Appendix:Dictionary of Mining, Mineral, and Related Terms/S/5
shear
a. A deformation resulting from stresses that cause or tend to cause contiguous parts of a body to slide relatively to each other in a direction parallel to their plane of contact. It is the mode of failure of a body or mass whereby the portion of the mass on one side of a plane or surface slides past the portion on the opposite side. In geological literature the term refers almost invariably to strain rather than to stress. It is also used to refer to surfaces and zones of failure by shear, and to surfaces along which differential movement has taken place.
b. See: shearing.
c. To make vertical cuts in a coal seam that has been undercut.
shear bursts
In deep mining fields, shear bursts are the most common type. By the occurrence of a single shear crack parallel to the face in one of the walls, the wall rock behind the shear plane is able to expand freely into the stope, heavily compressing those supports that until then have not taken stress, throwing still more stress on those that have, and causing the wall rock between the nearest supports and the face to disrupt and fill the place with debris. Shear bursts frequently occur at the working face of a pillar, remnant, or promontory. In such cases, they should not be mistaken for true pillar bursts.
shear-cake
A counterweighted refractory slab used as a gate or door to a small furnace or oven.
shear cleavage
Refers to cleavage where there is displacement of preexisting surfaces across the cleavage plane by movement parallel to it. Syn: slip cleavage.
shear cut
A vertical cut made by a special type of coal cutter or arc-shearing machine. Syn: vertical cut. See also: turret jib.
shearer
a. In bituminous coal mining, one who operates a type of coal-cutting machine that shears (cuts) out a channel down the sides of the working face of coal (as distinguished from undercutting) prior to blasting the coal down. Also called shearing-machine operator.
b. A person who operates the shearing machine on a longwall face.
shearer loader
Machine that shears coal or other easily broken mineral from the longwall face of a seam and delivers the broken material continuously to a conveying system.
shear failure
Failure in which movement caused by shearing stresses in a soil mass is of sufficient magnitude to destroy or seriously endanger a structure. Syn: failure by rupture.
shear fold
A fold model of which the mechanism is shearing or slipping along closely spaced planes parallel to the fold's axial surface. The resultant structure is a similar fold. Syn: slip fold.
shear fracture
A fracture that results from stresses that tend to shear one part of a rock past the adjacent part. See also: shear joint. CF: tension fracture.
shearing
a. The vertical side cutting that, together with holing or horizontal undercutting, constitutes the attack upon a face of coal.
b. Making a vertical cut or groove in a coal face, breast, or block, as opposed to a kerf, which is a horizontal cut. Called in Arkansas a cut or cutting. See also: shear.
c. Vertical cuts applied in coal headings only to provide an additional free face, since in heading work it is usual to employ deeper cuts than on longwall faces, and the shots in headings are much tighter.
d. The deformation of rocks by cumulative small lateral movements along innumerable parallel planes, generally resulting from pressure, and producing schistosity, cleavage, minute application, and other metamorphic structures.
shearing force
A straining action wherein tangentially applied forces tend to produce a skewing type of deformation. Shear forces are usually accompanied by normal forces produced by tension, thrust, or bending.
shearing jib
A jib of a coal cutter or cutter loader that makes a vertical or shear cut in the coal, ore, or rock.
shearing-machine operator
An electrically driven machine used to cut coal during longwall mining. Usually used in a double-drum configuration. �W d�s �s �A�� � 4 DICTIONARY TERMS:shearing-machine operator See: shearer. See: shearer.
shear joint
Joint that formed as a shear fracture. See also: shear fracture.
shear lag
On account of shear strain, the longitudinal tensile or compressive bending stress in wide beam flanges diminishes with the distance from the web or webs; this stress diminution is called shear lag.
shear legs
a. A high wooden frame placed over an engine or pumping shaft fitted with small pulleys and rope for lifting heavy weights.
b. A tripod on which miners sometimes stand in drilling.
shear modulus
Also known as the modulus of rigidity, it equals the shear stress divided by the shear strain.
shear of ore
Ore shoot or orebody.
shearpin
A small soft-metal pin, connecting or pinning together two parts of a tool that will break by shearing if an excessive load is placed on the pinned components. The shearing of the pin prevents damage to the overloaded components; thus it is a safety device.
shear plane
A fracture that produces a positive draw. It differs from a weight break in that the character of the fracture is less ragged and heaving takes place over the unwrought coal instead of the waste.
shear rivet
Soft copper rivets used in the Hall-Rowe wedge to connect the drive and pilot wedges; they can be sheared off to leave the drive wedge as a permanent reference in the borehole at the point at which the hole is to be deflected.
shear slide
A slide produced by shear failure, usually along a plane of weakness, as bedding or cleavage.
shear steel
A steel produced by heating blister steel (sheared to short lengths) to a high heat, welding by hammering or rolling, or both, and finally finishing under the hammer at the same or slightly greater heat.
shear strain
Angular displacement of a structural member due to a force acting across it, measured in radius. See also: shear modulus.
shear strength
a. The stress or load at which a material fails in shear.
b. A measure of the shear value of a fluid. Also a measure of the gelling properties of a fluid.
c. The internal resistance of a body to shear stress, typically including a frictional part and a part independent of friction called cohesion.
shear stress
a. The shear force operating in a material, measured per unit of cross-sectional area. See also: stress; shear modulus; punching shear.
b. The stress component tangential to a given plane. Also called shearing stress; tangential stress.
shear structure
Any rock structure caused by shearing, e.g., crushing, crumpling, or cleavage.
shear wave
See: S wave.
shear zone
a. A tabular zone of rock that has been crushed and brecciated by many parallel fractures due to shear strain. Such an area is often mineralized by ore-forming solutions. Syn: sheeted zone; sheeted-zone deposit.
b. Hogback.
sheath
a. To enclose or encase with a covering.
b. A chemical compound or mixture incorporated in a sheathed explosive unit that forms a flame-inhibiting cloud on detonation of the explosive.
sheathed explosive
A permitted explosive surrounded by a sheath containing a noncombustible powder. The powder acts as a cooling agent and reduces the temperature of the resultant gases of the explosion, and therefore reduces the risk of these hot gases causing a combustible gas ignition. See also: eq.s. explosive; explosive.
sheathed explosive unit
A device consisting of an approved or permissible explosive covered by a sheath encased in a sealed covering and designed to be fired outside the confines of a borehole.
sheathing driver
Essentially a paving breaker, an impact hammer driven by air, designed and adapted for driving wood sheathing.
sheave
Grooved pulley wheel much used in underground rope haulage. See also: Koepe sheave; tail sheave; winding sheave.
sheave block
A pulley and a case provided with a means to anchor it.
sheave wheel
See: sheave.
shed
a. Eng. A thin, smooth parting in rocks, having both sides polished.
b. Eng. A very thin layer of coal.
c. A divide of land; e.g., a watershed.
shedline
The summit line of elevated ground; the line of a watershed.
sheen
a. A subdued and commonly iridescent or metallic glitter that approaches but is just short of optical reflection and that modifies the surface luster of a mineral; e.g., the optical effect still visible in the body of a gem (such as tiger's-eye) after its silky surface appearance has been removed by polishing.
b. A luster that emanates from just beneath the surface of a mineral; e.g., opalescence. CF: luster.
sheep's-foot
A tamping roller with feet expanded at their outer tips.
sheep silver
A Scottish term for mica.
sheer legs
See: shear legs.
sheet
a. A general term for a tabular igneous intrusion, e.g., dike and sill, esp. if concordant or only slightly discordant. CF: intrusive vein.
b. A term used in the Upper Mississippi lead-mining region of the United States for galena occurring in thin, continuous masses.
c. See: blanket.
sheet deposit
A mineral deposit that is generally stratiform, more or less horizontal, and areally extensive relative to its thickness.
sheet drying conveyor
A disk type of live roller conveyor equipped with air outlets from a blower to remove dampness from processed sheet metal while being conveyed.
sheeted ground
a. Several closely spaced parallel faults along which the wall rocks are broken into thin sheets.
b. See: shear zone.
sheeted vein
A group of closely spaced, distinct parallel fractures filled with mineral matter and separated by layers of barren rock.
sheeted zone
See: shear zone.
sheeted-zone deposit
See: shear zone.
sheeters
Light steel poling boards driven down to protect trench sides from collapse.
sheet flow
See: laminar flow.
sheet ground
A term used in the Joplin district, Missouri, and applied to horizontal, low-grade, disseminated zinc-lead deposits, covering an extensive area. See also: sheet deposit. CF: bed vein.
sheeting
a. The development, in rock formations, of small, closely spaced, parallel fractures.
b. In a restricted sense, the gently dipping joints that are essentially parallel to the ground surface; they are more closely spaced near the surface and become progressively farther apart with depth. Esp. well-developed in granitic rocks. See also: bedding. CF: exfoliation.
sheeting caps
A row of caps placed on blocks about 14 in (36 cm) high placed on top of the drift sets when constructing the permanent floor in the stope. Round poles are then laid lengthwise of the stope on the sheeting caps and are covered with lagging.
sheeting driver
An air hammer attachment that fits on plank ends so that they can be driven without splintering.
sheeting jacks
Push-type turnbuckles, used to set ditch bracing.
sheeting pile
See: sheet pile.
sheet iron
See: sheet.
sheet-iron pitch
The inclination of a coal seam at which loose coal will not move on the natural bottom, but at which it will slide or can be easily pushed along on iron slides placed on the bottom in the chambers or rooms.
sheet jointing
See: exfoliation.
sheet metal
See: sheet.
sheet-metal gage
A gage used for measuring the thickness of sheet metal.
sheet mica
Mica that is relatively flat and sufficiently free from structural defects to enable it to be punched or stamped into specified shapes for use by the electronic and electrical industries. Sheet mica is classified further as block, film, and splittings.
sheet pile
A pile with a generally flat cross section, which may be meshed or interlocked with adjacent similar members to form a diaphragm, wall, or bulkhead, and designed to resist lateral earth pressure or to reduce ground-water seepage. Syn: sheeting pile.
sheet piles
Closely spaced piles of timber, reinforced concrete, prestressed concrete, or steel driven vertically into the ground to support earth pressure, to keep water out of an excavation, and often to form an integral part of a permanent structure.
sheet-pile wall
A wall formed of sheet piles which may be of cantilever design, or anchored back at one or two levels. A retaining wall.
sheet piling
A diaphragm made up of meshing or interlocking members of wood, steel, concrete, etc., driven individually to form an obstruction to percolation, to prevent movement of material, for cofferdams, for stabilization of foundations, etc.
sheet quarry
Often used in granite quarrying to designate a quarry having strong horizontal joints and few vertical ones.
sheets
Eng. Coarse cloth curtains or screens for directing the ventilation underground. Syn: brattice cloth; brattice sheeting.
sheet sand
A sandstone of great areal extent, presumably deposited by a transgressing sea advancing over a wide front and for a considerable distance. See also: blanket sand.
sheet structure
See: sheeting.
Sheffield process
A basic open-hearth process using charges so low in sulfur and phosphorus that they could be used in the acid process; the pig iron charged is hematite iron. The charge contains all the elements required to give the required analysis, plus the usual margin of carbon. The charge contains about 0.5% silicon and a maximum amount of manganese, to ensure correct conditions in the bath.
Shelby tube
A thin-walled soil-sampling tube, 12 to 30 in (30.5 to 76.2 cm) long, attached to a special rod adapter or sub by means of machine screws. The device is designed to take soil samples by pressing or pushing the tube down into the formation sampled. Syn: Shelby-tube sampler; thin-wall drive sampler. CF: thick-wall sampler; thin-wall sampler.
Shelby-tube sampler
See: Shelby tube. CF: thick-wall sampler.
shelf
a. Corn. The solid rock or bedrock, esp. under alluvial tin deposits.
b. Corn. A rock, ledge or rock, reef, or sandbank in the sea.
c. Corn. A projecting layer or ledge of rock on land.
d. Corn. The submerged border of a continent or of an island extending from the shoreline to the depth at which the sea floor begins to descend steeply toward the bottom of the ocean basin. See also: continental shelf.
e. Corn. A ledge of bedrock upon which drift rests.
shelf angle
A mild steel angle section, riveted or welded to the web of a comparatively deep I-beam supporting the formwork for hollow tiles or forming the seating for precast concrete floor or roof units.
shelf quarry
An open pit quarry where the ledge of stone forms a hill and the floor of the quarry worked on a hillside may be little, if any, lower than the surrounding country. In such openings, both transportation and drainage are favorable.
shelf retaining wall
A retaining wall of reinforced concrete having a relieving platform built onto its upper part.
shelf sea
The sea overlying the continental shelf.
shell
a. A thin, hard layer of rock encountered in drilling a well. CF: shale break. Syn: shelly formation.
b. The crust of the Earth. Also, any of the continuous and distinctive concentric zones or layers composing the interior of the Earth (beneath the crust). The term was formerly used for what is now called the mantle. Syn: Earth shell.
c. A sedimentary deposit consisting primarily of animal shells.
d. A steel tube from which air or other gas at high pressure is discharged with explosive force in a shothole; as used with Cardox, Hydrox, and air blasting.
e. Incorrectly used by some drillers as a syn. for reaming shell; also incorrectly used as a syn. for the inner or outer tube of a core barrel.
f. A metal or paper case that holds a charge of powder.
g. A group of electrons in an atom, all of which have the same principal quantum number.
h. Any thin-wall tubular device.
i. A torpedo used in oil wells.
j. A hollow structure or vessel.
k. An article formed by deep drawing.
l. The metal sleeve remaining when a billet is extruded with a dummy flock of somewhat smaller diameter.
m. In shell molding, a hard layer of sand and thermosetting plastic or resin formed over a pattern and used as the mold wall.
n. A tabular casting used in making seamless drawn tube.
o. A pierced forging.
p. In a grinding mill, external cylinder and ends.
q. The falling away of a 1- to 2-in (2.5- to 5.1-cm) internal layer of refractory from the roof of an all-basic open-hearth steel furnace; the probable cause is the combined effect of flux migration, temperature gradient, and stress. This form of wear is also known as slabbing.
r. The shell of a hollow clay building block refers to the outer walls of the block.
s. A curved form of plate constuction applicable to roofs.
shell-and-auger boring
Method of making exploratory shallow bores in soft ground using an auger for clay and a shell, or sandpump, for sands. Syn: post-hole auger.
shell cameo
A cameo carved from shell with raised figure cut from white layers and the background cut away to the darker layers.
shell clearance
The difference between the outside diameter of a bit or core barrel and the outside set or gage diameter of a reaming shell.
shelling
See: shell.
shell lime
Lump lime which, when flaked, has a characteristic shell-like appearance. It is used mainly in Scotland.
shell marl
a. A sandy, clayey, or limy deposit, loose or weakly consolidated, containing abundant molluscan shells; a common term in the coastal plain of the Southeastern United States.
b. A light-colored calcareous deposit formed on the bottoms of small freshwater lakes, composed largely of uncemented mollusk shells and precipitated calcium carbonate, along with the hard parts of minute organisms.
shell pump
A simple form of sand pump or sludger consisting of a hollow cylinder with a ball or clack valve at the bottom, which is used with a flush of water to remove detritus. See also: sand pump; sludger.
shelly formation
A thin and generally hard stratum encountered in drilling. See also: shell.
shelter hole
In coal mining, a niche in the rib along a haulage road into which one may step to avoid passing trains. Also known as a manhole.
Shelton loader
An adapted coal-cutting machine in which the picks of the cutter chain are replaced by loading flights. The machine hauls itself along the face, the jib leading, by means of an anchored rope. The flights push the prepared coal up a ramp onto the face conveyor, and on their return path to the back of the prepared coal; they fold back and then open up for coal loading as they emerge at the end of the jib. It requires well-prepared coal for successful operation, and will load only in one direction; consequently it has to be flitted back along the coal face. The jib can be swung into line with the body for flitting.
shepherd
Aust. A miner who preserves legal rights to a claim without working on it.
shepherding
Preserving the rights in a mining claim while doing the minimum possible amount of developing.
sherardize
To coat an article of iron or steel with zinc by covering with zinc dust in a tightly closed drum and heating for several hours at 300 to 420 degrees C so that a zinc-iron alloy is formed at the surface through the action of zinc vapor.
sherardizing
A galvanizing process in which the metal to be coated is heated, with or without tumbling, in contact with zinc dust.
sherd
a. A fragment or broken piece of pottery.
b. See: shard.
sheridanite
A variety of clinochlore of the chlorite group.
sherry topaz
a. A valuable and important variety of topaz the color of sherry wine.
b. An incorrect name for citrine of the same color.
Sherwen shaker
An electromagnetic vibrator used in shaking table mechanisms, concrete consolidation, ore feeders, and screens.
sherwoodite
A tetragonal mineral, Ca (sub 9) Al (sub 2) V (sub 28) O (sub 80) .56H (sub 2) O ; blue-black.
shield
a. A framework or diaphragm of steel, iron, or wood, used in tunneling and mining in unconsolidated materials. It is moved forward at the end of the tunnel or adit in process of excavation, and is used to support the ground ahead of the lining and to aid in its construction.
b. A large area of exposed basement rocks in a craton, commonly with a very gently convex surface, surrounded by sediment-covered platforms; e.g., Canadian Shield, Baltic Shield. The rocks of virtually all shield areas are Precambrian. Syn: continental shield; cratogene; continental nucleus.
c. In longwall mining, the hydraulically powered roof supports that protect the face workers and advance as the panel is extracted.
shield basalt
A basaltic accumulation of smaller size than the plateau or flood basalts, arising from the confluence of lava flows from a large number of small, closely spaced volcanoes. CF: plateau basalt. Syn: multiple-vent basalt.
shield volcano
A volcano in the shape of a flattened dome, broad and low, built by flows of very fluid basaltic lava or by rhyolitic ash flows. Syn: lava dome; basaltic dome.
shift
a. A small fault or slip. See also: subsidence.
b. A fault or dislocation.
c. The maximum relative displacement of points on opposite sides of a fault and far enough from it to be outside the dislocated zone. Also called net shift. See also: dip shift; normal shift; strike shift; vertical shift.
d. The number of hours or the part of any day worked. Also called tour.
e. The gang of workers employed for the period, such as the day shift or the night shift.
shifter
a. In bituminous coal mining, a general term for workers who assist brattice men, repairmen, timbermen, and other workers not engaged in the actual mining of coal.
b. See: track shifter.
shift gear
A gear on a gear-feed swivel head of a diamond drill by means of which the feed-shifter rod may be moved to engage the shifter-rod pin into the selected feed gear.
shifting clothes
Street clothes into which the miner changes on emerging from a mine.
shift lever
A short rod or shaft attached to the shift-gear shaft by means of which the ratio of the driving to the driven gears may be changed in a gear-feed swivel head of a diamond drill or other transmission-gear mechanism.
shift work
Work performed at a mine and paid for by day wage as opposed to payment by results, namely by tonnage, yardage, or price list.
shinarump
See: silicified wood.
shinbone protectors
A form of leggings that protect the shinbone. They are designed in both metal and tough plastic and are secured by leather straps around the legs.
shindle stone
Stone from which shindles or roofing slates are made. Local variant of shingle.
shingle
a. Coarse, loose, well-rounded waterworn detritus or alluvial material of various sizes; esp. beach gravel, composed of smooth and spheroidal or flattened pebbles, cobbles, and sometimes small boulders, generally measuring 20 to 200 mm in diameter; it occurs typically on the higher parts of a beach. The term is more widely used in Great Britain than in the United States. See also: chingle.
b. A place strewn with shingle; e.g., a shingle beach. Etymol: probably Scandinavian, akin to singel, coarse gravel that sings or crunches when walked on.
shingler
A machine for squeezing puddled iron.
shingle structure
The arrangement of closely spaced veins overlapping in the manner of shingles on a roof. Syn: imbricate structure.
shingling
In wrought iron manufacture, the operation by which sinter and other impurities are removed from a bloom and the metal solidly welded together by hammering and squeezing. Also called nobbing.
shining
As applied to the degree of luster of minerals, means those that produce an image by reflection, but not one well-defined, as celestite.
shin plaster
See: suspension.
ship auger
An auger having a simple spiral (helical) body and a single cutting edge, with or without a screw on the end without a spur at the outer end of the cutting edge, used to obtain soil samples in sticky material.
shiplap liners
Longitudinal lining plates for ball mill of wedgelike shape. The thin edge of each wedge underlies the thick edge of the preceding plate in the direction of revolution.
ship observations
Meteorological and oceanographic data taken for a specific location, observed from a ship underway or at anchor.
shipper shaft
In a dipper shovel, the hinge on which the stick pivots when the bucket is hoisted.
shipping measure
For measuring entire internal capacity of a vessel: One register ton equals 100 ft (super 3) (1.8 m (super 3) ); for measuring cargo; one U.S. shipping ton equals 40 ft (super 3) (1.1 m (super 3) ) or 32.143 U.S. bushels.
shipping ore
a. Any ore of greater value when broken than the cost of freight and treatment.
b. See: first-class ore.
shirt
The inner lining of a blast furnace.
shiver
An old English term for soft and crumbly shale, or slate clay approaching shale. Also spelled chiver. Etymol: Middle English scifre. Adj: shivery.
shiver spar
A variety of calcite with slaty structure; specif. argentine. Syn: slate spar.
shivery post
Eng. See: scamy.
shoad
a. Waterworn fragments of vein minerals found on the surface, such as beds of streams, away from the outcrop.
b. Float ore, which has broken from outcrop and gravitated to a distance.
c. To shoad, to trace a lode by following up shoad.
d. Corn. Stream tin, or any surface rubble or talus containing fragments of tin, copper, or lead ore, and signifying proximity of a lode.
e. See: shode.
shoaling effect
Alteration of a wave proceeding from deep water into shallow water. The wavelength decreases and the wave height increases.
shock bump
a. A rock bump caused by the sudden collapse of a thick sandstone or other strong deposit. See also: rock burst; pressure bump.
b. A thump experienced in a mine when the breakage of overlying rocks produces the effect of a hammer blow.
c. See: bumps.
shock loading
In winding, shock loads produced by picking up a cage from the pit bottom with slack chains or by lifting heavy pithead gates or covers. This often causes dry fatigue in the winding ropes.
shock losses
Head losses resulting from changes in direction of flow or area of duct. They also occur at the inlet or discharge of a system, at splits or junctions of two or more currents of air, and at obstructions in airways.
shock pressure loss
There is a constant ratio between shock pressure loss and the velocity pressure corresponding to the mean velocity of flow. Shock pressure losses can be calculated from the following formula: P (sub s) =XP (sub v) , where P (sub s) equals the total shock pressure loss in inches of water, P (sub v) equals the velocity pressure, in inches of water corresponding to the mean velocity of flow (equals approx. [V/4,000] (super 2) at standard air density of 0.075 lb/ft (super 3) or 1.2 kg/m (super 3) ), and X equals an empirical factor or shock factor found by experiment. P (sub s) and P (sub v) are expressed in the same units and are equally affected by density. X is therefore independent of both the density and the units used and is the number of velocity pressures equivalent to the shock pressure loss.
shock-proof
As applied to the current-carrying parts of an electric system, excepting trolley wires, is taken to mean that contact with such parts is prevented by the use of grounded metallic coverings or sheaths.
shock tube system
A system for initiating blasting caps in which the energy is transmitted to the cap by means of a shock wave inside a hollow plastic tube. See also: gas detonation system; nonelectric blasting.
shock wave
a. The wave of air and dust that, in some cases, travels ahead of the flame of a coal dust explosion. It may occur when an ignition takes place near the closed end of a mine roadway, and the reaction products behind the flame cannot escape freely.
b. The wave sent out through the air by the discharge of the shot initiating an explosion. The wave travels with the velocity of sound and produces to the human ear a noise like the boom of a cannon.
c. A compressional wave formed whenever the speed of a body relative to a medium exceeds that at which the medium can transmit sound, having an amplitude that exceeds the elastic limit of the medium in which it travels, and characterized by a disturbed region of small but finite thickness within which very abrupt changes occur in the pressure, temperature, density, and velocity of the medium; e.g., the wave sent out through the air by the discharge of the shot initiating an explosion. In rock, it travels at supersonic velocities and is capable of vaporizing, melting, mineralogically transforming, or strongly deforming rock materials.
shock-wave compression
Nonisentropic adiabatic compression in a wave traveling at greater than local sound velocity.
shode
a. Corn. A loose fragment of veinstone. Ore washed or detached from the vein naturally. See also: float ore.
b. Eng. To search for ore by tracing the shode. See also: shoad.
shoe
a. A trough to convey ore to a crusher.
b. A metal block used in a variety of bending operations to form or support the part being processed.
c. A coupling of rolled, cast, or forged steel to protect the lower end of the casting or drivepipe in overburden, or the bottom end of a sampler when pressed into a formation being sampled.
d. A wearing piece in various types of machines used to break rock, such as a column of drill pipes; bottom of crushing stamp; muller of amalgamating pan.
e. The lower replaceable part of a gravity stamp which falls on the mineral ore or rock.
shoepite-III
See: paraschoepite.
shoestring claim
A mining claim in the form of a long narrow strip.
shoestring location
A location of a long and narrow strip of mineral land.
shonkinite
A dark-colored syenite composed chiefly of augite and alkali feldspar, and possibly containing olivine, hornblende, biotite, and nepheline. Its name, given by Weed and Pirsson in 1895, is derived from Shonkin, the Indian name for the Highwood Mountains of Montana.
shoo-fly
a. Miner's work train.
b. Any crosscut between a haulageway and airway through which cars are run. See also: pickup; slant.
shoot
a. See: ore shoot; pipe; blast; chute. Also spelled chute.
b. To break coal loose from a seam by the use of explosives; loosely used, also as applied to other coal-breaking devices.
c. To break down by airblasting.
d. A body of ore, usually of elongated form, extending downward or upward in a vein. Also called ore shoot.
e. The payable section of a lode; an enriched portion of a continuous orebody.
f. Any considerable and somewhat regular mass of ore in a vein, frequently a rich ore streak in a vein; a chimney; also, a vein branching at a small angle from and reentering the main vein.
g. The valuable minerals are commonly concentrated in certain portions of a vein that have one dimension much longer than the others. This shoot or chimney of ore is usually highly inclined to the horizontal.
h. To explode a charge in blasting operations.
i. See: blast. A shot is a single operation of blasting.
j. In seismic exploration, the firing of the explosive by an electrical impulse; also, the process of carrying out a seismic survey, to shoot an area or prospect.
shooter
See: blaster.
shooting
The use of explosives in rock breaking.
shooting against the bank
See: blanket shooting.
shooting boat
In marine seismic exploration, a boat equipped to carry explosives, and from which the placing and firing of shots are performed.
shooting by seismograph
The making of a seismographic survey. The term shooting derives from the setting off of explosions in the ground. The shock waves from these explosions are recorded by a seismograph, and from these records a contour map can be made.
shooting needle
A blasting needle; a metallic rod used in the stemming of a drill hole for the purpose of leaving a cavity through which a charge may be fired.
shooting off-the-solid
Mining coal by heavy blasting without undermining or shearing it. In England, called shooting fast.
shooting on-the-free
The use of a smaller charge of powder to blow down the face of the coal after it has been undercut, as distinguished from "shooting off-the-solid".
shooting rights
The right to enter upon land and make a geophysical survey.
shooting truck
In seismic operations, a truck equipped to carry explosives, materials, and equipment for preparing, loading, tamping, and firing explosive charges.
shooting valve
The control valve provided for the purpose of admitting compressed air to an airblasting shell and of venting residual air, in the shell and hose, to the atmosphere.
shop rivet
A rivet driven in a workshop, as distinct from a field or site rivet.
shoran
A precise electronic measuring system for indicating distance from an airborne or shipborne station to each of two fixed ground stations simultaneously by recording (by means of cathode-ray screens) the time required for round-trip travel of radar signals or high-frequency radio waves and thereby determining the position of the mobile station. Its range is effectively limited to line-of-sight distances (or about 40 nmi or 74 km). Shoran is used in control of aerial photography, airborne geophysical prospecting, offshore hydrographic surveys, and geodetic surveying for measuring long distances. CF: loran. Etymol: short-range navigation.
shore drift
The coarse material covering the bottom where the agitation of the water at the bottom is effective constitutes shore drift. See also: littoral drift.
Shore hardness test
A scale of hardness of rocks as determined by the Shore scleroscope test. The scale avoids the limitation of Mohs' scale of hardness and gives better assessment of rock hardness. See also: tungsten carbide bit.
shore reef
See: fringing reef.
Shore scleroscope
An instrument comprising a small diamond-shaped hammer that falls freely down a graduated tube of glass from a constant height. The hardness of the surface under test is measured by the height of the rebound. In one type of this instrument, the rebound of the hammer actuates the pointer of a scale so that the height of rebound is recorded. See also: scleroscope hardness test.
shore terrace
a. A terrace produced by the action of waves and currents along the shore of a lake or sea; e.g., a wave-built terrace.
b. Marine terrace.
shore up
To stay, prop up, or support by braces.
shoring
Timbers braced against a wall as a temporary support. Also, the timbering used to prevent a sliding of earth adjoining an excavation.
short
a. Said of roof shale that tends to break up or crush under pressure into small fragments and that will not hold in any span over a few inches. Also called tender.
b. Brittle; friable; breaking or crumbling readily; inclined to flake off; said of coal.
c. Used to denote a roof that has very little structural strength.
short awn
A direction of more than 45 degrees to the main natural line of cleat or cleavage in the coal. Also spelled horn. CF: long awn.
short coal
See: short.
short column
A column so short in relation to its cross section that, if overloaded, it will fail by crushing rather than by buckling. CF: long column.
short-delay blasting
a. A method of blasting where the explosive charges are detonated with a very short delay interval between them. It enables shots to assist one another as in simultaneous firing, and also each shot or group of shots establishes a free or semifree face for the following group of shots.
b. Method of blasting by which charges are caused to explode in a given sequence with time intervals of 0.001 to 0.1 s.
short-delay detonator
a. A detonator in which the interval of time delay is incremental in milliseconds. Syn: millisecond-delay detonator.
b. The original 1-s delay detonators are no longer used, and the choice now lies between the one-half-second type and those known as short-delay detonators. These give better fragmentation of rock and consequently better loading rates.
short-delay electric detonator
An electric detonator with a designated delay period of 25 to 1,000 ms.
short-flame explosive
See: permissible explosive.
short hole
Taphole in a furnace that is not properly stopped and that is likely to release the molten charge prematurely.
short-hole work
Diamond drilling where the length of borehole generally does not exceed 100 ft (30 m).
short period
The time required to drill a few holes for trolley hangers or a few short block holes, or one or two holes for bringing down a piece of loose roof.
short-period delay
An electric blasting cap that explodes one-fiftieth to one-half second after passage of an electric current. Syn: millisecond delay.
short-range order
a. Identical first-neighbor coordination of atoms. Typical of glassy structures.
b. A structural state in which cations have coordination polyhedra as predicted by radius ratios but lack the long-range order of crystallinity; e.g., silicate glasses. CF: long-range order.
c. The type of order in which the probability of a given type of atom having neighbors of a given type (for example, that an Alpha atom is surrounded by Beta atoms) is greater than would be expected on a purely random basis. There is thus a tendency to form small ordered domains, but these do not link together at long distances.
short run
To be forced by adverse conditions or core blockage to pull the drill string before the core barrel being used is filled to capacity with core. CF: long run.
shorts
a. As applied to asbestos, consist of the very shortest of classified grades; the fibers may vary from microscopical thin filaments to crude bundles of fibers of appreciable thickness. Included may be particles of nonfibrous serpentine ranging from a palpable powder to granules of visible size.
b. The product that is retained on a specified screen in the screening of a crushed or ground material.
c. In gold cyanidation, the oversize after the gold-rich zinc from the precipitation boxes has been rubbed through.
d. The shortage in production under a royalty lease.
short section
A section of land according to the U.S. Governmental Survey that contains less than 640 acres.
short shot
Colloquialism for weathering (or low-velocity layer) shot in seismic prospecting.
short-term exposure limit
A 15-min time-weighted average exposure that should not be exceeded at any time during a work day even if the 8-h time-weighted average is within the threshold limit value. Abbrev: STEL.
shortwall
a. The reverse of longwall, frequently used to mean the face of a room.
b. A method of mining in which comparatively small areas are worked separately, as opposed to longwall; e.g., room and pillar.
c. A length of coal face intermediate between a stall and a normal longwall face. A shortwall face may be any length between about 5 yd and 30 yd (4.6 m and 27 m) and is generally employed in pillar methods of working. Rooms and stables may also be classified as shortwall faces. See also: shortwall development.
shortwall coal cutter
a. A machine for undercutting coal that has the cutter bar fixed in relation to the main body of the machine. It sumps and cuts across a face in a more or less continuous motion, except when it becomes necessary to stop to change the position of the ropes used to move the machine through the action of rope drums, or when difficulties in cutting are experienced.
b. A coal cutter that has a long, rigid chain jib in line with the body of the machine; it cuts across a heading from right to left, being drawn across by means of a steel wire rope. This machine cannot be readily flitted from one heading to another unless a power-propelled flitting truck is available; otherwise each heading requires its own shortwall cutter. A shortwall cutter will make a 6-ft (1.8-m) cut across a 15-ft (4.6-m) heading in 20 min, including sumping in and out of the cut.
shortwall development
A system of coal working sometimes employed in seams 4 ft (1.2 m) or under in thickness, with the aid of machines. Short faces, each 15 to 30 yd (13.7 to 27 m) wide, are driven at 50- to 70-yd (46- to 61-m) centers, with crosscuts to assist coal transport and ventilation. The rippings are used to form roadside packs. The shortwalls are driven to the boundary, and the coal pillars are worked by longwall retreating. See also: shortwall.
shoshonite
A trachyandesite composed of olivine and augite phenocrysts in a groundmass of labradorite with alkali feldspar rims, olivine, augite, a small amount of leucite, and some dark-colored glass. Shoshonite grades into absarokite with an increase in olivine and into banakite with more sanidine. Its name, given by Iddings in 1895, is derived from the Shoshone River, WY.
shot
a. Coal that has been broken by blasting or other devices.
b. A single explosive charge fired in coal, stone, or ore.
c. A detonation (or its equivalent) as used in seismic shooting. See also: gouging shot.
d. Small spherical particles of brittle hard steel used as the cutting agent in drilling a borehole with a shot drill. Also called adamantine shot; buckshot; chilled shot. See also: gripping shot; blast; shot drill.
shot blasting
A method similar to sandblasting for cleansing the surface of metals, using broken shot or steel grit instead of sand.
shot boring
The act or process of producing a borehole with a shot drill. See also: shot drill.
shot-boring drill
See: shot drill.
shot bort
a. Incorrectly used to designate a small spherical-shaped drill diamond. See: drill diamond.
b. See: ballas.
c. Variety of bort with little impurity, in milky-white to steel-gray spherical stones with radiating structure and great toughness.
d. Spheres of translucent diamond with more cohesion than ordinary bort. See also: bort.
shot break
In seismic prospecting, a record of the instant of generation of seismic waves, as by an explosion. Syn: time break; shot instant.
shot copper
Small, rounded particles of native copper, molded by the shape of vesicles in basaltic host rock, and resembling shot in size and shape.
shotcrete
Gunite that commonly includes coarse aggregate (up to 2 cm).
shot datum
Seismic calculations are usually reduced to a convenient reference surface or plane. These calculations simulate a condition where the charge is shot on the reference surface and the energy is also recorded on this same reference surface. At this reference surface, the time-depth charts have their origin.
shot depth
The distance from the surface to the explosive charge. In the case of small charges, the shot depth is measured to the center of the charge or to the bottom of the hole. In the case of large charges, the distances to the top and to the bottom of the column of explosives are frequently given, and may be reduced to effective shot depth to give the equivalent of a concentrated charge.
shot drill
A core drill generally employed in rotary-drilling boreholes of less than 3 in (7.62 cm) to more than 6 ft (1.8 m) in diameter in hard rock or concrete, using chilled-steel shot as a cutting medium. Also called adamantine drill; calyx drill; chilled-shot drill. See also: core drill; shaft drilling. Syn: shot-boring drill.
shot-drilled shaft
Shafts of up to 5 ft (1.5 m) in diameter drilled through rock to a maximum depth of 1,200 ft (366 m) by means of a shot drill. The latter makes use of shot for cutting a circular groove in the rock being penetrated, from which solid cores are extracted.
shot elevation
a. Elevation of the dynamite charge in the shothole.
b. The elevation of the explosive charge in the shot hole. Not to be confused with shothole elevation.
shot fast
Coal mined by blasting; shot off the solid.
shot feed
A device to introduce chilled-steel shot, at a uniform rate and in the proper quantities, into the circulating fluid flowing downward through the rods or pipe connected to the core barrel and bit of a shot drill.
shot firer
a. A worker whose special duty is to fire shots or blasts, esp. in coal mines. A shot lighter. Also called a shooter.
b. In a coal mine, a qualified miner who tests for gas before firing explosive shots.
c. See: blaster.
Shot Firer
A multiple-shot permissible blasting unit introduced in 1948, known as Capacitor Type Permissible Shot Firer. Weighing approx. 1 lb (0.454 kg) and about the size of an ordinary flashlight, the nonmetallic unit is equipped with a belt hook which permits its being carried under supervision of the shot firer. If desired, shots can be fired without removing the unit from the belt. It is capacitor operated, eliminating dependence on speed of operation for energy output. Capacitors supply high voltage, for a few milliseconds, more than ample to fire from 1 to 10 electric blasting caps.
shot firing
a. The action of detonating or igniting a charge of explosive, usually in a drilled hole.
b. The firing of an explosive charge in a drilled hole to break the material to a suitable size for loading.
shot-firing blasting cord
A two-conductor cable used for completing the circuit between the electric blasting cap (or caps) and the blasting unit or other source of electric energy. Syn: blasting cord.
shot-firing cable
A pair of insulated copper conductors which lead from the exploder to the detonator wires. It may be either twin-core (both conductors contained in the one cable) or single-core (each conductor contained in a separate cable). Twin-core cables having cores of four strands, each 0.018 in (0.046 cm) in diameter (4/0.018) with a resistance of approx. 5 Omega per 100 yd (91 m), are commonly used. Actual choice of cable must depend upon conditions of use and the relevant regulations. Syn: twin-core shot-firing cable.
shot-firing cable tests
The methods of testing twin-core and single-core cables are identical. Two tests are applied, one for insulation and one for continuity, and where large and important charges are being fired, as in tunnel, wellhole, and quarry blasts, tests are made before every blast. For the cable insulation test, an approved circuit tester or ohmeter is connected to one end of the cable, the two conductors at the other end being separated. No current should flow, and the resistance should be infinite. For the continuity test, the two far ends of the cable should be joined. The tester should show that the current is complete, or if an ohmeter is used, this should show the correct resistance of the shot-firing cable.
shot-firing circuit
Extends from the exploder along the shot-firing cable, detonator wires, and finally the detonator. The shot-firing circuit is the path taken by the electric current from the exploder when a shot is detonated.
shot-firing curtain
A steel chain mat suspended from the roof about 9 to 12 ft (2.74 to 3.66 m) from the face of an advancing tunnel to limit damage to equipment and danger from flying debris when shot firing at the face. It consists of a steel frame with chains suspended about 6 in (15 cm) apart. See also: blasting curtain.
shot firing in rounds
The firing of a number of shots in a tunnel, or shaft sinking at one operation with instantaneous or delay detonators.
shot-firing unit
See: blasting unit.
shothole
a. A hole drilled for the purpose of shot firing.
b. A hole drilled in coal, ore, or rock, usually from 3 to 9 ft (0.9 to 2.7 m) in length (underground), for breaking down the material by means of explosives.
c. The borehole in which an explosive is placed for blasting. See also: blasthole.
d. See: shot point.
e. A borehole drilled with a shot drill.
f. In seismic prospecting, a borehole in which an explosive is placed for generating seismic waves.
shothole bridge
a. When an obstruction in the shothole makes it difficult or impossible to get the charge deeper, the hole is said to be bridged. A narrow diameter in the hole due to a resistant bed often makes it difficult to get the charge down the hole. A mechanical device that purposely bridges the hole at a shallow depth in order that the hole may be filled.
b. An obstruction in a shothole that prevents an explosive charge from going deeper. It may be accidental or intentional.
shothole casing
Lightweight pipe, usually about 4 in (10 cm) in diameter. A typical joint of casing is 10 ft (3 m) long and has threaded connections on both ends. The primary use of casing is to prevent the shothole from caving and bridging. The lightweight casing may be considered as an expendable item.
shothole drill
a. Generally, a rotary percussion or auger type drill for making shotholes for blasting.
b. Drills for shotholes are of two general types: (1) the rotary drill and (2) the churn drill. Rotary drill methods can be subdivided into (1) mechanical feed and (2) hydraulic feed. Both types provide a means for rotating the pipe, and both make provisions for circulating fluid down through the pipe, thus washing the cuttings away from the bit and conveying them up to the surface in the annular space between the wall of the hole and the string of drill pipe. The churn drill is similar to the larger cable-tool type. It is seldom used except in areas where underground cavities hamper the return flow of the circulating fluid used in the rotary methods. Portable drills, water jets, and airblast equipment and augers are also used in certain areas. Syn: blasthole drill.
shothole elevation
The elevation of the ground at the top of the shothole.
shothole fatigue
Phenomenon causing observed travel times to a fixed receiver point to increase with successive shots in the same hole.
shothole log
The drillers' record of the depths, thicknesses, and lithologic characteristics of the formations encountered in the seismic shothole.
shothole plug
A plug, usually of wood, used by seismic field parties to plug a hole upon completion of shooting. This prevents caving, protects the public from injury, and protects the exploration company from damage claims that might result from open holes.
shot instant
The elevation of the explosive charge in the shot hole. Not to be confused with shothole elevation. Syn: shot break; time break; shot moment.
shot metal
Metal in the form of small, spherical, or nearly spherical, pellets. It is usually made by causing molten metal to fall, dropwise, from a suitable height into a quenching medium. Also called shot.
shot moment
See: time break; shot instant.
shot-moment line
An electric line wrapped around a dynamite charge and connected to a telephone or radio circuit. The explosion breaks the circuit to record the shot instant or moment. Use is largely obsolete.
shot off the solid
A method of breaking coal from the solid seam by the use of explosives, when the seam has not previously been cut or sheared to prepare the coal for blasting. Also called shot fast.
shot point
The point at which a charge of dynamite is exploded for the generation of seismic energy. In field practice, the shot point includes the hole and its immediately surrounding area. See also: shothole.
shot rock
Blasted rock.
shot runner
See: fire runner.
shot samples
Samples taken for assay from molten metal by pouring a portion into water to granulate it.
shot-sawed surface
Term used to describe the surface finish of building limestone that is deeply scored by using steel-shot abrasive with gangsaws.
shot soil
Soil in which small pellets of iron oxide occur or are forming.
shot tamper
See: tamper.
shotter
Bedded pebbles and sand; glacial outwash gravels.
shotting
The production of shot by pouring molten metal in finely divided streams. Solidified spherical particles are formed during descent and are cooled in a tank of water.
shotty gold
Small granular pieces of gold resembling shot.
shoulder
a. A line formed by the intersection of the face or leading surface of a bit crown and the straight-wall side surface of the crown.
b. A ledge formed by an abrupt change in the course of a borehole.
c. A ledge or projection on drill rods, couplings, pipe, or bits formed at points where an increase or decrease in diameter occurs.
d. The side of a horizontal pipe, at the level of the center line.
e. A short, rounded spur projecting laterally from the side of a mountain or hill.
f. The sloping part of a mountain or hill below the summit.
shoulder cutting
S. Staff. Cutting the sides of the upper lift of a working place in a thick coal colliery next to the rib, preparatory to breaking the coal.
shoulder stone
The diamonds set in a bit at or along the line formed by the intersection of the face or leading surface of a bit crown and the straight-walled side surfaces of the bit crown or shank. CF: kerf stone.
shovel
a. Any bucket-equipped machine used for digging and loading earthy or fragmented rock materials.
b. There are two types of shovels, the square-point and the round-point. These are available with either long or short handles. The round-point shovel is used for general digging since its forward edge, curved to a point, most readily penetrates moist clays and sands. The square-point shovel is used for shoveling against hard surfaces or for trimming.
c. See: power shovel.
shovel craneman
In bituminous coal mining, a maintenance mechanic who inspects, oils, greases, adjusts, and repairs machinery of a power shovel used to dig and load coal (after blasting) into cars in a strip mine. May be designated according to type of power, as electric-shovel craneman; steam-shovel craneman. Also called stripping-shovel craneman.
shovel dozer
A tractor equipped with a front-mounted bucket that can be used for pushing, digging, and truckloading.
shovel front
In power-shovel nomenclature, the shovel front is composed of a main boom and a secondary boom known as the dipper stick, at the outer end of which is the dipper or shovel bucket.
shovel loader
A loading machine mounted on driven wheels by which it is forced into the loose rock at the tunnel face. A bucket hinged to the chassis scoops up the material, which is elevated over and discharged behind the machine. There are two types: (1) the bucket is discharged directly into a mine car behind the machine, and (2) a short conveyor, built into the loader, receives the dirt from the bucket and conveys it back into a car or conveyor. See also: mechanical shovel; loader; loading shovel.
shovel trough
In a duckbill, the shovel part of the loading mechanism that is advanced into a coal pile or retracted according to the adjustment of the operating carrier.
show
a. When the flame of a safety lamp becomes elongated or unsteady, owing to the presence of combustible gases in the air, it is said to show.
b. The detectable presence of mineral, oil, or gas in a borehole, as determined by examination of the core or cuttings.
c. Visual particles of gold found in panning a gravel deposit.
shower roasting
Rapid oxidation-roast of finely ground sulfide ores, which are caused to fall through rising heated air.
showing
a. The first appearance of float, indicating the approach to an outcropping vein or seam.
b. Can. Surface occurrence of mineral.
shrinkage
a. The decrease in volume of a soil or fill material through the reduction of voids by mechanical compaction, superimposed loads, or natural consolidation.
b. The settling or reduction in volume of earthen fills, cement slurries, or concrete on setting.
c. In bitmaking by the powder-metal processes, the difference between the dimensions of the finished bit crown and those of the bit mold.
d. The decrease in volume of clayey soil or sediment owing to reduction of void volume, principally by drying.
shrinkage cavity
A void left in cast metals as a result of solidification shrinkage.
shrinkage crack
A crack produced in fine-grained sediment or rock by the loss of contained water during drying or dehydration; e.g., a desiccation crack or a mud crack.
shrinkage index
The numerical difference between the plastic and shrinkage limits.
shrinkage stope
One in which only part of the severed ore is removed during stoping, the balance being temporarily available as support of workings. Used in steeply dipping lodes with strong walls.
shrinkage stoping
A vertical, overhand mining method whereby most of the broken ore remains in the stope to form a working floor for the miners. Another reason for leaving the broken ore in the stope is to provide additional wall support until the stope is completed and ready for drawdown. Stopes are mined upward in horizontal slices. Normally, about 35% of the ore derived from the stope cuts (the swell) can be drawn off ("shrunk") as mining progresses. As a consequence, no revenues can be obtained from the ore remaining in the stope until it is finally extracted and processed for its mineral values. The method is labor intensive and cannot be readily mechanized. It is usually applied to orebodies on narrow veins or orebodies where other methods cannot be used or might be impractical or uneconomical. The method can be easily applied to ore zones as narrow as 4 ft (1.2 m), but can also be successfully used in ore widths up to 100 ft (30 m). Syn: shrinkage with waste fill.
shrinkage with waste fill
See: shrinkage stoping.
Shropshire method
See: longwall.
shroud laid rope
A rope of four strands laid around a core.
shungite
A hard black amorphous material containing >98% carbon, interbedded among Precambrian schists; probably the metamorphic equivalent of bitumen, but possibly merely impure graphite. Also spelled schungite.
shunt
A connection between two wires of a blasting cap that prevents building up of opposed electric potential in them.
shunt back
A track arrangement for bringing a wagon or mine car to another track without the need for a curve, turntable, or traverser. Also called back shunt; switchback.
shutdown time
One of the rate provisions in drilling contracts, specifying the compensation to the independent drilling contractor when drilling operations have been suspended at the request of the operator.
shute
See: chute.
shutoff valve
A device by means of which the flow of gas or fluid can be made to cease--usually not with the intention of metering or regulating the flow.
shuts
Scot. Movable or hinged supports for the cage at a shaft landing. Also called keps; keeps; chairs; dogs; seats.
shuttle
A back-and-forth motion of a machine that continues to face in one direction.
shuttle car
A vehicle on rubber tires or continuous treads to transfer raw materials, such as coal and ore, from loading machines in trackless areas of a mine to the main transportation system. See also: rubber-tired haulage; trackless tunneling.
shuttle-car operator
In bituminous coal mining, one who drives an electrically powered truck (shuttle car) in a coal mine to transport coal from the excavation point to the conveyor belt.
shuttle conveyor
a. A conveyor that is moved forward or backward in normal operation to vary the loading or discharge points, or both. It may be designed to move only in a straight path, or in either a straight or a curved path. See also: movable conveyor.
b. Any conveyor, such as belt, chain, pan, apron, screw, etc., in a self-contained structure movable in a defined path parallel to the flow of the material.
shuttle multispectral infrared radiometer
See: multispectral scanner.