Appendix:Dictionary of Mining, Mineral, and Related Terms/S/8

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small coal

a. Coal broken into small pieces, usually smaller than stove size; slack.

b. Coal with a top size less than 3 in (7.6 cm).

small colliery

Gr. Brit. Generally a colliery producing less than 1,000 st/d (907 t/d). See: large colliery.

small-diameter blastholes

Multiple row blasting with holes 1 to 3 in (2.5 to 7.6 cm) in diameter in low-face quarries. Short-delay blasting is usually adopted using explosive factors similar to those of large diameter holes. With smaller diameter blastholes, the explosive charges can be brought up higher in the holes and so provide better breakage in blocky ground.

Smalley process

A method for desulfurizing iron and steel with metal hydrides in which a molten slag is floated on a mass of molten ferrous metal and at least one metal hydride is introduced into the mass. The molten ferrous metal is separated from the slag, the metallic hydrides breaking down into metal and nascent hydrogen. Hydrides of the alkali metals have been found very satisfactory and are readily available.

small mine

A coal mine employing not more than 50 persons below ground.

small ore

Eng. Copper, lead, and zinc ore dressed to a small size. See also: smalls.


a. Small coal; slack.

b. One of the three main size groups by which coal is sold by the National Coal Board of Great Britain. It embraces all coals with no lower size limit and ranges from a top size of 2 to 1/8 in (50 to 3.3 mm), and can be either untreated, i.e., have received no preparation other than dry screening; or treated, having been washed or dry cleaned. See also: graded coal; large coal. c. Small particles of mixed ore and gangue. d. See: small ore.

small-stone bit

In mineral exploration drilling, a diamond bit set with 100% size or smaller diamonds.

small tin

Eng. Tin recovered from slimes.


An arsenide of cobalt, often containing nickel and iron. Also called gray cobalt; tin-white cobalt. See also: smaltite.


a. Arsenic-deficient variety of skutterudite. Syn: smaltine; tin-white cobalt; gray cobalt; white cobalt; speisscobalt.

b. A general term for undetermined, apparently isometric, arsenides of cobalt or for a mixture of cobalt minerals.


a. A precious stone of light green color; a variety of beryl.

b. See: emerald.


A thin-foliated variety of amphibole, near actinolite in composition but carrying some alumina. It has a light green color resembling much common green diallage.

smart aleck

A limit switch that cuts off power if a machine part is moved beyond its safe range.


A wreck, usually of haulage equipment.

smectic state

Liquid-crystalline state of some fatty acids and soaps in which bundles of long molecules are oriented into parallel layers. Smectic liquid crystals are composed of a series of planes. They glide rather than flow. When less completely oriented (nematic), they are distributed at random and flow.


a. Any clay mineral with swelling properties and high cation-exchange capacities; an expansive clay.

b. A term originally applied to fuller's earth and later to montmorillonite; also to certain clay deposits that are apparently bentonite, and to a greenish variety of halloysite. c. The mineral group beidellite, hectorite, montmorillonite, nontronite, pimelite, saponite, sauconite, sobotkite, stevensite, and swinefordite.


a. Fine particles of coal or ore.

b. Fine coal slack. Also spelled smiddam; smiddum; smitham; smithem; smitten; smytham.


See: smelting.


a. Person engaged in smelting or works in an establishment where ores are smelted.

b. An establishment where ores are smelted to produce metal. c. A furnace in which the raw materials of the frit batch are melted. See also: batch smelter; continuous smelter; rotary smelter.

smelter returns

In a contract, returns from the ore, less the smelting charges, without deducting transportation charges.


a. The chemical reduction of a metal from its ore by a process usually involving fusion, so that earthy and other impurities separate as lighter and more fusible slags and can readily be removed from the reduced metal. An example is the reduction of iron ore (iron oxide) by coke in a blast furnace to produce pig iron. Smelting may also involve preliminary treatment of ore, such as by calcination and further refining processes, before the metal is fit for a particular industrial use.

b. A process distinct from roasting, sintering, fire refining, and other pyrometallurgical operations. The two most important types are reduction smelting, which produces molten metal and molten slag, and matte smelting, which produces molten matte and molten slag. Smelting may be conducted in a blast furnace, a reverberatory furnace, or an electric furnace. Reduction smelting is usually performed in blast furnaces and matte smelting in reverberatories, but there are exceptions in both cases. Syn: smelt.

smelting furnace

A blast furnace, reverberatory furnace, or electric furnace in which ore is smelted for the separation of a metal.

smelting works

An establishment in which metals are extracted from ores by furnaces.


Derb. Lead-ore dust. A variation of smeddum.


Eng. A variation of smeddum.

smiddum tails

Eng.; Scot. Ore sludge; ore slime. A variation of smeddum.

Smidth agglomerating kiln

A rotary kiln providing an alternative method to sintering for the treatment of fine ores and flue dust.

smith forge

A small, open-hearth furnace utilizing an air blast with coal or coke for fuel. It is commonly used for heating small metal parts previous to manual, hot-working operations.


A monoclinic mineral, AgAsS (sub 2) ; dimorphous with trechmannite; red.

Smith process

a. A variation of the series system of copper refining in which the plates are placed horizontally, the top surface of each one acting as cathode, the lower as anode. Linen diaphragms must be placed between the plates to catch the slime. When these diaphragms break and allow the slime to drop on the cathode, it is difficult to remedy any short circuits without dismantling the tank.

b. A process for sponge iron production that is carried out in vertical ovens or retorts, similar to coke ovens in design. Crushed ore or iron oxide material is mixed with carbonaceous material and charged into the oven, where it is heated and cooled by means of horizontal flues. It is preheated in the upper part of the oven by the waste gases; then the charge enters the reduction zone, and is subsequently cooled by the incoming air for combustion in the heating flues.


a. A white to yellow, or to brown and rarely green or blue variety of zinc carbonate. See also: zinc carbonate.

b. A trigonal mineral, ZnCO (sub 3) , with Zn replaced by Fe; of the calcite group; rhombohedral cleavage; varicolored; commonly reniform, botryoidal, stalactitic, or granular; commonly altered from sphalerite in oxidized zones of limestone replacement; a source of zinc; distinguished from hemimorphite by its effervescence in acids. Syn: dry-bone ore; calamine; zinc spar; szaskaite. c. A term sometimes used as a syn. of hemimorphite.


Fine gravellike ore, occurring free in mud openings, or derived from the breaking of the ore in blasting. A variation of smeddum.


The exhalation, visible vapor, or material that escapes or is expelled from a burning substance during combustion; applied esp. to the volatile matter expelled from wood, coal, peat, etc. together with the solid matter that is carried off in suspension with it. That which is expelled from metallic substances is generally called fume or fumes. See also: fume; metallurgical smoke.

smokeless powder

Nitrocellulose containing 13.1% nitrogen. Produced by blending material of somewhat lower (12.6%) and slightly higher (13.2%) nitrogen content; converting to a dough with an alcohol-ether mixture; extruding; cutting; and drying to a hard, horny product. Small amounts of stabilizers (amines) and plasticizers are usually present, as well as various modifying agents (nitrotoluene and nitroglycerin salts).

smoke stick

A means of making a smoke cloud to measure the velocity of air. Fuming sulfuric acid or anhydrous tin tetrachloride are favorite smoke producers.


See: cairngorm; smoky quartz.

smoke technique

A technique used to measure only very low-speed air velocity. The release of smoke enables the fluid motion to be observed with the eye. If the smoke is timed over a measured distance along an airway of constant cross section then the velocity of flow can be determined. Usually a spot reading, that of maximum velocity, is obtained.

smoke tester

One who tests the efficiency of the Cottrell plant and flue recovery method by determining the rate of discharge of gases and solids from the smelter smokestack.

smoke tube

To determine the presence of moving air, the direction of flow, and the approximate velocity of flow, the smoke tube method is commonly used, particularly in metal mines. The device consists of an aspirator bulb, which discharges air through a glass tube containing a smoke-generating reagent. Usually pumice stone saturated with anhydrous tin or titanium tetrachloride is employed. The dense white cloud of smoke released when the bulb is squeezed travels with the air current; the approximate air velocity in a mine airway is determined by timing how long the cloud takes to travel between two points.

smoke washer

A device in which smoke is forced upward against a downward spray of water in order to remove the solid particles in the smoke.

smoke zone

The area surrounding a smelting plant in which the smoke or fumes damage vegetation, or in which it may be classed as a public menace or nuisance.

smoky quartz

A light to very dark brown variety of quartz sometimes used as a semiprecious gemstone. Syn: cairngorm; smokestone.

smoky topaz

A trade name for smoky quartz used for jewelry.

smooth blasting

A technique used in surface and underground blasting in which a row or closely spaced drill holes are loaded with decoupled charges (charges with a smaller diameter than the drill hole) and fired simultaneously to produce an excavation contour without fracturing or damaging the rock behind or adjacent to the blasted face. See also: controlled blasting.

smooth drilling

A rock formation in which a high recovery of core can be attained at a high rate of penetration.

smoother bar

A drag that breaks up lumps behind a leveling machine.

smooth-faced drum

Plain-faced drum without grooves.

smooth head

York. A smooth plane of cleavage. See also: bright head.

smoothing trowel

Trowel used by plasterers and cement workers for finishing surfaces.

smooth roll

A crusher in which the material passes between a moving set of rolls with smooth surfaces. See also: roll.

S.M.R.E. combustible gases recorder

This methane recorder is a combination of the principles used in the Ringrose and McLuckie detectors. Two combustion chambers are used, each of which operates every 6 min, the operation being staggered so that 20 determinations are made per hour. Samples are drawn into the instrument by means of an electrically driven pump, the operation of the pump and the combustion filaments being controlled by cams on a shaft driven by the motor. Pressures are measured by an aneroid cell and recorded on a clockwork driven drum.


a. Soft, inferior coal.

b. S. Staff. Bad, soft coal, containing much earthy matter. See also: muck. c. Coal smuts. d. Worthless outcrop material of a coal seam. e. Poor, dull, sooty portions of a coal seam. f. A reaction product sometimes left on the surface of a metal after a pickling or etching operation.


Lead ore that has been stamped or pounded down to a sand or powder to remove rock and earth from the ore.


A trigonal mineral, (Fe,Ni) (sub 9) S (sub 11) or (Fe,Ni) (sub 13) S (sub 16) ; physical properties are almost identical with monoclinic pyrrhotine.

snag boat

A boat equipped with a hoist and grapple for clearing obstacles from the path of a dredge.

snake fashion

A method of boxing core. Beginning in the upper-right-hand corner of the core box the core is run from right to left in the first row, from left to right in the second row, left to right in the third, etc., until the box is filled. CF: reverse book fashion.


a. A borehole driven horizontally or nearly so and approx. on a level with the quarry floor.

b. A borehole driven under a boulder for containing a charge of explosives. In quarry work, it is called a lifter. c. Nearly horizontal holes drilled at the bottom of the face of a bench. The holes are not quite horizontal but are inclined slightly downward so the bottoms will be a few feet below grade. d. A hole driven into a toe for blasting, with or without vertical holes.


a. A method of blasting boulders to break them up, by boring a hole under a boulder and firing a charge in it; this is more efficient but slower than using plaster shots. See also: plaster shooting.

b. A horizontal bore on the quarry floor. c. Drilling under a rock or face in order to blast it.

snake line

A line used to skid a drill rig from place to place using a block and tackle or cable, one end of which is attached to a deadman and the other wrapped around the hoisting drum.

snake statement

A monthly statement by a coal company on which a crooked line in red ink was drawn to show a miner's indebtedness. The company checked off rent, supplies, and groceries, which often added up to more than a miner's monthly earnings.


a. The progressive sliding forward of an armored flexible conveyor, by means of hydraulic rams, as the coal is removed by a cutter loader. See also: self-advancing supports.

b. Moving a drill rig by the use of its own cathead or hoist unit. See also: bulldog. c. Towing a load with a long cable. d. Inserting a tow or hoist line under an object without moving the object.

snaking conveyor

See: armored flexible conveyor.

snaphead rivet

A rivet having a hemispherical head.


a. A car coupler, trip rider, or brakeman.

b. See: grab sampler.

snatch block

a. A pulley in a case that can be easily fastened to lines or objects by means of a hook, ring, or shackle.

b. A single-rope sheave set in a housing provided with a latch link, which can be opened for admission of a rope or line without the necessity of threading the end of the rope through the block. c. A block or sheave with an eye through which lashing can be placed for fastening to a scaffold or pole. d. A sheave in a case having a pull hook or ring.


a. The latch or catch of a door.

b. To lay (rubblework) with spalls and fragments to fill the interstices.

Snell's law

a. The concept that the ray path of sound or light undergoes certain specific changes as it passes through different layers of water; the ratio of the sine of the angle of incidence to the sine of the angle of refraction is the same for all angles of incidence and is equal to the index of refraction.

b. Ordinary refraction where the index of refraction equals the sine of the angle of incidence divided by the sine of the angle of refraction. Syn: law of refraction. CF: ordinary ray.


The hole in the lower part of the windbore of a mining pump to admit the water.

snort valve

A butterfly valve opening from the cold-blast main of a blast furnace to the atmosphere. It allows casting at the furnace without shutting down the blowing engines; operated by large wheel or lever in the cast house.


Vapor-deposited skeletal ice crystals without a substrate; their accumulation; used for recreation and as a coolant. See: ice.

snow gage

See: rain gage.


a. To increase the height of an undercut by means of explosives or otherwise.

b. To check descent of a car, by a turn of a rope around a post. CF: jig chain. c. To check the descent of any object being lowered by hand.


In bituminous coal mining, a laborer who follows in the wake of a coal-cutting machine as it undercuts the face of coal, and breaks down the front of the working face above the channel with a pick so that the coal will drop freely when it is blasted.


a. A term applied by bluestone quarrymen to the process of forcing a cross break in the absence of an open seam.

b. Increasing the height of an undercut by picking or blasting down the coal, just above the undercut.

snub-drive conveyor

A conveyor in which a snub pulley is used.

snub pulley

An idler pulley so mounted as to increase the arc of contact between a belt and a drive pulley. When used in a wrap drive, it has the added function of changing the direction of the return belt travel.

Snyder sampler

A mechanical sampler consisting of a cast-iron plate revolving in a vertical plane on a horizontal axis, and having an inclined sample spout passing through the flange. The ore to be sampled comes to the sampler by way of an inclined chute and impinges upon the flange of the sampling disk. Whenever the sample spout comes in line with the ore stream, the ore passes through the plate and into the sample; at all other times the ore is deflected from the plate and drops into the reject. Generally, the sampler makes from 10 to 30 rpm, and removes about 1/5 of the ore stream.


a. A phase of a heating operation during which metal is maintained at the requisite temperature until the temperature is uniform throughout the mass.

b. Prolonged holding at a selected temperature.

soap earth

See: steatite.


See: soapstone.


a. Massive talc. Syn: steatite; soaprock.

b. A metamorphic rock of massive, schistose, or interlaced fibrous or flaky texture and soft, unctuous (greasy) feel; composed essentially of talc with variable amounts of mica, chlorite, amphibole, and pyroxene; alteration product of ultramafic rock; may be carved into art objects or sawn into dimension stone for use where chemical resistance or high heat capacity is needed. c. A miners' and drillers' term for any soft, unctuous rock. Syn: agalmatolite; Manchurian jade; talcum. d. See: saponite; talc.

soapy feel

Unctuous; said of talc and other magnesium minerals.

soapy heads

Eng. In stones, joints filled with saponaceous or talclike mineral.


An aluminum-rich variety of saponite(?).


a. A device fastened to the end of a rope by means of which the rope may be attached to its load; the socket may be opened or closed.

b. In blasting, the hole left after firing. c. A hollow tool for grasping and lifting tools that have been dropped into a well boring. d. The point in a borehole, usually in bedrock, at which the bottom end of a string of casing or drivepipe is set. e. To lower casing or drivepipe into, and seat it in, a borehole. f. An overshot. g. A fishing tool designed to encircle and grasp a cylindrical object. h. To spring a borehole. See also: camouflet. i. See: bootleg.


a. The normal carbonate of sodium, Na (sub 2) CO (sub 3) , soda ash; the latter being the common name of the commercial product used in chemical industries.

b. Sodium carbonate, Na (sub 2) CO (sub 3) ; esp. the decahydrate, Na (sub 2) CO (sub 3) .10H (sub 2) O. Loosely used for sodium oxide, sodium hydroxide, sodium bicarbonate, and even for sodium in informal expressions such as soda spar. A prefix added to the names of igneous rocks to indicate that they contain soda pyroxenes and/or soda amphiboles; e.g., soda rhyolite, soda trachyte, soda granite, etc. c. A former name for natron.

soda alum

a. An alum of aluminum and sodium. Occurs in nature as the mineral mendozite. See also: mendozite.

b. See: sodium alum.

soda-and-cleanup man

A laborer who sifts soda ash for use in refining copper.

soda ash

Commercial term for sodium carbonate, Na (sub 2) CO (sub 3) .

soda feldspar

A sodium-aluminum silicate occasionally used as a refractory raw material in the manufacture of porcelain enamels, giving a softer enamel when used to replace potash feldspar in equal weights. See also: albite.

soda hornblende

See: arfvedsonite.

soda lakes

a. Salt lakes, the water of which contains a high content of sodium salts (chiefly chloride, sulfate, and acid carbonate). These salts also occur as an efflorescence around the lakes.

b. For soda lakes where the water has evaporated leaving behind evaporite salts, the term "dry soda lakes" may be used.

soda lime

a. A granular mixture of calcium hydroxide with sodium hydroxide, or potassium hydroxide, or both, and sometimes with other substances (such as kieselguhr). Used to absorb moisture and acid gases, esp. carbon dioxide, as in gas masks.

b. Can refer to a type of glass container in which the principal ingredients are soda ash and lime.

soda-lime sinter process

Process for recovering alumina from red mud by mixing it with soda ash (Na (sub 2) CO (sub 3) ) and ground limestone, and sintering in a rotary kiln at temperatures of 1,800 to 2,000 degrees F (980 to 1,090 degrees C). This breaks up the sodium aluminum silicate and forms an insoluble calcium silicate and sodium aluminate. The sinter is leached with water to recover the sodium silicate, which is then treated in the same way as in the standard Bayer process.


a. An isometric mineral, Na (sub 8) Al (sub 6) Si (sub 6) O (sub 24) Cl (sub 2) ; sodalite group; typically blue or blue-violet; in various sodium-rich igneous rocks.

b. The mineral group hauyne, lazurite, nosean, and sodalite.


An urtite composed chiefly of sodalite, with smaller amounts of acmite, eudialyte, and alkali feldspar.

soda mica

See: paragonite.

soda microcline

A microcline in which sodium replaces potassium.

soda niter

See: nitratine; sodium nitrate.

soda nitrate

NaNO (sub 3) , widely used as a fluxing raw material in enamels, usually in conjunction with soda ash. A small percentage is beneficial in oxidizing any organic impurities. Also called Chile nitre; saltpeter. Syn: sodium nitrate.

soda orthoclase

Apparently monosymmetric feldspars with a notable amount of soda may be called soda orthoclase. When the soda equals or exceeds the potash, the crystals exhibit triclinic symmetry and are soda microcline.

soda prairie

An extensive level barren tract of land covered with a whitish efflorescence of sodium carbonate (natron), as in parts of southwestern and western United States and Mexico. Syn: salt prairie.

soda richterite

To replace the name astochite. See also: astochite.

soda spar

An informal term for sodic feldspar, i.e. albite, or for a feldspar mixture assaying at least 7% Na (sub 2) O. Syn: Na-spar. CF: potash spar.


An orthorhombic mineral, (UO (sub 2) ) (sub 2) SiO (sub 4) .2H (sub 2) O ; pale yellow; in pegmatites with malachite, in fissure fillings with curite and sklodowskite. Also spelled soddite.

Soderberg anode

A continuously formed anode for aluminum production in which the mixture of petroleum coke and coal-tar pitch is continuously added to a steel casing and is baked as it passes through the heated casing, such that the baked anode emerging into the cell continuously replaces the anode being consumed.

Soderberg electrode

A continuously formed electrode used in a metallurgical electrical furnace, in which a mixture of petroleum coke and coal-tar pitch is continuously added to a steel casing and is baked as it passes through the heated casing, such that the baked electrode emerging into the furnace continuously replaces the electrode being consumed; e.g., used in aluminum and ferroalloy production; may be oriented either vertically or horizontally.


a. A soft, bright, silvery metallic element; one of the alkali metals. Symbol, Na. It is a very reactive element and is never found free in nature. The most common compound is sodium chloride. Sodium compounds are important to the paper, glass, soap, textile, petroleum, chemical, and metal industries. Metallic sodium should be handled with great care; it should be kept in an inert atmosphere and contact with water avoided.

b. For some minerals with the "sodium" prefix, search under the root mineral name.

sodium alum

An isometric mineral, NaAl(SO (sub 4) ) (sub 2) .12H (sub 2) O . Syn: soda alum.

sodium arc light

See: sodium light.

sodium autunite

A tetragonal mineral, Na (sub 2) (UO (sub 2) )(PO (sub 4) ) (sub 2) .8H (sub 2) O ; meta-autunite group; radioactive; yellow.

sodium bentonite

See: Wyoming bentonite.

sodium-calcium feldspar

See: plagioclase.

sodium ethylxanthate

Pale green; NaC (sub 2) H (sub 5) OCSS ; molecular weight, 144.19; and soluble in water and in ethyl alcohol. An ore-flotation agent.

sodium feldspar

See: albite.

sodium hydroxide

See: caustic soda.

sodium illite

A sodium-rich illite. See: brammallite.

sodium light

Yellow light emitted by the glowing vapor of sodium, consisting of the D lines of sodium at wavelengths 5,890 Aa and 5,896 Aa; produced by special lamps and filters. Syn: sodium vapor light; sodium arc light.

sodium niobate

NaNbO (sub 3) ; a compound believed to be ferro-electric and having potential use as a special electroceramic. The Curie temperature is 360 degrees C.

sodium nitrate

Colorless; transparent; odorless; hexagonal; NaNO (sub 3) ; molecular weight, 84.99; slightly bitter taste; sp gr, 2.267; melting point, 308 degrees C; no boiling point because it decomposes at 380 degrees C; soluble in water, in ethyl alcohol, and in methyl alcohol; very soluble in ammonia; only slightly soluble in acetone; and slightly soluble in glycerol. Used as an oxidizer in solid rocket propellants, a flux, in glass manufacture, in military explosives, and in enamel for pottery. Also used in enamel frit batches to prevent reduction of any easily reducible ingredients, such as lead oxide. The function of sodium nitrate, when used in glass batches, is to oxidize organic matter and to prevent reduction of some of the batch constituents. Syn: soda niter. See also: soda nitrate.

sodium nitrate gelignites

These explosives are sometimes referred to as straight gelatins. They are really modifications of blasting gelatin in which varying percentages of nitroglycerin are replaced by sodium nitrate and combustible material to give a range of gelatinous explosives of varying strengths. The nitroglycerin content may be from about 30% to 80%. Straight gelatins are characterized by their plastic consistency; high densities of 1.5 to 1.6 g/cm (super 3) ; medium velocity of detonation of 2,500 m/s; good resistance to the effects of water, which also gives them good storage properties, and they possess fume characteristics suitable for underground workings. All the various requirements for metal mining, tunneling, and quarrying operations are covered by this wide range of gelatinous explosives. Their high resistance to water makes them particularly useful in wet conditions, and their relatively high density is advantageous where a powerful concentration of explosive energy is required.

sodium regulations

A permit, not including more than 2,560 acres (1,037 ha) in one State, is granted to prospect for chlorides, sulfates, carbonates, borates, silicates, or nitrates of sodium, and the royalty and rentals are similar to those for potash. Where necessary to secure the most economical mining, a person, association, or corporation may be permitted to hold up to 15,360 acres (6,221 ha) in one State.

sodium sesquicarbonate

Colorless, gray, or yellowish-white; monoclinic; Na (sub 3) (CO (sub 3) )(HCO (sub 3) ).2H (sub 2) O ; mol wt, 226.03; sp gr, 2.112, but ranges from 2.11 to 2.147 in the mineral; Mohs hardness, 2.5 to 3.0; soluble in water. Extensive deposits of sodium sesquicarbonate, variously known as the mineral natrona, trona, or urao, occur in California and Wyoming; in Hungary and Egypt; and in the deserts of Africa, Asia, and South America. Syn: natrona; trona; urao.

sodium tannate

Sometimes used as a deflocculant for clay slips; the effect is marked, only a small proportion being required. The material used for this purpose is generally prepared from NaOH and tannic acid; the former should be in excess and the pH should be about 8 to 9.

sodium tantalate

NaTaO (sub 3) ; a ferro-electric compound having the ilmenite structure at room temperature; the Curie temperature is approx. 475 degrees C. Of potential interest as a special electroceramic.

sodium uranate

Na (sub 2) (UO (sub 2) ) (sub 2) (ASO (sub 4) ) (sub 2) .8H (sub 2) O ; has been used as a source of uranium for uranium red.

sodium uranospinite

A tetragonal mineral, (Na (sub 2) ,Ca)(UO (sub 2) ) (sub 2) (AsO (sub 4) ) (sub 2) .5H (sub 2) O ; meta-autunite group; radioactive; yellow-green to yellow; forms fine, tabular to elongated crystals or radial fibrous aggregates; in the oxidation zone of primary hydrothermal deposits. It is the most abundant secondary uranium mineral.

sodium vanadate

NaVO (sub 3) ; a ferro-electric compound having potential use as a special electroceramic. The Curie temperature is approx. 330 degrees C.

sodium vapor light

See: sodium light.

sodium xanthate

a. Yellowish; amorphous; NaS.CS.OC (sub 2) H (sub 5) ; molecular weight, 144.19; and soluble in water and in ethyl alcohol. Used as a flotation agent.

b. See: sodium ethylxanthate.


An emanation, from the Earth, of vapors that are principally boric acid; also, the opening from which the vapors issue. See also: solfatara; fumarole; mofette.


a. Bituminous as opposed to anthracite coal.

b. In mineralogy, usually refers to minerals readily scratched by a needle or knife blade. c. Tender, friable, or full of slips and joints. d. As applied to a glass or glaze, refers to a low softening temperature; such a glass or glaze, when cold, is also likely to be relatively soft; i.e., of lower than average hardness, in the normal sense.

soft coal

Bituminous coal as opposed to anthracite. See also: bituminous coal.


To heat ore so that the minerals are cracked and fissured, permitting easier crushing.


a. Treatment in which metal is heated below its critical point and then slowly cooled.

b. Of lead, the removal of antimony and other impurities.

softening point

a. Certain materials do not have a definite melting point but soften over a range of temperatures. In certain refractory substances, the softening point is measured as the pyrometric cone equivalent (PCE), which is the number of that standard pyrometric cone whose tip would touch the supporting plaque simultaneously with a cone of the refractory material being investigated.

b. When referring to glass, the temperature at which the viscosity is 10 (super 7.6) P (10 (super 0.6) MPa.s); this viscosity corresponds to the temperature at which tubes, for example, can be conveniently bent. Also known as the 7.6 temperature; Littleton softening point.

soft formation

See: soft ground.

soft ground

a. That part of a mineral deposit that can be mined without drilling and shooting. It is commonly the upper, weathered portion of the deposit.

b. Heavy ground. Rock about underground openings that does not stand well and requires timbering.

soft-ground boring tool

Drilling tool used in soft ground, such as overburden, clay, soft shale, etc.

soft inclusion

Applied in the grading of quartz crystals to feathery or fernlike types of foreign inclusions, which look soft (no implication of physical hardness).

soft iron

Iron which can be worked with ordinary cutting tools or which can be readily abraded with files. It is darker gray in color than the harder cast iron.

soft mica

Mica which, when slightly flexed or distorted with thumb pressure, generally shows a tendency toward delamination. Such mica, in thick pieces, generally gives a dull sound when tapped against a hard surface.


ultimate tensile stress and large reduction in area. Usually the elongation is also high. In a notched bar test, specimens bend instead of fracturing, and energy absorbed is relatively small. See also: toughness; brittleness.

soft ore

A term used in the Lake Superior region for an earthy, incoherent iron ore mainly composed of hematite or limonite (goethite) and containing 45% to 60% iron.

soft phosphate

A term which is applied arbitrarily to anything phosphatic that is not distinctly hard rock.

soft radiation

Ionizing radiation of long wavelength and low penetration.

soft rock

a. A term used loosely for sedimentary rock, as distinguished from igneous or metamorphic rock.

b. Rock that can be removed by air-driven hammers, but cannot be handled economically by pick. CF: hard rock.

soft-rock geology

A colloquial term for geology of sedimentary rocks, as opposed to hardrock geology.

soft skin

A soft outer skin developed on burned diamonds.

soft steel

A general term applied to steels of low carbon content that do not temper. See also: mild steel.

soft vector

A plane or direction in a diamond or other mineral having less resistance to abrasion than that of the hard-vector planes. CF: hard vector.

soft water

Water free from calcium carbonate and calcium sulfate. CF: hard water; hardness.


a. All unconsolidated materials above bedrock. This is the meaning of the term as used by early geologists and in some recent geologic reports, and has been vigorously advocated by Legget (1967, 1973). It is the common usage among engineering geologists (see, e.g., compaction; soil mechanics). In recent years the approx. syn. regolith has come into wide geological use.

b. The natural medium for growth of land plants.--Etymol: Latin solum, ground. See also: sounding.

soil analysis

See: soil survey.

soil catena

A related sequence of soil profile types created by changes from one drainage condition to another. These changes are usually transitional.

soil cement

The addition of cement to a soil, as a binding agent, and converting it into a weak form of concrete. See also: cement stabilization.

soil classification tests

The tests are of two main types, namely: (1) mechanical analysis, performed by sieving or sedimentation, to determine the size-distribution of the constituent particles; and (2) index property tests, for soils passing a 36-mesh British Standard sieve, by means of which the type is deduced from the moisture content at standard consistencies. See also: index properties.

soil core

A cylindrical sample of soil for tests and examination. Undisturbed samples may be obtained by the use of special appliances, which allow extraction of soil cores of diameter usually 1-1/2 in (3.8 cm) or 4 in (10.2 cm). The core barrel, forming part of the coring tool, is detachable and is capped and the core hermetically sealed for delivery to the laboratory. The natural moisture content and other properties are preserved for examination. Individual soil cores, up to 3 ft (0.9 m) in length, may be obtained by continuous coring if necessary. See also: borehole samples; undisturbed sample.

soil creep

The gradual, steady downhill movement of soil and loose rock material on a slope that may be very gentle but is usually steep. Syn: surficial creep.

soil flow

See: solifluction.

soil fluction

See: solifluction.

soil formation

The processes whereby fragmental material resulting from rock weathering is transformed into a medium that can support plant growth.

soil-forming factors

Factors, such as parent material, climate, vegetation, topography, organisms, and time, involved in the transformation of an original geologic deposit into a soil profile.

soil horizon

A layer of a soil that is distinguishable from adjacent layers by characteristic physical properties, such as structure, color, or texture, or by chemical composition, including content of organic matter or degree of acidity or alkalinity. Soil horizons are generally designated by a capital letter, with or without a numerical annotation, e.g. A horizon, A2 horizon. Syn: horizon; soil zone; pedologic horizon.

soil mechanics

The application of the principles of mechanics and hydraulics to engineering problems dealing with the behavior and nature of soils, sediments, and other unconsolidated accumulations of solid particles; the detailed and systematic study of the physical properties and utilization of soils, esp. in relation to highway and foundation engineering and to the study of other problems relating to soil stability.

soil penetrometer

A sounding instrument, which may be used to supplement the vane test. It consists essentially of a rod inside a tube. When the appliance is mechanically jacked into the ground, the point or cone of the rod records all differences in resistance to penetration. It thus determines quickly the soil strength profile in depth and detects any soft beds in advance of the vane tests. See also: penetration log.

soil physics

The organized body of knowledge concerned with the physical characteristics of soil and with the methods employed in their determinations.

soil profile

A vertical section of a soil that displays all its horizons. Syn: profile.

soil sampler

a. A tube driven into the ground so as to obtain an undisturbed soil sample. In sands, such tubes would be fitted with a core catcher.

b. One of a number of different mechanical devices used for taking samples of an unconsolidated material. See also: solid-barrel sampler; split-tube barrel; split-tube sampler.

soil science

The study of the properties, occurrence, and management of soil as a natural resource. Generally it includes the chemistry, microbiology, physics, morphology, and mineralogy of soils, as well as their genesis and classification. Syn: pedology.

soil shredder

A machine employed in soil stabilization comprising two nearly touching half drums, which rotate in opposite directions and break up the soil.

soil stabilization

Chemical or mechanical treatment designed to increase or maintain the stability of a mass of soil or otherwise to improve its engineering properties. See also: cement-modified soil; cement stabilization; processing; pulverization.

soil structure

The arrangement and state of aggregation of soil particles in a soil mass. See also: flocculent structure; honeycomb structure; single-grained structure.

soil survey

a. A detailed investigation of the soils at a site, including boreholes and tests to determine their nature, thickness, strength, and depth to bedrock. See also: site investigation; soil mechanics.

b. Geochemical prospecting term for the chemical analysis of systematically collected samples of soil and weathered rock.

soil test

The laboratory procedure followed in examining and determining the physical characteristics of a soil sample.

soil zone

See: soil horizon.

Soisson Rodange process

A process for the manufacture of high-quality killed basic Bessemer steel in which the steel, after dephosphorization, is poured into another ladle containing the solid components of a basic oxidizing and fluid slag. Blowing for 30 to 40 s generates sufficient heat to promote mixing and to avoid skull. Phosphorus contents are readily lowered and high-quality killed steel is produced with low additional cost.


a. A homogeneous suspension or dispersion of colloidal matter in a fluid (liquid or gas).

b. A completely mobile mud. A sol is in a more fluid form than a gel.


a. A platform in a Cornish Mine shaft and esp. between a series of ladders; a longitudinal partition forming an air passage between itself and the roof in a mine. Usually spelled sollar or soller. See also: sollar.

b. A colloquialism used by surveyors to mean an observation on the sun.

solar salt

Salt obtained by solar evaporation of seawater or other brine in shallow lagoons or ponds.


a. To unite the surfaces of metals.

b. An alloy of uniting metals. Brazing solders are alloys of zinc and copper, while soft solders are alloys of tin and lead

soldier frame

Frame set into the inside of a shaft prior to breaking through for a heading.


a. The under surface of a rock body or vein, esp. the bottom of a sedimentary stratum.

b. The fault plane underlying a thrust sheet. c. The middle and lower parts of the shear surface of a landslide. d. The major fault plane over which other beds ride forward as a group during distributive faulting. e. The lowest thrust plane in an area of overthrusting. Commonly rocks above are imbricated. f. The bottom of a level.

Solenhofen stone

A lithographic limestone of Late Jurassic age found at Solenhofen (Solnhofen), a village in Bavaria, West Germany. It is evenly and thinly stratified and contains little clays. See also: lithographic limestone.


A type of fumarole, the gases of which are characteristically sulfurous. Etymol: the Solfatara volcano, Italy.


Applied to a dormant or decadent stage of volcanic activity characterized by the emission at the surface of gases and vapors of volatile substances.


a. Coal that has not been undermined, shear cut, or otherwise prepared for blasting. Used in the expression, "shooting off the solid."

b. That part of the coal that cannot be thrown out by a single shot, or the coal beyond the loose end. Used in expressions describing holes drilled for blasting, such as "three feet into the solid," or "on the solid." c. Unmined; ungot. d. A rock having few open cracks, crevices, or joints and relatively unaffected by the weakening effects of weathering. e. A diamond free of cracks discernible by eye. f. The rock near underground openings that stands well without artificial support.

solid-barrel sampler

A straight-walled cylinder with or without a valve on the bottom. Used for taking soil samples. CF: soil sampler; split-tube sampler.

solid bearing

A one-piece bushing.

solid bit

See: noncoring bit.

solid bituminous material

Material having a penetration at 77 degrees F (25 degrees C), under a load of 100 g applied for 5 to 10 s.

solid car

A mine car equipped with a swivel coupling and generally used with a rotary dump. One or more cars are pulled into the rotary dump, which turns through 180 degrees and the coal is emptied out. See also: mine car.

solid couplings

Generally of either the flanged-face or the compression type. They are used to connect two shafts to make a permanent joint and usually are designed to be capable of transmitting the full load capacity of the shaft. This coupling has no flexibility, either torsional, angular, or axial, hence it is limited to those installations where rigid connections are suitable, particularly in line shafts and extension shafts.

solid crib timbering

Shaft timbering with cribs laid solidly upon one another.

solid-crown bit

See: noncoring bit.


Drawn from hollow ingots, or otherwise, on mandrels of successively decreasing diameters; said of certain seamless metal tubes.

solid drilling

In diamond drilling, using a bit that grinds the whole face, without preserving a core for sampling.

solid explosives

These explosives are employed to a certain extent in the form of a powder in cartridges, or as a light-running granulated mass, or as solid sticks. They have the disadvantage that the density of charging will be small, which means that the cost of drilling will be comparatively high.

solid fuels

Any fuel that is a solid; such as wood, peat, lignite, bituminous, and anthracite coals of the natural variety and the prepared varieties such as, pulverized coal, briquettes, charcoal, and coke. Divided into two broad classes: naturally occurring and manufactured.

solidification range

Temperature range over which mixtures (alloys, fluxes) melt. In a constitutional diagram, the area between liquidus and solidus.

solidification shrinkage

The decrease in volume of a metal during solidification.

solid loading

Filling a drill hole with all the explosive that can be crammed into it, except for stemming space at top.

solid map

Gr. Brit. A geological map showing the extent of solid rock, on the assumption that all surficial deposits, other than alluvium, are absent or removed.

solid packing

See: solid stowing.

solid road

Any roadway driven through the solid coal seam with rib sides. See also: narrow stall; narrow work.

solid rock

Gr. Brit. Bedrock.

solids handling pump

Usually a centrifugal pump designed to resist abrasion and used for pumping sand, gravel, fine coal, and ore tailings. Rubber linings are generally used, which last longer than steel or iron. See also: pulsometer.

solid smokeless fuel

A solid fuel, such as coke, which produces comparatively no smoke when burned in an open grate. See also: anthracite; briquette; coke.

solid solubility

The extent to which one metal is capable of forming solid solutions with another. This varies widely between different pairs of metals, some of which are mutually soluble in all proportions, while others are practically insoluble in each other.

solid solution

a. A single crystalline phase that may be varied in composition within finite limits without the appearance of an additional phase. Syn: mix-crystal; mixed crystal.

b. Partial or total miscibility between two or more crystal structures; e.g., ionic substitution. Syn: crystal solution. CF: isomorphous mixture; isomorphous series.

solid stowing

The complete filling of the waste area behind a longwall face with stone and dirt. The packing operation may be by hand or mechanical methods, e.g., pneumatic stowing. See also: double packing; stowing method; strip packing.


On a temperature-composition diagram, the locus of points in a system at temperatures above which solid and liquid are in equilibrium and below which the system is completely solid. In binary systems without solid solutions, it is a straight line; in binary systems with solid solutions, it is a curved line or a combination of straight and curved lines; in ternary systems, it is a flat plane or a curved surface.

solid web

The web of a steel beam consisting of a rolled section or a plate as distinct from a lattice.

solid woven conveyor belt

A construction of conveyor belt consisting of multiple plies of fabrics woven into one piece, which is done on looms designed for this purpose. Stripes are woven into the belt to show the number of plies, which range from 2 to 10. Impregnating and coating treatments are frequently employed.


The slow, viscous downslope flow of waterlogged soil and other surficial material, normally at 0.5 to 5.0 cm/yr; esp. the flow occurring at high elevations in regions underlain by frozen ground (not necessarily permafrost) that acts as a downward barrier to water percolation, initiated by frost action and augmented by meltwater resulting from alternate freezing and thawing of snow and ground ice. The term has been extended to include similar movement in temperate and tropical regions; also, it has been used as a syn. of soil creep, although solifluction is generally more rapid. It is preferable to restrict the term to slow soil movement in periglacial areas. Also spelled solifluxion. Syn: soil flow; soil fluction; sludging.


a. Landing stage in a mine shaft. Also spelled soller; solar.

b. A timber staging, alongside a haulage level, for piling ore ready for loading into mine cars. c. A staging between ladderway sections in a shaft. d. The plank flooring of a gallery covering a gutterway beneath. e. A longitudinal partition forming an air passage between itself and the roof in a mine working. f. A platform from which trammers shovel or throw the ore or rock into a car. g. A wooden platform fixed in a shaft for ladders to rest on. See also: air sollar.


See: sollar.

solonetz soil

A soil occurring most commonly under arid conditions, but may also be found in semiarid and subhumid regions. Usually found in depressions where it has originated by evaporation under shallow ground-water conditions. Characterized by sodium carbonate as the predominant salt and a dark-colored B horizon, which is strongly alkaline in reaction.


a. The extent that one material will dissolve in another, generally expressed as mass percent, or as volume percent or parts per 100 parts of solvent by mass or volume. The temperature should be specified.

b. The weight of a dissolved substance that will saturate 100 g of a solvent. c. Concentration of a substance in a saturated solution; i.e., in equilibrium between dissolved and undissolved phases at given temperature.

solubility product concentration

In a saturated solution of an electrovalent compound having limited solubility, the product of the ionic concentrations, at the exponential value shown in the stoichiometric equation for its dissociation, is constant at a given temperature.


Capable of being dissolved in a fluid.

soluble anode

An anode that goes into solution during an electrolytic process.

soluble glass

Solid sodium silicate or potassium silicate. Syn: water glass.


a. The substance dissolved in a solution, as distinguished from the solvent.

b. A substance dissolved in a liquid.


A substance that is a homogeneous mixture and has a continuous variation of composition up to a solubility limit.

solution breccia

A collapse breccia formed where soluble material has been partly or wholly removed by solution, thereby allowing the overlying rock to settle and become fragmented; e.g. a breccia consisting of chert fragments gathered from a limestone whose carbonate material has been dissolved away. See also: evaporite-solution breccia. Syn: ablation breccia.

solution cavity

A cavity formed in certain rocks in which percolating sollutions have filled with valuable minerals; cavities formed in certain rocks, such as limestones, where portions have been dissolved by percolating waters. See also: mineralization.

solution injection

Artificial cementing of loose soils or strata to increase their load-bearing capacity.

solution mining

a. The in-place dissolution of water-soluble mineral components of an ore deposit by permitting a leaching solution, usually aqueous, to trickle downward through the fractured ore to collection galleries at depth. It is a type of chemical mining. CF: in situ leaching.

b. The mining of soluble rock material, esp. salt, from underground deposits by pumping water down wells into contact with the deposit and removing the artificial brine thus created. c. Hydrometallurgical treatment of ore for recovery of the mineral values at the mine site, in conjunction with conventional open pit or underground mining procedures. See also: surface leaching.

solution pipe

A vertical cylindrical hole, formed by solution and often without surface expression, that is filled with detrital matter.

solution plane

A crystallographic direction of chemical solubility in a crystal, possibly due to exsolution of a second crystalline phase on falling temperature and/or pressure or to unannealed slip during plastic deformation. Solution planes may lead to parting in some mineral specimens.

solution ripple

See: scallop.

solution subsidence

Gradual subsidence of nonsoluble strata due to the solution of underlying rock.


A chemical compound consisting of a dissolved substance and its solvent, e.g. hydrated calcium sulfate.

Solvay process

Manufacture of sodium carbonate or soda ash, Na (sub 2) CO (sub 3) from salt (sodium chloride), ammonia, carbon dioxide, and limestone by a sequence of reactions involving recovery and reuse of practically all the ammonia and part of the carbon dioxide. Limestone is calcined to quicklime and carbon dioxide. The carbon dioxide is dissolved in water containing the ammonia and salt, with resulting precipitation of sodium bicarbonate. This is separated by filtration, dried, and heated to form sodium carbonate. The liquor from the bicarbonate filtration is heated and treated with lime to regenerate the ammonia. Calcium chloride is a major byproduct.


a. A substance used to dissolve another substance.

b. That component of a solution that is present in excess; or the physical state of which is the same as that of the solution.

solvent extraction

a. A method of separating one or more substances from a mixture, by treating a solution of the mixture with a solvent that will dissolve the required substances, leaving the others.

b. A process in which one or more components are removed from a liquid mixture by intimate contact with a second liquid, which is itself nearly insoluble in the first liquid and dissolves the impurities and not the substance that is to be purified. Syn: liquid-liquid extraction.


The method or equipment for determining, by underwater sound, the presence, location, or nature of objects in the sea. The word sonar is an acronym derived from the expression SOund NAvigation and Ranging.

sonar boomer seismic system

A complete continuous seismic profiling system consists of the boomer unit, sonar recorder, transducer fish, receiving hydrophone, preamplifier, if necessary, and variable filter. Sonar boomer units are available from 1000 W-second models up to 13,000 W-second (experimental models). The standard boomer consists of a power supply, capacitor bank and transducer. Boomers are used for marine geological studies and dredging surveys. The power supply output is fed to the capacitor bank, which is discharged into the transducer producing a precisely repeatable pressure pulse in the water.


A metamorphic rock composed of cordierite, quartz, garnet, tourmaline, and kyanite.


The elongate cylindrical tool assembly used in a borehole to acquire a well log. It contains various energy-input devices and/or response sensors. The sonde is lowered into the borehole by a multi-conductor cable, or wire line.

sonic drilling

Core drilling through high-powered vibrations transmitted down the drill casing to a cutting shoe. The casing and the shoe vibrate into the ground and through the rock, resulting in an undisturbed core of unconsolidated material.

sonic gage

See: acoustic-strain gage.

sonic log

An "acoustic log" showing the interval-transit time of compressional seismic waves in rocks near the well bore of a liquid-filled borehole. Used chiefly for estimating porosity and lithology.

sonic method

A method of measuring underground rock pressure by determining the velocity of sound through the rock. Sonic velocity is a function of the elastic modulus of the rock traversed by the wave, and this, in turn, is a function of the pressure. A hammer blow on the rock face is used to initiate the sound waves, which are picked up by a microphone placed at the site of the blow and by a second microphone at the other end of the path through the rock under test. The difference between the times of the signals received from the two microphones will equal the time taken by the sonic pulse to pass through the rock. The signals are converted into visible waveforms on the screen of an oscillograph, and these are photographed or otherwise recorded to form a permanent record.

sonic pile driver

A driver based on the principle of delivering vertical vibrations to the head of a pile in alternating up and down cycles at a rate of 100 Hz. These vibrations set up high-amplitude waves of tension and compression in the pile, producing alternate expansion and contraction in minute amounts. The elongation of the pile in expansion displaces the soil at the pile tip, and the weight of the pile, hammer, and added loads shoves the pile into the miniscule void. Since this action is occurring at the rate of 100 Hz, the individual movements need not be of great magnitude to produce rapid penetration of the pile.


An ultrasonic testing instrument used primarily for the measurement of the thickness of materials.


Solid, nonmetallic inclusions in metal.


An inspection instrument, which sends, by electronic means, pulses of high frequency through the material to be tested and measures the time of travel from the transmitter on one face to the receiver on the distant face of the material. This method of inspection is known as pulse testing.


Seismograph developed by Frank Rieber for the application of reflection methods to areas of complex geology and steeply dipping beds. The ordinary oscillograph traces are replaced by sound tracks of variable transparency on a moving picture film. The analyzer adds up impulses which are in phase while the random effects tend to cancel one another.


A monoclinic mineral, Mn (sub 9) (SiO (sub 4) )(OH,F) (sub 2) ; humite group; dimorphous with jerrygibbsite; red-orange.


An instrument for measuring rock stress. Piano wire is tuned between two bolts cemented into drill holes in the rock, and a change of pitch after destressing is observed and used to indicate stress.


A type of echo sounder that generates sound waves and records their reflections. It is used in subbottom profiling.

Sonstadt solution

A solution of mercuric iodide in potassium iodide with a density of 3.2 g/cm (super 3) and used as a "heavy liquid." CF: bromoform; Klein solution; methylene iodide; Clerici solution. Syn: Thoulet solution.


A black substance, consisting essentially of carbon from the smoke of wood or coal, esp. that which adheres to the inside of the chimney, containing also volatile products condensed from the combustion of the wood or coal, including certain ammonia salts.

sooty chalcocite

A black, pulverent variety of chalcocite of supergene origin.

sooty streamers

Fine and often unburned dust settling out in steamy, warm conditions in stagnant situations.


a. Cumb. A hematite iron-orebody of circular or oval plan and conical section, formed in a swallow hole.

b. Cumb. A nest or pocket of black lead.

Sophia-Jacoba process

See: Barvoys process.

sopwith staff

A telescopic self-reading staff dividing into three sections, set one above the other when the staff is at its full extent of 14 ft (4.3 m). Graduations are marked in feet, tenths and hundredths of a foot, and the thickness of the horizontal lines is 0.01 ft (3.05 mm), alternately black and white.


An old name for the glassy salbands of small, diabase dikes formerly regarded as a mineral. It is derived from Sordavala, Finland.

Sorel cement

Calcined magnesite or magnesia mixed with a solution of magnesium chloride. It sets to a hard mass within a few hours. The basis of artificial flooring cements.


A titanium slag containing about 80% TiO (sub 2) . It is made by electric-furnace smelting of iron-titanium ores.

Soret's principle

If differences of temperature are induced in a solution of sodium chloride or some other substance in water, the dissolved material will become relatively more concentrated in those portions in which the temperature is lowest.


A mountain sickness that attacks miners who are newcomers in high altitudes. Symptoms are headaches, nausea, vomiting, and nosebleed. If the symptoms do not soon pass, there is nothing to be done except return to a lower altitude.


Any type of retention of a material at a surface, esp. when the mechanism is not specified. Adsorption is then restricted to the physical process that leads to the formation of a unimolecular surface layer; chemisorption refers to the corresponding chemical process; and absorption to the entrance of the sorbed material within the solid.


See: graded.


a. In a genetic sense, it may be applied to the dynamic process by which granular or fragmental material having some particular characteristic, such as similar size, shape, specific gravity, or hydraulic value, is selected from a larger heterogeneous mass.

b. The degree of similarity, in respect to some particular characteristic, of the component parts in a mass of material. c. A measure of the spread of a distribution on either side of an average. d. The separation of coal or ore as mined into valuable material and waste. e. See: handpicking.

sorting coefficient

a. A coefficient used in describing the distribution of grain sizes in a sample of unconsolidated material. It is defined as S (sub 0) = Q (sub 1) /Q (sub 3) , where Q (sub 1) is the diameter that has 75% of the cumulative size-frequency (by weight) distribution smaller than itself and 25% larger than itself, and Q (sub 3) is that diameter having 25% of the distribution smaller and 75% larger than itself.

b. Dimensionless measure for degree of sorting.

soude emerald

See: emerald triplet.


a. The act of striking a mine roof with a metal testing bar to ascertain whether or not it is strong and safe.

b. A dam or barrier in a mine in which the frictional resistance to the passage of water is high. Such a dam permits little water to pass through it and is said to be "sound." c. Elastic waves in which the direction of particle motion is longitudinal; i.e., parallel with the direction of propagation. The term is sometimes restricted to such waves in gases, particularly air, and in liquids, particularly water, but it is also applied to wave motion in solids. It is the type of wave motion most often used in reflection-seismic exploration.

sound channel

Sound waves in the surface layers of the ocean tend to be refracted downward due to decrease of temperature with depth. In deep waters the sound waves are refracted upward by high and increasing pressure, which has a greater influence on the resulting refractive index of these layers than the decreasing temperature. The result is the formation at mid-depth of a wave guide that permits compressional waves of acoustic frequencies to travel great distances.


a. See: roof testing.

b. Rapping on a pillar to signal a person on the other side or to enable the person to estimate its width. c. A rough method of judging by sound the direction and distance apart of two roadways driven in coal to meet each other. The sounding is made by giving two slow and three sharp knocks on the solid coal, which is answered in similar manner from the opposite roadway. The method is sometimes called chap. d. Subsurface investigation by observing the penetration resistance of the subsurface material without drilling holes. This can be done by driving a rod into the ground or by using a penetrometer. See also: penetrometer; soil.

sounding lead

In measuring water depth, the hand lead used in sounding. See also: hand lead.

sounding rod

A closed pipe, 1 in (2.5 cm) in diameter, with a flush point and a driving tip, used in sounding. See also: sounding.

sounding the top

Tapping the roof with a pick or bar to test its soundness.

sound intensity

In a specified direction at any point, the average rate of sound energy transmitted in the specified direction through a unit area normal to this direction at the point considered.

sound velocity

The rate at which a sound wave travels through a medium. Velocity is equal to the square root of the bulk modulus divided by density.

sound wave

a. Sometimes used interchangeably with shock wave; technically, a wave motion in the air which affects the human ear as sound. Owing to the reflection of waves from the various surfaces, the sound is more or less prolonged, and as it reaches a given point is really a series of vibrations.

b. The wave of compression emanating from any sound source. Since sound travels as a wave of compression it heats the water as it passes through a water mass. Density and compressibility thus influence the velocity of sound; increasing density due to temperature, salinity, and pressure changes increases the velocity. High frequency waves above 10,000 Hz have very short range because absorption is high. Low frequencies have greater range. See: longitudinal wave.


a. Having an acid or tart taste; applied to minerals having the taste of sulfuric acid.

b. Said of crude oil or natural gas containing significant fractions of sulfur compounds. CF: sweet.


a. In seismic prospecting either: (1) the point of origin or shot from which elastic waves are propagated, or (2) the formation, horizon, interface, or boundary at which a seismic wave is refracted and/or reflected and returned to the surface. In earthquake seismology, the point of origin of an earthquake. In neutron logging, the source of neutrons at one end of the logging tool.

b. A radioactive material packaged to produce radiation for experimental or industrial use. c. The point of origin or procurement.

source area

The area from which the sedimentary material is derived.

source-receiver product

In seismic prospecting, the product of the number of detectors per trace and the number of sources used simultaneously.

source rock

The geological formation in which oil, gas, and/or other minerals originate.


a. Old-fashioned and seasoned prospector.

b. A miner who has lived in Alaska more than one season.

sour gas

Slang for either natural gas or a gasoline contaminated with odor-causing sulfur compounds. In natural gas the contaminant is usually hydrogen sulfide, which can be removed by passing the gas mixture through carbonate solutions containing special metal or organic activators. In gasolines, the sour contaminents are usually mercaptans, which are removed in the doctor treatment or by ethylene oxide with a phenolic catalyst. The improved gas or gasoline is known as sweet gas.


a. An alternative term for aging. See also: aging.

b. The storage for a short time of the moistened batch for making basic refractories; some magnesium hydroxide is formed and this acts as a temporary bond after the bricks have been shaped and dried. If souring is allowed to proceed too far, cracking of the bricks is likely during drying and the initial stages of firing. The high pressure exerted by modern brick presses generally gives sufficient dry strength without the bricks being soured, and souring is therefore now generally omitted.

South African diamond

Whole-stone diamonds having outside faces that are smooth as contrasted to the pebbly, encrusted surface of a Congo diamond; also applied to diamonds produced in South African mines as contrasted to those found in the Sierra Leone, Congo, Brazil, etc.


A distance measured southwards from an east-west reference line.

south-seeking pole

See: north-seeking pole.

South Staffordshire method

See: room-and-pillar.

southwestern cell

Pneumatic flotation machine consisting of a long tank with V-shaped base into which pipes connected with a low-pressure source deliver compressed air. Internal baffles provide an air lift and the cell discharges a mineralized froth along one or both sides, the tailing leaving at the far end. The Britannia cell is a modified form. See also: Britannia cell.


A monoclinic mineral, (Mg,Fe) (sub 3) (Al,Fe) (sub 4) (PO (sub 4) ) (sub 4) (OH) (sub 6) .2H (sub 2) O ; forms a series with gormanite; green.

sovereign gold

Standard 22 carat gold, containing 91.7% gold and 8.3% copper.


A carbonatite that contains calcite as a dominant phase. The name, given by Broegger in 1921, is for Soeve, Fen complex, Norway.


a. Mold of larger size than a pig.

b. A channel or runner that conducts molten metal to the rows of molds in a pig bed. c. A mass of metal solidified in such a channel or mold. d. An accretion that frequently forms in the hearth or crucible of a furnace; it consists mainly of iron. Also called salamander, bear, or shadrach.

Soxhlet thimble

A dust-sampling instrument. The apparatus gives a gravimetric mass sample, with no information on the size distribution of the dust collected. Is useful where a sample is needed for determining mass concentration and for collecting dust for chemical, petrological, and X-ray analysis. See also: Hexhlet sampler; tyndallometer.