode.

swivel coupling

a. A coupling where one link is made so that it can be rotated independently of other links. When such a coupling is used, one or more cars can be rotated on a revolving dump without uncoupling from the rest of the trip.

b. A coupling that gives complete rotary freedom to a deflecting wedge-setting assembly in boreholes.

swivel head

a. The assembly of a spindle, chuck, feed nut, and feed gears on a diamond-drill machine that surrounds, rotates, and advances the drill rods and drilling stem. On a hydraulic-feed drill, the feed gears are replaced by a hydraulically actuated piston assembly. Also called boring head; drill head; drilling head; gate.

b. In a diamond drill, the mechanism that rotates the kelly and drill string.

swivel-head bevel gear

The bevel gear mounted on the outside of the drive quill in the swivel head of hydraulic-feed and/or some types of gear-feed diamond drills. The gear meshes with, and is driven by, a matching gear on the drill-motor shaft.

swivel hoisting plug

See: hoisting plug.

swivel neck

Syn. for a water or a mud swivel in borehole drilling. Also called gooseneck.

swivel plug

See: hoisting plug.

swivel trough

A short, adjustable-angle trough that permits turning the conveyor panline any amount up to 30 degrees , either to the right or to the left. The position of the swivel is controlled by a roof jack and a pendulum.

swivel vise

A bench vise that may be rotated on its base to bring the work that it holds into better position.

sycee silver

Pure, uncoined, lump silver of various sizes, usually stamped with a banker's or assayer's seal; used by the Chinese as a medium of exchange and reckoned by weight. The larger lumps, sometimes called shoes, are boat shaped and weigh about 1 lb troy (370 g).


A group of plutonic rocks containing alkali feldspar (usually orthoclase, microcline, or perthite), a small amount of plagioclase (less than in "monzonite"), one or more mafic minerals (esp. hornblende), and quartz, if present, only as an accessory; also, any rock in that group; the intrusive equivalent of "trachyte." With an increase in the quartz content, syenite grades into "granite." Its name is derived from Syene, Egypt. A.G. Werner in 1788 applied the name in its present meaning; the Egyptian rock is a granite containing much quartz.


A group of plutonic rocks intermediate in composition between syenite and diorite, containing both alkali feldspar (usually orthoclase) and plagioclase feldspar, commonly more of the former; also, any rock in that group. Generally considered a syn. of monzonite, but may also include both monzonite and rocks intermediate between monzonite and diorite (Streckeisen, 1967). See also: monzonite.


A plutonic rock differing in composition from gabbro by the presence of alkali feldspar.


Former name for native tellurium and for sylvanite.


a. A monoclinic mineral, 2[AuAgTe (sub 4) ] ; soft; metallic; commonly in implanted crystals resembling written characters; sp gr, 8.1; in quartz veins; a source of gold and silver. Also spelled silvanite. Syn: graphic ore; graphic tellurium; white tellurium; yellow tellurium; goldschmidtite.

b. An old name for native tellurium.


A hand-operated device for withdrawing supports from the waste or old workings. The appliance enables a leverage of about 30 to 1 to be applied. A long chain allows it to be positioned a safe distance from the support to be extracted. It may also be used for applying tension or for moving machines short distances. See also: tension end; monkey winch.

Sylvester process

A three-step method for the recovery of manganese and iron from open-hearth slag and low-grade ores.


The name for potassium chloride found native in the salt deposits at Stassfurt, Germany. See also: sylvite.


A mining term for the mixtures of sylvite and halite occurring in the Prussian salt deposits; mined as potassium ore.


An isometric mineral, 4[KCl] ; cubic cleavage; bitter salty taste; soft; white; in evaporite deposits and around fumaroles; the chief source of potassium. Syn: sylvine; leopoldite.


Two or more organisms living together to the mutual benefit of both.


A diagram, design, letter, color hue, abbrev., or other graphic device placed on maps, charts, and diagrams, that by convention, usage, or reference to a legend is understood to represent a specific characteristic, feature, or object, such as structural data, rock outcrops, or mine openings.

symbols of crystal faces

a. The mathematical expressions for designating the position of crystal faces on coordinate axes. See also: Miller indices; plane.

b. Any sign or letter used in crystallography to designate a group of smaller faces.

symmetrical dispersion

In optical mineralogy, the dispersion that produces an interference figure with color distribution symmetrical to the trace of the axial plane and also to a line normal to it.

symmetrical fold

A fold whose limbs have the same angle of dip relative to the axial surface. CF: asymmetric fold. Syn: normal fold.

symmetric spread

See: split spread.


a. Symmetry in crystallography results from periodic repetition. A symmetry element is the geometrical locus about which a group of repeating operations acts. It may be a center, a mirror plane, or a rotation axis.

b. A symmetry group is a collection of symmetry elements that may intersect at a point (point group) or that may be distributed in three-dimensional space (space group). See also: point group. c. The symmetry of a fabric is the combined symmetry of all the elements making up the fabric. There are five possible symmetries: (1) spherical, for fabrics having the symmetry of a sphere; (2) axial, for fabrics having the symmetry of a spheroid; (3) orthorhombic, for fabrics having the symmetry of a triaxial ellipsoid; (4) monoclinic, for fabrics having one unique plane of symmetry; and (5) triclinic, for fabrics having no planes of symmetry.

symmetry axis

See: axis of symmetry; crystal axis.


Red shale, Shropshire, United Kingdom. See also: calamanco.

symond strings

Thin veins of calcium carbonate running through the coal. Also spelled simon strings.

symon fault

A syn. of horseback, named after such a structure in the Coalbrookdale coalfield of England that was originally thought to be a large fault. See also: horseback.

Symon's cone crusher

A modified gyratory crusher used in secondary ore crushing that consists of a downward-flaring bowl within which is gyrated a conical crushing head. The main shaft is gyrated by means of a long eccentric that is driven by bevel gears. See also: gyrasphere crusher.

Symon's disk crusher

A mill in which the crushing is done between two cup-shaped plates that revolve on shafts set at a small angle to each other. These disks revolve with the same speed in the same direction and are so set as to be widest apart at the bottom. Feed is from the center, and the material is gradually crushed as it nears the edge and is then thrown out by centrifugal force.

sympathetic detonation

a. Detonation of an explosive material by means of an impulse from another detonation through air, earth, or water.

b. The initiation of an explosive charge without a priming device by the detonation of another charge close by. Syn: flash over.


Said of a rock texture produced by the intimate intergrowth of two different minerals; sometimes the term is restricted to such textures of secondary origin. One of the minerals may assume a vermicular habit. Also, said of a rock exhibiting such texture, or of the intergrowth itself; i.e., symplectite. Also spelled: symplektic; symplectitic; symplektitic. CF: dactylitic.


An intimate intergrowth of two different minerals, sometimes restricted to those of secondary origin; also, a rock (igneous or thermally metamorphosed) characterized by symplectic texture. Also spelled: symplektite. CF: pegmatite.


A triclinic mineral, Fe (sub 3) (AsO (sub 4) ) (sub 2) .8H (sub 2) O ; vivianite group; dimorphous with parasymplesite; soft.

symptomatic mineral

See: diagnostic mineral.


A triclinic mineral, (Mn,Mg,Ca,Pb) (sub 9) (AsO (sub 3) )(AsO (sub 4) ) (sub 2) (OH) (sub 9) .2H (sub 2) O(?) ; pseudo-orthorhombic.


Proposed by Sederholm and applied to those primary minerals in igneous rocks that are formed by the reaction of two other minerals, as in kelyphite rims, reaction rims, etc.


A rare, weakly radioactive, orthorhombic or monoclinic mineral, Ca(Ce,Nd,Y,La)(CO (sub 3) ) (sub 2) F , usually found in pegmatites associated with aegirite, microcline, astrophyllite, fluorite, gadolinite, xenotime, cordylite, and catapleiite. May be related to parisite. Also spelled synchysite.


A silent-shift transmission construction in which hub speeds are synchronized before engagement by contact of leather cones.


See: synchronous.


The state of being synchronous or simultaneous; coincident existence, formation, or occurrence of geologic events or features in time, such as glacial synchroneity. Syn: synchronism.


See: synchronous.


The state when the phase difference between two or more periodic quantities is zero; they are then said to be in phase. See: synchroneity.


Occurring, existing, or formed at the same time; contemporary or simultaneous. The term is applied to rock surfaces on which every point has the same geologic age, such as the boundary between two ideal time-stratigraphic units in continuous and unbroken succession. It is also applied to growth (or depositional) faults and to plutons emplaced contemporaneously with orogenies. CF: isochronous; diachronous. Syn: synchronal; synchronic.

synchronous motor

This type of motor has a stator similar to a squirrel cage motor, but the rotor has a direct-current field winding with salient poles equal in number to the stator poles. The direct current is supplied to the field winding through slip rings. In addition to the direct-current field windings, the rotor normally has a squirrel cage (amortisseur) winding that is used for starting.


Orthorhombic minerals, synchysite-(Ce) CaCe(CO (sub 3) ) (sub 2) F , synchysite-(Nd) CaNd(CO (sub 3) ) (sub 2) F , and synchysite-(Y) CaY(CO (sub 3) ) (sub 2) F (doverite) of the bastnaesite group; pseudohexagonal. See: doverite.


An obsolete form of syncline.--adj. Pertaining to a syncline. CF: anticlinal.

synclinal axis

In geology, the central line of a syncline, toward which the beds dip from both sides. See also: axis.

synclinal mountain

A mountain whose geologic structure is that of a syncline. CF: anticlinal mountain.

synclinal valley

A valley whose geologic structure is a syncline. CF: anticlinal valley.


A fold in which the core contains the stratigraphically younger rocks; it is generally concave upward. CF: anticline. See also: synform; synclinal.


a. A compound syncline; a closely folded belt, the broad general structure of which is synclinal. Also called synclinore.

b. A major syncline composed of many smaller folds. See also: geosyncline.

syndicate man

In bituminous coal mining, a person who works with a party of miners who operate machines for undercutting, drilling, and loading coal into cars at the working face and are paid on a basis of tonnage of coal mined.


a. Action of two agents, usually two chemicals, to produce an end effect greater than or different from the sum of the effects of the two agents acting separately.

b. Used in metallurgy with reference to reagent combinations to obtain the maximum possible recovery of ore or metal.


A fold whose limbs close downward in strata for which the stratigraphic sequence is unknown. CF: syncline; antiform.


a. Said of a mineral deposit formed contemporaneously with, and by essentially the same processes as, the enclosing rocks. CF: epigenetic.

b. Said of a primary sedimentary structure, such as a ripple mark, formed contemporaneously with the deposition of the sediment.

syngenetic deposit

A deposit formed contemporaneously with the parent rock and enclosed by it. There are two types of syngenetic deposits, igneous and sedimentary. Some examples are nickeliferous sulfides, nontitaniferous magnetite, diamond, chromite, and corundum.


See: syntectonic.


A mechanism by which small plagioclase crystals float into growing phenocrysts of potassium feldspar. Also, said of the texture of a rock showing such crystals. Etymol: Greek, to swim together.


Said of a geologic process or event occurring during a period of orogenic activity; or said of a rock or feature so formed. CF: syntectonic.

synorogenic pluton

An igneous intrusion emplaced during a period of orogenic activity.


An intergrowth between two mineral species in which single or multiple unit cells coincide in size and shape, e.g., bastnaesite-synchisite. CF: distaxy; epitaxy; topotaxy; polycrystal.


The adj. of syntexis.


A rock formed by syntexis.


Said of a geologic process or event occurring during any kind of tectonic activity, or of a rock or feature so formed. CF: synorogenic. Syn: synkinematic.


a. The formation of magma by melting of two or more rock types and assimilation of country rock; anatexis of two or more rock types.

b. Modification of the composition of a magma by assimilation. c. Any kind of reaction between a rising body of magma and the crustal rocks with which it comes into contact.--Adj: syntectic. See also: anatexis.


The production of a chemical compound by the union of elements or of simpler compounds or by the degradation of a complex compound, esp. by laboratory or industrial methods.


See: synthetic stone.

synthetic diamond

a. A diamond produced artificially by subjecting a carbonaceous material to extremely high temperature and pressure; currently and commonly called MM and/or manmade diamond. See also: manmade diamond.

b. A misnomer for sintered tungsten carbide.

synthetic gem

One artificially made from chemicals.

synthetic mineral

An artificial substance having all the properties of a mineral.

synthetic ore

Material that is the equivalent of, or better than, natural ore, can be put to the same uses, and is produced by means other than ordinary concentration, calcining, sintering, or nodulizing.

synthetic ruby

In chemical composition and in all their physical characters, including optical properties, synthetic ruby and synthetic sapphire are true crystalline ruby or sapphire, but they are produced in quantity in the laboratory by fusing pure precipitated alumina with a predetermined amount of pigmentary material. They can be distinguished from natural stones only by the most careful examination. Syn: synthetic sapphire.

synthetic sapphire

See: synthetic ruby.

synthetic stone

A man-made stone that has the same physical, optical, and chemical properties, and the same chemical composition, as the genuine or natural stone that it reproduces. Many gem materials have been made synthetically as a scientific experiment, but only corundum, spinel, emerald, rutile, garnet, quartz, chrysoberyl (alexandrite), opal, and turquoise have been made commercially and cut as gemstones for the jewelry trade. Syn: imitation. See also: synthetic.

syntron feeder

A feeder placed under a bin, hopper, or ore pass opening (or raise) that vibrates by the use of magnetic force to distribute ore evenly onto a moving conveyor belt. It can by adjusted to regulate the flow through various degrees of vibration.

syphon brick

A brick for tapping metal from the cupola, the primary object of which is to eliminate the tapping and botting up of the cupola tap hole each time metal is drawn off. With the syphon brick, the orifice from which the metal is drawn is continually open to the atmosphere, and the flow of metal is controlled by shutting the blast on and off. The case of control permits the use of quite small ladles at the cupola, so that there is no need for redistribution from large to small ladles.

Syrian garnet

Trade name for almandine garnet, of gem stone quality.


Former name for iridosmine.


a. A standard, worldwide division; contains rocks formed during a fundamental chronologic unit, a period. An example is the Devonian system.

b. The fundamental time-rock unit is the system. c. In crystallography, the division of first rank, in the classification of crystals according to form. The six systems ordinarily recognized are the isometric, tetragonal, hexagonal, orthorhombic (or rhombic), monoclinic, and triclinic; some divide the hexagonal system into hexagonal and trigonal. d. Applied to the sum of the phases that can be formed from one, two (binary system), three (ternary system), or more components under different conditions of temperature, pressure, and composition. e. The term system or general system of work means simply that the work, as it is commenced on the ground is such that, if continued, will lead to a discovery and development of the veins or orebodies that are supposed to be in the claim, or, if these are known, that the work will facilitate the extraction of the ores and mineral.

systematic error

Any error that persists and cannot be considered as due entirely to chance, or an error that follows some definite mathematical or physical law or pattern and that can be compensated, at least partly, by the determination and application of a correction; e.g., an error whose magnitude changes in proportion to known changes in observational conditions, such as an error caused by the effects of temperature or pressure on a measuring instrument or on the object to be measured. CF: random error.

systematic sampling error

a. An error that arises from some basic defect in the sampling or preparation process such that the result obtained is always either higher or lower than the true figure. Systematic errors are additive; i.e., if there are two sources of error, the total error is obtained by adding the individual errors.

b. An error due to some known physical law by which it might be predicted; those errors produced by the same cause affect the mean in the same sense and do not tend to balance each other but rather give a definite bias to the mean. An error that results from some bias in the measurement process and is not due to chance, in contrast to random error.

systematic support

The setting of timber or steel supports regularly at fixed intervals irrespective of the condition of the roof and sides; a support in accordance with a system specified in rules made by the manager of the mine.

systematic timbering

Placing mine timbers according to a predetermined plan, regardless of roof conditions.

systems of crystals

The seven large divisions into which all crystallizing substances can be placed, namely isometric (or cubic), tetragonal, hexagonal, trigonal, orthorhombic (or rhombic), monoclinic, and triclinic. This classification is based on the degree of symmetry displayed by the crystals.