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A-Z of Mining Terms Glossary

October 15 2020, 14:29 GMT+01:00

Mining is a complex space. One can be forgiven for feeling daunted when they first consider mining investment opportunities and proceed to conduct research because they have to navigate a maze of unfamiliar vocabulary and specific terminology. As a consequence, prospective investors can be detracted from holding mining stock and potentially making good returns. It is a great shame to see individuals miss out on opportunities because of the convoluted nature of a subject.

The message is loud and clear: mining is complicated. However, mining need not be as complicated as one often thinks. In this article, Crux Investor hopes to bring a transparency to the mining sector, allowing investors to feel more confident in the topic; thus, enhancing their ability to make strong investment decisions.

So, terminology: what do these words with far too many syllables actually mean? We’ve drawn from glossaries on Sec.gov, RockAndMinerals.com and AngloAmerican.com to complement our own knowledge.

Use this page as a reference, come back to it whenever you find mining jargon. Here's a link to Add to favorites.

Glossary of Mining Terms

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

0-9

  • 360-degree collision avoidance system – the sensing of threats and hazards within a 360-degree awareness of the position of other vehicles and the threat or hazard they present. The system also calculates risk, issues driver advisories or warnings, or take pre-emptive actions to avoid and mitigate potential accidents.

A

  • Abutment — In coal mining, (1) the weight of the rocks above a narrow roadway is transferred to the solid coal along the sides, which act as abutments of the arch of strata spanning the roadway; and (2) the weight of the rocks over a longwall face is transferred to the front abutment, that is, the solid coal ahead of the face and the back abutment, that is, the settled packs behind the face.
  • Acid mine drainage - Acidic run-off water from mine waste dumps and mill tailings ponds containing sulphide minerals. Also refers to ground water pumped to surface from mines.
  • Acidic precipitation - Snow and rain that have a low pH, caused by sulphur dioxide and nitric oxide gases from industrial activity released into the atmosphere.
  • Acidic rocks - Igneous rock carrying a high (greater than 65%) proportion of silica.
  • Active workings — Any place in a mine where miners are normally required to work or travel and which are ventilated and inspected regularly.
  • Adit — A nearly horizontal passage from the surface by which a mine is entered and dewatered. A blind horizontal opening into a mountain, with only one entrance.
  • Advance — Mining in the same direction, or order of sequence; first mining as distinguished from retreat.
  • Aerial magnetometer - An instrument used to measure magnetic field strength from an airplane.
  • Aeromagnetic survey - A geophysical survey using a magnetometer aboard, or towed behind, an aircraft.
  • Agglomerate - A breccia composed largely or entirely of fragments of volcanic rocks.
  • Agglomeration — A family of processes which can be used to concentrate valuable minerals (including coal) based on their adhesive properties.
  • Agitation - In metallurgy, the act or state of being stirred or shaken mechanically, sometimes accomplished by the introduction of compressed air.
  • Air split — The division of a current of air into two or more parts.
  • Airborne survey - A survey made from an aircraft to obtain photographs, or measure magnetic properties, radioactivity, etc.
  • Airway — Any passage through which air is carried. Also known as an air course.
  • AISC – All-in sustaining cost.
  • Alloy - A compound of two or more metals.
  • Alloy stream – a patented process which is used to convert ore directly into a metal. The process, which was developed by a company called Exxaro, is cheaper and more environmentally friendly than other similar approaches.
  • Alluvium - Relatively recent deposits of sedimentary material laid down in riverbeds, flood plains, lakes, or at the base of mountain slopes. (adj. alluvial)
  • Alpha meter - An instrument used to measure positively charged particles emitted by radioactive materials.
  • Alpha ray - A positively charged particle emitted by certain radioactive materials.
  • Alteration - Any physical or chemical change in a rock or mineral subsequent to its formation. Milder and more localized than metamorphism.
  • Amorphous - A term applied to rocks or minerals that possess no definite crystal structure or form, such as amorphous carbon.
  • Amortization - The gradual and systematic writing off of a balance in an account over an appropriate period.
  • Amphibolite - A gneiss or schist largely made up of amphibole and plagioclase minerals.
  • Anemometer — Instrument for measuring air velocity.
  • ANFO - Acronym for ammonium nitrate and fuel oil, a mixture used as a blasting agent in many mines.
  • Angle of dip — The angle at which strata or mineral deposits are inclined to the horizontal plane.
  • Angle of draw — In coal mine subsidence, this angle is assumed to bisect the angle between the vertical and the angle of repose of the material and is 20° for flat seams. For dipping seams, the angle of break increases, being 35.8° from the vertical for a 40° dip. The main break occurs over the seam at an angle from the vertical equal to half the dip.
  • Angle of repose — The maximum angle from horizontal at which a given material will rest on a given surface without sliding or rolling.
  • Annual report - The formal financial statements and report on operations issued by a corporation to its shareholders after its fiscal year-end.
  • Anode - A rectangular plate of metal cast in a shape suitable for refining by the electrolytic process.
  • Anomaly - Any departure from the norm which may indicate the presence of mineralization in the underlying bedrock.
  • Anthracite - A hard, black coal containing a high percentage of fixed carbon and a low percentage of volatile matter.
  • Anticline - An arch or fold in layers of rock shaped like the crest of a wave.
  • Apex - The top or terminal edge of a vein on surface or its nearest point to the surface.
  • Aquifer - A water-bearing bed of porous rock, often sandstone.
  • Arching - Fracture processes around a mine opening, leading to stabilization by an arching effect.
  • Area (of an airway) — Average width multiplied by average height of airway, expressed in square feet.
  • Ash - The inorganic residue remaining after ignition of coal.
  • Assay - A chemical test performed on a sample of ores or minerals to determine the amount of valuable metals contained.
  • Assay foot (metre, inch, centimetre) - The assay value multiplied by the number of feet, metres, inches, centimetres across which the sample is taken.
  • Assay map - Plan view of an area indicating assay values and locations of all samples taken on the property.
  • Assessment work - The amount of work, specified by mining law, that must be performed each year in order to retain legal control of mining claims.
  • Auger — A rotary drill that uses a screw device to penetrate, break, and then transport the drilled material (coal).
  • Authorized capital - see capital stock.
  • Autogenous grinding - The process of grinding ore in a rotating cylinder using large pieces of the ore instead of conventional steel balls or rods.
  • Automation – the technique of making an apparatus, process, or system operate automatically. It is the creation and application of technology to monitor and control the production and delivery of products and services.
  • Auxiliary operations — All activities supportive of but not contributing directly to mining.
  • Auxiliary ventilation — Portion of main ventilating current directed to face of dead end entry by means of an auxiliary fan and tubing.
  • Azimuth — A surveying term that references the angle measured clockwise from any meridian (the established line of reference). The bearing is used to designate direction. The bearing of a line is the acute horizontal angle between the meridian and the line.

B

  • Back – the roof or upper part in any underground mining cavity.
  • Back sample - Rock chips collected from the roof or back of an underground opening for the purpose of determining grade.
  • Backfill - Waste material used to fill the void created by mining an orebody.
  • Background - Minor amounts of radioactivity due not to abnormal amounts of radioactive minerals nearby, but to cosmic rays and minor residual radioactivity in the vicinity.
  • Backwardation - A situation when the cash or spot price of a metal stands at a premium over the price of the metal for delivery at a forward date.
  • Balance sheet - A formal statement of the financial position of a company on a particular day, normally presented to shareholders once a year.
  • Ball mill - A steel cylinder filled with steel balls into which crushed ore is fed. The ball mill is rotated, causing the balls to cascade and grind the ore.
  • Banded iron formation - A bedded deposit of iron minerals.
  • Barren — Said of rock or vein material containing no minerals of value, and of strata without coal, or containing coal in seams too thin to be workable.
  • Barricading — Enclosing part of a mine to prevent inflow of noxious gasses from a mine fire or an explosion.
  • Barrier — Something that bars or keeps out. Barrier pillars are solid blocks of coal left between two mines or sections of a mine to prevent accidents due to inrushes of water, gas, or from explosions or a mine fire.
  • Basal till - Unsorted glacial debris at the base of the soil column where it comes into contact with the bedrock below.
  • Basalt - An extrusive volcanic rock composed primarily of plagioclase, pyroxene and some olivine.
  • Base camp - Centre of operations from which exploration activity is conducted.
  • Base metals – natural metals, such as copper and nickel, that are more readily available and less expensive than their precious metal cousins such as gold.
  • Basement rocks - The underlying or older rock mass. Often refers to rocks of Precambrian age which may be covered by younger rocks.
  • Basic rocks - Igneous rocks that are relatively low in silica and composed mostly of dark-coloured minerals.
  • Batholith - A large mass of igneous rock extending to great depth with its upper portion dome-like in shape. Similar, smaller masses of igneous rocks are known as bosses or plugs.
  • Bauxite - A rock made up of hydrous aluminium oxides; the most common aluminium ore.
  • Beam — A bar or straight girder used to support a span of roof between two support props or walls.
  • Beam building — The creation of a strong, inflexible beam by bolting or otherwise fastening together several weaker layers. In coal mining this is the intended basis for roof bolting.
  • Bear market - Term used to describe market conditions when share prices are declining.
  • Bearing — A surveying term used to designate direction. The bearing of a line is the acute horizontal angle between the meridian and the line. The meridian is an established line of reference. Azimuths are angles measured clockwise from any meridian.
  • Bearing plate — A plate used to distribute a given load. In roof bolting, the plate used between the bolt head and the roof.
  • Bed — A stratum of coal or other sedimentary deposit.
  • Bedding - The arrangement of sedimentary rocks in layers.
  • Belt conveyor — A looped belt on which coal or other materials can be carried and which is generally constructed of flame-resistant material or of reinforced rubber or rubber-like substance.
  • Belt idler — A roller, usually of cylindrical shape, which is supported on a frame and which, in turn, supports or guides a conveyor belt. Idlers are not powered but turn by contact with the moving belt.
  • Belt take-up — A belt pulley, generally under a conveyor belt and inby the drive pulley, kept under strong tension parallel to the beltline. Its purpose is to automatically compensate for any slack in the belting created by start-up, etc.
  • Bench – in an underground mine, this is the horizontal low ledge or floor on which material is quarried or worked on.
  • Beneficiate - To concentrate or enrich; often applied to the preparation of iron ore for smelting.
  • Beneficiation — The treatment of mined material, making it more concentrated or richer.
  • Bentonite - A clay with great ability to absorb water and which swells accordingly.
  • Berm — A pile or mound of material capable of restraining a vehicle.
  • Bessemer - An iron ore with a very low phosphorus content.
  • Binder — A streak of impurity in a coal seam.
  • Bio-leaching - A process for recovering metals from low-grade ores by dissolving them in solution, the dissolution being aided by bacterial action.
  • Biotite - A platy magnesium-iron mica, common in igneous rocks.
  • Bit - The cutting end of a drill frequently made of an extremely hard material such as industrial diamonds or tungsten carbide.
  • Bituminous coal — A middle rank coal (between subbituminous and anthracite) formed by additional pressure and heat on lignite. Usually has a high Btu value and may be referred to as "soft coal." A general term descriptive of coal intermediate in rank between sub-bituminous and anthracite and including metallurgical coals. Low and medium volatile bituminous coals are ranked by their carbon content, while high volatile bituminous coals are ranked by their heating value.
  • Black damp — A term generally applied to carbon dioxide. Strictly speaking, it is a mixture of carbon dioxide and nitrogen. It is also applied to an atmosphere depleted of oxygen, rather than having an excess of carbon dioxide.
  • Black smoker - Volcanic vent found in areas of active ocean floor spreading, through which sulphide-laden fluids escape.
  • Blackjack - A miner's term for sphalerite (zinc sulphide).
  • Blast furnace - A reaction vessel in which mixed charges of oxide ores, fluxes and fuels are blown with a continuous blast of hot air and oxygen-enriched air for the chemical reduction of metals to their metallic state.
  • Blaster - A mine employee responsible for loading, priming and detonating blastholes.
  • Blasthole - A drill hole in a mine that is filled with explosives in order to blast loose a quantity of rock.
  • Blasting agent — Any material consisting of a mixture of a fuel and an oxidizer.
  • Blasting cap — A detonator containing a charge of detonating compound, which is ignited by electric current or the spark of a fuse. Used for detonating explosives.
  • Blasting circuit — Electric circuits used to fire electric detonators or to ignite an igniter cord by means of an electric starter.
  • Bleeder or bleeder entries — Special air courses developed and maintained as part of the mine ventilation system and designed to continuously move air-methane mixtures emitted by the gob or at the active face away from the active workings and into mine-return air courses. Alt: Exhaust ventilation lateral.
  • Blind sink – the establishment of a "hole" in the ground from surface to a required depth, by creating a shaft collar and then drilling, blasting, loading the blasted rock to surface and shaft lining.
  • Blister copper - A crude form of copper (assaying about 99%) produced in a smelter, which requires further refining before being used for industrial purposes.
  • Block caving - An inexpensive method of mining in which large blocks of ore are undercut, causing the ore to break or cave under its own weight.
  • Board lot - One hundred shares.
  • Boiler— A tank in which water is heated or steam is generated.
  • Bolt torque — The turning force in foot-pounds applied to a roof bolt to achieve an installed tension.
  • Bond - An agreement to pay a certain amount of interest over a given period of time.
  • Boom - A telescoping, hydraulically powered steel arm on which drifters, manbaskets and hydraulic hammers are mounted.
  • Bord and pillar mining – a system of coal mining in which tunnels are driven in a checkerboard pattern with massive square pillars between them. These are gradually cut away as the work proceeds.
  • Borehole — Any deep or long drill-hole, usually associated with a diamond drill.
  • Boss — Any member of the managerial ranks who is directly in charge of miners (e.g., "shift-boss," "face-boss," "fire-boss," etc.).
  • Bottom — Floor or underlying surface of an underground excavation.
  • Box hole - A short raise or opening driven above a drift for the purpose of drawing ore from a stope, or to permit access.
  • Box-type magazine — A small, portable magazine used to store limited quantities of explosives or detonators for short periods of time at locations in the mine which are convenient to the blasting sites at which they will be used.
  • Brattice or brattice cloth — Fire-resistant fabric or plastic partition used in a mine passage to confine the air and force it into the working place. Also termed "line brattice," "line canvas," or "line curtain."
  • Break - Loosely used to describe a large-scale regional shear zone or structural fault.
  • Break line — The line that roughly follows the rear edges of coal pillars that are being mined. The line along which the roof of a coal mine is expected to break.
  • Breaker — A machine which combines coal crushing and screening. Normally consists of a rotating drum in which coal is broken by gravity impact against the walls of the drum.
  • Breakthrough — A passage for ventilation that is cut through the pillars between rooms.
  • Breast - A working face in a mine, usually restricted to a stope.
  • Breccia - A rock in which angular fragments are surrounded by a mass of fine-grained minerals.
  • Bridge carrier — A rubber-tire-mounted mobile conveyor, about 10 meters long, used as an intermediate unit to create a system of articulated conveyors between a mining machine and a room or entry conveyor.
  • Bridge conveyor — A short conveyor hung from the boom of mining or lading machine or haulage system with the other end attached to a receiving bin that dollies along a frame supported by the room or entry conveyor, tailpiece. Thus, as the machine boom moves, the bridge conveyor keeps it in constant connection with the tailpiece.
  • Broken reserves - The ore in a mine which has been broken by blasting but which has not yet been transported to surface.
  • Brow — A low place in the roof of a mine, giving insufficient headroom.
  • Brownfield exploration – exploration work that’s done close to or at existing mines.
  • Brunton compass - A pocket compass equipped with sights and a reflector, used for sighting lines, measuring dip and carrying out preliminary surveys.
  • Brushing — Digging up the bottom or taking down the top to give more headroom in roadways.
  • Btu — British thermal unit. A measure of the energy required to raise the temperature of one pound of water one degree Fahrenheit.
  • Bug dust — The fine particles of coal or other material resulting form the boring or cutting of the coal face by drill or machine.
  • Bulk commodity – the raw form of products such as iron ore and coal that is shipped and sold in large quantities.
  • Bulk mining - Any large-scale, mechanized method of mining involving many thousands of tonnes of ore being brought to surface per day.
  • Bulk sample - A large sample of mineralized rock, frequently hundreds of tonnes, selected in such a manner as to be representative of the potential orebody being sampled. Used to determine metallurgical characteristics.
  • Bull market - Term used to describe financial market conditions when share prices are going up.
  • Bull quartz - A prospector's term for white, coarse-grained, barren quartz.
  • Bullion - Metal formed into bars or ingots.
  • Bump (or burst) — A violent dislocation of the mine workings which is attributed to severe stresses in the rock surrounding the workings.
  • Butt cleat — A short, poorly defined vertical cleavage plane in a coal seam, usually at right angles to the long face cleat.
  • Butt entry — A coal mining term that has different meanings in different locations. It can be synonymous with panel entry, submain entry, or in its older sense it refers to an entry that is "butt" onto the coal cleavage (that is, at right angles to the face).
  • By-product - A secondary metal or mineral product recovered in the milling process.

C

  • Cable bolt - A steel cable, capable of withstanding tens of tonnes, cemented into a drillhole to lend support in blocky ground.
  • Cage — In a mine shaft, the device, similar to an elevator car, that is used for hoisting personnel and materials.
  • Calcine - Name given to concentrate that is ready for smelting (i.e. the sulphur has been driven off by oxidation).
  • Call - An option to buy shares at a specified price. The opposite of a "put".
  • Calorific value — The quantity of heat that can be liberated from one pound of coal or oil measured in BTU's.
  • Cannel coal — A massive, non-caking block coal with a fine, even grain and a conchoidal fracture which has a high percentage of hydrogen, burns with a long, yellow flame, and is extremely easy to ignite.
  • Canopy — A protective covering of a cab on a mining machine.
  • Cap — A miner's safety helmet. Also, a highly sensitive, encapsulated explosive that is used to detonate larger but less sensitive explosives.
  • Cap block — A flat piece of wood inserted between the top of the prop and the roof to provide bearing support.
  • Capital stock - The total ownership of a limited liability company divided among a specified number of shares.
  • Capitalization - A financial term used to describe the value financial markets put on a company. Determined by multiplying the number of outstanding shares of a company by the current stock price.
  • Captive stope - A stope that is accessible only through a manway.
  • Car — A railway wagon, especially any of the wagons adapted to carrying coal, ore, and waste underground.
  • Car-dump — The mechanism for unloading a loaded car.
  • Carbide bit — More correctly, cemented tungsten carbide. A cutting or drilling bit for rock or coal, made by fusing an insert of molded tungsten carbide to the cutting edge of a steel bit shank.
  • Carbon Dioxide — A colorless, odorless, non-toxic radiative gas that is essential to plant and animal life. It is also emitted as a result of burning organic materials, including fossil fuels.
  • Carbon-in-pulp - A method of recovering gold and silver from pregnant cyanide solutions by adsorbing the precious metals to granules of activated carbon, which are typically ground up coconut shells.
  • Cash flow - The net of the inflow and outflow of cash during an accounting period. Does not account for depreciation or bookkeeping write-offs which do not involve an actual cash outlay.
  • Cast — A directed throw; in strip-mining, the overburden is cast from the coal to the previously mined area.
  • Cathode - A rectangular plate of metal, produced by electrolytic refining, which is melted into commercial shapes such as wirebars, billets, ingots, etc.
  • Certified — Describes a person who has passed an examination to do a required job.
  • Cesium magnetometer - An geophysical instrument which measures magnetic field strength in terms of vertical gradient and total field.
  • Chain conveyor — A conveyor on which the material is moved along solid pans (troughs) by the action of scraper crossbars attached to powered chains.
  • Chain pillar — The pillar of coal left to protect the gangway or entry and the parallel airways.
  • Chalcocite - A sulphide mineral of copper common in the zone of secondary enrichment.
  • Chalcopyrite - A sulphide mineral of copper and iron; the most important ore mineral of copper.
  • Change house - The mine building where workers change into work clothes; also known as the "dry".
  • Channel sample - A sample composed of pieces of vein or mineral deposit that have been cut out of a small trench or channel, usually about 10 cm wide and 2 cm deep.
  • Charcoal — The residue, primarily carbon, from the partial combustion of wood or other organic matter.
  • Charter - A document issued by a governing authority creating a company or other corporation.
  • Chartered bank - A financial institution that accepts deposits and provides loans.
  • Check curtain — Sheet of brattice cloth hung across an airway to control the passage of the air current.
  • Chip sample - A method of sampling a rock exposure whereby a regular series of small chips of rock is broken off along a line across the face.
  • Chlorofluorocarbons (CFCs) — Human-produced chemical compounds containing chlorine, fluorine and carbon which are thought to be responsible for ozone-layer depletion. CFCs also act as a radiative gas.
  • Chock — Large hydraulic jacks used to support roof in longwall and shortwall mining systems.
  • Chromite - The chief ore mineral of chromium.
  • Chute - An opening, usually constructed of timber and equipped with a gate, through which ore is drawn from a stope into mine cars.
  • Cinnabar - A vermilion-colored ore mineral of mercury.
  • Circulating load - Over-sized chunks of ore returned to the head of a closed grinding circuit before going on to the next stage of treatment.
  • Claim - A portion of land held either by a prospector or a mining company. In Canada, the common size is 1,320 ft. (about 400 m) square, or 40 acres (about 16 ha).
  • Clarification - Process of clearing dirty water by removing suspended material.
    Classifier - A mineral-processing machine which separates minerals according to size and density.
  • Clay - A fine-grained material composed of hydrous aluminum silicates.
  • Clay vein — A body of clay-like material that fills a void in a coal bed.
  • Clean Air Act Amendments of 1990 — A comprehensive set of amendments to the federal law governing the nation's air quality. The Clean Air Act was originally passed in 1970 to address significant air pollution problems in our cities. The 1990 amendments broadened and strengthened the original law to address specific problems such as acid deposition, urban smog, hazardous air pollutants and stratospheric ozone depletion.
  • Clean Coal Technologies — A number of innovative, new technologies designed to use coal in a more efficient and cost-effective manner while enhancing environmental protection. Several promising technologies include: fluidized-bed combustion, integrated gasification combined cycle, limestone injection multi-stage burner, enhanced flue gas desulfurization (or "scrubbing"), coal liquefaction and coal gasification.
  • Cleat — The vertical cleavage of coal seams. The main set of joints along which coal breaks when mined.
  • Cleavage - The tendency of a mineral to split along crystallographic planes.
  • Closed circuit - A loop in the milling process wherein a selected portion of the product of a machine is returned to the head of the machine for finishing to required specification.
  • Coal — A solid, brittle, more or less distinctly stratified combustible carbonaceous rock, formed by partial to complete decomposition of vegetation; varies in color from dark brown to black; not fusible without decomposition and very insoluble.
  • Coal desulphurisation — Removal of sulphur from coal or coal gas.
  • Coal dust — Particles of coal that can pass a No. 20 sieve.
  • Coal Gasification — The conversion of coal into a gaseous fuel.
  • Coal mine — An area of land and all structures, facilities, machinery, tools, equipment, shafts, slopes, tunnels, excavations, and other property, real or personal, placed upon, under, or above the surface of such land by any person, used in extracting coal from its natural deposits in the earth by any means or method, and the work of preparing the coal so extracted, including coal preparation facilities. British term is "colliery".
  • Coal reserves — Measured tonnages of coal that have been calculated to occur in a coal seam within a particular property.
  • Coal washing — The process of separating undesirable materials from coal based on differences in densities. Pyritic sulfur, or sulfur combined with iron, is heavier and sinks in water; coal is lighter and floats.
  • Coalification - The metamorphic processes of forming coal.
  • Coke — A hard, dry carbon substance produced by heating coal to a very high temperature in the absence of air. Coke is used in the manufacture of iron and steel.
  • Collar - The term applied to the timbering or concrete around the mouth of a shaft; also used to describe the top of a mill hole.
  • Colliery — British name for coal mine.
  • Collision avoidance system – these are systems installed to help vehicles and heavy machinery at mines avoid each other and people in adverse condition such as dust, fog or heavy rain.
  • Column flotation - A milling process, carried out in a tall cylindrical column, whereby valuable minerals are separated from gangue minerals based on their wetability properties.
  • Combustion chamber — The part of a boiler in which fuel is burned.
  • Comminution – the process of reducing the size of a particle by crushing and grinding it, using crusher machines.
  • Common stock - Shares in a company which have full voting rights which the holders use to control the company in common with each other. There is no fixed or assured dividend as with preferred shares, which have first claim on the distribution of a company's earnings or assets.
  • Competent rock — Rock which, because of its physical and geological characteristics, is capable of sustaining openings without any structural support except pillars and walls left during mining (stalls, light props, and roof bolts are not considered structural support).
  • Complex ore - An ore containing a number of minerals of economic value. The term often implies that there are metallurgical difficulties in liberating and separating the valuable metals.
  • Concentrate – what is left after the raw ore has been ground down and the waste has been removed; a fine powdery product of the milling process.
  • Concentrator - A milling plant that produces a concentrate of the valuable minerals or metals. Further treatment is required to recover the pure metal.
  • Concept study – a business case to determine whether it’s worth proceeding to extract ore from a specific area or mine.
  • Cone crusher - A machine which crushes ore between a gyrating cone or crushing head and an inverted, truncated cone known as a bowl.
  • Confirmation - A form delivered by a broker to the client, setting forth the details of stock sales or purchases for the client.
  • Conglomerate - A sedimentary rock consisting of rounded, water-worn pebbles or boulders cemented into a solid mass.
  • Contact — The place or surface where two different kinds of rocks meet. Applies to sedimentary rocks, as the contact between a limestone and a sandstone, for example, and to metamorphic rocks; and it is especially applicable between igneous intrusions and their walls.
  • Contact metamorphism - Metamorphism of country rocks adjacent to an intrusion, caused by heat from the intrusion.
  • Contango - A situation in which the price of a metal for forward or future delivery stands at a premium over the cash or spot price of the metal.
  • Continuous miner — A machine that constantly extracts coal while it loads it. This is to be distinguished from a conventional, or cyclic, unit which must stop the extraction process in order for loading to commence.
  • Contour — An imaginary line that connects all points on a surface having the same elevation.
  • Controlled blasting - Blasting patterns and sequences designed to achieve a particular objective. Cast blasting, where the muck pile is cast in a particular direction, and deck blasting, where holes are loaded once but blasted in successive blasts days apart, are examples.
  • Conventional mining — The first fully-mechanized underground mining method involving the insertion of explosives in a coal seam, the blasting of the seam, and the removal of the coal onto a conveyor or shuttle car by a loading machine.
  • Converter - In copper smelting, a furnace used to separate copper metal from matte.
  • Conveyor — An apparatus for moving material from one point to another in a continuous fashion. This is accomplished with an endless (that is, looped) procession of hooks, buckets, wide rubber belt, etc.
  • Cordillera - The continuous chain of mountain ranges on the western margin of North and South America.
  • Core - The long cylindrical piece of rock, about an inch in diameter, brought to surface by diamond drilling.
  • Core barrel - That part of a string of tools in a diamond drill hole in which the core specimen is collected.
  • Core sample — A cylinder sample generally 1-5" in diameter drilled out of an area to determine the geologic and chemical analysis of the overburden and coal.
  • Country rock - Loosely used to describe the general mass of rock adjacent to an orebody. Also known as the host rock.
  • Cover — The overburden of any deposit.
  • Creep — The forcing of pillars into soft bottom by the weight of a strong roof. In surface mining, a very slow movement of slopes downhill.
  • Crib — A roof support of prop timbers or ties, laid in alternate cross-layers, log-cabin style. It may or may not be filled with debris. Also may be called a chock or cog.
  • Cribbing — The construction of cribs or timbers laid at right angles to each other, sometimes filled with earth, as a roof support or as a support for machinery.
  • Crop coal — Coal at the outcrop of the seam. It is usually considered of inferior quality due to partial oxidation, although this is not always the case.
  • Cross entry — An entry running at an angle with the main entry.
  • Crossbar — The horizontal member of a roof timber set supported by props located either on roadways or at the face.
  • Crosscut — A passageway driven between the entry and its parallel air course or air courses for ventilation purposes. Also, a tunnel driven from one seam to another through or across the intervening measures; sometimes called "crosscut tunnel", or "breakthrough". In vein mining, an entry perpendicular to the vein.
  • Crusher — A machine for crushing rock or other materials. Among the various types of crushers are the ball mill, gyratory crusher, Handsel mill, hammer mill, jaw crusher, rod mill, rolls, stamp mill, and tube mill.
  • Crust - The outermost layer of the Earth; includes both continental and oceanic crust.
  • Cum-dividend - Buyer entitled to pending dividend payment.
  • Current assets - Assets of company which can and are likely to be converted into cash within a year. Includes cash, marketable securities, accounts receivable and supplies.
  • Current liabilities - A company's debts that are payable within a year's time.
  • Custom smelter - A smelter which processes concentrates from independent mines. Concentrates may be purchased or the smelter may be contracted to do the processing for the independent company.
  • Cut off – low grade ore that can just about be mined profitably.
  • Cut value - Applies to assays that have been reduced to some arbitrary maximum to prevent erratic high values from inflating the average.
  • Cut-and-fill - A method of stoping in which ore is removed in slices, or lifts, and then the excavation is filled with rock or other waste material (backfill), before the subsequent slice is extracted.
  • Cutter; Cutting machine — A machine, usually used in coal, that will cut a 10- to 15-cm slot. The slot allows room for expansion of the broken coal. Also applies to the man who operates the machine and to workers engaged in the cutting of coal by prick or drill.
  • Cyanidation - A method of extracting exposed gold or silver grains from crushed or ground ore by dissolving it in a weak cyanide solution. May be carried out in tanks inside a mill or in heaps of ore out of doors.
  • Cyanide - A chemical species containing carbon and nitrogen used to dissolve gold and silver from ore.
  • Cycle mining — A system of mining in more than one working place at a time, that is, a miner takes a lift from the face and moves to another face while permanent roof support is established in the previous working face.

D

  • Day order - An order to buy or sell shares, good only on the day the order was entered.
  • Debenture - See bonds.
  • Debt financing - Method of raising capital whereby companies borrow money from a lending institution.
  • Deck - The area around the shaft collar where men and materials enter the cage to be lowered underground.
  • Decline - A sloping underground opening for machine access from level to level or from surface; also called a ramp.
  • Decline tunnel – this is a tunnel driven from the surface towards the base of the mine to allow vehicles and equipment to go in and out of the mine.
  • Deferred charges - Expenses incurred but not charged against the current year's operation.
  • Demonstrated reserves — A collective term for the sum of coal in both measured and indicated resources and reserves.
  • Depletion - An accounting device, used primarily in tax computations. It recognizes the consumption of an ore deposit, a mine's principal asset.
  • Deposit – an amount of ore or mineral that makes exploitation worthwhile.
  • Depreciation - The periodic, systematic charging to expense of plant assets reflecting the decline in economic potential of the assets.
  • Depth — The word alone generally denotes vertical depth below the surface. In the case of incline shafts and boreholes it may mean the distance reached from the beginning of the shaft or hole, the borehole depth, or the inclined depth.
  • Detectors — Specialized chemical or electronic instruments used to detect mine gases.
  • Detonator — A device containing a small detonating charge that is used for detonating an explosive, including, but not limited to, blasting caps, exploders, electric detonators, and delay electric blasting caps.
  • Development - Underground work carried out for the purpose of opening up a mineral deposit. Includes shaft sinking, crosscutting, drifting and raising.
  • Development drilling - drilling to establish accurate estimates of mineral reserves.
  • Development mining — Work undertaken to open up coal reserves as distinguished from the work of actual coal extraction.
  • Diabase - A common basic igneous rock usually occurring in dykes or sills.
  • Diamond - The hardest known mineral, composed of pure carbon; low-quality diamonds are used to make bits for diamond drilling in rock.
  • Diamond drill - A rotary type of rock drill that cuts a core of rock that is recovered in long cylindrical sections, two cm or more in diameter.
  • Diamond driller - A person who operates a diamond drill.
  • Diffuser fan — A fan mounted on a continuous miner to assist and direct air delivery from the machine to the face.
  • Diffusion — Blending of a gas and air, resulting in a homogeneous mixture. Blending of two or more gases.
  • Dilute — To lower the concentration of a mixture; in this case the concentration of any hazardous gas in mine air by addition of fresh intake air.
  • Dilution (mining) - Rock that is, by necessity, removed along with the ore in the mining process, subsequently lowering the grade of the ore.
  • Dilution (of shares) - A decrease in the value of a company's shares caused by the issue of treasury shares.
  • Diorite - An intrusive igneous rock composed chiefly of sodic plagioclase, hornblende, biotite or pyroxene.
  • Dip — The inclination of a geologic structure (bed, vein, fault, etc.) from the horizontal; dip is always measured downwards at right angles to the strike.
  • Dip needle - A compass with the needle mounted so as to swing in a vertical plane, used for prospecting to determine the magnetic attraction of rocks.
  • Directional drilling - A method of drilling involving the use of stabilizers and wedges to direct the orientation of the hole.
  • Discount - The minimum price below the par value at which treasury shares may legally be sold.
  • Disseminated ore - Ore carrying small particles of valuable minerals spread more or less uniformly through the host rock.
  • Dividend - Cash or stock awarded to preferred and common shareholders at the discretion of the company's board of directors.
  • Dividend claim - Made when a dividend has been paid to the previous holder because stock has not yet been transferred to the name of the new owner.
  • Dor bar - The final saleable product of a gold mine. Usually consisting of gold and silver.
  • Drag fold - The result of the plastic deformation of a rock unit where it has been folded or bent back on itself.
  • Dragline — A large excavation machine used in surface mining to remove overburden (layers of rock and soil) covering a coal seam. The dragline casts a wire rope-hung bucket a considerable distance, collects the dug material by pulling the bucket toward itself on the ground with a second wire rope (or chain), elevates the bucket, and dumps the material on a spoil bank, in a hopper, or on a pile.
  • Drainage — The process of removing surplus ground or surface water either by artificial means or by gravity flow.
  • Draw slate — A soft slate, shale, or rock from approximately 1 cm to 10 cm thick and located immediately above certain coal seams, which falls quite easily when the coal support is withdrawn.
  • Drawpoint - An underground opening at the bottom of a stope through which broken ore from the stope is extracted.
  • Drift - A horizontal underground opening that follows along the length of a vein or rock formation as opposed to a crosscut which crosses the rock formation.
  • Drift mine — An underground coal mine in which the entry or access is above water level and generally on the slope of a hill, driven horizontally into a coal seam.
  • Drifter - A hydraulic rock drill used to drill small-diameter holes for blasting or for installing rock bolts.
  • Drill — A machine utilizing rotation, percussion (hammering), or a combination of both to make holes. If the hole is much over 0.4m in diameter, the machine is called a borer.
  • Drill-indicated reserves - The size and quality of a potential orebody as suggested by widely spaced drillholes; more work is required before reserves can be classified as probable or proven.
  • Drilling — The use of such a machine to create holes for exploration or for loading with explosives.
  • Dry - A building where the miner changes into working clothes.
  • Due diligence - The degree of care and caution required before making a decision; loosely, a financial and technical investigation to determine whether an investment is sound.
  • Dummy — A bag filled with sand, clay, etc., used for stemming a charged hole.
  • Dump — To unload; specifically, a load of coal or waste; the mechanism for unloading, e.g. a car dump (sometimes called tipple); or, the pile created by such unloading, e.g. a waste dump (also called heap, pile, tip, spoil pike, etc.).
  • Dyke - A long and relatively thin body of igneous rock that, while in the molten state, intruded a fissure in older rocks.

E

  • Electrical grounding — To connect with the ground to make the earth part of the circuit.
  • Electro-refining – the use of electrolysis to improve the purity of the metal extracted from ore.
  • Electro-winning – a process that uses electric currents to remove metal ions from liquid solutions, usually to recover precious metals.
  • Electrolysis - An electric current is passed through a solution containing dissolved metals, causing the metals to be deposited onto a cathode.
  • Electrolytic refining - The process of purifying metal ingots that are suspended as anodes in an electrolytic bath, alternated with refined sheets of the same metal which act as starters or cathodes.
  • Electrostatic precipitator - An electrical device for removing fine particles (fly ash) from combustion gases prior to release from a power plant's stack.
  • EM survey - A geophysical survey method which measures the electromagnetic properties of rocks.
  • En echelon - Roughly parallel but staggered structures.
  • Endowment – the full economic potential of an area due to be mined.
  • Energy — The capacity to do work; more commonly used as an all-encompassing generic term describing fuel sources used to provide power.
  • Energy mix — The combination of sources used to provide energy at any given time and place. Energy sources include coal, oil, gas, water (hydro), uranium (nuclear), wind, sunlight, geothermal, and others.
  • Entry — An underground horizontal or near-horizontal passage used for haulage, ventilation, or as a mainway; a coal heading; a working place where the coal is extracted from the seam in the initial mining; same as "gate" and "roadway," both British terms.
  • Environmental impact study (EIS) - A written report, compiled prior to a production decision, that examines the effects proposed mining activities will have on the natural surroundings.
  • Epigenetic - Orebodies formed by hydrothermal fluids and gases that were introduced into the host rocks from elsewhere, filling cavities in the host rock.
  • Epithermal deposit - A mineral deposit consisting of veins and replacement bodies, usually in volcanic or sedimentary rocks, containing precious metals or, more rarely, base metals.
  • Equity financing - The provision of funds by buying shares.
  • Era - A large division of geologic time - the Precambrian era, for example.
  • Erosion - The breaking down and subsequent removal of either rock or surface material by wind, rain, wave action, freezing and thawing and other processes.
  • Erratic - Either a piece of visible gold or a large glacial boulder.
  • Escrowed shares - Shares deposited in trust pending fulfilment of certain conditions, and not ordinarily available to trading until released.
  • Evaluation — The work involved in gaining a knowledge of the size, shape, position and value of coal.
  • Ex-dividend - On stocks selling "ex-dividend", the seller retains the right to a pending dividend payment.
  • Exploration - Prospecting, sampling, mapping, diamond drilling and other work involved in searching for ore.
  • Explosive — Any rapidly combustive or expanding substance. The energy released during this rapid combustion or expansion can be used to break rock.
  • Extraction — The process of mining and removal of cal or ore from a mine.

F

  • Face - The end of a drift, crosscut or stope in which work is taking place.
  • Face cleat — The principal cleavage plane or joint at right angles to the stratification of the coal seam.
  • Face conveyor — Any conveyor used parallel to a working face which delivers coal into another conveyor or into a car.
  • Face drilling – a method used in conventional mining to drill a hole in the coalbed for inserting explosive charges. The holes are drilled into the rock and packed with explosives.
  • Factor of safety — The ratio of the ultimate breaking strength of the material to the force exerted against it. If a rope will break under a load of 6000 lbs., and it is carrying a load of 2000 lbs., its factor of safety is 6000 divided by 2000 which equals 3.
  • Fall — A mass of roof rock or coal which has fallen in any part of a mine.
  • Fan signal — Automation device designed to give alarm if the main fan slows down or stops.
  • Fan, auxiliary — A small, portable fan used to supplement the ventilation of an individual working place.
  • Fan, booster — A large fan installed in the main air current, and thus in tandem with the main fan.
  • Fault — A slip-surface between two portions of the earth's surface that have moved relative to each other. A fault is a failure surface and is evidence of severe earth stresses.
  • Fault zone — A fault, instead of being a single clean fracture, may be a zone hundreds or thousands of feet wide. The fault zone consists of numerous interlacing small faults or a confused zone of gouge, breccia, or mylonite.
  • Feeder — A machine that feeds coal onto a conveyor belt evenly.
  • Feldspar - A group of common rock-forming minerals that includes microcline, orthoclase, plagioclase and others.
  • Felsic - Term used to describe light-colored rocks containing feldspar, feldspathoids and silica.
  • Ferrous - Containing iron.
  • Fill — Any material that is put back in place of the extracted ore to provide ground support.
  • Fine gold - Fineness is the proportion of pure gold or silver in jewelry or bullion expressed in parts per thousand. Thus, 925 fine gold indicates 925 parts out of 1,000, or 92.5% is pure gold.
  • Fine-grained - a material consisting of very small particles, each with an average size smaller than 1 mm in diameter.
  • Fire damp — The combustible gas, methane, CH4. Also, the explosive methane-air mixtures with between 5% and 15% methane. A combustible gas formed in mines by decomposition of coal or other carbonaceous matter, and that consists chiefly of methane.
  • First class ore – ore of sufficient quality to be sent to market without any treatment or processing.
  • Fissure - An extensive crack, break or fracture in rocks.
  • Fixed Assets - Possessions such as buildings, machinery and land which, as opposed to current assets, are unlikely to be converted into cash during the normal business cycle.
  • Fixed carbon — The part of the carbon that remains behind when coal is heated in a closed vessel until all of the volatile matter is driven off.
  • Flat-lying — Said of deposits and coal seams with a dip up to 5 degrees.
  • Fleet monitoring collision avoidance system – the basic hardware and software infrastructure required to provide fleet monitoring capabilities. This system provides information about haul truck utilization without any additional communication infrastructure.
  • Flight — The metal strap or crossbar attached to the drag chain-and-flight conveyor.
  • Float – pieces of rock that become separated from the main body over time.
  • Float dust — Fine coal-dust particles carried in suspension by air currents and eventually deposited in return entries. Dust consisting of particles of coal that can pass through a No. 200 sieve.
  • Floor — That part of any underground working upon which a person walks or upon which haulage equipment travels; simply the bottom or underlying surface of an underground excavation.
  • Flotation - A milling process in which valuable mineral particles are induced to become attached to bubbles and float as others sink.
  • Flow-through shares - Shares in an exploration company that allow the tax deduction or credits for mineral exploration to be passed to the investor.
  • Flowsheet - An illustration showing the sequence of operations, step by step, by which ore is treated in a milling, concentration or smelting process.
  • Flue Gas Desulfurization — Any of several forms of chemical/physical processes that remove sulfur compounds formed during coal combustion. The devices, commonly called "scrubbers," combine the sulfur in gaseous emissions with another chemical medium to form inert "sludge" which must then be removed for disposal.
  • Fluidized Bed Combustion — A process with a high degree of ability to remove sulfur from coal during combustion. Crushed coal and limestone are suspended in the bottom of a boiler by an upward stream of hot air. The coal is burned in this bubbling, liquid-like (or "fluidized") mixture. Rather than released as emissions, sulfur from combustion gases combines with the limestone to form a solid compound recovered with the ash.
  • Flux - A chemical substance that reacts with gangue minerals to form slags, which are liquid at furnace temperature and low enough in density to float on the molten bath of metal or matte.
  • Fluxgate magnetometer - An instrument used in geophysics to measure total magnetic field.
  • Fly ash — The finely divided particles of ash suspended in gases resulting from the combustion of fuel. Electrostatic precipitators are used to remove fly ash from the gases prior to the release from a power plant's smokestack.
  • Fold - Any bending or wrinkling of rock strata.
  • Footwall - The rock on the underside of a vein or ore structure.
  • Formation — Any assemblage of rocks which have some character in common, whether of origin, age, or composition. Often, the word is loosely used to indicate anything that has been formed or brought into its present shape.
  • Forward contract - The sale or purchase of a commodity for delivery at a specified future date.
  • Fossil fuel — Any naturally occurring fuel of an organic nature, such as coal, crude oil and natural gas.
  • Fracture - A break in the rock, the opening of which allows mineral-bearing solutions to enter. A "cross-fracture" is a minor break extending at more-or-less right angles to the direction of the principal fractures.
  • Free milling - Ores of gold or silver from which the precious metals can be recovered by concentrating methods without resorting to pressure leaching or other chemical treatment.
  • Friable — Easy to break, or crumbling naturally. Descriptive of certain rocks and minerals.
  • Froth flotation – a process used to separate water-loving materials from material that repel water. In mining it’s used to separate valuable mineral or metal from waste material making making it gather on the surface of a ‘froth’ layer.
  • Fuse — A cord-like substance used in the ignition of explosives. Black powder is entrained in the cord and, when lit, burns along the cord at a set rate. A fuse can be safely used to ignite a cap, which is the primer for an explosive.

G

  • Gabbro - A dark, coarse-grained igneous rock.
  • Galena - Lead sulphide, the most common ore mineral of lead.
  • Gallery — A horizontal or a nearly horizontal underground passage, either natural or artificial.
  • Gamma - A unit of measurement of magnetic intensity.
  • Gangue – the worthless material surrounds or is mixed with the mineral in ore.
  • Gasification — Any of various processes by which coal is turned into low, medium, or high Btu gases.
  • Gathering conveyor; gathering belt — Any conveyor which is used to gather coal from other conveyors and deliver it either into mine cars or onto another conveyor. The term is frequently used with belt conveyors placed in entries where a number of room conveyors deliver coal onto the belt.
  • Geiger counter - An instrument used to measure the radioactivity that emanates from certain minerals by means of a Geiger-Mueller tube.
  • Geochemistry - The study of the chemical properties of rocks.
  • Geologist — One who studies the constitution, structure, and history of the earth's crust, conducting research into the formation and dissolution of rock layers, analysing fossil and mineral content of layers, and endeavouring to fix historical sequence of development by relating characteristics to known geological influences (historical geology).
  • Geology - The science concerned with the study of the rocks which compose the Earth.
  • Geophysical survey - A scientific method of prospecting that measures the physical properties of rock formations. Common properties investigated include magnetism, specific gravity, electrical conductivity and radioactivity.
  • Geophysics - The study of the physical properties of rocks and minerals.
  • Geotechnical engineering — The branch of engineering that specializes in assessing the stability and strength of soil and rock materials, as well as groundwater conditions. With regard to mining, geotechnical engineering principles are used to determine the appropriate design of mine features such as pit walls, tunnels, and earthen embankments.
  • Geothermal - Pertains to the heat of the Earth's interior.
  • Glacial drift - Sedimentary material that has been transported by glaciers.
  • Glacial striations - Lines or scratches on a smooth rock surface caused by glacial abrasion.
  • Global climate change — This term usually refers to the gradual warming of the earth caused by the greenhouse effect. Many scientists believe this is the result of man-made emissions of greenhouse gases such as carbon dioxide, chlorofluorocarbons (CFC) and methane, although there is no agreement among the scientific community on this controversial issue.
  • Glory hole - An open pit from which ore is extracted, especially where broken ore is passed to underground workings before being hoisted.
  • Gneiss - A layered or banded crystalline metamorphic rock, the grains of which are aligned or elongated into a roughly parallel arrangement.
  • Gob — The term applied to that part of the mine from which the coal has been removed and the space more or less filled up with waste. Also, the loose waste in a mine. Also called goaf.
  • Gold loan - A form of debt financing whereby a potential gold producer borrows gold from a lending institution, sells the gold on the open market, uses the cash for mine development, then pays back the gold from actual mine production.
  • Gossan - The rust-colored capping or staining of a mineral deposit, generally formed by the oxidation or alteration of iron sulphides.
  • Gouge - Fine, putty-like material composed of ground-up rock found along a fault.
  • Grab sample - A sample from a rock outcrop that is assayed to determine if valuable elements are contained in the rock. A grab sample is not intended to be representative of the deposit, and usually the best-looking material is selected.
  • Graben - A downfaulted block of rock.
  • Grade – the amount of mineral contained in a piece of ore.
  • Grain — In petrology, that factor of the texture of a rock composed of distinct particles or crystals which depends upon their absolute size.
  • Granite - A coarse-grained intrusive igneous rock consisting of quartz, feldspar and mica.
  • Gravity meter, gravimeter - An instrument for measuring the gravitational attraction of the earth; gravitational attraction varies with the density of the rocks in the vicinity.
  • Greenhouse effect — The natural phenomenon that occurs when certain atmospheric gases (see greenhouse gases) trap radiated heat in the atmosphere. The greenhouse effect keeps the atmosphere warm and makes life on earth possible.
  • Greenstone belt - An area underlain by metamorphosed volcanic and sedimentary rocks, usually in a continental shield.
  • Grind – to crush ore into grains or powder.
  • Grizzly (or mantle) - A grating, usually constructed of steel rails, placed over the top of a chute or ore pass for the purpose of stopping large pieces of rock or ore that may hang up in the pass.
  • Gross value - The theoretical value of ore determined simply by applying the assay of metal or metals and the current market price. It must be used only with caution and severe qualification.
  • Gross value royalty - A share of gross revenue from the sale of minerals from a mine.
  • Ground control — The regulation and final arresting of the closure of the walls of a mined area. The term generally refers to measures taken to prevent roof falls or coal bursts.
  • Ground pressure — The pressure to which a rock formation is subjected by the weight of the superimposed rock and rock material or by diastrophic forces created by movements in the rocks forming the earth's crust. Such pressures may be great enough to cause rocks having a low compressional strength to deform and be squeezed into and close a borehole or other underground opening not adequately strengthened by an artificial support, such as casing or timber.
  • Ground-penetrating radar – radar used to scan images of what lies beneath the surface.
  • Grouting - The process of sealing off a water flow in rocks by forcing a thin slurry of cement or other chemicals into the crevices; usually done through a diamond drill hole.
  • Grubstake - Finances or supplies of food, etc., furnished to a prospector in return for an interest in any discoveries made.
  • Guides - The timber rails installed along the walls of a shaft for steadying, or guiding, the cage or conveyance.
  • Gunite — A cement applied by spraying to the roof and sides of a mine passage.
  • Gypsum - A sedimentary rock consisting of hydrated calcium sulphate.
  • Gyratory crusher - A machine that crushes ore between an eccentrically mounted crushing cone and a fixed crushing throat. Typically has a higher capacity than a jaw crusher.

H

  • Halite - Rock salt.
  • Hanging wall - The rock on the upper side of a vein or ore deposit.
  • Haulage — The horizontal transport of ore, coal, supplies, and waste. The vertical transport of the same is called hoisting.
  • Haulageway — Any underground entry or passageway that is designed for transport of mined material, personnel, or equipment, usually by the installation of track or belt conveyor.
  • Head grade - The average grade of ore fed into a mill.
  • Head section — A term used in both belt and chain conveyor work to designate that portion of the conveyor used for discharging material.
  • Headframe — The structure surmounting the shaft which supports the hoist rope pulley, and often the hoist itself.
  • Heading — A vein above a drift. An interior level or airway driven in a mine. In longwall workings, a narrow passage driven upward from a gangway in starting a working in order to give a loose end.
  • Heap leaching - A process whereby valuable metals, usually gold and silver, are leached from a heap, or pad, of crushed ore by leaching solutions percolating down through the heap and collected from a sloping, impermeable liner below the pad.
  • Heaving — Applied to the rising of the bottom after removal of the coal; a sharp rise in the floor is called a "hogsback".
  • Hedging - Taking a buy or sell position in a futures market opposite to a position held in the cash market to minimize the risk of financial loss from an adverse price change.
  • Hematite - An oxide of iron, and one of that metal's most common ore minerals.
  • High grade - Rich ore. As a verb, it refers to selective mining of the best ore in a deposit.
  • High-grader - One who steals rich ore, especially gold, from a mine.
  • Highwall — The unexcavated face of exposed overburden and coal in a surface mine or in a face or bank on the uphill side of a contour mine excavation.
  • Highwall miner — A highwall mining system consists of a remotely controlled continuous miner which extracts coal and conveys it via augers, belt or chain conveyors to the outside. The cut is typically a rectangular, horizontal cut from a highwall bench, reaching depths of several hundred feet or deeper.
  • Hogsback — A sharp rise in the floor of a seam.
  • Hoist — A drum on which hoisting rope is wound in the engine house, as the cage or skip is raised in the hoisting shaft.
  • Hoisting — The vertical transport coal or material.
  • Holding company - A corporation engaged principally in holding a controlling interest in one or more other companies.
  • Hopper — A bin or funnel that is loaded from the top and which discharges through a door or chute at the bottom.
  • Horizon — In geology, any given definite position or interval in the stratigraphic column or the scheme of stratigraphic classification; generally used in a relative sense.
  • Hornfels - A fine-grained contact metamorphic rock.
  • Horse - A mass of waste rock lying within a vein or orebody.
  • Horseback — A mass of material with a slippery surface in the roof; shaped like a horse's back.
  • Horst - An upfaulted block of rock.
  • Host rock - The rock surrounding an ore deposit.
  • Hydraulic — Of or pertaining to fluids in motion. Hydraulic cement has a composition which permits it to set quickly under water. Hydraulic jacks lift through the force transmitted to the movable part of the jack by a liquid. Hydraulic control refers to the mechanical control of various parts of machines, such as coal cutters, loaders, etc., through the operation or action of hydraulic cylinders.
  • Hydrocarbon — A class of compounds containing hydrogen and carbon formed by the decomposition of plant and animal remains, including coal, mineral oil, petroleum, natural gas, paraffin, the fossil resins, and the solid bitumens occurring in rocks. Gasoline is a mixture of hydrocarbons.
  • Hydrometallurgy - The treatment of ore by wet processes, such as leaching, resulting in the solution of a metal and its subsequent recovery.
  • Hydrothermal - Relating to hot fluids circulating in the earth's crust.

I

  • Igneous rocks - Rocks formed by the solidification of molten material from far below the earth's surface.
  • Ilmenite - An ore mineral of titanium, being an iron-titanium oxide.
  • Immediate roof — The roof strata immediately above the coalbed, requiring support during the excavation of coal.
  • In situ — In the natural or original position. Applied to a rock, soil, or fossil when occurring in the situation in which it was originally formed or deposited.
  • Inby — In the direction of the working face.
  • Inbye – the direction in a coal mine away from the pit shaft towards the coal face.
  • Incline — Any entry to a mine that is not vertical (shaft) or horizontal (adit). Often incline is reserved for those entries that are too steep for a belt conveyor (+17 degrees -18 degrees), in which case a hoist and guide rails are employed. A belt conveyor incline is termed a slope. Alt: Secondary inclined opening, driven upward to connect levels, sometimes on the dip of a deposit; also called "inclined shaft".
  • Incompetent — Applied to strata, a formation, a rock, or a rock structure not combining sufficient firmness and flexibility to transmit a thrust and to lift a load by bending.
  • Indicated resources — Resources for which estimates of the rank, quality, and quantity have been computed partly from sample analyses and measurements and partly from reasonable geologic projections. The points of observation are * to 1 * miles apart. Indicated resource is projected to extend as an * mile wide belt that lies more than * mile from the outcrop or points of observation or measurement.
  • Induced polarization - A method of ground geophysical surveying employing an electrical current to determine indications of mineralization.
  • Industrial minerals - Non-metallic, non-fuel minerals used in the chemical and manufacturing industries. Examples are asbestos, gypsum, salt, graphite, mica, gravel, building stone and talc.
  • Inferred resources — Resources in unexplored extensions of the demonstrated resources for which estimates of the quality and size are based on geologic evidence and projection. Quantitative estimates are based largely on broad knowledge of the geologic character of the deposit and for which there are few, if any, samples or measurements. The estimates are based on an assumed continuity or repletion of which there is geologic evidence; this evidence may include comparison with deposits of similar type. Bodies that are completely concealed may be included if there is specific geologic evidence of their presence. The points of observation are 1 * to 6 miles apart.
  • Initial public offering - The first sale of shares to the public, usually by subscription from a group of investment dealers.
  • Institutional investors - Pension funds and mutual funds, managing money for a large number of individual investors.
  • Intake — The passage through which fresh air is drawn or forced into a mine or to a section of a mine.
  • Intermediate rock - An igneous rock containing 52% to 66% quartz.
  • Intermediate section — A term used in belt and chain conveyor network to designate a section of the conveyor frame occupying a position between the head and foot sections.
  • Intrusive - A body of igneous rock formed by the consolidation of magma intruded into other rocks, in contrast to lavas, which are extruded upon the surface.
  • Ion exchange - An exchange of ions in a crystal with irons in a solution. Used as a method for recovering valuable metals, such as uranium, from solution.
  • Iron ore – rocks and minerals from which metallic iron can be profitably extracted.
  • Isopach — A line, on a map, drawn through points of equal thickness of a designated unit. Synonym for isopachous line; isopachyte.

J

  • Jackleg — A percussion drill used for drifting or stoping that is mounted on a telescopic leg which has an extension of about 2.5 m. The leg and machine are hinged so that the drill need not be in the same direction as the leg.
  • Jackrock — A caltrop or other object manufactured with one or more rounded or sharpened points, which when placed or thrown present at least one point at such an angle that it is peculiar to and designed for use in puncturing or damaging vehicle tires. Jackrocks are commonly used during labor disputes.
  • Jaw crusher - A machine in which rock is broken by the action of steel plates.
  • Jig - A piece of milling equipment used to concentrate ore on a screen submerged in water, either by the reciprocating motion of the screen or by the pulsation of water through it.
  • Job Safety Analysis (J.S.A.) — A job breakdown that gives a safe, efficient job procedure.
  • Joint — A divisional plane or surface that divides a rock and along which there has been no visible movement parallel to the plane or surface.

K

  • Kerf — The undercut of a coal face.
  • Kettle bottom — A smooth, rounded piece of rock, cylindrical in shape, which may drop out of the roof of a mine without warning. The origin of this feature is thought to be the remains of the stump of a tree that has been replaced by sediments so that the original form has been rather well preserved.
  • Kimberlite - A variety of peridotite; the most common host rock of diamonds.
  • Koepe winding – a system of winding, using the friction between the winding ropes and the drive pulley, used in coal mines. It was developed in Germany and introduced to England by the National Coal Board.

L

  • Lagging - Planks or small timbers placed between steel ribs along the roof of a stope or drift to prevent rocks from falling, rather than to support the main weight of the overlying rocks.
  • Lamp — The electric cap lamp worn for visibility. Also, the flame safety lamp used in coal mines to detect methane gas concentrations and oxygen deficiency.
  • Lamprophyre - An igneous rock, composed of dark minerals, that occurs in dykes; sometimes contains diamonds.
  • Laterite - A residual soil, usually found in tropical countries, out of which the silica has been leached. May form orebodies of iron, nickel, bauxite and manganese.
  • Launder - A chute or trough for conveying pulp, water or powdered ore in a mill.
  • Lava - A general name for the molten rock ejected by volcanoes.
  • Layout — The design or pattern of the main roadways and workings. The proper layout of mine workings is the responsibility of the manager aided by the planning department.
  • Leachable - Extractable by chemical solvents.
  • Leaching - A chemical process for the extraction of valuable minerals from ore; also, a natural process by which ground waters dissolve minerals, thus leaving the rock with a smaller proportion of some of the minerals than it contained originally.
  • Lens - Generally used to describe a body of ore that is thick in the middle and tapers towards the ends.
  • Lenticular - A deposit having roughly the form of a double convex lens.
  • Level - The horizontal openings on a working horizon in a mine; it is customary to work mines from a shaft, establishing levels at regular intervals, generally about 50 metres or more apart.
  • Liberation – the crushing, grinding and sieving of ore.
  • Life of mine – the plan for the way in which a company will mine in a particular area and for how long.
  • Lift — The amount of coal obtained from a continuous miner in one mining cycle.
  • Lignite — A low-rank coal with a relatively high moisture content and relatively low heat/energy content.
  • Limestone - A bedded, sedimentary deposit consisting chiefly of calcium carbonate.
  • Limit order - An order made by a client to a broker to buy or sell shares at a specified price or better.
  • Limonite - A brown, hydrous iron oxide.
  • Line cutting - Straight clearings through the bush to permit sightings for geophysical and other surveys.
  • Liquefaction — The process of converting coal into a synthetic fuel, similar in nature to crude oil and/or refined products, such as gasoline.
  • Lithology — The character of a rock described in terms of its structure, color, mineral composition, grain size, and arrangement of its component parts; all those visible features that in the aggregate impart individuality of the rock. Lithology is the basis of correlation in coal mines and commonly is reliable over a distance of a few miles.
  • Load — To place explosives in a drill hole. Also, to transfer broken material into a haulage device.
  • Load haul dumper – these vehicles are used in underground mines to load and transport ore and minerals. They can be operated manually or automatically.
  • Loading machine — Any device for transferring excavated coal into the haulage equipment.
  • Loading pocket — Transfer point at a shaft where bulk material is loaded by bin, hopper, and chute into a skip.
  • Lode – a mineral deposit contained in solid rock.
  • Logging - The process of recording geological observations of drill core either on paper or on computer disk.
  • London fix - The twice-daily bidding session held by five dealing companies to set the gold price. There are also daily London fixes to set the prices of other precious metals.
  • London Metals Exchange - A major bidding market for base metals, which operates daily in London.
  • Long position - Securities owned outright or carried on margin.
  • Long ton - 2,240 lbs. avoirdupois (compared with a short ton, which is 2,000 lbs.).
  • Longwall Mining — One of three major underground coal mining methods currently in use. Employs a steal plow, or rotation drum, which is pulled mechanically back and forth across a face of coal that is usually several hundred feet long. The loosened coal falls onto a conveyor for removal from the mine.
  • Loose coal — Coal fragments larger in size than coal dust.
  • Low Sulphur coal — Coal which has a sulphur content generally ranging from 0.1 per cent to 1.0 per cent. All western Canadian coal is low in sulphur.
  • Low voltage — Up to and including 660 volts by federal standards.

M

  • Mafic - Igneous rocks composed mostly of dark, iron- and magnesium-rich minerals.
  • Magma - The molten material deep in the Earth from which rocks are formed.
  • Magmatic segregation - An ore-forming process whereby valuable minerals are concentrated by settling out of a cooling magma.
  • Magnetic gradient survey - A geophysical survey using a pair of magnetometers a fixed distance apart, to measure the difference in the magnetic field with height above the ground.
  • Magnetic separation - A process in which a magnetically susceptible mineral is separated from gangue minerals by applying a strong magnetic field; ores of iron are commonly treated in this way.
  • Magnetic survey - A geophysical survey that measures the intensity of the Earth's magnetic field.
  • Magnetic susceptibility - A measure of the degree to which a rock is attracted to a magnet.
  • Magnetite - Black, magnetic iron ore, an iron oxide.
  • Magnetometer - An instrument used to measure the magnetic attraction of underlying rocks.
  • Main entry — A main haulage road. Where the coal has cleats, main entries are driven at right angles to the face cleats.
  • Main fan — A mechanical ventilator installed at the surface; operates by either exhausting or blowing to induce airflow through the mine roadways and workings.
  • Man trip — A carrier of mine personnel, by rail or rubber tire, to and from the work area.
  • Manhole — A safety hole constructed in the side of a gangway, tunnel, or slope in which miner can be safe from passing locomotives and car. Also called a refuge hole.
  • Manway — An entry used exclusively for personnel to travel form the shaft bottom or drift mouth to the working section; it is always on the intake air side in gassy mines. Also, a small passage at one side or both sides of a breast, used as a traveling way for the miner, and sometimes, as an airway, or chute, or both.
  • Map-staking - A form of claim-staking practised in some jurisdictions whereby claims are staked by drawing lines around the claim on claim maps at a government office.
  • Marble - A metamorphic rock derived from the recrystallization of limestone under intense heat and pressure.
  • Margin - Cash deposited with a broker as partial payment of the purchase price for any type of listed stock. The stock is held by the broker as security for the loan.
  • Marginal deposit - An orebody of minimal profitability.
  • Market order - An order to buy or sell at the best price available. In absence of any specified price or limit, an order is considered to be "at the market".
  • Matte - A product of a smelter, containing metal and some sulphur, which must be refined further to obtain pure metal.
  • Measured coal resources — Coal for which estimates of the rank, quality, and quantity have been computed from sample analyses and measurements from closely spaced and geologically well-known sample sites, such as outcrops, trenches, mine workings, and drill holes. The points of observation and measurement are so closely spaced and the thickness and extent of coals are so well defined that the tonnage is judged to be accurate within 20 percent of true tonnage. Although the spacing of the points of observation necessary to demonstrate continuity of the coal differs from region to region according to the character of the coal beds, the points of observation are no greater than * mile apart. Measured coal is projected to extend as a *-mile wide belt from the outcrop or points of observation or measurement.
  • Meridian — A surveying term that establishes a line of reference. The bearing is used to designate direction. The bearing of a line is the acute horizontal angle between the meridian and the line. Azimuths are angles measured clockwise from any meridian.
  • Metallurgical coal — The type of coal which is converted to coke for use in manufacturing steel; often referred to as coking coal.
  • Metallurgy – the art of working metals, especially extracting them from their ores.
  • Metamorphic rocks - Rocks which have undergone a change in texture or composition as the result of heat and/or pressure.
  • Metamorphism - The process by which the form or structure of rocks is changed by heat and pressure.
  • Methane — A potentially explosive gas formed naturally from the decay of vegetative matter, similar to that which formed coal. Methane, which is the principal component of natural gas, is frequently encountered in underground coal mining operations and is kept within safe limits through the use of extensive mine ventilation systems.
  • Methane monitor — An electronic instrument often mounted on a piece of mining equipment, that detects and measures the methane content of mine air.
  • Migmatite - Rock consisting of thin, alternating layers of granite and schist.
  • Mill - A plant in which ore is treated and metals are recovered or prepared for smelting; also a revolving drum used for the grinding of ores in preparation for treatment.
  • Milling ore - Ore that contains sufficient valuable mineral to be treated by milling process.
  • Millivolts - A measure of the voltage of an electric current, specifically, one-thousandth of a volt.
  • Mineable reserves - Ore reserves that are known to be extractable using a given mining plan.
  • Mine development — The term employed to designate the operations involved in preparing a mine for ore extraction. These operations include tunneling, sinking, cross-cutting, drifting, and raising.
  • Mine mouth electric plant — A coal burning electric-generating plant built near a coal mine.
  • Mine recovery – the percentage of mined ore that makes it to the processing plant.
  • Mine value chain – the entire mining process, from the moment the potential of an area is identified to the day product is delivered to customers.
  • Miner — One who is engaged in the business or occupation of extracting ore, coal, precious substances, or other natural materials from the earth's crust.
  • Mineral - A naturally occurring homogeneous substance having definite physical properties and chemical composition and, if formed under favorable conditions, a definite crystal form.
  • Mining Engineer — A person qualified by education, training, and experience in mining engineering. A trained engineer with knowledge of the science, economics, and arts of mineral location, extraction, concentration and sale, and the administrative and financial problems of practical importance in connection with the profitable conduct of mining.
  • Misfire — The complete or partial failure of a blasting charge to explode as planned.
  • MSHA — Mine Safety and Health Administration; the federal agency which regulates coal mine health and safety.
  • Muck – in open pit mining, muck is the ore that has been broken into pieces by explosives. In underground mining, muck is the clearing up that’s done after blasting to sort the rich ore from the poor rock.
  • Muck sample - A representative piece of ore that is taken from a muck pile and then assayed to determine the grade of the pile.
  • Mud cap — A charge of high explosive fired in contact with the surface of a rock after being covered with a quantity of wet mud, wet earth, or sand, without any borehole being used. Also termed adobe, dobie, and sandblast (illegal in coal mining).

N

  • Nanotesla - The international unit for measuring magnetic flux density.
  • Native metal - A metal occurring in nature in pure form, uncombined with other elements.
  • Natural ventilation — Ventilation of a mine without the aid of fans or furnaces.
  • Net profit interest - A portion of the profit remaining after all charges, including taxes and bookkeeping charges, such as depreciation, have been deducted.
  • Net smelter return - A share of the net revenues generated from the sale of metal produced by a mine.
  • Net worth - The difference between total assets and total liabilities.
  • Nip — Device at the end of the trailing cable of a mining machine used for connecting the trailing cable to the trolley wire and ground.
  • Nitrogen oxides (NOx) — Formed when nitrogen (N2) combines with oxygen (O2) in the burning of fossil fuels, from the natural degradation of vegetation, and from the use of chemical fertilizers. A significant component of acid deposition and photochemical smog. The primary source of nitrogen oxide emissions is automobile exhaust.
  • Non-destructive testing – a way to measure the integrity of materials or structures, without causing any harm.
  • Norite - A coarse-grained igneous rock that is host to copper/nickel deposits in the Sudbury area of Ontario.
  • Nugget - A small mass of precious metal, found free in nature.

O

  • Odd lot - A block of shares that is less than a board lot.
  • Open-end pillaring — A method of mining pillars in which no stump is left; the pockets driven are open on the gob side and the roof is supported by timber.
  • Open order - An order to buy or sell stock, which is good until cancelled by the client.
  • Open-pit - A mine that is entirely on surface. Also referred to as open-cut or open-cast mine.
  • Opencast mining – a method of mining rock or minerals by removing them from an open-pit mine situated close to the surface above ground.
  • Option - An agreement to purchase a property reached between the property vendor and some other party who wishes to explore the property further.
  • Option (on stock) - The right to buy or sell a share at a set price, regardless of market value.
  • Ore - A mixture of ore minerals and gangue from which at least one of the metals can be extracted at a profit.
  • Ore pass - Vertical or inclined passage for the downward transfer of ore connecting a level with the hoisting shaft or a lower level.
  • Ore Reserves - The calculated tonnage and grade of mineralization which can be extracted profitably; classified as possible, probable and proven according to the level of confidence that can be placed in the data.
  • Orebody - A natural concentration of valuable material that can be extracted and sold at a profit.
  • Oreshoot - The portion, or length, of a vein or other structure that carries sufficient valuable minerals to be extracted profitably.
  • Organic maturation - The process of turning peat into coal.
  • Orogeny - A period of mountain-building characterized by the folding of a portion of the earth's crust.
  • Outby; outbye — Nearer to the shaft, and hence farther from the working face. Toward the mine entrance. The opposite of inby.
  • Outcrop - An exposure of rock or mineral deposit that can be seen on surface, that is, not covered by soil or water.
  • Overburden— Layers of soil and rock covering a coal seam. In surface mining operations, overburden is removed prior to mining using large equipment. When mining has been completed, it is either used to backfill the mined areas or is hauled to an external dumping and/or storage site.
  • Overcast (undercast) — Enclosed airway which permits one air current to pass over (under) another without interruption.
  • Overturned - Where the oldest sedimentary rock beds are lying on top of a younger beds.
  • Oxidation - A chemical reaction caused by exposure to oxygen that results in a change in the chemical composition of a mineral.
  • Ozone (O3) — A bluish, toxic gas, with a pungent odour, formed of three oxygen atoms rather than the usual two. Occurs in the stratosphere and plays a role in filtering out ultraviolet radiation from the sun's rays. At ground-level ozone is a major component of photochemical smog.

P

  • Pan - To wash gravel, sand or crushed rock samples in order to isolate gold or other valuable metals by their higher density.
  • Panel — A coal mining block that generally comprises one operating unit.
  • Panic bar — A switch, in the shape of a bar, used to cut off power at the machine in case of an emergency.
  • Par value - The stated face value of a stock. Par value shares have no specified face value, but the total amount of authorized capital is set down in the company's charter.
  • Participating interest - A company's interest in a mine, which entitles it to a certain percentage of profits in return for putting up an equal percentage of the capital cost of the project.
  • Parting — (1) A small joint in coal or rock; (2) a layer of rock in a coal seam; (3) a sidetrack or turnout in a haulage road.
  • Patent - The ultimate stage of holding a mineral claim, after which no more assessment work is necessary because all mineral rights have been earned.
  • Peat— A dark brown or black deposit resulting from the partial decomposition of vegetative matter in marshes, swamps and bogs. One of the earliest stages of coal formation.
  • Pegmatite - A coarse-grained, igneous rock, generally coarse, but irregular in texture, and similar to a granite in composition; usually occurs in dykes or veins and sometimes contains valuable minerals.
  • Pellet - A marble-sized ball of iron ore fused with clay for transportation and use in steelmaking.
  • Pentlandite - Nickel iron sulphide, the most common nickel ore.
  • Percentage extraction — The proportion of a coal seam which is removed from the mine. The remainder may represent coal in pillars or coal which is too thin or inferior to mine or lost in mining. Shallow coal mines working under townships, reservoirs, etc., may extract 50%, or less, of the entire seam, the remainder being left as pillars to protect the surface. Under favourable conditions, longwall mining may extract from 80 to 95% of the entire seam. With pillar methods of working, the extraction ranges from 50 to 90% depending on local conditions.
  • Percussion drill — A drill, usually air powered, that delivers its energy through a pounding or hammering action.
  • Peridotite - An intrusive igneous rock consisting mainly of olivine.
  • Permissible — That which is allowable or permitted. It is most widely applied to mine equipment and explosives of all kinds which are similar in all respects to samples that have passed certain tests of the MSHA and can be used with safety in accordance with specified conditions where hazards from explosive gas or coal dust exist.
  • Permit — As it pertains to mining, a document issued by a regulatory agency that gives approval for mining operations to take place.
  • Phaneritic - A term used to describe the coarse-grained texture of some igneous rocks.
  • Picket line - A reference line, marked by pickets or stakes, established on a property for mapping and survey purposes.
  • Pig iron - Crude iron from a blast furnace.
  • Piggy-back — A bridge conveyor.
  • Pillar - A block of solid ore or other rock left in place to structurally support the shaft, walls or roof of a mine.
  • Pillar robbing — The systematic removal of the coal pillars between rooms or chambers to regulate the subsidence of the roof. Also termed "bridging back" the pillar, "drawing" the pillar, or "pulling" the pillar.
  • Pinch — A compression of the walls of a vein or the roof and floor of a coal seam so as to "squeeze" out the coal.
  • Pinning — Roof bolting.
  • Pit de-watering – the removal of water by pumping or evaporation to remove or drain groundwater or surface water from a site or mine shaft.
  • Pit Ponies — Small horses, mules, or ponies which were used to pull coal shuttle cars from underground mines during the 1800s.
  • Pitch — The inclination of a seam; the rise of a seam.
  • Pitchblende - An important uranium ore mineral. It is black in colour, possesses a characteristic greasy lustre and is highly radioactive.
  • Placer - A deposit of sand and gravel containing valuable metals such as gold, tin or diamonds.
  • Plan — A map showing features such as mine workings or geological structures on a horizontal plane.
  • Plant - A building or group of buildings in which a process or function is carried out; at a mine site it will include warehouses, hoisting equipment, compressors, maintenance shops, offices and the mill or concentrator.
  • Plate tectonics - A geological theory which postulates that the Earth's crust is made up of a number of rigid plates which collide, rub up against and spread out from one another.
  • Plug - A common name for a small offshoot from a large body of molten rock.
  • Plunge - The vertical angle a linear geological feature makes with the horizontal plane.
  • Plutonic - Refers to rocks of igneous origin that have come from great depth.
  • Pneumoconiosis — A chronic disease of the lung arising from breathing coal dust.
  • Point - Unit of value of a stock as quoted by a stock exchange. May represent one dollar, one cent or one-eighth of a dollar, depending on the stock exchange.
  • Polishing pond - The last in a series of settling ponds through which mill effluent flows before being discharged into the natural environment.
  • Pooling shares - See escrowed shares.
    Porphyry - Any igneous rock in which relatively large crystals, called phenocrysts, are set in a fine-grained groundmass.
  • Porphyry copper - A deposit of disseminated copper minerals in or around a large body of intrusive rock.
  • Portal — The structure surrounding the immediate entrance to a mine; the mouth of an adit or tunnel.
  • Portal bus — Track-mounted, self-propelled personnel carrier that holds 8 to 12 people.
  • Portfolio - A list of financial assets.
  • Possible reserves - Valuable mineralization not sampled enough to accurately estimate its tonnage and grade, or even verify its existence. Also called "inferred reserves."
  • Post - The vertical member of a timber set.
  • Potash - Potassium compounds mined for fertilizer and for use in the chemical industry.
  • Pre-feasibility – a detailed examination of the business case for mining in a particular location.
  • Precambrian Shield - The oldest, most stable regions of the earth's crust, the largest of which is the Canadian Shield.
  • Precious metal – rare and sought-after, naturally occurring metallic chemical elements regarded as investments or used in industry. Examples include gold, silver and the platinum group metals or PGMS: ruthenium, rhodium, palladium, osmium, iridium, and platinum.
  • Preferred shares - Shares of a limited liability company that rank ahead of common shares, but after bonds, in distribution of earnings or in claim to the company's assets in the event of liquidation. They pay a fixed dividend but normally do not have voting rights, as with common shares.
  • Preparation plant — A place where coal is cleaned, sized, and prepared for market.
  • Price-to-earnings ratio - The current market price of a stock divided by the company's net earnings per share for the year.
  • Primary deposits - Valuable minerals deposited during the original period or periods of mineralization, as opposed to those deposited as a result of alteration or weathering.
  • Primary roof — The main roof above the immediate top. Its thickness may vary from a few to several thousand feet.
  • Primer (booster) — A package or cartridge of explosive which is designed specifically to transmit detonation to other explosives and which does not contain a detonator.
  • Private placement - Sale of shares to individuals or corporations outside the normal market, at a negotiated price. Often used to raise capital for a junior exploration company.
  • Pro-rata - In proportion, usually to ownership, income or contribution.
  • Probable reserves - Valuable mineralization not sampled enough to accurately estimate the terms of tonnage and grade. Also called "indicated reserves."
  • Process recovery – the percentage of product we can extract by processing.
  • Processing – extracting metals and minerals from ore and then purifying them.
  • Production – the amount of ore mined in a specific timescale, which is often measured on a quarterly basis.
  • Profit and loss statement - The income statement of a company detailing revenues minus total costs to give total profit.
  • Prop — Coal mining term for any single post used as roof support. Props may be timber or steel; if steel--screwed, yieldable, or hydraulic.
  • Prospect - A mining property, the value of which has not been determined by exploration.
  • Prospectus - A document filed with the appropriate securities commission detailing the activities and financial condition of a company seeking funds from the public through the issuance of shares.
  • Proton precession magnetometer - A geophysical instrument which measures magnetic field intensity in terms of vertical gradient and total field.
  • Proven reserves - Reserves that have been sampled extensively by closely spaced diamond drill holes and developed by underground workings in sufficient detail to render an accurate estimation of grade and tonnage. Also called "measured reserves."
  • Proximate analysis — A physical, or non-chemical, test of the constitution of coal. Not precise, but very useful for determining the commercial value. Using the same sample (1 gram) under controlled heating at fixed temperatures and time periods, moisture, volatile matter, fixed carbon and ash content are successfully determined. Sulfur and Btu content are also generally reported with a proximate analysis.
  • Proxy - A power of attorney given by the shareholder so that his stock may be voted by his nominee(s) at shareholders' meetings.
  • Pulp - Pulverized or ground ore in solution.
  • Put - An option to sell a stock at an agreed-upon price within a specified time. The owner can present his put to the contracting broker at any time within the option period and compel him to buy the stock.
  • Pyramiding - The use of increased buying power to increase ownership arising from price appreciation.
  • Pyrite — A hard, heavy, shiny, yellow mineral, FeS2 or iron disulfide, generally in cubic crystals. Also called iron pyrites, fool's gold, sulfur balls. Iron pyrite is the most common sulfide found in coal mines.
  • Pyrrhotite - A bronze-coloured, magnetic iron sulphide mineral.

Q

  • Quartoze – sedimentary rock made up primarily of quartz.
  • Quartz - Common rock-forming mineral consisting of silicon and oxygen.
  • Quartzite - A metamorphic rock formed by the transformation of a sandstone by heat and pressure.

R

  • Radioactivity - The property of spontaneously emitting alpha, beta or gamma rays by the decay of the nuclei of atoms.
  • Radon survey - A geochemical survey technique which detects traces of radon gas, a product of radioactivity.
  • Raise — A secondary or tertiary inclined opening, vertical or near-vertical opening driven upward from a level to connect with the level above, or to explore the ground for a limited distance above one level.
  • Rake - The trend of an orebody along the direction of its strike.
  • Ramp — A secondary or tertiary inclined opening, driven to connect levels, usually driven in a downward direction, and used for haulage.
  • Ranks of coal — The classification of coal by degree of hardness, moisture and heat content. "Anthracite" is hard coal, almost pure carbon, used mainly for heating homes. "Bituminous" is soft coal. It is the most common coal found in the United States and is used to generate electricity and to make coke for the steel industry. "Subbituminous" is a coal with a heating value between bituminous and lignite. It has low fixed carbon and high percentages of volatile matter and moisture. "Lignite" is the softest coal and has the highest moisture content. It is used for generating electricity and for conversion into synthetic gas. In terms of Btu or "heating" content, anthracite has the highest value, followed by bituminous, sub-bituminous and lignite.
  • Rare earth elements - Relatively scarce minerals such as niobium and yttrium.
  • Reaming shell - A component of a string of rods used in diamond drilling, it is set with diamonds and placed between the bit and the core barrel to maintain the gauge (or diameter) of the hole.
  • Reclamation — The restoration of land and environmental values to a surface mine site after the coal is extracted. Reclamation operations are usually underway as soon as the coal has been removed from a mine site. The process includes restoring the land to its approximate original appearance by restoring topsoil and planting native grasses and ground covers.
  • Reconnaissance - A preliminary survey of ground.
  • Record date - The date by which a shareholder must be registered on the books of a company in order to receive a declared dividend, or to vote on company affairs.
  • Recovery - The percentage of valuable metal in the ore that is recovered by metallurgical treatment/the proportion or percentage of coal or ore mined from the original seam or deposit.
  • Red dog — A nonvolatile combustion product of the oxidation of coal or coal refuse. Most commonly applied to material resulting from in situ, uncontrolled burning of coal or coal refuse piles. It is similar to coal ash.
  • Refine – to produce the pure state of a commodity from its ore.
  • Refractory ore - Ore that resists the action of chemical reagents in the normal treatment processes and which may require pressure leaching or other means to affect the full recovery of the valuable minerals.
  • Regional metamorphism - Metamorphism caused by both the heat of igneous processes and tectonic pressure.
  • Regulator — Device (wall, door) used to control the volume of air in an air split.
  • Rehabilitation – leaving the mine area in the condition in which you find it or the condition agreed with the local community.
  • Reject – the coarse (pebbles) and fine (tailings) waste produced at processing plants.
  • Replacement ore - Ore formed by a process during which certain minerals have passed into solution and have been carried away, while valuable minerals from the solution have been deposited in the place of those removed.
  • Reserve — That portion of the identified coal or mineral deposit resource that can be economically mined at the time of determination. The reserve is derived by applying a recovery factor to that component of the identified resource designated as the reserve base or proven reserves.
  • Resin bolting — A method of permanent roof support in which steel rods are grouted with resin.
  • Resistivity survey - A geophysical technique used to measure the resistance of a rock formation to an electric current.
  • Resource - The calculated amount of material in a mineral deposit, based on limited drill information.
  • Resources — Concentrations of coal in such forms that economic extraction is currently or may become feasible. Coal resources broken down by identified and undiscovered resources. Identified coal resources are classified as demonstrated and inferred. Demonstrated resources are further broken down as measured and indicated. Undiscovered resources are broken down as hypothetical and speculative.
  • Respirable dust — Dust particles 5 microns or less in size.
  • Respirable dust sample — A sample collected with an approved coal mine dust sampler unit attached to a miner, or so positioned as to measure the concentration of respirable dust to which the miner is exposed, and operated continuously over an entire work shift of such miner.
  • Resuing - A method of stoping in narrow-vein deposits whereby the wallrock on one side of the vein is blasted first and then the ore.
  • Retreat mining — A system of robbing pillars in which the robbing line, or line through the faces of the pillars being extracted, retreats from the boundary toward the shaft or mine mouth.
  • Return — The air or ventilation that has passed through all the working faces of a split.
  • Return idler — The idler or roller underneath the cover or cover plates on which the conveyor belt rides after the load which it was carrying has been dumped at the head section and starts the return trip toward the foot section.
  • Reverberatory furnace - A long, flat furnace used to slag gangue minerals and produce a matte.
  • Rhyolite - A fine-grained, extrusive igneous rock which has the same chemical composition as granite.
  • Rib — The side of a pillar or the wall of an entry. The solid coal on the side of any underground passage. Same as rib pillar.
  • Rib samples - Ore taken from rib pillars in a mine to determine metal content.
  • Rider — A thin seam of coal overlying a thicker one.
  • Rights - In finance, a certified right to purchase treasury shares in stated quantities, prices and time limits; usually negotiable at a price which is related to the prices of the issue represented; also referred to as warrants. Rights and warrants can be bought and sold prior to their expiry date because not all shareholders wish to exercise their rights.
  • Ripper — A coal extraction machine that works by tearing the coal from the face.
  • Rob — To extract pillars of coal previously left for support.
  • Robbed out area — Describes that part of a mine from which the pillars have been removed.
  • Rock - Any natural combination of minerals; part of the earth's crust.
  • Rock factor - The number of cubic metres of a particular rock type required to make up one tonne of the material. One tonne of a highly siliceous ore may occupy 0.40 cubic metres, while a tonne of dense sulphide ore may occupy only 0.25 cubic metres.
  • Rock mechanics - The study of the mechanical properties of rocks, which includes stress conditions around mine openings and the ability of rocks and underground structures to withstand these stresses.
  • Rockbolting - The act of supporting openings in rock with steel bolts anchored in holes drilled especially for this purpose.
  • Rockburst - A violent release of energy resulting in the sudden failure of walls or pillars in a mine, caused by the weight or pressure of the surrounding rocks.
  • Rod mill - A rotating steel cylinder that uses steel rods as a means of grinding ore.
  • Roll — A high place in the bottom or a low place in the top of a mine passage/ a local thickening of roof or floor strata, causing thinning of a coal seam.
  • Roll protection — A framework, safety canopy, or similar protection for the operator when equipment overturns.
  • Roof — The stratum of rock or other material above a coal seam; the overhead surface of a coal working place. Same as "back" or "top."
  • Roof bolt - A long steel bolt driven into the roof of underground excavations to support the roof, preventing and limiting the extent of roof falls. The unit consists of the bolt (up to 4 feet long), steel plate, expansion shell, and pal nut. The use of roof bolts eliminates the need for timbering by fastening together, or "laminating," several weaker layers of roof strata to build a "beam."
  • Roof bolting – a common application in underground coal mines for securing the mine roof to be self-supportive.
  • Roof fall — A coal mine cave-in especially in permanent areas such as entries.
  • Roof jack — A screw- or pump-type hydraulic extension post made of steel and used as temporary roof support.
  • Roof sag — The sinking, bending, or curving of the roof, especially in the middle, from weight or pressure.
  • Roof stress — Unbalanced internal forces in the roof or sides, created when coal is extracted.
  • Roof support — Posts, jacks, roof bolts and beams used to support the rock overlying a coal seam in an underground mine. A good roof support plan is part of mine safety and coal extraction.
  • Roof trusses — A combination of steel rods anchored into the roof to create zones of compression and tension forces and provide better support for weak roof and roof over wide areas.
  • Room and pillar mining — A method of underground mining in which approximately half of the coal is left in place to support the roof of the active mining area. Large "pillars" are left while "rooms" of coal are extracted.
  • Room neck — The short passage from the entry into a room.
  • Room-and-pillar mining - A method of mining flat-lying ore deposits in which the mined-out area, or rooms, are separated by pillars of approximately the same size.
  • Rotary drill - A machine that drills holes by rotating a rigid, tubular string of drill rods to which is attached a bit. Commonly used for drilling large-diameter blastholes in open-pit mines.
  • Round — Planned pattern of drill holes fired in sequence in tunneling, shaft sinking, or stoping. First the cut holes are fired, followed by relief, lifter, and rib holes.
  • Royalty - An amount of money paid at regular intervals by the lessee or operator of an exploration or mining property to the owner of the ground. Generally based on a certain amount per tonne or a percentage of the total production or profits. Also, the fee paid for the right to use a patented process.
  • Run of Mine (ROM) – ore that’s mined and ready to go to the processing plant/a term used loosely to describe ore of average grade.

S

  • 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.
  • Salting - The act of introducing metals or minerals into a deposit or samples, resulting in false assays. Done either by accident or with the intent of defrauding the public.
  • Sample - A small portion of rock or a mineral deposit taken so that the metal content can be determined by assaying.
  • 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 - The act of removing loose slabs of rock from the back and walls of an underground opening, usually done with a hand-held scaling bar or with a boom-mounted scaling hammer.
  • Scarp - An escarpment, cliff or steep slope along the margin of a plateau, mesa or terrace.
  • Schist - A foliated metamorphic rock the grains of which have a roughly parallel arrangement; generally developed by shearing.
  • Scintillation counter - An instrument used to detect and measure radioactivity by detecting gamma rays; more sensitive than a Geiger counter.
  • 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 – an underground layer of a mineral such as coal/a stratum.
  • Secondary enrichment - Enrichment of a vein or mineral deposit by minerals that have been taken into solution from one part of the vein or adjacent rocks and redeposited in another.
  • 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.
  • Sedimentary rocks - Secondary rocks formed from material derived from other rocks and laid down underwater. Examples are limestone, shale and sandstone.
  • Seismic prospecting - A geophysical method of prospecting, utilizing knowledge of the speed of reflected sound waves in rock.
  • 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 stoping 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-potential - A technique, used in geophysical prospecting, which recognizes and measures the minute electric currents generated by sulphide deposits.
  • 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 vapour 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.
  • Semi-autogenous grinding (SAG) - A method of grinding rock into fine powder whereby the grinding media consist of larger chunks of rocks and steel balls.
  • Serpentine - A greenish, metamorphic mineral consisting of magnesium silicate.
  • Severance — The separation of a mineral interest from other interests in the land by grant or reservation. A mineral deed 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 vertical or inclined excavation in rock for the purpose of providing access to an orebody. Usually equipped with a hoist at the top, which lowers and raises a conveyance for handling workers and materials/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.
  • Shaft sinking – the activity of establishing a vertical or declined tunnel to obtain the precious metal and/or mineral.
  • Shale — A rock formed by consolidation of clay, mud, or silt, having a laminated structure and composed of minerals essentially unaltered since deposition.
  • Shear or shearing - The deformation of rocks by lateral movement along innumerable parallel planes, generally resulting from pressure and producing such metamorphic structures as cleavage and schistosity.
  • Shear zone - A zone in which shearing has occurred on a large scale.
  • 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.
  • Sheave wheel - A large, grooved wheel in the top of a headframe over which the hoisting rope passes.
  • Shift — The number of hours or the part of any day worked.
  • Shoot - A concentration of mineral values; that part of a vein or zone carrying values of ore grade.
  • Short selling - The borrowing of stock from a broker in order to sell it in the hope that it may be purchased at a lower price later on.
  • Short ton - 2,000 lbs. avoirdupois.
  • 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.
  • Shrinkage stoping - A stoping method which uses part of the broken ore as a working platform and as support for the walls of the stope.
  • 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.
  • Siderite - Iron carbonate, which when pure, contains 48.2% iron; must be roasted to drive off carbon dioxide before it can be used in a blast furnace. Roasted product is called sinter.
  • Silica - Silicon dioxide. Quartz is a common example.
  • Siliceous - A rock containing an abundance of quartz.
  • Sill - An intrusive sheet of igneous rock of roughly uniform thickness that has been forced between the bedding planes of existing rock.
  • Silt - Muddy deposits of fine sediment usually found on the bottoms of lakes.
  • Sinking — The process by which a shaft is driven.
  • Sinter - Fine particles of iron ore that have been treated by heat to produce blast furnace feed.
  • Skarn - Name for the metamorphic rocks surrounding an igneous intrusive where it comes in contact with a limestone or dolostone formation.
  • 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 self-dumping bucket used in a shaft for hoisting ore or rock.
  • Slack — Small coal; the finest-sized soft coal, usually less than one inch in diameter.
  • Slag - The vitreous mass separated from the fused metals in the smelting process.
  • Slash - The process of blasting rock from the side of an underground opening to widen the opening.
  • 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 - The striated, polished surface of a fault caused by one wall rubbing against the other.
  • 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.
  • Slope stability – the walls of a pit have a certain slope (stepped, benched or side) determined by the strength of the rock mass and other factors. The stability of these walls and even of individual benches and groups of benches is very important particularly as the pit gets deeper. Increasing the pit slope angle by only a few degrees can decrease stripping costs tremendously or increase revenues through increased ore recovery.
  • Sloughing — The slow crumbling and falling away of material from roof, rib, and face.
  • Sludge - Rock cuttings from a diamond drill hole, sometimes used for assaying.
  • Sodium cyanide - A chemical used in the milling of gold ores to dissolve gold and silver.
  • Solid — Mineral that has not been undermined, sheared out, or otherwise prepared for blasting.
  • Solvent extraction-electrowinning (SX-EW) - A metallurgical technique, so far applied only to copper ores, in which metal is dissolved from the rock by organic solvents and recovered from solution by electrolysis.
  • 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 ° Celsius.
  • Spelter - The zinc of commerce, more or less impure, cast from molten metal into slabs or ingots.
  • Sphalerite - A zinc sulphide mineral; the most common ore mineral of zinc.
  • Split - The shareholder-approved division of a company's outstanding common shares into a larger number of new common shares/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.
  • Spot price - Current delivery price of a commodity traded in the spot market.
  • Square-set system — A method of timbering a mine invented by Philipp Deidesheimer in which heavy timbers, 18 inches square, are mortised together in rectangular sets from 6 or 7 feet high and from 4-6 feet long.
  • 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.
  • Station - An enlargement of a shaft made for the storage and handling of equipment and for driving drifts at that elevation.
  • 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 non-combustible material used on top or in front of a charge or explosive.
  • Step-out drilling - Holes drilled to intersect a mineralization horizon or structure along strike or down dip.
  • Stock exchange - An organized market concerned with the buying and selling of common and preferred shares and warrants by stockbrokers who own seats on the exchange and meet membership requirements.
  • Stockpile - Broken ore heaped on surface, pending treatment or shipment.
  • Stop-loss order - An arrangement whereby a client gives his broker instructions to sell a stock if and when its price drops to a specified figure on the market.
  • Stope – a step-like excavation that’s formed as ore is removed from around the mine shaft.
  • Stratigraphy - Strictly, the description of bedded rock sequences; used loosely, the sequence of bedded rocks in a particular area.
  • Streak - A diagnostic characteristic of minerals, where scratching a sample on a piece of unglazed porcelain leaves powder of a characteristic colour.
  • Street certificate - A certificate representing ownership in a specified number of shares that is registered in the name of some previous owner who has endorsed the certificate so that it may be transferred to a new owner without referral to transfer agent.
  • Striations - Prominent parallel scratches left on bedrock by advancing glaciers.
  • 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.
  • Stringer - A narrow vein or irregular filament of a mineral or minerals traversing a rock mass.
  • Strip - To remove the overburden or waste rock overlying an orebody in preparation for mining by open-pit methods.
  • Strip mine - An open-pit mine, usually a coal mine, operated by removing overburden, excavating the coal seam, then returning the overburden.
  • Stripping ratio - The ratio of tonnes removed as waste relative to the number of tonnes of ore removed from an open-pit mine/the unit amount of overburden that must be removed to gain access to a similar unit amount of coal or mineral material.
  • Stull — A timber prop or a timber wedged in place between two walls of a stope as part of a protective covering or platform.
  • Stump — Any small pillar.
  • Sub-bituminous (coal) - Coal with an energy/heat value between lignite and bituminous.
  • Sublevel - A level or working horizon in a mine between main working levels.
  • 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.
  • Subsidiary company - A company in which the majority of shares (a controlling position) is held by another company.
  • Sulphide - A compound of sulphur and some other element.
  • Sulphide dust explosions - An underground mining hazard involving the spontaneous combustion of airborne dust containing sulphide minerals.
  • Sulphur dioxide - A gas liberated during the smelting of most sulphide ores; either converted into sulphuric acid or released into the atmosphere in the form of a gas.
  • 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.
  • Sustainable development - Industrial development that does not detract from the potential of the natural environment to provide benefits to future generations.
  • Syenite - An intrusive igneous rock composed chiefly of orthoclase.
  • Sylvite - potassium chloride, the principal ore of potassium mined for fertilizer manufacturing.
  • Syncline — A fold in rock in which the strata dip inward from both sides toward the axis. The opposite of anticline.
  • Syngenetic - A term used to describe when mineralization in a deposit was formed relative to the host rocks in which it is found. In this case, the mineralization was formed at the same time as the host rocks. (The opposite is epigenetic.)

T

  • Taconite - A highly abrasive iron ore.
  • 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.
  • 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.
  • Tailings – the material or waste left over after the valuable product/commodity has been extracted from ore.
  • Tailings dam – a dam used to store the waste byproducts or tailings produced during the process of extracting the valuable commodity/product from ore.
  • Tailings pond - A low-lying depression used to confine tailings, the prime function of which is to allow enough time for heavy metals to settle out or for cyanide to be destroyed before water is discharged into the local watershed.
  • 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.
  • Talus - A heap of broken, coarse rock found at the base of a cliff or mountain.
  • Tectonic forces — Forces pertaining to, causing, or resulting from structural deformation of the earth's crust.
  • Telluride - A chemical compound consisting of the element tellurium and another element, often gold or silver.
  • Tension — The act of stretching.
  • Tertiary - Lateral or panel openings (e.g., ramp, crosscut).
  • Thermal coal — A generic term used to describe coal which is used primarily to generate heat as opposed to metallurgical coal which is converted to coke for use in steel production. Sometimes referred to as steam coal.
  • Thickener - A large, round tank used in milling operations to separate solids from liquids; clear fluid overflows from the tank and rock particles sink to the bottom.
  • 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.
  • Timber set — A timber frame to support the roof, sides, and sometimes the floor of mine roadways or shafts.
  • Timbering — The setting of timber supports in mine workings or shafts for protection against falls from roof, face, or rib.
  • 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.
  • Tonnes-per-vertical-metre - Common unit used to describe the amount of ore in a deposit; ore length is multiplied by the width and divided by the appropriate rock factor to give the amount of ore for each vertical metre of depth.
  • 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.
  • Trading floor - the area of a stock exchange building where shares are bought and sold.
  • Trading post - An area on the trading floor of a stock exchange where current stock prices are listed and where the floor traders (representatives of brokerage firms) meet to buy or sell the stocks listed at that particular post.
  • 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.
  • Transformation – the refining and smelting of metal.
  • Treasury shares - The unissued shares in a company's treasury.
  • Trench - A long, narrow excavation dug through overburden, or blasted out of rock, to expose a vein or ore structure.
  • Trend - The direction, in the horizontal plane, of a linear geological feature, such as an ore zone, measured from true north.
  • 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.
  • Tube mill - An apparatus consisting of a revolving cylinder about half-filled with steel rods or balls and into which crushed ore is fed for fine grinding.
  • Tuff - Rock composed of fine volcanic ash.
  • 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.
  • Tunnel boring machine – a machine that is used as an alternative to drilling and blasting. These machines can excavate tunnels with a circular cross section and can bore through anything from hard rock to sand.
  • Tunnel-boring-machine - A machine used to excavate a tunnel through soil or rock by mechanical means as opposed to drilling and blasting.

U

  • Ultimate analysis — Precise determination, by chemical means, of the elements and compounds in coal.
  • Umpire sample or assay - An assay made by a third party to provide a basis for settling disputes between buyers and sellers of ore.
  • Uncut value - The actual assay value of a core sample as opposed to a cut value which has been reduced by some arbitrary formula.
  • 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.
  • Underwrite - A firm commitment made by a broker or other financial institution to purchase a block of shares at a specified price.
  • Unit train — A long train of between 60 and 150 or more hopper cars, dedicated to the transport of a single commodity such as 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.
  • Uraninite - A uranium mineral with a high uranium oxide content. Frequently found in pegmatite dykes.
  • Uranium - A radioactive, silvery-white, metallic element.

V

  • Valuation — The act or process of valuing or of estimating the value or worth; appraisal.
  • Vein - A fissure, fault or crack in a rock filled by minerals that have travelled upwards from some deep source.
  • Velocity — Rate of airflow in lineal feet per minute.
  • Vendor - A seller. In the case of mining companies, the consideration paid for properties purchased is often a block of treasury shares. These shares are termed vendor shares and are normally pooled or escrowed.
  • 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.
  • Visible gold - Native gold which is discernible, in a hand specimen, to the unaided eye.
  • 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.
  • Volcanic rocks - Igneous rocks formed from magma that has flowed out or has been violently ejected from a volcano.
  • Volcanogenic - A term used to describe the volcanic origin of mineralization.
  • Voting right - The stockholder's right to vote in the affairs of the company. Most common shares have one vote each. Preferred stock usually has the right to vote when preferred dividends are in default.
  • Vug - A small cavity in a rock, frequently lined with well-formed crystals. Amethyst commonly forms in these cavities.
  • Vug – a small to medium-size rock crevice or cavity.

W

  • Wall rocks - Rock units on either side of an orebody. The hanging wall and footwall rocks of an orebody.
  • Warrant - See Rights.
  • Waste - Unmineralized, or sometimes mineralized, rock that is not mineable at a profit/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 technique of directing a diamond drill hole in a desired direction away from its current orientation/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 haemoglobin 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.
  • Witness post - A claim post placed on a claim line when it cannot be placed in the corner of a claim because of water or difficult terrain.
  • 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 capital - The liquid resources a company has to meet day-to-day expenses of operation; defined as the excess of current assets over current liabilities.
  • Working face – the location where ore and waste is removed from solid rock.
  • Working place — From the outby side of the last open crosscut to the face.
  • Working section — From the faces to the point where coal is loaded onto belts or rail cars to begin its trip to the outside.
  • Workings — The entire system of openings in a mine for the purpose of exploitation.
  • Writeoffs - Amounts deducted from a company's reported profit for depreciation or preproduction costs. Writeoffs are not an out-of-pocket expense, but reduce the amount of taxable profit.


X

  • Xenolith - A fragment of country rock enclosed in an intrusive rock.

Y

  • Yield - The current annual dividend rate expressed as a percentage of the current market price of the stock.

Z

  • Zone - An area of distinct mineralization.
  • Zone of oxidation - The upper portion of an orebody that has been oxidized.

 

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