MINING GLOSSARY

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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Scraper Loader - A machine used for loading coal or rock by pulling an open-bottomed scoop back and forth between the face and the loading point by means of ropes, sheaves, and a multiple drum hoist. The filled scoop is pulled on the bottom to an apron or ramp where the load is discharged onto a car or conveyor.

Screen - A large sieve for grading or sizing coal, ore, rock, or aggregate. It consists of a suitably mounted surface of woven wire or of punched plate. It may be flat or cylindrical, horizontal or inclined, stationary, shaking, or vibratory, and either wet or dry operation.

Screenings - Coal which will pass through the smallest mesh screen normally loaded for commercial sale for industrial use.

Seam - A stratum or bed of coal or other mineral; generally applied to large deposits of coal.

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

Shaker Conveyor - A conveyor consisting of a length of metal troughs, with suitable supports, to which a reciprocating motion is imparted by drives. In the case of a downhill conveyor, a simple to-and-fro motion is sufficient to cause the coal to slide. With a level or a slight uphill gradient, a differential motion is necessary, that is, a quick backward and slower forward strokes. The quick backward stroke causes the trough to slide under the coal, while the slower forward stroke moves the coal along to a new position. Also called jigger.

Shale - A laminated sediment, in which the constituent particles are predominantly of the clay grade.

Shearing - 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 as cut or cutting.

Shoot - To break coal loose from the seam by the use of explosives; loosely used, also as applied to other coal breaking devices.

Shooter - The person who fires a charged hole after satisfying himself/herself that the area is free from firedamp. A shot firer.

Short Ton - A unit of weight that equals 20 short hundredweights or 2,000 avoirdupois pounds. Used chiefly in the United States, in Canada, and in the Republic of South Africa.

Shortwall - The reverse of longwall, frequently used to mean the face of a room. A method of mining in which comparatively small areas are worked separately, as opposed to longwall; for example, room and pillar.

Shot Firer - A person whose special duty is to fire shots or blasts, especially in coal mines. A shot lighter.

Shovel - Any bucket-equipped machine used for digging and loading earthy or fragmented rock materials. 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.

Shuttle Car - A vehicle on rubber tires or caterpillar treads and usually propelled by electric motors, electrical energy which is supplied by a diesel-driven generator, by storage batteries, or by a power distribution system through a portable cable. Its chief function is the transfer of raw materials, such as coal and ore, from loading machines in trackless areas of a mine to the main transportation system.

Silt - A fine-grained sediment having a particle size intermediate between that of fine sand and clay.

Slack - Small coal, usually less than 1/8 inch. 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.

Slice - In an ore body of considerable lateral extent and thickness, the ore is removed in layers termed slices.

Slope - The main working gallery or entry of a coal seam which dips at an angle and along which mine cars are hauled. An entrance to a mine driven down through an inclined coal seam; also, a mine having such an entrance.

Slope Mine - 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.

Sludge - Mineral, mud, and slurry too thick to flow. A soft mud, slush, or mire; for example the solid product of a filtration process before drying (filter cake).

Slurry - The fine carbonaceous discharge from a colliery 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. Also, in some cases, it is economical to extract the fine coal from the effluent.

Spoil Bank - To leave coal and other minerals that are not marketable in the mine.

Stoker Coal - A screen size of coal specifically for use in automatic firing equipment. This coal can be of any rank and the stoker is usually designed to fit the coal available. Factors of importance in the selection of coal for stoker use are: size limits, size consist, uniformity of shipments, coking properties, ash fusion characteristics, ash, sulfur and volatile-matter percentages.

Strip - In coal mining, to remove the earth, rock, and other material from a seam of coal, generally by power shovels. Generally practiced only where the coal seam lies close to the earth's surface. To remove from a quarry, or other open working, the overlying earth and disintegrated or barren surface rock.

Strip Mine - An opencut mine in which the overburden is removed from a coal bed before the coal is taken out.

Subsidence - A sinking down of a part of the earth's crust. The lowering of the strata, including the surface, due to underground excavations. Surface caving or distortion due to effects of collapse of deep workings.

Surface Mining - The mining in surface excavations. It includes placer mining, mining in open glory-hole or milling pits, mining and removing ore from open cuts by hand or with mechanical excavation and transportation equipment, and the removal of capping or overburden to uncover the ores. Mining at or near the surface. This type of mining is generally done where the overburden can be removed without too much expense. Also called strip mining, placer mining, opencast mining, opencut mining, or open-pit mining.

Surface Rights - The ownership of the surface of land only, where mineral rights are reserved. Those reserved to the owner of the land beneath which ore is being mined. The right of a mineral owner or an oil and gas lessee to use so much of the surface of land as may be reasonably necessary for the conduct of operations under the lease.