Appendix:Dictionary of Mining, Mineral, and Related Terms/S/7

skares

See: scares.

skarn

An old Swedish mining term for silicate gangue (amphibole, pyroxene, garnet, etc.) of certain iron ore and sulfide deposits of Archean age, particularly those that have replaced limestone and dolomite. Its meaning has been generally expanded to include lime-bearing silicates, of any geologic age, derived from nearly pure limestone and dolomite with the introduction of large amounts of Si, Al, Fe, and Mg. In American usage, the term is more or less synonymous with tactite. See also: calc-silicate hornfels.

skate-wheel conveyor

A type of wheel conveyor making use of a series of skate wheels mounted on common shafts or axles or mounted on parallel spaced bars on individual axles.

skeletal crystal

Crystals that develop under conditions of rapid growth and high degrees of supersaturation so that atoms or ions are added more rapidly to edges and corners of growing crystals, resulting in branched "dendrites" or hollow stepped depressions, "hoppers." Ice on windowpanes (frost) and pyrolusite on agate (moss agate) are dendrites; halite and gold may form hopper crystals. CF: dendrite; hopper crystal.

skeleton crystals

Hollow or imperfectly developed crystals formed by rapid crystallization.

skeleton sheathing

Consists of a continuous wood frame with sheathing planks placed vertically at intervals, usually of about 4 ft (1.2 m), behind it. Used where the banks consist of compacted, stable soils, primarily to prevent initial yield at the top. CF: close sheathing; tight sheathing.

skeleton tubbing

A temporary method of supporting a circular shaft sinking. It consists essentially of iron curbs or rings. Each ring consists of segments of wrought iron, 3 to 5 in (7.62 to 12.7 cm) deep, 5/8 to 7/8 in (1.59 to 2.22 cm) thick, and from 6 to 8 ft (1.82 to 2.44 m) in length. The segments are bent to the curvature of the shaft and bolted together, each ring being suspended from the ring above. Laggings or backing deals are wedged behind the rings. Every fourth ring or so is supported on steel strata bolts driven into holes drilled in the rock sides. See also: temporary shaft support.

skelp

Mild steel strip, often of Bessemer steel, from which tubes are made by drawing it through a welding bell, at welding temperature, to produce butt-welded or lap-welded tubes or pipes. See also: butt weld.

skelp iron

Wrought iron rolled into flat bars suitable for making pipe.

skerry

a. An old English term meaning, variously, thin layers of micaceous sandstone in the Coal Measures, a thin ferruginous sandstone crowded with fossils, or a hard gritty clay used in making firebricks.

b. Eng. Thin layers of sandstone in the Keuper Marls, Leicestershire, and Derbyshire coalfield. c. Micaceous sandstones in the Coal Measures of Wales and the Midlands. d. Eng. A thin band of ferruginous, micaceous rock, crowded with fossils, Middle Lias, Sutton Basset, Rutland.

skerrystone

Mid. Hard, thin-bedded sandstone.

skew

a. An irregular discontinuous vein striking out from the principal vein in an uncertain direction, lying in a slanting and irregular position.

b. The angled support from which an arch is sprung.

skewed

On a horizontal angle, or in an oblique course or direction.

skewed roller conveyor

A roller conveyor having a series of rolls skewed to direct objects laterally while being conveyed.

skewness

In coal sampling, a lack of symmetry in the particle-size distribution. It is a tendency of the observed data to extend farther to one side of the average than to the other.

skew plate

See: bloomery.

skews

a. Stones cut to form the coping of a gable.

b. Cracks on irregular joints in a mine, sometimes indicating danger from falls.

skiagite

A hypothetical garnet "molecule," Fe (sub 3) Fe (sub 2) (SiO (sub 4) ) (sub 3) .

skialith

A vague remnant of country rock in granite, obscured by the process of granitization. CF: schlieren; xenolith.

skid

a. An iron shoe or clog attached to a chain and placed under a wheel to prevent its turning when descending a steep hill; a drag.

b. An arrangement upon which certain coal-cutting machines travel along a working face. c. A metal slide placed under a mine car wheel temporarily to restrict the speed of a trip on a descending grade. d. A metal plate placed under a shortwall cutting machine to control it while cutting. e. The sledlike platform forming the base on which a machine or structure is set and slid or skidded into position; also, the sled runner, bottom-most part of the base of a drill or other machine.

skid-mounted

A term applied when a drill or other machine is attached permanently to a skid.

ski-lift conveyor

A method of transporting miners to the coal face in special chairs that move continuously on an endless conveyor.

skim gate

A gating arrangement designed to prevent the passage of slag and other undesirable materials into a casting.

skimmer

a. A single-bucket excavator in which the bucket travels along the boom, which is kept almost horizontal during operation.

b. An excavator base machine equipped with jib and bucket for digging and loading from a shallow face above track level.

skimmer equipment

A digging bucket mounted to slide along the boom of an excavator so that the bucket can be used to trim various angles of slope from the horizontal to about 60 degrees elevation.

skimming

The removal of the top layer of soil or of irregularities in the ground surface at new mine or opencast sites. See also: skimping.

skimming gate

A channel in a sand mold having over it a bridge that removes the dross from the molten metal as it passes through. See also: skimmer.

skimming ladle

Any ladle used in skimming; specif., a ladle used for pouring molten metal, having its lip covered with a guard to retain the dross.

skimping

a. The skimmings of the dross from the ore in the vat or tank.

b. See: jigging.

skin effect

a. Tendency of an alternating current to concentrate at the surface of a conductor.

b. The frequency-dependent reduction of resistivity log measurements in conductive formations due to inductive interaction between the current paths; the induction logs now operating at about 20 kHz are most affected. c. The reduction of formation permeability in the vicinity of a well bore caused by drilling and completion operations. d. The concentration of alternating current in a conductor towards its exterior boundary.

skin flotation

a. A concentration process in which adhesion is effected between a free water surface and particles, usually larger than those involved in froth flotation.

b. In skin flotation processes, the separation between minerals and gangue is accomplished at the surface of a body of water, or, in other words, at the air-water interface. Use is made of the surface tension of the water and of the fact that certain minerals, such as sulfides and hydrocarbons, resist being wetted by water. See also: flotation.

skin friction

a. Friction between a fluid and the surface of a solid moving through it, or between a moving fluid and its enclosing surface.

b. The frictional resistance developed between soil and a structure. c. Resistance of ground to the movement of a pile or caisson, generally proportional to the area in contact. d. See: wall friction.

skin rock

The thin band of rock immediately surrounding an excavation.

skip

a. A guided steel hoppit, usually rectangular, with a capacity up to 50 st (45.4 t), which is used in vertical or inclined shafts for hoisting coal or minerals. It can also be adapted for personnel riding. The skip is mounted within a carrying framework, having an aperture at the upper end to permit loading, and a hinged or sliding door at the lower end to permit discharge of the load. The cars at the pit bottom deliver their load either directly into two measuring chutes located at the side of the shaft or into a storage bunker from which the material is fed to the measuring chutes.

b. A large hoisting bucket, constructed of boiler plate that slides between guides in a shaft, the bail usually connecting at or near the bottom of the bucket so that it may be automatically dumped at the surface. c. An open iron vehicle or car on four wheels, running on rails and used esp. on inclines or in inclined shafts. Sometimes spelled skep. d. A thin slice taken off a breast, pillar, or rib along its entire length or part of its length. Also called slab. e. A truck used in a mine. f. A small car that conveys the charge to the top of a blast furnace.

skip bucket

The tub or bucket used for containing the material conveyed by a skip hoist.

skip haulage

A method of underground haulage sometimes adopted in steep workings, where the gradient is 1:2 to 1:1.5. There are two kinds: (1) a skip carriage on which the tub is placed in a horizontal position; and (2) a self-dumping system in which the skip, which is permanently attached to the rope, is discharged automatically at the top of the incline and then returned for reloading.

skip hoist

A bucket or car operating up and down a defined path, receiving, elevating, and discharging bulk materials.

skip loader I

In metal mining, one who loads ore into a skip (large can-shaped container) from skip pockets (underground storage bins) at different shaft stations in a mine, operating a mechanical device to open and close the gates of the loading chutes. Also called skipman; skipper.

skip miner

In bituminous coal mining, one who drills holes into pillars of coal supporting the roof, charges holes with explosives, and blasts out slabs (skips) of coal to widen haulageway or working place.

skip operator

In the iron and steel industry, one who controls the skip hoist by which a skip car containing coke, limestone, or ore is hauled up an inclined runway to the furnace top and dumped into the charging bell of the furnace.

skipping

The working of 2 to 10 yd (1.8 to 9.1 m) of coal along the side or sides of a narrow stall or heading to gain coal and make room for ripping stone. See also: rib-side pack.

skipping the pillar

a. To take a slice off a pillar before abandoning the workings; to rob.

b. Widening a gangway or entry.

skip shaft

A mine shaft esp. prepared for hauling a skip.

skip system

A system used for moving material from a quarry floor to a plant located at a considerable elevation. This system utilizes two parallel inclined tracks with a skip car operating on each track. The cars are operated by cables controlled by a winding gear at the head of the incline. The quarry trucks or cars deliver their loads to the skips through a chute at the base of the incline. A hopper at the top of the incline receives the loads from the skips and feeds the rock to a crusher.

skirt

A vertical strip placed at the side of a conveyor belt to prevent spillage or to increase capacity.

skirting

In pillar extraction, it refers to a stall or roadway working a slice or lift of coal along the side of a pillar.

skirt plates

Steel sideplates that overlap a conveyor belt slightly and assist in settling the coal on the belt at the tail end or at a transfer point.

skirts

That which bounds and limits a vein's breadth, Derbyshire, U.K.

skirt-type core spring

A core lifter, usually a split-ring type, having a split, thin tubular extension attached above the beveled portion of the core spring, which slides upward and inside the lower end of the inner tube of a core barrel.

skleropelite

A rock produced by low-grade metamorphism of an argillaceous sediment without the development of cleavage. See also: hornfels.

sklodowskite

A monoclinic mineral, (H (sub 3) O) (sub 2) Mg(UO (sub 2) ) (sub 2) (SiO (sub 4) ) (sub 2) .2H (sub 2) O ; structurally similar to uranophane and cuprosklodowskite; strongly radioactive; citron-yellow. Also spelled sklodovskite.

skrin

Derb. Cross fissures in limestone, sometimes containing small quantities of ore. Also called scrin.

skull cracker

A heavy iron ball allowed to drop from a height to break up, or crack, hard substances, as aloxite, rock, etc.

skull drop

A place where heavy ladle skulls are broken.

skulls

See: sculls.

skutterudite

An isometric mineral, CoAs (sub 2-3) , having Co replaced by Ni toward nickel-skutterudite; metallic; tin white to silver gray showing iridescent tarnish; a minor source of cobalt. Syn: cobalt skutterudite.

slab

a. A piece of metal, intermediate between ingot and plate, with the width at least twice the thickness.

b. Cleaved or finely parallel jointed rocks, which split into tabular plates from 1 to 4 in (2.54 to 10.16 cm) thick. Slabs are seldom as strong as flags. Syn: slabstone.

slabbing

a. Close timbering between sets of timber.

b. Lagging placed over bars. Also called slabs. c. Cutting a slice or slab from the side of a pillar.

slabbing cut

A drill hole pattern suitable for a wide rectangular tunnel; e.g, 8 ft by 15 ft (2.4 m by 4.6 m) wide. The entire face is fired in three separate rounds of shots, the first or cut holes providing a free face for the remaining shots. The face is broken in successive lifts or slabs from one side to the other. Also called swing cut.

slabbing machine

a. A power-driven, mobile cutting machine, which is a single-purpose cutter in that it cuts only a horizontal kerf at variable heights. Syn: arcwall machine.

b. A coal-cutting machine designed to make cuts in the side of a room or entry pillar preparatory to skipping or slabbing the pillar.

slabbing method

A method of mining pillars in which successive slabs are cut from one side or rib of a pillar after a room is finished, until as much of the pillar is removed as can safely be recovered. This system has the disadvantage that the open area is always increasing and the loaders are working away from the solid pillars toward the goaf.

slab entry

An entry widened or slabbed to provide a working place for a second miner.

slabstone

A rock that readily splits into slabs; flagstone. See also: slab.

slack

a. Fine-grained coaly material resulting from weathering, screening, or washing of coal.

b. To disintegrate rapidly when exposed to weathering. c. Commonly used to describe the smaller sizes of coal passing through screen openings, approx. 1 in (25.4 mm) or less in diameter. d. The process by which soft coal disintegrates when exposed to the air and weather; also to slake, as lime. e. Small coal, usually less than 1/8 in (3.2 mm). It has a high ash content and is difficult to clean in the washery. High-ash slack is being used increasingly in special boilers and power stations. See also: culm; duff.

slack adjuster

In air brakes, the connection between the brake chamber and the brake cam.

slack box

Aust. A bin in which fine coal (slack) is stored.

slack-brake switch

See: hoist slack brake switch.

slacken

In metal smelting, the scoria of previous operations, mixed with the ores to retard or prevent fusion of the nonmetallic portions. Also spelled slakin.

slack hauler

In bituminous coal mining, one who hauls small cars of slack (fine coal) from tipple to boiler room of power plant at mine to maintain fuel supply.

slacking

a. Degradation in size (coal).

b. Coals having a pronounced tendency to disintegrate or slack on exposure to weather, particularly when alternately wetted and dried or subjected to hot sunshine. Coals that slack readily contain relatively large amounts of moisture. When exposed to the weather, such coals lose moisture rapidly. As the coal loses moisture at the surface, the moisture from the interior of the piece gradually drifts outward to the surface. If the loss of moisture at the surface proceeds at a faster rate than that at which it is replaced by moisture from the interior of the piece, then the shrinkage of the coal at the surface is greater than that in the interior; consequently, stresses are generated in the surface coal. These stresses cause the coal to crack and disintegrate. Also called weathering. See also: weathering; weathering index.

slacking index

See: weathering index.

slackline cableway

a. A cableway having one low and one high tower and a track cable with adjustable tension suspended between them. One end of the track cable is attached to a hoist drum by means of which the tension on the cable can be rapidly changed so as to position, lower, or raise the digging skip.

b. A cable excavator having a track cable that is loosened to lower the bucket and tightened to raise it.

slack quenching

The process of hardening steel by quenching from the austenitizing temperature at a rate slower than the critical cooling rate for the particular steel--resulting in incomplete hardening and the formation of one or more transformation products in addition to or instead of martensite.

slack water

The state of a tidal current when its velocity is near zero, the moment when a current reverses direction. Sometimes considered the intermediate period between ebb and flood currents during which the velocity of the currents is less than 0.1 knot (0.16 km/h).

slag

a. Material from the iron blast furnace, resulting from the fusion of fluxstone with coke ash and the siliceous and aluminous impurities remaining after separation of iron from the ore. Slag is also produced in steelmaking. Formerly a solid waste, slag is now utilized for various purposes, chiefly in construction.

b. A scoriaceous or cindery pyroclastic rock. c. A British term for a friable shale with many fossils. d. A substance formed in any one of several ways by chemical action and fusion at furnace operating temperatures: (1) in smelting operations, through the combination of a flux, such as limestone, with the gangue or waste portion of the ore; (2) in the refining of metals, by substances such as lime added for the purpose of effecting or aiding the refining; or (3) by chemical reaction between refractories and fluxing agents, such as coal ash, or between different types of refractories. e. Partially fused mixture of spilled batch, overflowed glass, breeze coal, and clay from the siege. f. The top layer of the multilayer melt formed during some smelting and refining operations. In smelting, it contains the gangue minerals and the flux; in most refining operations, the oxidized impurities. g. Oxide liquids (exclusive of the commercial glasses) with a high melting temperature. h. See: blast-furnace slag; granulated slag.

slag blanket

The coating of slag, or scum, that forms on the top of the bath in the open-hearth furnace.

slag buggy

A very large pot for holding slag obtained in the smelting or ores. It is mounted on a railway truck or the like, so as to permit easy dumping. See also: slag pot.

slag car

Iron vessel on wheels used to transport molten slag from furnace to dump. Also called slag buggy.

slag dump

A dumping place for the shell or cone that forms in a slag pot.

slaggable

Capable of becoming or forming into a slag.

slagging

Destructive chemical reaction between refractories and external agents at high temperatures, resulting in the formation of a molten liquid.

slagging of refractories

Destructive chemical reaction between refractories and external agencies at high temperatures, resulting in the formation of a liquid.

slag hearth

A hearth, on the principle of the Scotch hearth, for the treatment of slags, etc., produced by lead smelting in the reverberatory furnace. The English slag hearth has one tuyere; the Castillian or Spanish, three.

slag inclusion

Slag (dross) entrapped in a metal.

slag lead

Lead obtained by a resmelting of gray slag.

slag pot

A vessel for the disposal of slag at furnaces. Small pots are mounted on wheels and moved by hand, while the larger ones are mounted on trucks for mechanical transportation. See also: slag buggy; slag car.

slag runoff

Tapping off excess slag after the ore boil in the basic open-hearth process of steelmaking.

slake

a. To crumble or disintegrate, such as coal or lime.

b. Small coal. c. To mix with water, so that a chemical combination takes place, as in the slaking of lime. d. To crumble in water.

slaking

a. The crumbling and disintegration of earth materials upon exposure to air or moisture; specif. the breaking up of dried clay or soil when saturated with or immersed in water, or of coal or clay-rich sedimentary rocks when exposed to air.

b. The disintegration of the walls of tunnels in swelling clay, owing to inward movement and circumferential compression. c. The treating of lime with water to give hydrated (slaked) lime.

slam

Eng. Thin slurry and mud, Yorkshire lead mines.

slant

a. Any short, inclined crosscut connecting the entry with its air course to facilitate the hauling of coal. Commonly called a dip switch when the coal is not level. See also: shoo-fly.

b. A heading driven diagonally between the dip and the strike of a coal seam. Also called a run. See also: counter; stone drift; surface drift.

slant chute

Chute driven diagonally across to connect a breast manway with a manway chute. See also: slant.

slant drilling

See: directional drilling.

slants

Eng. A set of joints in slate parallel to the main cleavage, Denbighshire.

slant vein

York. One vein crossing another at an acute angle.

slape back

Eng. See: back.

slash

a. There are many successive ridges of shingle running in varying directions, and often with narrow strips of marsh enclosed between successive ridges. Such bands of marsh have been given the very appropriate name of slashes in New Jersey.

b. Swampy land, overgrown with dense underbrush. Local in the Northeast. c. An open or cutover tract in a forest strewn with debris, as from logging; also such debris.

slat bucket

A digging bucket of basket construction, used in handling sticky, chunky mud.

slate

a. A compact, fine-grained metamorphic rock that possesses slaty cleavage and hence can be split into slabs and thin plates. Most slate was formed from shale.

b. A coal miner's term for any shale accompanying coal; also, sometimes the equivalent of bone coal. c. Dark shale lying next to the coalbeds. It contains impressions of the plant life of distant ages, proving the vegetable origin of coal. d. A fine-grained metamorphic rock that breaks into thin slabs or sheets. Usually gray to black, sometimes green, yellow, brown, or red. Slates are composed of micas, chlorite, quartz, hematite, clays, and other minerals. Found in Pennsylvania, Vermont, Maine, Virginia, California, Colorado; Europe. Used for roofing; decorative stone; various building applications; in crushed form on shingles; abrasive; pigment. See also: clay slate; phyllite; spotted slate.

slate chute

a. A chute for the passage of slate and bony coal to a pocket from which it is loaded into dump cars.

b. A chute driven through slate.

slate cutter

In the stonework industry, one who operates an upright drilling machine to drill holes into slate so that the slabs may be fastened in place with wires or rods when installed in a building.

slate ground

A term used in southern Wales for a dark fissile shale, resembling slate.

slate handler

In bituminous coal mining, a laborer who shovels up falls of slate or rock along haulageways in a mine and loads it into cars. Also called rock handler.

slate larryman

See: slate motorman.

slateman

In anthracite and bituminous coal mining, a general term for a worker handling slate or rock as distinguished from coal. Usually designated according to type of activity, as rock driller; rock loader; slate motorman; slate picker; slate shooter. Also called rockman; slate handler. See also: rockman; slate handler.

slateman helper

See: slate-shooter helper.

slate motorman

In anthracite and bituminous coal mining, a person who operates a mine locomotive to haul trains of cars loaded with slate or shale, underground and at the surface of a mine. Also called larryman; slate larryman.

slate saw

See: marble saw.

slate shooter

In bituminous coal mining, one who drills holes into the slate roof of haulageways, and charges and sets off explosives to blast down slate to increase height or improve the safety of the roof.

slate-shooter helper

In bituminous coal mining, a laborer who assists the slate shooter in removing the slate and rock from the roof, ribs, and face of haulageways. Also called rockman helper; slateman helper.

slate spar

A variety of crystallized calcite. Also called shiver spar.

slat gate

A gate, for controlling water, composed of two upright grooved posts with boards between the boards of slats being removed or added to regulate the height of water.

slaty band

Scot. Ironstone and flaky blaes.

slaty cleavage

A pervasive, parallel foliation of fine-grained, platy minerals (mainly chlorite and sericite) in a direction perpendicular to the direction of maximum finite shortening, developed in slate or other homogeneous sedimentary rocck by deformation and low-grade metamorphism. Most slaty cleavage is also axial-plane cleavage. Syn: flow cleavage.

slave cylinder

A small cylinder whose piston is moved by a piston rod controlled by a larger cylinder.

slave piston

A small piston having a fixed connection with a larger one.

slave unit

A machine controlled by or through another unit of the same type.

sleck

a. Eng. A kind of reddish sandstone.

b. Eng. Small pit coal. c. Newc. Mud deposited by water in a mine. d. See: slack.

sled

A drag used to convey coal along the road to where it is loaded into cars, or to the chute. Also called sledge; slype.

sledger

a. In bituminous coal mining, one who digs out dirt, rock, or coal with a long-handled pick (sledge) in a strip mine so that it may be loaded into cars by hand or with a power shovel.

b. In the quarry industry, one who breaks up large stone into small pieces suitable for use in building work. Also called laborer, stone; rock breaker; spawl beater; stone sledger.

sledging roll

Crushing roll with projection that breaks the rock, instead of fracturing it by squeezing. Also called slugging roll.

sleeping rent

A fixed rent stated in leases of coal mines, as distinguished from royalty or share of profits.

sleeve catcher

A skirt-type core lifter.

slender beam

A beam, which if overloaded, will fail by buckling of the compression flange.

slew

a. To turn around (slue).

b. See: slough.

slewing

a. The rotation of a crane jib so that the load moves through the arc of a circle on a horizontal line.

b. To turn or twist.

slice

a. To remove ore by successive slices from the top of an orebody of considerable lateral extent and thickness. The slices may be 6 ft, 12 ft, 20 ft, or 40 ft (1.8 m, 3.6 m, 6.1 m, or 12.2 m) thick.

b. A thin broad piece cut off, such as a portion of ore cut from a pillar or face.

slice bar

A thin, wide iron tool for cleaning clinkers from the grate bars of a furnace.

slice drill

In sublevel caving, the crosscuts driven between every other slice from 18 to 36 ft (5.47 to 10.94 m) apart.

slicing

In continuous mining, slicing consists of driving up some four to six places the set or desired distance, which may be 1,000 ft (304.8 m) or more, and then pulling the pillars on retreat. After completion of one slice, the unit moves over and mines another along the gob. See also: top slicing.

slicing-and-filling system

See: overhand stoping.

slicing method

Removal of a horizontal layer from a massive orebody. In top slicing extraction retreats along the top of the orebody, leaving a horizontal floor that becomes the top of the next slice. A timber mat separates this from the overburden, which caves downward as the slices are made. Other methods attack from the bottom (sublevel caving) or side.

slick

Ore in a state of fine subdivision. Syn: slime. Also called slickens.

slickens

Extremely fine-grained material, such as finely pulverized tailings discharged from hydraulic mines or a thin layer of extremely fine silt deposited by a stream during a flood.

slickensided clay

See: stiff-fissured clay.

slickensides

The striations, grooves, and polish on joints and fault surfaces. CF: striation. See also: fault striae; fault gouge.

slicker

A small implement used in a foundry for smoothing the surface of a mold.

slick hole

A hole column loaded with explosive, without springing.

slicking

A narrow vein of ore.

slick top

In coal mining, a term used to describe the roof of the coal vein when it is very smooth.

slide

a. An upright rail fixed in a shaft with corresponding grooves for steadying the cages.

b. A trough used to guide and to support rods in a tripod when drilling an angled hole. Also called rod slide. c. The bottom of a gold-washing cradle. d. As used by churn drillers, a fault plane or opening encountered in a hole that deflects the bit. e. A mass movement of descent resulting from failure of earth, snow, or rock under shear stress along one or several surfaces that are either visible or may reasonably be inferred; e.g., landslide, snowslide, and rockslide. The moving mass may or may not be greatly deformed, and movement may be rotational or planar. A slide can result from lateral erosion, lateral pressure, weight of overlying material, accumulation of moisture, earthquakes, expansion owing to freeze-thaw of water in cracks, regional tilting, undermining, and human agencies. f. The mass of material moved in or deposited by a slide.

slide coupling

See: slip joint.

slide rail

A mounting of steel or cast iron for a belt driven machine enabling it to be moved along as the belt stretches in order to take up the slack.

slide rock

Rock making up the mass of material in a landslide or talus.

sliding angle

Angle at or above which rock in movement will continue to slide, but less than the angle needed to initiate movement from rest.

sliding friction

Sliding friction is the resistance offered when one body slides over another body. The amount of friction or resistance is dependent on the laws of friction.

sliding gate

A crest gate that has a high frictional resistance to opening and is therefore suitable only for small gates. See also: roller gate.

sliding scale

A method of paying for the coal in proportion to the amount of lump coal it contains.

sliding-scale system

A system which regulated colliers' wages by the ascertained selling price of coal.

sliding shoe

A metal plate that serves as partial or total support for devices used with shaker conveyors where the device must move or slide on the bottom. The shovel trough of a duckbill and certain types of swivels or angle troughs use this device.

slime

a. Extremely fine sediment (#200 mesh), produced in the processing of ore or rock, esp. phosphate rock, which remains suspended in water indefinitely. Consists chiefly of clay.

b. A material of extremely fine particle size encountered in ore treatment. c. Anode slimes are the metals or metal compounds left at, or falling from, the anode during electrolytic refining of metals. See also: anode slime. d. A mixture of metals and some insoluble compounds that forms on the anode in electrolysis. e. A product of wet grinding containing valuable ore in particles so fine as to be carried in suspension by water; chiefly used in the plural. f. In metallurgy, ore reduced to a very fine powder and held in suspension in water so as to form a kind of thin ore mud; generally used in the plural. g. Primary slimes are extremely fine particles derived from ore, associated rock, clay, or altered rock. They are usually found in old dumps and in ore deposits that have been exposed to climatic action; they include clay, alumina, hydrated iron, near-colloidal common earths, and weathered feldspars. Secondary slimes are very finely ground minerals from the true ore.

slime coating

In mineral processing, adherence of an impalpably fine layer of particles of another (for example, calcite on galena), therefore hindering or preventing true surface reaction in leaching or flotation.

slime deliveryman

In beneficiation, smelting, and refining, a laborer who washes slime from cloth strainers, electrolysis tank debris, and collection barrels into a settling tank, using a water spray preparatory to recovery of precious metals from slime. Becoming obsolete.

slime leaching

A leaching method in which the slime and the leach solution are agitated in one or more agitators until the ore minerals have been dissolved. Some agitators have mechanically driven paddles or elevators inside an agitation tank, which serve to keep the pulp in circulation until dissolution is complete. This method may be either continuous or intermittent.

slime pit

A tank or large reservoir of any kind into which the slimes are conducted in order that they may have time to settle, or in which they may be reserved for subsequent treatment. See also: slime.

slimer

A machine that makes slime; e.g., a tube mill.

slime sludge

a. The pulp or fine mud from a drill hole.

b. See: slime.

slime table

a. A table for the treatment of slime; a buddle.

b. A shaking table used in gravity concentration of finely ground coal or ore, characterized by special riffles and shallow pools in which stratification is gently produced.

slime tin

Cassiterite too finely ground to be readily concentrated by the use of gravity treatment. Usually associated with hydrated iron.

slime water

Water defiled in washing ore.

slim hole

a. A rotary borehole having a diameter of 12.7 cm or less.

b. A drill hole of the smallest practicable size, often drilled with a truck-mounted rig; used primarily for mineral exploration or as a stratigraphic or structure test. See also: structure test hole.

slim-hole drilling and casing

Use of the smallest feasible drill hole and casing size.

sliming

Overgrinding in a ball mill.

sline

a. Mid. Potholes in a mine roof.

b. The principal cleat in coal. c. A natural transverse cleavage of rock; a joint.

sling

a. A rope or chain put around stones or heavy weights for raising them.

b. A lifting hold consisting of two or more strands of chain or cable. c. A ropelike device used to give additional support to lengths of drill rod too long to stand in the drill derrick without sagging unduly. d. A short loop or length of cable with small loops at either end.

sling block

A frame in which two sheaves are mounted so as to receive lines from opposite directions.

sling hygrometer

See: Storrow whirling hygrometer.

sling psychrometer

A hygrometer held on a short length of cord and whirled around, the observer standing sideways to the air current. The wet bulb is thereby rapidly reduced to its final reading.

slink

Scot. A wide clayey joint; a stage.

slip

a. Landslip, or subsiding mass of rock or clay in a quarry or pit; a minor landslide.

b. A small fault. c. The relative displacement of formerly adjacent points on opposite sides of a fault, measured in the fault surface. See also: dip slip; strike slip. Partial syn: shift. Syn: total displacement. d. A joint or cleat in a coal seam. e. See: kettle bottom. Syn: horseback; kettleback. f. A joint in coal upon which there may have been no perceptible movement. g. See: back. h. A joint or pronounced cleavage plane. i. A sudden descent of a hanging or sticking charge in a blast furnace. j. One of a set of serrated-face wedges that fits inside the spider of a drill-rod clamping device. See also: spider; slips. k. The percentage of water leaking through valves, expressed as a percentage of the volume swept out by the bucket or ram, a measure of the volumetric efficiency of a pump. Generally for normal pumping speeds, the slip is between 5% and 10% but it may rise to 20% with higher pumping speeds. l. Under stress, minerals deform plastically along specific crystallographically determined slip planes in slip directions, analogous either to the sliding in a deck of playing cards, such as in quartz, or to a bundle of pencils, such as in olivine. Deformation lamellae may be preserved or destroyed by annealing. Although such slip is referred to as glide, it is not to be confused with a crystallographic glide--the combined symmetry element of translation and reflection. CF: glide; glide direction; glide plane; gliding.

slip bowl

A spider. See also: spider and slips.

slip-casting process

One in which clay, or other slip, is poured into plaster molds that absorb the water, leaving a body the shape of the mold.

slip clay

An easily fusible clay containing a high percentage of fluxing impurities, used to produce a natural glaze on the surface of clayware. See also: slip.

slip cleavage

a. That variety of foliation along which there has been visible displacement, usually shown by bedding that is cut by the cleavage. Such displacements are commonly shown along many adjacent cleavage planes.

b. Microscopic folding and fracture accompanied by slippage; quarrymen's false cleavage. c. S. Wales. The cleat of coal in planes parallel with slips or faults. d. A type of cleavage that is superposed on slaty cleavage or schistosity, and is characterized by finite spacing of cleavage planes between which occur thin, tabular bodies of rock displaying a crenulated cross-lamination. Syn: shear cleavage; strain cleavage; strain-slip cleavage; close-joints cleavage.

slip clutch

A friction clutch that protects a mechanism by slipping under excessive load.

slip dike

A dike that has been intruded along a fault plane.

slip direction

The crystallographic direction in which the translation of slip takes place. See also: glide direction.

slipes

S. Staff. Sledge runners, upon which a skip is dragged from the working breast to the tramway.

slip fiber

Veins of fibrous minerals, esp. asbestos, in which the fibers are more or less parallel to slickensided vein walls. CF: cross fiber.

slip-fiber amphibole

See: anthophyllite.

slip fold

See: shear fold.

slip grip

A hold or grip on a drill rod, casing, or pipe by means of serrated-face steel wedges or slips.

slip joint

a. A contraction joint between two adjoining sections of wall, or at the horizontal bearing of beams, concrete slabs, and precast units, to allow slight movement in relation to one of the other.

b. A splined connection loose enough to allow its two parts to slide on each other to change shaft length.

slip line

Line that appears on the polished surface of a crystal or crystalline body that has been stressed beyond the elastic limit. In quantity, they represent the intersection of the surface by planes on which shear stress has produced plastic slip or gliding. Syn: Lueders line.

slip maker

See: clay maker.

slip mixer

See: clay maker.

slippage

See: slip.

slippery parting

Eng. See: back.

slipping cut

In blasting underground, a cut used in a wide tunnel face, in which each successive vertical line of shots (round) breaks to the face made by the previous round, so that the relieving cut moves across the end being blasted. Also known as slabbing cut; swing cut.

slip plane

a. Closely spaced surfaces along which differential movement takes place in rock. Analogous to surfaces between playing cards. Syn: glide plane; gliding plane.

b. The crystallographic plane in which slip occurs in a crystal.

slip process

See: wet process.

slips

a. Small faults.

b. A tool used at the mouth of a borehole to grip the drill rods or the casing, as these are being inserted or withdrawn. c. See: backs; slickensides.

slip spear

A tool for extracting tubing from a borehole.

slip surface

The surface along which an earth bank is liable to fail under load.

slip surface of failure

In a bank of homogeneous earth or clay, the slip surface of failure closely follows the arc of a circle that usually intersects the toe of the bank. Stability depends upon fixing the position of the center of rotation of the slip surface along which the greatest shearing resistance would be required for equilibrium. See also: circular slip; landslide.

slip switch

A sensor installed on a conveyor drive pulley snub roller, on a return roller, on a bend roller, or on a head pulley that will detect a slowing of the conveyor, resulting in conveyor shut-down to avoid conveyor belt fires or overloading of the conveyor because of the slipping.

slip-type core lifter

A device used like a core spring, consisting of a series of tapered wedges contained in slotted recesses in a circular ring or sleeve; as the core enters the inner tube, it lifts the wedges along the taper, and when the barrel is lifted, the wedges are pulled tight against the core.

slip vein

A mineral vein accompanied by faulting or dislocation.

slip velocity

The rate, expressed in feet (meters) per minute, at which a given size and shape of rock particle will descend or settle in water; e.g., the slip velocity in water of a round, flat particle of rock, 1/2 in (1.27 cm) in diameter, is about 54 ft/min (16.5 m/min).

slit-side solid sampler

A solid-tube sampler with a slight twist on the bottom and an offset slit in the side. When rotated, the lip of the slit scrapes a sample from the side of a borehole.

slitter

Eng. A pick.

slitting disk

Circular saw used in preparing rock specimens. The cutting edge incorporates diamond dust, and the thin steel disk revolves at high speed.

slitting shot

A shot put into a large mass of coal detached by a previous blast.

slocking stone

Eng. A piece of rich ore used to tempt persons into a mining enterprise. See also: salting a mine.

slope

a. The entry, passage, or main working gallery of a coal seam that dips at an angle. See also: incline.

b. Inside slope. c. See gradient. d. An inclined passage driven from the dip of a coal vein. CF: slant. When not open at one end to the surface, it is known as an inside slope. See also: incline; plane. e. The inclination of a mine roadway or coal seam. f. The main working gallery or entry of a coal seam that dips at an angle and along which mine cars are hauled. g. An entrance to a mine driven down through an inclined coal seam; also, a mine having such an entrance. An inside slope is a passage in the mine driven through the seam by which coal is brought up from a lower level. h. In a mining statute or in mining parlance, an inclined way, passage, or opening used for the same purpose as a shaft. Sometimes used to embrace the main haulage passageway, whether inclined or level. i. The degree of inclination to the horizontal. Usually expressed as a ratio, such as 1:25, indicating one unit rise in 25 units of horizontal distance; or in a decimal fraction (0.04); degrees (2 degrees 18'); or percent (4%). It is sometimes expressed as steep, moderate, gentle, mild, flat, etc. Also called gradient. j. In surface mining, the steepest possible slope of an excavation that is consistent with safety of working. k. An inclined passageway (tunnel) from the surface, through the strata, that intersects the coal bed to be developed.

slope air course

A passageway parallel to the haulage slope used for the passage of the air current.

slope cage

A truck on which the cars are raised at slopes or steep dips. Also called slope carriage. See also: carriage.

slope conveyor

a. Usually a troughed belt conveyor used for transporting coal or ore through an inclined passage to the surface from an underground mine. See also: apron conveyor; belt conveyor; flight conveyor.

b. Generally less than 1,000 ft (304.8 m) in length, the conveyor is designed to raise or lower material on steep grades and is commonly used to transport material from discharge bins or a main haulage conveyor to the outside. It is often used as a transfer conveyor from a lower to a higher entry or to a gangway in a pitching seam.

slope correction

A calculation of deduction from a length as measured on a slope to bring it to its true horizontal length. See also: tape corrections.

slope engineer

In anthracite and bituminous coal mining, one who operates a hoisting engine to haul loaded and empty mine cars along a level or inclined haulage road (slope or plane) in a mine on a level, or from a lower to an upper level, or to the mine surface. Also called drag engineer; dragline engineer; drumman; plane engineer; plane tender; slope tender.

slope failure

a. The downward and outward movement of rock or unconsolidated material as a unit or as a series of units. Also called slump.

b. Failure of the mass of soil beneath a natural slope or a slope of an embankment by the formation of a slide. c. Slope failure may take place by one or more of three processes: (1) raveling, in which the material will assume an angle of repose approx. equal to the angle of friction of the material, and within limits the stable slope is independent of the weight of the mass, the height of the slope, and the size of the fragments. It is, however, characteristic of each rock material and is dependent on angularity, grading, and mineral content; (2) transitional failure, in which failure occurs mostly along existing fault planes or other planes of weakness. Stability is a function of rock cohesion, the angle of internal friction, the angle of dip of the slip plane, the length of the slip surface, and the total weight of the block; and (3) rotational or base failure, which is uncommon in open-pit mines or rock cuts because of geologic structure. However, in the case of homogeneous cohesive material--very deep excavation or low rock strength--failure may occur along a cylindrical surface. Four types of slope failure are rockfall, rock flow, plane shear, and rotational shear. See also: rockfall; rock flow; plane shear; rotational shear. Syn: base failure. d. Gradual or rapid downslope movement of soil or rock under gravitational stress, often as a result of man-caused factors; e.g., removal of material from the base of a slope.

slope gage

A staff gage placed on an incline and graduated to indicate vertical heights.

slope hoist

See: direct-rope haulage.

slope mine

a. A mine opened by a slope or incline.

b. A mine with an inclined opening used for the same purpose as a shaft or a drift mine. It resembles a tunnel, a drift, or a shaft, depending on its inclination.

slope stability

a. The resistance of any inclined surface, as the wall of an open pit or cut, to failure by sliding or collapsing.

b. The resistance of a natural or artificial slope or other inclined surface to failure by landsliding.

slope stake

a. Stake set at the point where the finished side slope of an excavation or embankment cuts the surface of the ground. It is usually placed on a line at right angles to the center line and passing through the station point.

b. A stake marking the line where a cut or fill meets the original grade.

slope staking

Marking the ground surface by pegs at points where proposed new slopes in cut or fill coincide with the orginal surface.

slope tender

See: slope engineer.

slope test

A test to determine whether, and to what extent, the course of a well deviates from vertical. Syn: angularity test.

sloshing loss

A loss occurring when there is a fluid in the pores of the rock. This loss arises from the relative movement of the fluid and solid as the elastic waves pass through the rock.

slot

A narrow, vertical opening generally too small to permit traverse by a person.

slot-and-wedge bolt

A special rod designed for use in roof bolting. It consists of a mild steel rod, threaded at one end, the other end being split into halves for a length of about 5 in (12.7 cm). When the bolt is driven into the hole, a wedge opens the slotted end, thus forming the anchorage. See also: bolt; wedge-and-sleeve bolt.

slot dozing

A method of moving large quantities of material with a bulldozer. Each trip is made in the same path; thus the spillage from the sides of the blade builds up along each side. All material pushed into the slot is retained in front of the blade; bigger loads are handled.

slotted duct sampler

An instrument for sampling airborne dust consisting of a wide horizontal duct through which mine air enters in a streamline flow, so that dust particles will be deposited on the duct floor according to their falling speeds as derived from Stokes' law. The instrument combines the duties of monitoring and measuring airborne dust concentrations in mine roadways. See also: thermal precipitator.

slough

Fragmentary rock material that has crumbled and fallen away from the sides of a borehole or mine working. It may obstruct a borehole or be washed out during circulation of the drilling mud. Pron: sluff.

sloughing

Minor face and rib falls.

sloughing-off cone

Large cone (e.g., Callow) in pulp flow line designed to remove fine slimes as overflow while delivering a thickened spigot product containing the coarser particles.

slovan

a. Corn. The outcrop or back of a lode. This generally applies to the appearance of a lode in a marshy place.

b. A gallery in a mine; day level; esp. applied to damp places.

slow-banking device

An appliance for use in conjunction with the Lilly controller for controlling the landing speed of less than 5 ft/s (1.52 m/s) when workers are being transported by winding. On each dial of the Lilly controller, an auxiliary dial is bolted to carry a slow-banking cam engaging near the end of the wind with a roller arm. The action of the appliance depends on the relative rate of movement of this roller and that of the piston in an oil dashpot cylinder.

slow gear

a. When applied to speed at which the drill motor rotates the drill stem, the transmission gear position giving the lowest number of bit revolutions per minute; thus, slow gear corresponds to low gear in an automobile.

b. When applied to a screwfeed-type drill, the pair of feed gears in the feed mechanism that advances the bit the least amount for each revolution of drill drive rod and/or the coupled drill stem; e.g., a 400-feed gear is slower than a 100-feed gear. CF: feed ratio.

slow igniter cord

It consists of a plastic incendiary composition extruded around a central copper wire. An iron wire is added to give greater strength, and the whole is then enclosed in a thin extruded plastic coating. The diameter of slow cord is 0.07 in (1.8 mm).

slow powder

Blackpowder, often called gunpowder. Also, some of the slow-acting dynamites.

sludge

a. Refuse from a coal-washing plant.

b. In diamond drilling, the portion of core ground finely by accident or defect in drilling, and therefore reducing the reliability of the portion of the sample in which it happened. Mineral mud, slurry too thick to flow. c. Rock cuttings produced by a drill bit. d. See: cuttings. e. A semifluid, slushy, murky mass of sediment resulting from treatment of water, sewage, or industrial and mining wastes; often appearing as local bottom deposits in polluted bodies of water. f. See: slime. Sometimes called slurry.

sludge abatement

The control of the discharge into watercourses (or on adjacent land), of mineralized or impure water, or sludge, or mining debris.

sludge assay

The chemical assaying of drill cuttings for a specific metal or group of metals.

sludge barrel

a. See: sediment tube.

b. See: calyx.

sludgebound

Any part of the drill-string equipment clogged by impacted cuttings.

sludge box

a. A wooden box in which the sludge is allowed to settle from the mud flush and sometimes retained for examination.

b. See: settling box.

sludge bucket

See: calyx.

sludge channel

A tailrace for conveying the tailings away after the gold has been extracted from alluvial beds.

sludge mill

A machine in which the sludge (slime) from another mill is washed; as, e.g., a slime table.

sludge paddocks

Collecting or settling areas for the slurry which results from hydraulicking overburden.

sludge pit

See: sump.

sludge pump

Short iron pipe or tube fitted with a valve at the lower end, with which the sludge is extracted from a borehole. Also called bailer, mud pump. See also: mud hog; sand pump.

sludger

a. A long cylindrical tube, fitted with a valve at the bottom and open at the top, used for raising the mud that accumulates in the bottom of a boring during the sinking process. Also called sand pump; shell pump; sludge pump.

b. A scraper for clearing mud out of a shothole. c. A centrifugal pump designed for dealing with sand and slime. See also: bailer.

sludge sample

a. Samples of mud from a rotary drill, or sand from a churn drill, or fine materials from diamond drilling used to obtain information about the formation being drilled.

b. All or part of the drill cuttings collected, dried, and saved for assaying or chemical analysis. c. The mud and chippings made during boring with a diamond or churn drill and sometimes used for sampling purposes. Little reliance can be placed on the assay of the sludge, and it is not regularly saved for assay, except occasionally when drilling in weathered or friable ore zones. Sludge tanks are often used to collect sludge samples.

sludge sampler

a. An individual responsible for collecting and preparing drill cuttings for the purpose of examining, assaying, chemical analysis, or storage. Also called sampler.

b. A device used to collect and to split drill cuttings. See also: riffle.

sludge sampling

Process of collecting and preparing drill cuttings as samples.

sludge-saver

A device for collecting all the drill cuttings from a given interval of borehole.

sludge splitter

See: rifle.

sludge water

See: return water.

sludging

Filling or choking the waterways of a bit with drill cuttings; mudding up.

sludging formation

A formation from which it is nearly impossible to recover core, so that sampling is done by collecting the drill cuttings or sludge.

sludging up

See: sludging.

slue

To turn, twist, or swing about. To slide and turn or slip out of course. In cutting the coal, the machine moves from right to left, the back part moving faster than the front. It is necessary at intervals to stop the machine and straighten it, or "slue" it, as called by miners.

sluff

a. Mud cake detached from the wall of a borehole.

b. A variant, incorrect spelling of slough. c. The falling of decomposed, soft rocks from the roof or walls of mine openings.

slug

a. A piece of alluvial gold up to about 1 lb (0.45 kg) weight.

b. A lump of metal or valuable mineral. c. To inject a borehole with cement slurry or various liquids containing shredded materials in an attempt to restore lost circulation by sealing off the openings in the borehole-wall rocks. d. Small, shaped pieces of hard metal that can be brazed or handpeened in slots or holes cut in the face of a blank bit. Slugs may or may not contain diamonds. CF: insert. e. A mass of half-roasted ore.

slug bit

See: insert bit.

slugga

An Irish term for a hole in the ground surface, caused by the falling-in of limestone over a subterranean stream. CF: sinkhole.

slugger

A tooth on a roll-type rock crusher.

sluice

a. To mine an alluvial deposit by hydraulicking.

b. A conduit or passage for carrying off surplus water, often at high velocity. It may be fitted with a valve or gate for stopping or regulating the flow. c. A gate, such as a floodgate. d. A body of water flowing through or stored behind a floodgate. e. A long troughlike box set on a slope of about 1:20, through which placer gravel is carried by a stream of water. The sand and gravel are carried away, while most of the gold and other heavy minerals are caught in riffles or a blanket on the floor. See also: box sluice; ground sluice; placer mining. f. See: flume. g. An opening in a structure for passing debris. h. A channel, drain, or small stream for carrying off surplus or overflow water.

sluicebox

Long, inclined trough or launder containing riffles in the bottom that provide a lodging place for heavy minerals in ore concentration. The material to be concentrated is carried down through the sluices on a current of water. Sluiceboxes are widely used in placer operations for concentrating elements such as gold and platinum, and minerals such as cassiterite, from stream gravels.

sluice fork

A form of fork having many tines, used to remove obstructions from a sluiceway.

sluice gate

The sliding gate of a sluice.

sluice head

Aust. A supply of 1 ft (super 3) /s (0.028 m (super 3) /s) of water, regardless of the head, pressure, or size of orifice. CF: miner's inch.

sluice tender

In metal mining, a laborer who tends sluiceboxes (troughs) used in placer mining to separate gold from the sand or gravel in which it occurs; and removes wood and other obstructions to see that the gravel and water run freely through the sluices and that the riffles (cleats) are clear, so that the gold will be caught and held when settling to the bottom.

sluiceway

An artificial channel into which water is let by a sluice.

sluicing

Concentrating heavy minerals by washing unconsolidated material through a box (sluice) equipped with riffles that trap the heavier minerals on the floor of the box.

slum

a. The very finely divided clayey portion of the residue overflowing from a sluice box, particularly applied to deep lead mining.

b. A short roadway to the dip in coal mines used solely to stock spare cars or the spake until required at the end of the shift. c. A soft clayey or shaley bed of coal. Also spelled slumb. d. Used in the plural for the discharge or waste from hydraulic mines. See also: tailing; slime.

slumgullion

A usually red, muddy deposit in mining sluices.

slump

a. A landslide characterized by a shearing and rotary movement of a generally independent mass of rock or earth along a curved slip surface (concave upward) and about an axis parallel to the slope from which it descends, and by backward tilting of the mass with respect to that slope so that the slump surface often exhibits a reversed slope facing uphill. Syn: slumping. See also: slide.

b. The mass of material slipped down during, or produced by, a slump.

slump bedding

A term applied loosely to any disturbed bedding; specif. deformed bedding produced by subaqueous slumping or lateral movement of newly deposited sediment.

slumping

The downward movement, such as sliding or settling, of a slump. Syn: slump.

slung cartridges

Cartridges of explosive lowered into position in drill hole blasting at the end of a length of strong twine (not wire). As detonating cord is normally used for ignition in drill holes, the primed cartridge is lowered first in each charge by using a detaching hook or a length of twine, and it is followed by the remainder of the charge.

slurry

a. The fine carbonaceous discharge from a mine washery. All washeries produce some slurry, which must be treated to separate the solids from the water in order to have a clear effluent for reuse or discharge. See also: sludge. Syn: water gel.

b. Fine particles concentrated in a portion of the circulating water (usually by settling) and waterborne to treatment plant of any kind. c. A thin watery suspension; e.g., the feed to a filter press or other filtration equipment.

slurry blasting agents

Dense, insensitive, high-velocity explosives of great power and very high water resistance. They are usually mixtures of an explosive such as TNT, which is a reducing agent, or an oxidizing agent, such as ammonium nitrate and/or sodium nitrate, and water. A thickening or jelling substance such as guar gum is usually added. Slurries may also be made with nonexplosive reducing agents, including finely divided metals such as magnesium or aluminum, and with organic compounds such as sugar, molasses, or emulsified oil. These slurries are used chiefly in open pit mines where rock is hard and/or holes are wet. Also called DBA (dense blasting agent).

slurry helper

A laborer who makes slurry for use by furnace sprayer, mixing specified amounts of silica, clay, and water in large drums with air-pressure hose.

slurrying

The process of filling in joints with slurry.

slurry man

See: furnace sprayer.

slurry pond

Any natural or artificial pond or lagoon for settling and draining the solids from washery slurry.

slurry screen

A screen to recover a granular product from the circulating water in a washer, usually after a preliminary concentration of the solids and with or without the use of water sprays.

slush

a. To fill mine workings with sand, culm, or other material, by hydraulic methods. See also: hydraulic mine filling.

b. Silt. c. To move ore or waste filling with a scraper (slusher) hoist.

slusher

a. See: scraper loader.

b. A mechanical dragshovel loader. c. A mobile drag scraper with a metal slide to elevate the bucket to dump point.

slusher drift

Drift in stope block above haulage level, down which scraper loader conveys broken ore to loading chutes, which are usually without gates.

slusher operator

In metal mining, one who operates the hoisting engine of a scraper loader, known as a slusher, to load ore into cars or to scrape it into chutes, or to move sand or rock fill in the stopes.

slushing

Term sometimes applied to hydraulic stowing and also to scraper loader operations.

slushing drift

A drift in an orebody, equipped wth a scraper loader, for loading ore directly into cars in the haulage level. The drift is formed at right angles to the haulage level and over it so that the ore drops into the cars.

slushing oil

Used to coat metals, machine parts, etc., to prevent corrosion. It usually is nondrying oil or grease, which coats the metal very well but is easily removed when desired.

slush pit

An excavation dug near a drill to form a reservoir in which the returns from a borehole are collected and stored. Also called drill sump, mud pit, sludge pit, slush pond, sump.

slush pond

See: slush pit; sump.

sly bed

Eng. Soft, black, bituminous shale with a white efflorescence on exposure. A hard calcareous band near the base, Middle Purbeck Beds, Swanage.