Appendix:Dictionary of Mining, Mineral, and Related Terms/S/4

senaite
 * A trigonal mineral, Pb(Ti,Fe,Mn) (sub 21) O (sub 38) ; crichtonite group; black; forms rounded crystals and grains in diamond-bearing sands.

senarmontite
 * An isometric mineral, Sb (sub 2) O (sub 3) ; dimorphous with valentinite; resinous; Mohs hardness, 2 to 5; sp gr, 5.2 to 5.3.

sengierite
 * A monoclinic mineral, Cu (sub 2) (UO (sub 2) ) (sub 2) V (sub 2) O (sub 8) .6H (sub 2) O ; yellow-green.

sensible cooling effect
 * The difference between the total cooling effect and the dehumidifying effect.

sensible heat
 * a. Thermal energy, the transfer of which to or from a substance results in a change of temperature. CF: latent heat.

b. The heat added to a body when its temperature is changed. c. The sensible heat of a body is the heat given off when it cools to ordinary temperature.

sensitive earth fault protection
 * A system of earth fault protection in which the fault current is limited by design to a low value which generally requires amplification in order to operate an earth fault relay. In the case of three-phase alternating-current systems, the limitation of the leakage current may be effected by either (1) inserting a current-limiting device between the neutral point of the system and earth (single-point earthing), or (2) connecting, in each circuit to be protected, all phases, in star, through current-limiting devices, each star point being connected to earth through an earth leakage protective device (multipoint earthing).

sensitive explosive
 * See: explosive sensitiveness.

sensitiveness
 * The property in a high explosive that permits it to be exploded by a shock. The more insensitive an explosive is, the stronger detonator it requires to develop the full strength.

sensitive-tint plate
 * See: gypsum plate; selenite plate.

sensitivity
 * a. In explosives, a measure of the ease with which a substance can be caused to explode and its capacity to maintain explosion through the length of a borehole.

b. The least change in an observed quantity that can be perceived on the indicator of a given instrument. c. The displacement of the indicator of a recording unit of an instrument per unit of change of a measurable quantity. d. The effect of remolding on the shear strength and consolidation characteristics of a clay or cohesive soil. A sensitive clay is one whose shear strength is decreased to a fraction of its former value on remolding at constant moisture content. See also: sensitivity ratio.

sensitivity ratio
 * A measurement of the sensitivity of a clay to the action of remolding.

sensitivity to propagation
 * Sensitivity to propagation of an explosive can be ascertained by a method called the Ardeer double-cartridge, or ADC, test. The ADC test consists of firing an explosive cartridge with a standard detonator and determining the maximum length of the gap across which the detonation wave will travel and detonate a second, or receptor, cartridge. Both the primer and the receptor cartridges should be of the same composition, diameter, and weight.

sensor
 * The component of an instrument that converts an input signal into a quantity measured by another part of the instrument. Also called sensing element.

separate system
 * A drainage system in which sewerage and surface water are carried in separate sewers. See also: surface-water drain.

separate tandem electric mine locomotive
 * See: electric mine locomotive.

separate ventilation
 * An early term for auxiliary ventilation.

separating bath
 * a. A vessel containing dense medium in which the feed material is separated on a commercial scale into different fractions according to specific gravity.

b. The liquid in a separating bath.

separating medium
 * Dense medium of the density required to achieve a given separation.

separation
 * The distance between any two parts of an index plane (e.g., bed or vein) disrupted by a fault. See also: horizontal separation; vertical separation; stratigraphic separation.

separation coal
 * Eng. Coal that has been prepared by screening or washing.

separation density
 * The effective density at which a separation has taken place, calculated from a specific-gravity analysis of the products; commonly expressed as either partition density or equal errors cut point (density).

separation distances
 * Minimum recommended distance between explosive materials and other materials or specific locations.

separation door
 * a. A door to separate the air in an intake airway from that in a return airway and prevent leakage. It is normally constructed with tongued-and-grooved boards secured by battens, and it is built into brick or concrete walls to form an airtight closure of the airway. Separation doors are usually arranged in twos or threes several yards apart, to reduce leakage when workers or cars are passing along the roadway. See also: bearing door; steel separation door; ventilation doors.

b. See: air door.

separation size
 * A general term indicating the effective size at which separation has taken place, calculated from a size analysis of the product; commonly expressed as either partition size or equal errors size.

separation valve
 * Eng. A massive cast-iron plate suspended from the roof of a return airway, through which all the return air of a separate district flows, allowing the air to always flow past or underneath it; but in the event of an explosion of gas, the force of the blast closes it against its frame or seating, and prevents a communication with other districts.

separator
 * a. A machine for separating, with the aid of water, suspensions, or air, materials of different specific gravity. Strictly, a separator parts two or more ingredients, both valuable, while a concentrator saves but one and rejects the rest; but the terms are often used interchangeably.

b. Any machine for separating materials, such as the magnetic separator for separating magnetic materials from gangue. CF: concentrator. c. A screen, esp. a revolving screen, for separating things like stones or coal into sizes.

sepiolite
 * A monoclinic mineral, Mg (sub 4) Si (sub 6) O (sub 15) (OH) (sub 2) .6H (sub 2) O ; soft; sp gr, 2 (super ) but fibrous dry masses float on water; occurs in veins in calcite and in alluvial deposits formed from weathering of serpentine masses, chiefly in Asia Minor, as meerschaum; may be used in making pipes, ornamental carvings. Syn: meerschaum; sea-foam.

septaria
 * Plural of septarium.

septarian
 * Said of the irregular polygonal pattern of internal cracks developed in septaria, closely resembling the desiccation structure of mud cracks; also said of the epigenetic mineral deposits that may occur as fillings of these cracks.

septarian concretion
 * See: septarium.

septarian nodule
 * See: septarium.

septarium
 * a. A large, roughly spheroidal concretion, 8 to 90 cm in diameter, usually of an impure argillaceous carbonate, such as clay ironstone. It is characterized internally by irregular polyhedral blocks formed by a series of radiating cracks that widen toward the center and that intersect a series of cracks concentric with the margins; these cracks are invariably filled or partly filled by crystalline minerals (most commonly calcite) that cement the blocks together. Its origin involves the formation of an aluminous gel, case hardening of the exterior, shrinkage cracking due to dehydration of the colloidal mass in the interior, and vein filling. The veins sometimes weather in relief, thus producing a septate pattern. Syn: septarian nodule; septarian concretion; beetle stone; turtle stone.

b. A crystal-lined crack or fissure in a septarium. Pl: septaria.

septechlorite
 * An alternate name for serpentine minerals reflecting their 7Aa basal spacing and chloritelike formulae.

septum
 * Membrane separating two phases, for example, pulp and filtrate.

sequence control
 * A method of control whereby, once action has been initiated, a number of electrical circuits will automatically function in a prescribed order.

sequence interlock
 * An interlock provided between a number of manually controlled electrical circuits, which are required to function in a prescribed order, and which prevents a circuit from being operated unless the preceding circuit has completed its part in the sequence.

sequence starting
 * An arrangement whereby the starting of one belt conveyor starts all of its feeder conveyors in a predetermined manner. The purpose of sequence starting is to prevent spilling at transfer points and to reduce the power demand in starting the system. See also: power sequence; pilot sequence.

sequester
 * A sequestering agent forms soluble complex ions with a simple ion, thereby inhibiting the activity of that ion.

serandite
 * A triclinic mineral, Na(Mn,Ca) (sub 2) Si (sub 3) O (sub 8) (OH), with Mn replaced by Ca toward pectolite; pink.

serendibite
 * A triclinic mineral, Ca (sub 2) (Mg,Al) (sub 6) (Si,Al,B) (sub 6) O (sub 20) ; aenigmatite group; blue.

serial samples
 * Samples collected according to some predetermined plan, such as along the intersections of gridlines, or at stated distances or times. The method is used to ensure random sampling.

seriate
 * Said of the texture of an igneous rock, typically porphyritic, in which the sizes of the grains vary gradually or in a continuous series. CF: hiatal.

sericite
 * A white, fine-grained potassium mica occurring in small scales as an alteration product of various aluminosilicate minerals, having a silky luster, and found in various metamorphic rocks (esp. in schists and phyllites) or in the wall rocks, fault gouge, and vein fillings of many ore deposits. It is commonly muscovite or very close to muscovite in composition, but may also include paragonite and illite. See also: muscovite.

sericitization
 * A hydrothermal, deuteric, or metamorphic process involving the introduction of, alteration to, or replacement by sericitic muscovite.

series
 * a. Any number of rocks, minerals, or fossils having characteristics, such as growth patterns, succession, composition, or occurrence, that make it possible to arrange them in a natural sequence.

b. A conventional stratigraphic unit that is a division of a system. A series commonly constitutes a major unit of chronostratigraphic correlation within a province, between provinces, or between continents. c. May be applied to intrusive rocks in the same time-stratigraphic sense. Formal series names are binomial, usually consisting of a geographic name (generally but not necessarily with the adjectival ending -an or -ian) and the word Series, the initial letter of both terms being capitalized. See also: igneous-rock series. d. An arrangement of electric blasting caps in which the firing current passes through each of them in a single circuit.

series circuit firing
 * A method of connecting together a number of detonators that are to be fired electrically in one blast. Each detonator is connected to the adjacent detonator to form a continuous circuit having two free ends that are then connected to the firing cable. In British coal mines, all rounds of shots must be connected electrically in series. This results in large rounds having a high electrical resistance, requiring high voltage at the exploder that, in turn, increases the chance of misfires due to current leakage. See also: parallel circuit firing.

series firing
 * The firing of detonators in a round of shots by passing the total supply current through each of the detonators. CF: parallel firing.

series-in-parallel circuit
 * See: parallel blasting circuit; parallel series circuit.

series parallel firing
 * The firing of detonators in a round of shots by dividing the total supply current into branches, each containing a certain number of detonators wired in series.

series shots
 * A number of loaded holes connected and fired one after the other. In contradistinction to simultaneous firing, where the charges are connected electrically, and are all exploded at one time.

series ventilation
 * A system of ventilating a number of faces consecutively by the same air current.

serpentine
 * a. In petrology, a metamorphic rock serpentinite composed chiefly or wholly of the mineral serpentine.

b. A group of common rock-forming minerals having the formula (Mg,Fe,Ni) (sub 3) Si (sub 2) O (sub 5) (OH) (sub 4) ; mostly monoclinic, but also orthorhombic; greasy or silky luster; slightly soapy feel; tough conchoidal fracture; commonly compact but may be granular or fibrous (asbestiform); green; invariably secondary, derived by alteration of magnesium-rich silicate minerals (esp. olivines); in both igneous and metamorphic rocks; translucent varieties commonly substitute for jade for ornamental and decorative purposes; fibrous varieties are used for asbestos. c. The mineral group antigorite, clinochrysotile, orthochrysotile, and lizardite. d. In former usage, serpentine and antigorite were mineral species and chrysotile was a variety. See also: kaolinite-serpentine.

serpentine asbestos
 * See: chrysotile.

serpentine cat's-eye
 * See: satelite.

serpentine jade
 * A variety of the mineral serpentine, resembling bowenite, occurring in China; used as an ornamental stone.

serpentine marble
 * See: verde antique.

serpentine rock
 * See: serpentinite.

serpentinite
 * A rock consisting almost wholly of serpentine-group minerals, e.g., antigorite and chrysotile or lizardite, derived from the alteration of ferromagnesian silicate minerals, such as olivine and pyroxene. Accessory chlorite, talc, and magnetite may be present. Syn: serpentine rock.

serpentinization
 * The process of hydrothermal alteration by which magnesium-rich silicate minerals (e.g., olivine, pyroxenes, and/or amphiboles in dunites, peridotites, and/or other ultrabasic rocks) are converted into or replaced by serpentine minerals.

serpierite
 * A monoclinic mineral, Ca(Cu,Zn) (sub 4) (SO (sub 4) ) (sub 2) (OH) (sub 6) .3H (sub 2) O ; dimorphous with orthoserpierite; sky-blue.

serra
 * See: sierra.

serrate
 * a. Said of topographic features that are notched or toothed, or have a saw-edged profile; e.g., a serrate divide. Syn: saw-toothed.

b. Said of saw-toothed contacts between minerals, usually resulting from replacement; e.g., the serrate texture of megacrysts in contact with plagioclase in igneous rocks.

serumite
 * A bonding clay for foundry sands.

service factor
 * A factor by which the specified horsepower is multiplied to compensate for drive conditions.

service shaft
 * A shaft employed solely for the hoisting of workers and materials to and from underground.

serving
 * a. Fiber cord wrapping around the surface of a wire rope.

b. Corn. A supply of tin ready for smelting.

servomechanism
 * An automatic feedback control system for mechanical motion; it applies only to those systems in which the controlled quantity or output is mechanical position or one of its derivatives (velocity, acceleration, and so on). Also known as servo system.

set
 * a. A timber frame used for supporting the sides of an excavation, shaft, or tunnel. Syn: sett.

b. See: one-piece set; timber set; bench of timbers. c. The distance a pile penetrates with one blow from a driving hammer. d. A group of essentially parallel planar features, esp. joints, dikes, faults, veins, etc. e. A train of mine cars; a trip. f. The failure of a rock subjected to intense pressure below the point of rupture to recover its original form when the pressure is relieved. g. The discharge opening of a crushing machine to regulate the size of the largest escaping particle. h. To fix a prop or sprag in place. i. To place a diamond in the crown of a bit. j. To place casting in a borehole.

set bit
 * A bit insert with diamonds or other cutting media.

set casing
 * The cementing of casing in the hole. The cement is introduced between the casing and the wall of the hole and then allowed to harden, thus sealing off intermediate formations and preventing fluids from then entering the hole. It is customary to set casing in the completion of a producing well.

set casing shoe
 * A casing shoe set with diamonds. Often used for a one-shot attempt to drill casing down through overburden to bedrock. Also called casing-shoe bit.

set copper
 * An intermediate copper product containing about 3.5% cuprous oxide, obtained at the end of the oxidizing portion of the fire-refining cycle.

set i.d.
 * See: set inside diameter.

set inside diameter
 * The minimum inside diameter of a set core bit. Usually written set i.d. in drilling industry literature. Also called bore; center bore; inside gage. Abbrev. set i.d.

set o.d.
 * See: set outside diameter.

set of timber
 * The timbers composing any framing, whether used in a shaft, slope, level, or gangway. Thus, the four pieces forming a single course in the curbing of a shaft, or the three or four pieces forming the legs and collar, and sometimes the sill, of an entry framing are together called a set, or timber set.

set outside diameter
 * The maximum outside diameter of a set bit. Usually written set o.d. in drilling industry literature. Also called outside gage. Abbrev. set o.d.

set reaming shell
 * A reaming shell, a portion of the outside surface of which has embedded diamonds, diamond-inset inserts, or other cutting media, having a set diameter slightly greater than the standard set size of the bit to which the shell is coupled.

sett
 * a. A quarryman's term for a square-faced steel tool held in position and struck with a sledge to cause a fracture in a rock mass.

b. Corn. A lease; the boundaries and terms of the mining ground taken by the adventurers. See also: set. c. A timber frame used in underground support. Also spelled set. d. A small rectangular dressed stone of granite, quartzite, or whinstone, used as road paving in localized areas subject to esp. heavy traffic.

setting
 * a. Those runners, sheeting, or poling boards which are held in place by one pair of timber frames supporting the sides of an excavation. See also: timbering; top frame.

b. The timber frames used at intervals in shaft sinking and close-poled behind. c. See: heading. d. The act of contracting with miners for work to be done.

setting out
 * Marking out on the ground by means of pegs and lines the proposed positions and dimensions of earthworks, masonry, etc. Also called staking out. Syn: laying out.

setting pattern
 * The geometric arrangement of the inset diamonds in a bit crown.

setting plug
 * A cylindrical object, having a diameter equal to the inside set diameter of a specific-size bit, used to measure the inside set diameter of a core bit.

setting ring
 * A ringlike sleeve, the inside diameter of which is the same as a specific set outside diameter of a diamond bit or reaming shell; it is used to check the set diameter of a bit or reaming shell. Also called bit gage; bit ring; gage ring; gaging ring; ring gage; setting gage.

setting rod
 * A special diamond-drill rod used to set a deflecting wedge in a borehole.

setting up
 * a. See: rigging.

b. In mining, to gather the necessary tools and complete all work preparatory to drilling. Syn: setup. c. Hardening of air-setting or hydraulic-setting mortars. d. The act or process of setting a diamond bit.

settled ground
 * Ground that has ceased to subside over the waste area of a mine and has reached a state of full subsidence.

settlement
 * The lowering of the overlying strata in a mine, owing to extraction of the mined material. See also: subsidence; differential settlement; seat of settlement.

settlement date
 * Agreed terms on which payment for a consignment of mineral is made.

settlement price
 * The last unfulfilled offer to sell at cash price at the close of the second morning on the London Metal Exchange, prevails as the accepted cash price for the metal for the succeeding twenty-four hours.

settler
 * A separator; a tub, pan, vat, or tank in which a separation can be effected by settling. A tub or vat in which pulp from the amalgamating pan or battery pulp is allowed to settle; the pulp is stirred in water to remove the lighter portions. Syn: pug tub. See also: agitator; settling tank.

settling box
 * A box or container in which drill cuttings or sludges are accumulated and coarse materials permitted to settle.

settling cone
 * A conical tank used to settle coarse solids from the circulating water.

settlingite
 * A hard, brittle, pale-yellow to deep-red hydrocarbon (H:C about 1.53) in resinous drops on the walls of a lead mine at Settling Stones, Northumberland, U.K. See also: settling stones resin.

settling pit
 * An excavation through which mine water is conducted in order to reduce its velocity, thus allowing sediment to settle and to be cleaned out from time to time. Also called dredge sump; settling sump (undesirable usage).

settling pond
 * A pond, natural or artificial, for recovering the solids from washery effluent.

settling sand
 * Drillers' term for friable sandstone that caves into wells and settles around the bit.

settling stones resin
 * A resinoid, hard, brittle substance possessing a pale yellow to deep red color, a specific gravity of 1.16 to 1.54, and burning in a candle flame. It was found in an old lead mine in Northumberland, England. See also: settlingite.

settling tank
 * a. A reservoir or tank into which the return water from a borehole collects and the entrained drill cuttings settle.

b. A tank in which pulp is held while solids settle from suspension. Also called thickener; settler.

settling vat
 * A vat in which particles of ore are allowed to settle.

settling velocity
 * The rate at which suspended solids subside and are deposited. Syn: full velocity.

setup
 * a. In surveying, location of theodolite above a station point.

b. In drilling, location of machine. c. See: setting up; rigging; rig; rig-up.

set weight
 * The quantity of diamonds set in a bit, expressed in carats.

severance
 * a. Separation of a mineral or royalty interest from other interests in the land by grant or reservation. A mineral or royalty deed or a grant of the land reserving a mineral or royalty interest, by the landowner before leasing, accomplishes a severance, as does his execution of an oil and gas lease.

b. See: liberation.

severance tax
 * A State tax imposed on the severing of natural resources from the land based on the value or quantity of production. These types of taxes are usually calculated either as a flat rate per unit of production (sometimes called a "unit" or "specific" severance tax), or as a percentage of the value of the resource produced (sometimes called an "ad valorem" or "percentage" severance tax). The tax base for an ad valorem severance tax is generally either the gross or net value of resources produced or sold.

severed lands
 * These are lands where the surface estate is held by one party and the mineral estate is held be another. The owner of the mineral estate normally retains the right to enter and occupy the surface estate for the purposes of mineral development and extraction. Also called Split Estate Lands.

seyberite
 * See: clintonite.

seybertite
 * A former name for clintonite.

Seyler's classification
 * A classification of coals based primarily upon the carbon and hydrogen content calculated to a pure-coal basis, according to the Parr formula. See also: carbon-hydrogen ratio.

shackle
 * a. A connecting link or device for fastening parts together, usually in such a manner as to permit some motion.

b. A connecting device for lines and drawbars consisting of a U-shaped section pierced for cross bolt or a pin. c. A short wrought-iron or manganese-steel chain for connecting mine cars to form a journey or train, for transport by rope haulage or locomotive to and from the workings. Syn: coupling. See also: automatic clip.

shackler
 * A person employed to attach and detach the shackles between mine cars either at a junction near the face or at the pit bottom. Cars are attached at the junction to form trains for the locomotive or rope haulage. Another shackler detaches them at the pit bottom for loading into the cage. Syn: offtake lad.

shadd
 * a. Corn. Smooth, round stones on the surface, containing tin ore, and indicating a vein.

b. See: shoad.

shade
 * a. A color that has been darkened by the addition of black.

b. A term descriptive of that difference between colors resulting from a difference in luminosity only, the other color constants being essentially equal. A darker shade of a color is one that has a lower luminosity.

shading
 * A method of showing relief on a map by simulating the appearance of sunlight and shadows, assuming an oblique light from the northwest so that slopes facing south and east are shaded (the steeper slopes being darker), thereby giving a three-dimensional impression similar to that of a relief model. The method is widely used on topographic maps in association with contour lines.

shadow zone
 * a. Region in which refraction effects cause exclusion of echo-ranging sound signals.

b. An area in which there is little penetration of acoustic waves. c. A region 100 degrees to 140 degrees from the epicenter of an earthquake where, due to refraction from the low-velocity zone inside the core boundary, there are no direct arrivals of seismic waves. Syn: blind zone.

shaft
 * a. An excavation of limited area compared with its depth; made for finding or mining ore or coal, raising water, ore, rock, or coal, hoisting and lowering workers and material, or ventilating underground workings. The term is often specif. applied to an approx. vertical shaft, as distinguished from an incline or inclined shaft. A shaft is provided with a hoisting engine at the top for handling workers, rock, and supplies; or it may be used only in connection with pumping or ventilating operations.. CF: incline.

b. A brick or stone stack or chimney. c. The upper zone of a blast furnace. d. See: abyss.

shaft allowance
 * The difference between the excavation diameter and the finished diameter in the clear; the extra space allowed to accommodate the permanent shaft lining.

shaft bottom
 * See: loop-type pit bottom; pit bottom; single-approach pit bottom.

shaft cable
 * a. A specially armored cable of great mechanical strength running down the shaft of a mine.

b. See: borehole cable.

shaft capacity
 * The output of ore or coal that can be expected to be raised regularly and in normal circumstances, per day or week.

shaft casing
 * The structure enclosing the top of a shaft designed to prevent short circuiting of air into or out of the shaft. See also: air lock.

shaft cave
 * A cave formed primarily of a shaft or shafts.

shaft collar
 * See: collar structure.

shaft deformation bar
 * A useful contrivance for measuring the deformation in the cross section of a shaft. It consists of a length of 1-1/2-in (3.8-cm) pipe fitted at one end with a micrometer and at the other end with a hard steel cone. The micrometer should have a range of 3 to 4 in (7.6 to 10 cm) and should fit into a bushing in the pipe in some manner. It may thus be removed from the bar for safe keeping or during transport.

shaft drilling
 * The drilling of small shafts up to about 5 ft (1.5 m) in diameter with a shot drill. In Virginia, shafts up to 6 ft (1.8 m) in diameter have been sunk by core drilling. A ring 4 in (10 cm) wide is formed by roller bits similar to oilfield rotary drilling. Six tricone cutters are used, and a large core is formed. A central hole is drilled in the core, and a small explosive charge is fired to break it for removal. In some cases, it is removed bodily by a core catcher.

shaft feeder cable
 * A cable mounted in a shaft to transmit electrical power to the shaft bottom and/or to an intermediate level.

shaft foot
 * Scot. The bottom of a shaft.

shaft guides
 * See: cage guide; fixed guides; rope guide.

shaft-hoist engineer
 * See: hoistman.

shaft horsepower
 * a. Actual horsepower produced by the engine after deducting the drag of accessories. Also called flywheel horsepower; belt horsepower.

b. The shaft horsepower of a winding engine is the average load of coal or ore in pounds (kilograms) raised per wind multiplied by the average number of winds per minute (which may be a fraction) multiplied by the depth of the shaft in feet and the product divided by 33,000.

shaft house
 * A building at the mouth of a shaft, where ore or rock is received from a mine.

shaft inset
 * The point where a horizontal tunnel intersects a shaft. Syn: mounting. See also: inset.

shaft kip
 * Eng. See: kip.

shaft lighting
 * The lighting of shafts at landing stations is often found to be far from ideal. Work in the cages, during loading and unloading, and examination of shaft gear, are facilitated by the provision of fittings to provide a directional flux distribution in such a way that light is thrown forwards from the pit bottom or inset roadway into the shaft area. There must also be adequate illumination on a vertical plane at the shaft inset.

shaft lining
 * The timber, steel, brick, or concrete structure fixed around a shaft to support the walls. In modern shafts, a concrete lining is generally favored as a permanent shaft support.

shaft mine
 * a. A mine in which the coal seam is reached by a vertical shaft which may vary in depth from less than 100 ft (30 m) to several thousand feet.

b. A mine in which the main entry or access is by means of a shaft. CF: drift mining.

shaft mixer
 * See: mixer.

shaft pillar
 * a. A large area of a coal seam that is left unworked around the shaft bottom to protect the shaft and the surface buildings from damage by subsidence. All roadways in the shaft pillar are narrow, and coal faces are not opened out until the limit line of the shaft pillar is reached. The area of the shaft pillar is considerably greater than the surface area requiring protection. Syn: high pillar. See also: bottom pillar; pillar.

b. A solid block of ore left around the shaft where it crosses the lode, for protection against earth movement.

shaft plumbing
 * a. The operation of transferring one or more points at the surface of a vertical shaft to plumb line positions at the bottom of the shaft; a method to ensure that a shaft is sunk in the true vertical line. See also: centering of shaft.

b. Survey operation in which the orientation of two plumb bobs is measured both at the surface and at depth in order to transfer the bearing underground. See also: Weisbach triangle.

shaft pocket
 * a. Ore storage, excavated at depth, which receives trammed ore pending removal by skip.

b. Loading pockets of one or more compartments for different classes of ore and for waste built at the shaft stations. They are cut into the walls on one or both sides of a vertical shaft or in the hanging wall of an inclined shaft. See also: pocket. c. See: measuring chute.

shaft raising
 * See: raising.

shaft section
 * A drawing or log giving details of the structure and the nature of strata intersected by a shaft.

shaft set
 * a. Supporting frame of timber, masonry, or steel that supports the sides of a shaft and the gear. Composed of two wallplates, two end plates, and dividers that form shaft compartments.

b. A system of mine timbering similar to square sets. The shaft sets are placed from the surface downward, each new set supported from the set above until it is blocked in place. New wallplates are suspended from those of the set above by hanging bolts. Blocking, wedging, and lagging complete the work of timbering. At stations the shaft posts are made much longer than usual to give ample head room for unloading timber and other supplies.

shaft siding
 * The station or landing-place arranged for the full and empty tubs at the bottom of the winding shaft.

shaft signal
 * Code of electric ringing, or for shallow depths, knocking, among the onsetter or hitcher at the shaft bottom, the banksman at the top, and the engineman who operates the winder. Signals inform the latter as to type of load, etc. A telephone is also installed.

shaft signal indicator
 * A device, usually mounted in the winding engine house, which gives visual indication of the signals received from the banksman and the onsetter to regulate the movement of conveyances in a shaft, and that retains the indication until cancelled.

shaft signal recorder
 * A device that records, on paper or otherwise, the signals given by the banksman and the onsetter and the movements of the winder drum.

shaft sinking
 * a. Excavating a shaft downwards, usually from the surface, to the workable coal or ore. High sinking rates are possible by (1) mechanical mucking, (2) increased winding capacity, (3) improved concrete supply and placing, (4) improved surface layout, and (5) improved methods of blasting.

b. Excavating a shaft with a shaft-sinking drill. CF: raise.

shaft-sinking drill
 * A large-diameter drill with multiple rotary cones or cutting bits used for shaft sinking. An adaptation from oil well drills.

shaft-sinking power supply
 * A supply of compressed air at a working pressure of about 100 psi (690 kPa). The quantity required for a modern high-speed sinking may be 2,000 to 2,500 ft (super 3) /min (56.6 to 70.7 m (super 3) /min). At a new mine where two shafts are being sunk, the power installation may comprise eight slow-speed water-cooled compressors with a total output of almost 5,000 ft (super 3) /min (141.5 m (super 3) /min) at 100 psi.

shaft-sinking ventilation
 * The ventilation of a sinking shaft is by means of auxiliary fans. Axial flow fans powered by flameproof motors are commonly used.

shaft space
 * An opening created with the object of relieving pressure on the shaft.

shaft spragger
 * In anthracite and bituminous coal mining, a laborer who controls the movement of mine cars as they are run to the top or to the bottom of the shaft by poking sprags (short metal or wooden rods) between the spokes of the wheels.

shaft station
 * An enlargement of a level near a shaft from which ore, coal, or rock may be hoisted and supplies unloaded.

shaft survey
 * A survey to determine the alignment of a shaft.

shaft tackle
 * See: poppet head; headframe; poppet.

shaft tunnel
 * N. Staff. Headings driven across the measures from shafts to intersect inclined seams.

shaft wall
 * a. The brick or concrete lining in a shaft to support the surrounding ground. The construction of the permanent shaft wall is normally in concrete with reinforcement at insets and in bad ground. The wall thickness is between 12 in and 36 in (30 cm and 91 cm) depending on the shaft size and water pressure within the strata. Also applied to the rock masses surrounding the shaft. See also: permanent shaft support.

b. The side of a shaft.

shag boss
 * In the stonework industry, a foreperson who supervises the removal of waste stone, loading and unloading of finished and semifinished stone, and the moving and piling of stone slabs and blocks at a stoneworking mill.

shagreen
 * See: relief.

shake
 * a. In a coal mine, a vertical crack in the seam and roof.

b. Fissures in rock. c. Minute calcite veins traversing limestone or other rocks containing carbonates. These veinlets, unlike vents, have no harmful effect on the building stone. d. A cavern, usually in limestone. e. A close-joint structure in rock, due to natural causes, such as pressure, weathering, etc. Used in the plural.

shaker
 * A mechanically vibrated screen through which a returning drill fluid is passed to screen out larger chips, fragments, and drill cuttings before the drill fluid flows into the sump. Syn: shale screen; shale shaker.

shaker chutes
 * Metal troughs, operated mechanically, for the loading of coal into mine cars underground.

shaker conveyor
 * a. A conveyor consisting of a length of metal troughs, with suitable supports, to which a reciprocating motion is imparted by drives. In the case of a downhill conveyor, a simple to-and-fro motion is sufficient to cause the coal to slide. With a level or a slight uphill gradient, a differential motion is necessary; i.e., a quick backward and slower forward strokes. The quick backward stroke causes the trough to slide under the coal, while the slower forward stroke moves the coal along to a new position. Syn: jigger. See also: conveyor; conveyor shaker type; vibrating conveyor.

b. A type of oscillating conveyor.

shaker-conveyor engine
 * A reciprocating engine operated by compressed air which is used to impart the reciprocating motion to a shaker conveyor panline.

shaker screen
 * A screening medium mounted in a rectangular frame, supported in a horizontal or slightly inclined position, and reciprocated longitudinally by a crank or eccentric and connecting rod. The unique feature that differentiates the shaker from all other screens is that the load is made to travel over the screening medium by the shaking motion of the screen.

shaker-shovel loader
 * A machine for loading coal, ore, or rock usually in headings or tunnels. It consists of a wide flat shovel that is forced into the loose material along the floor by the forward motion of the conveyor. The shaking motion of the conveyor brings the material backwards, and it is loaded into cars or a conveyor. It works at its maximum efficiency to the rise or in flat tunnels. Also called duckbill loader. See also: loader.

shake wave
 * A wave that advances by causing particles in its path to move from side to side or up and down at right angles to the direction of the wave's advance, a shake motion.

shaking
 * a. See: springing; shaking a hole.

b. Corn. Washing ore; ore dressing.

shaking a hole
 * The enlargement of a blasthole, by exploding a stick of dynamite, so it will contain a larger amount of explosives for a big blast. Also called a shake blast. See also: springing.

shaking conveyor
 * An apparatus that slides under the broken coal and by reciprocating motion moves the coal along to a discharge point.

shaking-conveyor loader
 * The broad tapering shovellike end of a shaking conveyor that is thrust suddenly under the coal and slowly withdrawn so as to carry the coal that has been lifted toward the dumping point.

shaking down
 * The stirring of an open-hearth bath with a rod to assist in oxidizing and removal of carbon.

shaking screen
 * a. A screen for sizing coal or other material. It consists of a screening surface of punched plate or wire mesh mounted in a rectangular frame, supported in a horizontal or slightly inclined position and reciprocated longitudinally by a crank or eccentric and connecting rod. The slightly inclined shaking screen is favored. Also called jiggling screen. See also: trommel; jigging screen; wet screening.

b. A suspended screen moved with a back-and-forth or rotary motion with a throw of several inches or more.

shaking table
 * a. In ore dressing, flattish tables oscillated horizontally during separation of minerals fed onto them.

b. In concentration of finely crushed ores by gravity, a rectangular deck with longitudinal riffles. It is shaken rapidly in a compounded to-and-fro motion by a vibrator, in such a way as to move the sands along, while they are exposed to the sweeping action of a stream of water flowing across the deck, which is tilted about its long axis. In dry or pneumatic tabling the feed is dry, and air is blown upward through a porous deck. c. A slightly inclined table to which a lateral shaking motion is given by means of a small crank or an eccentric. One form is covered with copper plates coated with mercury for amalgamating gold or silver; other forms are provided with riffles and used in separating alluvial gold. Syn: jerking table; bumping table.

shale
 * a. A fine-grained detrital sedimentary rock, formed by the consolidation (esp. by compression) of clay, silt, or mud. It is characterized by finely laminated structure, which imparts a fissility approx. parallel to the bedding, along which the rock breaks readily into thin layers, and by an appreciable content of clay minerals and detrital quartz; a thinly laminated or fissile claystone, siltstone, or mudstone. It is generally soft but sufficiently indurated so that it will not fall apart on wetting; it is less firm than argillite and slate, commonly has a splintery fracture and a smooth feel, and is easily scratched. Its color may be red, brown, black, or gray. Etymol: Teutonic, probably Old English scealu, shell, husk, akin to German schale, shell.

b. One of the impurities associated with coal seams; this term should not be used as a general term for washery rejects.

shale-and-clay feeder
 * One who keeps conveyor belt that feeds dry mill constantly loaded with shale and clay. Also called clay-and-shale feeder; clay feeder; conveyor loader; shale-and-clay-conveyor man; shale feeder.

shale band
 * See: dirt band.

shale break
 * Thin layer or parting of shale between harder strata, primarily a driller's term. CF: shell.

shale dust
 * The dust obtained by drying and grinding shale.

shalene
 * A term proposed in place of gasoline for that product distilled from oil shale.

shale-off shale
 * Scot. Shale yielding oil on distillation. This term was formerly used as signifying argillaceous rock.

shale oil
 * A crude oil obtained from bituminous shales, esp. in Scotland, by submitting them to destructive distillation in special retorts.

shale pit
 * A dumping place for coarse material screened out of rotary drill mud.

shale screen
 * See: shaker.

shale shaker
 * a. A cylindrical sieve or vibrating table that removes the drill cuttings from the circulating mud stream.

b. See: shaker.

shaley blaes
 * Scot. See: bituminous shale.

shallow ground
 * Aust. Land having gold near its surface.

shallow well
 * A shaft sunk to pump surface water only. See also: well.

shaly
 * Pertaining to, composed of, or having the character of shale; esp. readily split along closely spaced bedding planes, such as shaly structure or shaly parting. Also, said of a fine-grained, thinly laminated sandstone having the characteristic fissility of shale owing to the presence of thin layers of shale; or said of a siltstone possessing bedding-plane fissility.

shamble
 * One of a set of shelves or benches, from one to the other of which ore is thrown successively in raising it to the level above, or to the surface. See also: shammel.

shammel
 * a. A stage for shoveling ore upon, or for raising water. See also: shamble.

b. To work a mine by throwing the material excavated onto a stage or bench in the "cast after cast" method, which was the usual way before the art of regular mining by means of shafts had been introduced.

Shand's classification
 * A classification of igneous rocks based on crystallinity, degree of saturation with silica, degree of saturation with alumina, and color index. This system was developed in 1927 by S.J. Shand.

shangie
 * Scot. A ring of straw or hemp put round a jumper in boring to prevent the water in the borehole from splashing out.

shank
 * a. The steel-threaded portion of a diamond bit to which the crown is attached. Also called bit blank; blank; blank bit.

b. The body portion of any bit above its cutting edge. c. That part of the drill steel which is inserted in the chuck of the drill. d. A bar or standard which connects a rooter tooth with the frame. e. A ladle for molten metal, with long handles for use by two or more workers.

Shanklin sand
 * Eng. A marine deposit of siliceous sands and sandstone of various shades of green and yellow gray. Also called Lower Greensand.

shaped charge
 * An explosive contained in a case so shaped as to concentrate the power of the explosion in one small area. Shaped charges are used in armor-penetrating weapons, such as the bazooka, for tapping open-hearth furnaces, for cutting deep-well linings, and for breaking boulders.

shaped stone
 * An artificially blunted or shaped carbon or diamond cut to form a point conforming to a specific profile.

shape factor
 * Property of a particle that determines the relation between its mass and surface area, and hence its response to frictional restraint.

shape-firebrick molder
 * One who makes shaped firebricks in steel molds.

shape-silica-brick molder
 * One who makes shaped silica bricks in steel molds.

shard
 * a. A vitric fragment in pyroclastics; some have a characteristically curved surface of fracture. Shards generally consist of bubble-wall fragments produced by disintegration of pumice during or after an eruption.

b. Syn: sherd.

sharp fire
 * Combustion with excess air and short flame.

sharp gravel
 * Angular flint gravel.

sharpite
 * An orthorhombic mineral, Ca(UO (sub 2) ) (sub 6) (CO (sub 3) ) (sub 5) (OH) (sub 4) .6H (sub 2) O ; very radioactive; yellow-green.

sharp sand
 * Sand composed of angular quartz grains, used in making mortar.

sharp stone
 * a. Drill diamonds or carbon having sharp edges and corners that have not been artificially blunted or rounded through use.

b. New-condition, unused carbon or drill diamonds. c. A sedimentary rock made up of angular particles more than 2 mm in its greatest dimension.

shatter belt
 * A less-preferred syn. of "fault zone."

shatter cut
 * See: burn cut.

shattered zone
 * Applied to a belt of country in which the rock is cracked in all directions, resulting in a network of small veins.

shatter index
 * The percentage of a specially prepared sample of coke remaining on a sieve of stated aperture after the sample has been subjected to a standardized dropping procedure.

shattery
 * S. Staff. Burnt clay in the vicinity of burnt coal.

shattuckite
 * An orthorhombic mineral, Cu (sub 5) (SiO (sub 3) ) (sub 4) (OH) (sub 2) ; blue.

Shaver's disease
 * See: bauxite pneumoconiosis.

shcherbakovite
 * An orthorhombic mineral, (K,Na,Ba) (sub 3) (Ti,Nb) (sub 2) Si (sub 4) O (sub 14) ; dark brown.