Illustrated Mining Terms


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.

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Salting - Introduction of particles of metal or mineral into a deposit, thus making the assays run higher than they actually are.  
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.

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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   

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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).

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.  
Short ton - Contains 2,000 lbs.  
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.

Shotcrete - the name usually given to mixes containing coarse aggregate, sand, and cement, mixed and applied under hydraulic pressure.  
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. wpe1.jpg (11123 bytes)
Siliceous - Containing an abundance of quartz.  
Sill - the floor or bottom of a passage in a mine  
Sinking - The process by which a shaft is driven.

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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.

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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.  
Sluicebox - a trough paved with riffles through which gravel and wash from placer mining operations is passed so the gold and other valuable minerals will be caught and saved.

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Slusher - a small double-drum hoist used to pull a bucket in underground openings to move ore or waste.

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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.  
Square set - A set of timbers used for support in underground mining, consists of cap, girt and post.

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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.

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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.  
Stockpile - Broken ore accumulated in a heap on surface, pending treatment or shipment.

Stull - a timber used to support loose rock, slabs, or the hanging wall. It may also be used to support a platform in a working place.

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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.

Generalized cross section of subsidence

Sulphide - A compound of sulphur and other elements to form minerals.  
Sump - The bottom of a shaft, or any other place in a mine, that is used as a collecting point for drainage water.


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.

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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.

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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.

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