Safety fuse - A train of powder enclosed in cotton, jute yarn, or waterproofing compounds, which burns at a uniform rate; used for firing a cap containing the detonation compound which in turn sets off the explosive charge.
Safety lamp - A lamp with steel wire gauze covering every opening from the inside to the outside so as to prevent the passage of flame should explosive gas be encountered.
Sampling - Cutting a representative part of an ore (or coal) deposit, which should truly represent its average value.
Sandstone - A sedimentary rock consisting of quartz sand united by some cementing material, such as iron oxide or calcium carbonate.
Scaling - Removal of loose rock from the roof or walls. This work is dangerous and a long bar (called a scaling bar)is often used.
Scoop - A rubber tired-, battery- or diesel-powered piece of equipment designed for cleaning runways and hauling supplies.
Scrubber – Any of several forms of chemical/physical devices that remove sulfur compounds formed during coal combustion. These devices, technically know as flue gas desulfurization systems, combine the sulfur in gaseous emissions with another chemical medium to form inert "sludge," which must then be removed for disposal.
Seam - A stratum or bed of coal.
Secondary roof - The roof strata immediately above the coalbed, requiring support during the excavating of coal.
Section - A portion of the working area of a mine.
Selective mining - The object of selective mining is to obtain a relatively high-grade mine product; this usually entails the use of a much more expensive stopping system and high exploration and development costs in searching for and developing the separate bunches, stringers, lenses, and bands of ore.
Self-contained breathing apparatus - A self-contained supply of oxygen used during rescue work from coal mine fires and explosions; same as SCSR (self-contained self rescuer).
Self-rescuer – A small filtering device carried by a coal miner underground, either on his belt or in his pocket, to provide him with immediate protection against carbon monoxide and smoke in case of a mine fire or explosion. It is a small canister with a mouthpiece directly attached to it. The wearer breathes through the mouth, the nose being closed by a clip. The canister contains a layer of fused calcium chloride that absorbs water vapor from the mine air. The device is used for escape purposes only because it does not sustain life in atmospheres containing deficient oxygen. The length of time a self-rescuer can be used is governed mainly by the humidity in the mine air, usually between 30 minutes and one hour.
Severance – The separation of a mineral interest from other interests in the land by grant or reservation. A mineral dead or grant of the land reserving a mineral interest, by the landowner before leasing, accomplishes a severance as does his execution of a mineral lease.
Shaft - A primary vertical or non-vertical opening through mine strata used for ventilation or drainage and/or for hoisting of personnel or materials; connects the surface with underground workings.
Shaft mine – An underground mine in which the main entry or access is by means of a vertical shaft.
Shale - A rock formed by consolidation of clay, mud, or silt, having a laminated structure and composed of minerals essentially unaltered since deposition.
Shearer - A mining machine for longwall faces that uses a rotating action to "shear" the material from the face as it progresses along the face.
Shift - The number of hours or the part of any day worked.
Shortwall – An underground mining method in which small areas are worked (15 to 150 feet) by a continuous miner in conjunction with the use of hydraulic roof supports.
Shuttle car – A self-discharging truck, generally with rubber tires or caterpillar-type treads, used for receiving coal from the loading or mining machine and transferring it to an underground loading point, mine railway or belt conveyor system.
Sinking - The process by which a shaft is driven.
Skid - A track-mounted vehicle used to hold trips or cars from running out of control. Also it is a flat-bottom personnel or equipment carrier used in low coal.
Skip - A car being hoisted from a slope or shaft.
Slack - Small coal; the finest-sized soft coal, usually less than one inch in diameter.
Slag - The waste product of the process of smelting.
Slate - A miner's term for any shale or slate accompanying coal. Geologically, it is a dense, fine-textured, metamorphic rock, which has excellent parallel cleavage so that it breaks into thin plates or pencil-like shapes.
Slate bar - The proper long-handled tool used to pry down loose and hazardous material from roof, face, and ribs.
Slickenside - A smooth, striated, polished surface produced on rock by friction.
Slip - A fault. A smooth joint or crack where the strata have moved on each other.
Slope - Primary inclined opening, connection the surface with the underground workings.
Slope mine – An underground mine with an opening that slopes upward or downward to the coal seam.
Sloughing - The slow crumbling and falling away of material from roof, rib, and face.
Solid - Mineral that has not been undermined, sheared out, or otherwise prepared for blasting.
Sounding - Knocking on a roof to see whether it is sound and safe to work under.
Spad – A spad is a flat spike hammered into a wooden plug anchored in a hole drilled into the mine ceiling from which is threaded a plumbline. The spad is an underground survey station similar to the use of stakes in marking survey points on the surface. A pointer spad, or sight spad, is a station that allows a mine foreman to visually align entries or breaks from the main spad.
Span - The horizontal distance between the side supports or solid abutments along sides of a roadway.
Specific gravity - The weight of a substance compared with the weight of an equal volume of pure water at 4 degrees Celsius.
Split - Any division or branch of the ventilating current. Also, the workings ventilated by one branch. Also, to divide a pillar by driving one or more roads through it.
Squeeze - The settling, without breaking, of the roof and the gradual upheaval of the floor of a mine due to the weight of the overlying strata.
Steeply inclined - Said of deposits and coal seams with a dip of from 0.7 to 1 rad (40 degrees to 60 degrees).
Stemming - The noncombustible material used on top or in front of a charge or explosive.
Strike - The direction of the line of intersection of a bed or vein with the horizontal plane. The strike of a bed is the direction of a straight line that connects two points of equal elevation on the bed.
Stripping ratio – The unit amount of overburden that must be removed to gain access to a similar unit amount of coal or mineral material.
Stump - Any small pillar.
Subbituminous – Coal of a rank intermediate between lignite and bituminous.
Subsidence – The gradual sinking, or sometimes abrupt collapse, of the rock and soil layers into an underground mine. Structures and surface features above the subsidence area can be affected.
Sump - The bottom of a shaft, or any other place in a mine, that is used as a collecting point for drainage water.
Sumping - To force the cutter bar of a machine into or under the coal. Also called a sumping cut, or sumping in.
Support - The all-important function of keeping the mine workings open. As a verb, it refers to this function; as a noun it refers to all the equipment and materials--timber, roof bolts, concrete, steel, etc.--that are used to carry out this function.
Surface mine – A mine in which the coal lies near the surface and can be extracted by removing the covering layers of rock and soil.
Suspension - Weaker strata hanging from stronger, overlying strata by means of roof bolts.
Syncline - A fold in rock in which the strata dip inward from both sides toward the axis. The opposite of anticline.
Tailgate - A subsidiary gate road to a conveyor face as opposed to a main gate. The tailgate commonly acts as the return airway and supplies road to the face.
Tailpiece - Also known as foot section pulley. The pulley or roller in the tail or foot section of a belt conveyor around which the belt runs.
Tail section - A term used in both belt and chain conveyor work to designate that portion of the conveyor at the extreme opposite end from the delivery point. In either type of conveyor it consists of a frame and either a sprocket or a drum on which the chain or belt travels, plus such other devices as may be required for adjusting belt or chain tension.
Tension - The act of stretching.
Tertiary - Lateral or panel openings (e.g., ramp, crosscut).
Through-steel - A system of dust collection from rock or roof drilling. The drill steel is hollow, and a vacuum is applied at the base, pulling the dust through the steel and into a receptacle on the machine.
Timber - A collective term for underground wooden supports.
Timbering - The setting of timber supports in mine workings or shafts for protection against falls from roof, face, or rib.
Timber set - A timber frame to support the roof, sides, and sometimes the floor of mine roadways or shafts.
Tipple - Originally the place where the mine cars were tipped and emptied of their coal, and still used in that same sense, although now more generally applied to the surface structures of a mine, including the preparation plant and loading tracks.
Ton – A short or net ton is equal to 2,000 pounds; a long or British ton is 2,240 pounds; a metric ton is approximately 2,205 pounds.
Top - A mine roof; same as "back."
Torque wrench - A wrench that indicates, as on a dial, the amount of torque (in units of foot-pounds) exerted in tightening a roof bolt.
Tractor - A battery-operated piece of equipment that pulls trailers, skids, or personnel carriers. Also used for supplies.
Tram - Used in connection with moving self-propelled mining equipment. A tramming motor may refer to an electric locomotive used for hauling loaded trips or it may refer to the motor in a cutting machine that supplies the power for moving or tramming the machine.
Transfer - A vertical or inclined connection between two or more levels and used as an ore pass.
Transfer point - Location in the materials handling system, either haulage or hoisting, where bulk material is transferred between conveyances.
Trip - A train of mine cars.
Troughing idlers - The idlers, located on the upper framework of a belt conveyor, which support the loaded belt. They are so mounted that the loaded belt forms a trough in the direction of travel, which reduces spillage and increases the carrying capacity of a belt for a given width.
Tunnel - A horizontal, or near-horizontal, underground passage, entry, or haulageway, that is open to the surface at both ends. A tunnel (as opposed to an adit) must pass completely through a hill or mountain.
Ultimate analysis - Precise determination, by chemical means, of the elements and compounds in coal.
Undercut - To cut below or undermine the coal face by chipping away the coal by pick or mining machine. In some localities the terms "undermine" or "underhole" are used.
Underground mine – Also known as a "deep" mine. Usually located several hundred feet below the earth's surface, an underground mine's coal is removed mechanically and transferred by shuttle car or conveyor to the surface.
Underground station - An enlargement of an entry, drift, or level at a shaft at which cages stop to receive and discharge cars, personnel, and material. An underground station is any location where stationary electrical equipment is installed. This includes pump rooms, compressor rooms, hoist rooms, battery-charging rooms, etc.
Unit train – A long train of between 60 and 150 or more hopper cars, carrying only coal between a single mine and destination.
Universal coal cutter - A type of coal cutting machine which is designed to make horizontal cuts in a coal face at any point between the bottom and top or to make shearing cuts at any point between the two ribs of the place. The cutter bar can be twisted to make cuts at any angle to the horizontal or vertical.
Upcast shaft - A shaft through which air leaves the mine.
Valuation - The act or process of valuing or of estimating the value or worth; appraisal.
Velocity - Rate of airflow in lineal feet per minute.
Ventilation - The provision of a directed flow of fresh and return air along all underground roadways, traveling roads, workings, and service parts.
Violation - The breaking of any state or federal mining law.
Virgin - Unworked; untouched; often said of areas where there has been no coal mining.
Void - A general term for pore space or other reopenings in rock. In addition to pore space, the term includes vesicles, solution cavities, or any openings either primary or secondary.
Volatile matter - The gaseous part, mostly hydrocarbons, of coal.
Waste - That rock or mineral which must be removed from a mine to keep the mining scheme practical, but which has no value.
Water Gauge (standard U-tube) - Instrument that measures differential pressures in inches of water.
Wedge - A piece of wood tapering to a thin edge and used for tightening in conventional timbering.
Weight - Fracturing and lowering of the roof strata at the face as a result of mining operations, as in "taking weight".
White damp - Carbon monoxide, CO. A gas that may be present in the afterdamp of a gas- or coal-dust explosion, or in the gases given off by a mine fire; also one of the constituents of the gases produced by blasting. Rarely found in mines under other circumstances. It is absorbed by the hemoglobin of the blood to the exclusion of oxygen. One-tenth of 1% (.001) may be fatal in 10 minutes.
Width - The thickness of a lode measured at right angles to the dip.
Winning - The excavation, loading, and removal of coal or ore from the ground; winning follows development.
Winze - Secondary or tertiary vertical or near-vertical opening sunk from a point inside a mine for the purpose of connecting with a lower level or of exploring the ground for a limited depth below a level.
Wire rope - A steel wire rope used for winding in shafts and underground haulages. Wire ropes are made from medium carbon steels. Various constructions of wire rope are designated by the number of strands in the rope and the number of wires in each strand. The following are some common terms encountered: airplane strand; cablelaid rope; cane rope; elevator rope; extra-flexible hoisting rope; flat rope; flattened-strand rope; guy rope; guy strand; hand rope; haulage rope; hawser; hoisting rope; lang lay rope; lay; left lay rope; left twist; nonspinning rope; regular lay; reverse-laid rope; rheostat rope; right lay; right twist; running rope; special flexible hoisting rope; standing rope; towing hawser; transmission rope.
Working - When a coal seam is being squeezed by pressure from roof and floor, it emits creaking noises and is said to be "working". This often serves as a warning to the miners that additional support is needed.
Working face - Any place in a mine where material is extracted during a mining cycle.
Working place - From the outby side of the last open crosscut to the face.
Workings - The entire system of openings in a mine for the purpose of exploitation.
Working section - From the faces to the point where coal is loaded onto belts or rail cars to begin its trip to the outside.