Glossary of Mining Terminology

Mining can be a confusing area to invest if you don’t know the “Lingo” this glossary will help you navigate through the technical jargon with ease.

This comprehensive guide is your key to understanding the intricate language used in the mining industry and help you better understand when investing

A

• Acidic precipitation – Snow and rain with a low pH caused by industrial gases released into the atmosphere.
• Acidic rocks – Igneous rock with a high proportion of silica.
• Acid mine drainage – Acidic run-off  water from mine waste dumps and mill tailings ponds.
• Adit – A horizontal opening into the side of a mountain or hill for access to a mineral deposit.
• Aerial magnetometer – An instrument to measure magnetic field strength from an airplane.
• Aeromagnetic survey – A geophysical survey using a magnetometer aboard an aircraft.
• Agglomerate – A breccia composed largely of volcanic rock fragments.
• Agglomeration – Concentrating valuable minerals based on their adhesion properties.
• Agitation – In metallurgy, the act of being stirred or shaken mechanically.
• Airborne survey – A survey from an aircraft to obtain photographs or measure magnetic properties.
• Alloy – A compound of two or more metals.
• Alluvial deposit – Sedimentary material, such as sand, gravel, and clay, which has been naturally deposited by running water.
• Alluvium – Deposits of sedimentary material in river beds, flood plains, or mountain bases.
• Alpha meter – An instrument to measure positively charged particles from radioactive materials.
• Alpha ray – A positively charged particle emitted by certain radioactive materials.
• Alteration – Physical or chemical change in a rock or mineral after its formation.
• Amorphous – Rocks or minerals without a definite crystal structure.
• Amortization – Writing off an account balance over an appropriate period.
• Amphibolite – A gneiss or schist made up of amphibole and plagioclase minerals.
• ANFO – Ammonium nitrate and fuel oil, used as a blasting agent in mines.
• Annual report – Financial statements and operations reports issued by a corporation annually.
• Anode – A metal plate cast for refining by the electrolytic process.
• Anomaly – Departure from the norm, indicating potential mineralization in the bedrock.
• Anthracite – Hard, black coal with a high percentage of fixed carbon.
• Anticline – An arch or fold in rock layers shaped like a wave crest.
• Apex – The top or terminal edge of a vein on the surface or its nearest point to the surface.
• Ash – Inorganic residue remaining after ignition of coal.
• Assay – A chemical test on ores or minerals to determine the amount of valuable metals.
• Assay foot (meter, inch, centimeter) – The assay value multiplied by the sample’s width.
• Assay map – An area map indicating assay values and sample locations.
• Assessment work – Work required annually to retain legal control of mining claims.
• Authorized capital – See capital stock.
• Autogenous grinding – Grinding ore in a rotating cylinder using large pieces of the ore itself.

B

• Back – The ceiling or roof of an underground opening.
• 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.
• Back sample – A rock sample collected from the roof or back of an underground opening to determine the grade.
• Backwardation – A market condition where the futures price of a commodity is lower than the spot price.
• Balance sheet – A financial statement showing a company’s assets, liabilities, and equity at a specific point in time.
• Ball mill – A rotating cylinder filled with  steel balls used to pulverize rock or ore in preparation for mineral extraction.
• Banded iron formation – Layers of iron-rich minerals alternating with bands of shale or chert, often a source of iron ore.
• Basalt – A hard, dense volcanic rock that can be used in the aggregate and is often found in basaltic lava flows.
• Basal till – Unsorted glacial debris at the base of the soil column where it comes into contact with the bedrock below.
• Basement rocks – The thick foundation stones of the earth’s crust, usually old and metamorphic.
• Base camp – The main area of operations for fieldwork or mining exploration activities.
• Base metal – Non-precious metals such as copper, lead,  zinc, and nickel.
• Basic rocks – Igneous rocks that are relatively low in silica and composed chiefly of dark-colored minerals.
• Batholith – A large mass of intrusive igneous rock believed to have solidified deep within the earth.
• Bauxite – The principal ore of aluminum, composed mainly of hydrous aluminum oxides and aluminum hydroxides.
• Bear market – A period of declining market prices.
• Bedding – The layering or stratification seen in rocks.
• Beneficiate – To process ores and raw materials to improve their quality or to remove impurities.
• Bentonite – A clay material composed primarily of smectite minerals, used in drilling muds and foundry sands.
• Bessemer – An inexpensive iron-making process in which air is blown through molten pig iron to oxidize and remove impurities.
• Bio-leaching – The extraction of specific metals from their ores using living organisms.
• Biotite – A black, magnesium-iron mica common in igneous rocks.
• Bit – The cutting end of a drill is frequently made of an extremely hard material such as industrial diamonds or tungsten carbide.
• Bituminous coal – A middle rank coal between sub-bituminous and anthracite formed by additional pressure and heat on lignite. It’s usually used for electricity generation and steel production.
• Blackjack – A miner’s term for sphalerite (zinc sulfide).
• Black smoker – A chimney formed from deposits of iron sulfide, which is black, that accumulates over an underwater hot spring.
• Blaster – A person qualified to handle and use explosives for breaking rock.
• Blast furnace – A large structure in which iron ore is smelted into iron metal.
• Blasthole: A hole drilled for the purpose of blasting rather than for exploration or geological information.
• Blister copper – A crude form of copper (assaying about 99%) produced in a smelter that 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 – A standard trading unit defined in the various trading venues.
• Bond – A financial instrument used as a promise to pay a specific amount of money at a future date.
• Boom – A period of increased economic or business activity.
• Box hole – A short raise or opening driven above a drift for the purpose of drawing ore from a stope, or to permit access.
• Break – A sudden drop in the market price of shares or commodities.
• Breast – A working face in a mine, usually restricted to a stope.
• Breccia – Rock characterized by large, angular fragments, often formed in volcanic eruptions.
• Broken reserves – The ore in a mine that has been broken by blasting but has not yet been transported to the surface.
• Brunton compass – A pocket-sized instrument used to measure the magnetic azimuth of geological features.
• Bulk mining – Any large-scale, mechanized method of mining involving many thousands of tonnes of ore being brought to the 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 ore body.
• Bullion – Precious metals, gold, and silver in the form of bars, ingots, or specialized coins valued by weight.
• Bull market – A period of rising market prices.
• Bull quartz – A prospector’s term for white, coarse-grained, barren quartz.
• Butt entry – A  coal mining term that varies in meaning depending on location, signifying either a panel entry, sub-main entry, or traditionally referring to an entry made at right angles to the coal face, aligning with the coal cleavage.
• Byproduct – A secondary product derived from a manufacturing process or chemical reaction, not the primary product or service being produced.

C

• Cable bolt – A  steel cable cemented into a drill hole to lend support in blocky ground.
• Cage – The conveyance used to transport men and equipment between the surface and the mine levels.
• Calcine – Concentrate that is ready for smelting.
• Call – An option to buy shares at a specified price.
• Capitalization – The value financial markets put on a company.
• Capital stock – The total ownership of a limited liability company divided among shares.
• Captive stope – A stope that is accessible only through a manway.
• Carbon-in-pulp – A method of recovering gold and silver from pregnant cyanide solutions.
• Cash flow – The net of the inflow and outflow of cash during an accounting period.
• Cathode – A rectangular plate of metal produced by electrolytic refining.
• Cesium magnetometer – An instrument that measures magnetic field strength.
• Chalcocite – A sulfide mineral of copper common in the zone of secondary enrichment.
• Chalcopyrite – A sulfide mineral of copper and iron; the most important ore mineral of copper.
• Change house – The mine building where workers change into work clothes.
• Channel sample – A sample composed of pieces of vein or mineral deposit that have been cut out of a small trench or channel.
• Charter – A document issued by a governing authority creating a company.
• Chartered bank – A financial institution that accepts deposits and provides loans.
• 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.
• 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.
• 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.
• 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 carbonaceous rock mined for use as a fuel.
• Coal mining –  The process of extracting coal from the ground, which is a valuable energy resource used primarily for generating electricity and heating.
• Coalification – The metamorphic processes of forming  coal.
• Collar – The timbering or concrete around the mouth of a shaft; also the top of a mill hole.
• Collision avoidance system – These are systems installed to help vehicles and heavy machinery at mines avoid each other and people in adverse conditions 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.
• 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.
• Complex ore – An ore containing a number of minerals of economic value.
• Cone crusher – A machine which crushes ore between a gyrating cone or crushing head and an inverted, truncated cone known as a bowl.
• Concentrate – A fine, powdery product of the milling process containing a high percentage of valuable metal.
• Concentrator – A milling plant that produces a concentrate of the valuable minerals or metals.
• Concept study – A business case to determine whether it’s worth proceeding to extract ore from a specific area or mine.
• 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 line or plane along which two different rock formations meet.
• 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 piece of mining equipment that produces a continuous flow of ore from the working face.
• Controlled blasting – Blasting patterns and sequences designed to achieve a particular objective.
• Converter – In copper smelting, a furnace separates copper metal from matte.
• Core or core sample – The long cylindrical piece of rock brought to the 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.
• Cordillera – The continuous chain of mountain ranges on the western margin of North and South America.
• Cornish pump – A type of pump developed in Cornwall, England, and used to pump  water out of mines.
• Country rock – Loosely used to describe the general mass of rock adjacent to an orebody. Also known as host rock.
• Crosscut – A horizontal opening driven from a shaft and (or near) right angles to the strike of a vein or other orebody.
• Crown pillar – A pillar of rock left to support the ceiling as mining progresses.
• Crucible – A refractory container used for melting metals in a furnace.
• Crusher – A machine for crushing rock or other materials.
• Crushing – The process of breaking up large rocks into smaller rocks, gravel or rock dust.
• Cut – A horizontal channel made by removing a section of rock for mining purposes.
• Cut-and-fill – A method of stoping in which ore is removed in slices, or lifts, and then the excavation is filled with waste or ore before the subsequent slice is extracted.
• Cut-off grade – The lowest grade of mineralized material that qualifies as ore in a given deposit; ore of the lowest assay value that is included in an ore shipment.
• Cyanidation – A method of extracting exposed gold or silver grains from crushed ore by dissolving the ore in a weak cyanide solution.

D

• Day order – An order to buy or sell shares, good only on the day the order was entered
• Debenture – A type of debt instrument that is not secured by physical assets or collateral
• 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 the surface, also called a ramp.
• Deferred charges – Expenses incurred but not charged against the current year’s operation
• Depletion – An accounting device used primarily in tax computations. It recognizes the consumption of an ore deposit, a mine’s principal asset.
• Depreciation – The periodic, systematic charging to expense of plant assets reflecting the decline in economic potential of the assets
• 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
• 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
• 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 angle at which a vein, structure, or rock bed is inclined from the horizontal as measured at right angles to the strike
• Dip needle – A compass with the needle mounted 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
• 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 that crosses the rock formation
• Drifter – A hydraulic rock drill used to drill small-diameter holes for blasting or for installing rock bolts
• Drill-indicated reserves – The size and quality of a potential orebody as suggested by widely spaced drill holes; more work is required before reserves can be classified as probable or proven
• 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
• Dump – A pile of broken rock or ore on the surface
• Dyke – A long and relatively thin body of igneous rock that, while in the molten state, intruded a fissure in older rocks

E

• Electrowinning – A process used to recover metals in aqueous solution by applying a current and causing the metal to deposit onto an electrode.
• Electrolysis – A technique that uses a direct electric current to drive an otherwise non-spontaneous chemical reaction.
• Electrolytic refining – A process of using electrolysis to increase the purity of a metal extracted from its ore.
• EM survey – An electromagnetic survey, a geophysical method used in mineral and petroleum exploration.
• Emulsion – A mixture of explosives consisting of an oxidizer dispersed in a liquid fuel, used for blasting in mining operations.
• En echelon – A pattern of fractures or faults that overlap in a staircase pattern.
• Environmental impact study – A report or study that predicts the environmental effects of a proposed industrial or infrastructural project.
• Epigenetic – A geological term referring to mineral deposits that formed after the host rock.
• Epithermal deposit – A type of mineral deposit formed from near-surface thermal waters.
• Equity financing – The process of raising capital through selling shares in an enterprise.
• Era – A large division of geologic time consisting of two or more periods.
• Erosion – The process by which soil and rock are removed from the Earth’s surface by exogenic processes such as wind or  water flow and then transported and deposited in other locations.
• Erratic – A piece of rock that differs from the size and type of rock native to the area in which it rests.
• Escrowed shares – Shares that are held in escrow and cannot be sold until certain conditions are met.
• Ex-dividend – A stock trading term referring to a stock that is trading without the value of the next dividend payment.
• Exploration – The search for mineral deposits and the work done to prove or establish the extent of a mineral deposit.
• Explosives – Substances used in mining to break rock by the energy released upon detonation.

F

• Face – The end of a drift, crosscut, or stope in which work occurs.
• Fault – A break in the Earth’s crust caused by tectonic forces that have moved the rock on one side with respect to the other.
• 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.
• Fine gold – Fineness is the proportion of pure gold or silver in jewelry or bullion expressed in parts per thousand.
• 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.
• Float – Pieces of rock that have been broken off and moved from their original location by natural forces such as frost or glacial action.
• Flotation – A milling process in which valuable mineral particles are induced to become attached to bubbles and float as others sink.
• Flowsheet – An illustration showing the sequence of operations, step by step, by which ore is treated in a milling, concentration, or smelting process.
• Flow-through shares – Shares in an exploration company that allow the tax deduction or credits for mineral exploration to be passed to the investor.
• 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.
• Fold – Any bending or wrinkling of rock strata.
• Footwall – The rock on the underside of a vein or ore structure.
• Forward contract – The sale or purchase of a commodity for delivery at a specified future date.
• Fossil fuels – Natural fuels formed in the earth from the remains of dead plants and animals over millions of years, typically including  coal, oil, and natural gas.
• Fracture – A break in the rock, the opening of which allows mineral-bearing solutions to enter.
• 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.

G

• Gabbro – A dark, coarse-grained igneous rock.
• Galena – Lead sulphide, the most common ore mineral of lead.
• Gamma – A unit of measurement of magnetic intensity.
• Gangue – The worthless minerals in an ore deposit.
• 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.
• Geology – The science concerned with the study of the rocks which compose the Earth.
• Geophysics – The study of the physical properties of rocks and minerals.
• Geophysical survey – A scientific method of prospecting that measures the physical properties of rock formations.
• 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.
• 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.
• 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.
• Graben – A downfaulted block of rock.
• Grade – The concentration of a valuable mineral or metal within ore, typically measured as the amount of metal per ton of rock.
• Granite – A coarse-grained intrusive igneous rock consisting of quartz, feldspar and mica.
• Gravity meter or gravimeter – An instrument for measuring the gravitational attraction of the earth.
• Greenstone belt – An area underlain by metamorphosed volcanic and sedimentary rocks, usually in a continental shield.
• Grind – The process of reducing rock to fine particles, often in preparation for mineral extraction via various methods, including milling.
• Grizzly (or mantle) – A grating, usually constructed of  steel rails, placed over the top of a chute or ore pass.
• Gross value – The theoretical value of ore determined by the assay of metal or metals and the current market price.
• Gross value royalty – A share of gross revenue from the sale of minerals from a mine.
• Ground-penetrating radar – A geophysical method that uses radar pulses to image the subsurface, often used to detect and map structures and materials such as mineral veins, faults, and underground voids.
• Grouting – The process of sealing off a  water flow in rocks by forcing a slurry of cement into the crevices.
• Grubstake – Finances or supplies 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.
• 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.

H

• Halite – Commonly known as rock salt, halite is often mined for use in the chemical industry or as a winter highway treatment.
• Hanging wall – The rock on the upper side of a vein or ore deposit.
• Head grade – The average grade of ore fed into a mill.
• Heap leaching – A process where valuable metals, usually gold and silver, are extracted from a heap of crushed ore by leaching solutions.
• Hedging – A financial strategy involving taking an opposite position in the futures market to minimize risk from price changes.
• Hematite – An iron oxide and one of the most common ore minerals for iron.
• High grade – Ore that contains a higher amount of the desired mineral.
• High-grader – An individual who steals high-grade ore from a mine.
• Hoist – A device used for lifting and lowering conveyances within a mine shaft.
• Holding company – A type of corporation that owns enough voting stock in another firm to control its policies and management.
• Hornfels – A fine-grained rock formed by contact metamorphism.
• Horse – Waste rock that is found within a vein or orebody.
• Horst – A raised block of the earth’s crust that has been uplifted relative to the surrounding terrain.
• Host rock – The rock in which a mineral deposit is found; the surrounding rock.
• Hydrometallurgy – A method for obtaining metals from their ores using aqueous chemistry.
• Hydrothermal – Pertaining to hot water, often used to describe the fluids involved in the formation of mineral deposits.

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.
• In situ – A term describing a natural material that has not been moved or altered by humans, where the mineral is extracted without removing the rock.
• Induced polarization (IP) – 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, such as asbestos, gypsum, salt, graphite, mica, gravel, building stone, and talc.
• Inferred Mineral Resource – A part of a mineral resource for which quantity and grade or quality are estimated on the basis of limited geological evidence and sampling.
• Initial public offering (IPO) – The first sale of shares to the public, usually by subscription from a group of investment dealers.
• Institutional investors – Entities like pension funds and mutual funds that manage money for many individual investors.
• Intermediate rock – An igneous rock containing 52% to 66% quartz.
• Intrusive or Intrusion – 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.
• Invert – The bottom of a tunnel or the floor of a shaft.
• Ion exchange – A process of exchanging ions in a crystal with ions in a solution, used as a method for recovering valuable metals, such as uranium, from the solution.
• Iron – A heavy, malleable, ductile, magnetic, silver-white metallic element, being the most common and useful metal and an important constituent of the earth’s core.
• Iron pyrite – A common sulfide mineral that is often mistaken for gold due to its brass-yellow color and metallic luster, also known as fool’s gold.

J

• Jaw Crusher – A machine used in mining to break down large pieces of ore into smaller pieces for further processing.
• Jig – A machine that separates particles within an ore body based on their relative movement in response to gravity and other forces.
• Joint – A geological feature visible as a plane of fracture or discontinuity in a volume of rock.
• Jumbo – A piece of mining equipment that drills holes in rock so that explosives can be inserted to blast the rock.
• Jumpers – A term that refers to small explosive charges used in drilling and blasting operations.

K

• Kiln – A type of oven used to produce high temperatures for various purposes in metallurgy and material science, including the smelting and forging of metal ores.
• Kimberlite – A type of igneous rock best known for sometimes containing diamonds, named after Kimberley in South Africa, where it was first discovered.
• Knelson Concentrator – A device used in the gold mining industry to recover gold from ore using centrifugal force.
• Kriging – A statistical method used in geostatistics for interpolating the value of a random field (like the concentration of minerals in an ore body) at an unobserved location from observations of its value at nearby locations.

L

• Lagging – These are planks or small timbers placed between  steel ribs along the roof of a stope or drift to prevent rocks from falling rather than supporting the weight of the overhead rocks.
• Lamprophyre – A type of igneous rock mainly composed of dark minerals. It is often found in dykes and may occasionally contain diamonds.
• Laterite – This is a type of residual soil commonly found in tropical countries from which silica has been leached out. It can form ore bodies of iron, nickel, bauxite, and manganese.
• Launder – In mining, a launder refers to a chute or trough used to transport pulp,  water, or powdered ore in a mill.
• Lava – The common term for molten rock expelled by volcanoes.
• Leachable – Minerals that can be extracted using chemical solvents are referred to as reachable.
• Leaching – This is a chemical procedure used to extract valuable minerals from ore. It’s also a natural process where groundwater dissolves minerals, thus altering the original mineral composition of the rock.
• Lens – This term is typically used to describe an ore body that is thickest in the middle and tapers towards the ends.
• Lenticular – Refers to a deposit shaped roughly like a double convex lens.
• Level – These are horizontal openings on a working horizon in a mine. Levels are usually established at regular intervals from a shaft, typically about 50 meters apart.
• Liberation – The process of extracting minerals from ore that involves crushing, grinding, and sieving.
• Life of mine – Refers to the planned duration and strategy for mining in a particular area.
• Lignite – A type of soft, low-rank, brownish-black coal.
• Limestone – A sedimentary deposit primarily composed of calcium carbonate.
• Limit order – An instruction given by a client to a broker to buy or sell shares at a specified price or better.
• Limonite – A hydrous iron oxide that is brown in color.
• Line cutting – The process of making straight clearings through the vegetation for geophysical and other surveys.
• Lithology – This term describes the physical characteristics of a rock or a rock type.
• Load haul dump (LHD) – These are vehicles typically used in underground mining operations for loading and transporting ores and minerals. They can be operated both manually or automatically.
• Lode – This refers to a deposit of valuable minerals that is contained within solid rock.
• Logging – The act of recording geological observations of drill core, either on paper or on a computer disk.
• London fix – A twice-daily session where five dealing companies set the gold price. Similar sessions are held for other precious metals.
• London Metals Exchange (LME) – A significant bidding market for base metals that operates daily in London.
• Long position – Refers to securities that are owned outright or held on margin.
• Long ton – A unit of weight equal to 2,240 lbs. avoirdupois, compared to a short ton, which is 2,000 lbs.
• Longwall mining – A specific method of underground coal mining where a long wall of coal is mined in a single slice.
• Loose – A term used to describe blasted material that has not yet been removed from its original location.
• Low-grade ore – Ore which runs a relatively small amount of the desired mineral.

M

• Magnetic survey – A geophysical survey using a magnetometer aboard, or towed behind, an aircraft.
• Magnetometer – An instrument used to measure magnetic field strength from an airplane.
• Metallurgy – The science and technology of extracting metals from their ores and modifying the metals for use.
• Mine – An excavation in the earth for extracting  coal or other minerals.
• Mine recovery – The percentage of valuable metal in the ore that is actually recovered in processing.
• Mine value chain – The series of steps and processes from the identification of a potential mineral deposit to the extraction and processing of the ore to the final product.
• Mineral – A naturally occurring, homogeneous inorganic solid substance having a definite chemical composition and characteristic crystalline structure, color, and hardness.
• Mineralization – Any process or activity that results in the formation of minerals in a geological body.
• Mining – The process of digging rocks out of the earth.
• Milling – The process of grinding ore in a rotating cylinder using large pieces of the ore instead of conventional  steel balls or rods.
• Muck – The loose material or debris removed by excavating or dredging operations.
• Muck sample – A sample of loose material or debris that is representative of a mineral deposit.

N

• Nanotesla – The international unit for measuring magnetic flux density.
• Native metal – A metal occurring in nature in pure form, uncombined with other elements.
• 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 (NSR) – 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.
• Norite – A coarse-grained igneous rock that is host to copper and 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 less than a board lot, often not qualifying for the same commissions or rates as larger lots.
• Open order – An instruction to a broker to buy or sell stock that remains in effect until the client cancels it.
• Open pit – A surface mining technique where the mine is entirely on the surface, also known as open-cut or open-cast mining.
• Opencast mining – A method of mining where minerals or rocks are extracted from a pit or quarry that is open to the surface.
• Option (on property) – A contractual agreement where a potential buyer obtains the right to buy a property under specific conditions.
• Option (on stock) – A financial derivative representing a contract sold by one party to another, offering the right, but not the obligation, to buy or sell a stock at an agreed-upon price within a certain period.
• Organic maturation – The geological process that converts peat to coal through heat and pressure over geological timescales.
• Ore – Material from which minerals can be extracted for economic use; naturally occurring material from which valuable minerals or metals can be profitably extracted.
• Ore pass – A vertical or inclined chute used to move ore from a higher level down to a lower level of the mine, or to a processing plant or waste area.
• Ore Reserves – The part of an orebody that has been fully evaluated and is deemed economically viable to extract.
• Orebody – A concentration of mineralization in the Earth’s crust that can be mined for a profit.
• Oreshoot – The section of a vein or zone carrying values of ore minerals rich enough to be mined profitably.
• Orogeny – A phase of mountain building characterized by intense deformation of the crust by folding and faulting.
• Outbye – The direction in a mine away from the  coal face, towards the exit or shaft.
• Outcrop – A visible occurrence of a coal seam or mineral deposit that is exposed on the Earth’s surface; a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth.
• Overturned – A geological condition where older layers of sedimentary rock are positioned above younger layers due to intense folding or faulting.
• Oxidation – The chemical reaction of a substance with oxygen, often resulting in a change in the mineral’s composition, such as the rusting of iron.
• Oxide ores – Deposits of metallic minerals that the weathering process has altered to contain oxides of the original metals.

P

• Pan – A shallow metal dish used for washing earth and stones to separate the gold.
• Panel – A coal mining block that generally comprises one operating unit.
• Panning – Separating gold from other materials using a pan and  water.
• Par value – The face value of a bond or the stock value stated in the corporate charter.
• Parting – A small joint in coal or rock; also, a layer of rock in a coal seam.
• Payable – A term used to indicate ores or minerals that are valuable enough to be mined profitably.
• Pellet – A marble-sized ball of iron ore fused with clay for transportation and use in steelmaking.
• Pillar – A block of solid ore or other rock left in place to structurally support the shaft, walls or roof of a mine.
• Pinch – A compression of the walls of a vein or the roof and floor of a coal seam so as to “squeeze” it out of existence.
• Pitchblende – An important uranium ore mineral.
• 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.
• Plate tectonics – A geological theory that states that the Earth’s lithosphere is comprised of plates that move on the fluid-like asthenosphere below them.
• Play – A petroleum prospecting term for a region where hydrocarbons are considered present.
• Plunge – The vertical angle the vein makes with the horizontal plane.
• Pollution controls – The equipment and/or strategies used to prevent or control the emission of pollutants into the environment.
• Porphyry – Any igneous rock in which relatively large crystals, known as phenocrysts, are set in a fine-grained groundmass.
• Portal – The surface entrance to a tunnel or adit.
• Portfolio – A list of financial assets.
• Precipitate – A solid substance that comes out of solution or suspension due to a chemical or physical change.
• Preparedness – The state of being ready and able to deal with potential mine emergencies.
• Primary deposits – Valuable minerals deposited during the original period or periods of mineralization, as opposed to those deposited due to alteration or weathering.
• Probable reserves – Reserves for which quantity and grade and/or quality are computed from information similar to that used for proven reserves, but the sites for inspection, sampling, and measurement are farther apart or are otherwise less adequately spaced.
• Production – The act or process of producing mineral products from the concentrated material.
• Profit – The positive financial gain after all expenses and taxes have been deducted from revenue.
• Prospect – A mining property, the value of which has not been determined by exploration.
• Prospecting – The search for mineral deposits suitable for mining.
• Proven reserves – Reserves for which (a) quantity is computed from dimensions revealed in outcrops, trenches, workings, or drill holes; grade and/or quality are computed from the results of detailed sampling and (b) the sites for inspection, sampling, and measurement are spaced so closely, and the geologic character is so well defined that size, shape, depth and mineral content of reserves are well-established.
• Pulverize – To reduce to small pieces or particles by pounding or abrading.
• Pump – A device for moving fluid by suction pressure or both.

Q

• Quarrying – The process of extracting stone, building materials, or other resources from a quarry, an open-pit mine typically used for mining stone or other materials used in construction.
• Quartz – A mineral composed of silicon dioxide (SiO2), a principal component of igneous rocks and sedimentary rocks like sandstone and shale, and is also the principal mineral in  sand.
• Quartzite – A metamorphic rock formed from quartz sandstone.
• Quicksilver – A historical term used for the element mercury, which was widely used to extract gold and silver from their ores.

R

• Recovery – In mining, recovery refers to the proportion of valuable material obtained in the processing of an ore, reflected as a percentage of the total material originally present.
• Reef – In gold mining, a reef is a vein or zone of gold-bearing ore.
• Refractory ore – Ore that resists the extraction of its valuable minerals, often requiring more complex processing techniques.
• Regulator – This device is used to control the airflow in a mine.
• Rehabilitation – The process of repairing the damage done by mining, restoring the site to its original state or another agreed-upon condition.
• Rehandle – In mining, rehandle refers to the process of moving ore or waste materials that have been previously excavated, often to a different location for further processing or disposal.
• Reserve – An economically mineable part of a mineral resource, which includes diluting materials and allowances for losses that may occur when the material is mined.
• Resource – The concentration of minerals in the earth that has reasonable prospects for eventual economic extraction.
• Retreat mining – A method of mining in which the mine retreats back towards the entrance as the ore is extracted, often used in  coal or salt mining.
• Rib pillar – Pillars of coal or ore left to support the mine roof in a room-and-pillar mine.
• Rich ore – Ore that contains a higher than average amount of the desired material to be mined.
• Rill mining – A stoping method used in steeply dipping ore bodies where the broken ore is washed down a chute by water.
• Ring drilling – A drilling pattern where a number of drill holes are drilled in a ring, often used for blasting.
• Ripper – A piece of heavy machinery used to break up or loosen the rock in underground mining.
• Rise – A vertical or steeply inclined opening that connects different levels in a mine.
• Roof bolting – The process of installing bolts into the roof of an underground mine to prevent roof collapse.
• Room-and-pillar mining – A method of mining where rooms of ore are dug out while pillars of untouched material are left to support the roof.
• Rotary drill – A drilling machine that uses a rotating motion to cut into the rock, typically used for drilling large-diameter blast holes in open-pit mines.
• Rougher cell – In the flotation process, a rougher cell is used for the initial concentration of minerals.
• Round – In blasting, a round refers to a series of holes loaded with explosives that are detonated simultaneously.
• Run-of-mine (ROM) – Ore in its natural, unprocessed state, just as it is when blasted and dumped out of the mine.

S

• Salting – The act of introducing metals or minerals into a deposit or samples, resulting in false assays done either in the field or lab.
• Sample – A small portion of rock or a mineral deposit taken so that the metal content can be determined by assaying.
• Sampling – Selecting a fractional but representative part of a mineral deposit for analysis.
• Sandfill – Waste  sand used to fill a void created by mining.
• Saprolite – A weathered or decomposed clay-rich rock.
• Scheelite – A calcium tungstate mineral; an important ore of tungsten.
• Schist – A foliated metamorphic rock composed chiefly of silicate minerals.
• Scintillometer – An instrument used to measure the radioactivity of a rock.
• Scoping study – A preliminary study of the economic potential of a mineral project that includes a broad range of parameters.
• Scrubber – An apparatus that cleans the gases passing through the smokestack of a coal-burning furnace.
• Secondary enrichment – Enrichment of a vein or mineral deposit by the later addition of valuable metals from an external source.
• Sedimentary rocks – Secondary rocks formed from material derived from other rocks and laid down under water.
• Sedimentation – The process of settling or being deposited as sediment.
• 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 using a much more expensive stopping system and high exploration and development costs in searching for and developing separate bunches, stringers, lenses, and bands of ore.
• Self-potential – This is a geophysical technique; the natural potential of the ground is measured.
• Semi-autogenous grinding (SAG) – A method of grinding rock into fine powder whereby the grinding media consists of larger chunks of rocks and  steel balls.
• Shaft – A vertical or inclined excavation in rock to provide access to an orebody.
• Shaft sinking – The activity of establishing a vertical or inclined passageway to an orebody.
• Shrinkage stoping – A stoping method used in steeply dipping, narrow orebodies where the wall rock is of such a nature that it will stand without caving.
• 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.
• Slag – The vitreous mass separated from the fused metals in the smelting process.
• Slimes – The finest of the crushed ore and gangue from mills.
• Sluice box – An elongated wooden or metal trough with riffles over which alluvial gravel is washed to recover gold.
• Smelter – A plant where ore is melted, and a metal or metals are separated from it.
• Sodium cyanide – A chemical used in the milling of gold ores to dissolve gold and silver.
• 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.
• Spelter – The zinc of commerce, more or less impure, cast from molten metal into slabs or ingots.
• Sphalerite – A zinc sulfide mineral, the most common ore mineral of zinc.
• Spile – A small peg or plug used in stopping a hole.
• Spot price – Current delivery price of a commodity traded in the spot market.
• Stake – To establish a claim to a mineral deposit by marking out its boundaries.
• Stope – An excavation in a mine from which ore is, or has been, extracted.
• Strata – A series of beds of rock.
• Stratigraphy – The study of the formation, sequence, and structure of layered sedimentary rocks.
• Strip mining – A method for extracting minerals by mining a series of parallel trenches to extract the minerals, used when the mineral is distributed widely and evenly throughout a rock formation.
• Stripping ratio – The ratio of tonnes removed as waste relative to the number of tonnes of ore removed from an open-pit mine.
• Stull – A timber or other support for crosswise support in stope or other working place.
• Subbituminous – A black  coal intermediate between lignite and bituminous.
• Sulphide – A compound of sulfur and some other element.
• Sump – An excavation where water accumulates before being pumped out.
• Swing – In geology, the compass direction of a geological structure, such as a vein or a fault.

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.
• Tailgate – A subsidiary gate road to a conveyor face, commonly acting 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, allowing time for heavy metals to settle out or for cyanide to be destroyed before  water is discharged.
• 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.
• Talc – A mineral composed of hydrated magnesium silicate, often used in powders and as a moisture absorber.
• Talus – A heap of broken, coarse rock found at the base of a cliff or mountain.
• Tectonic forces – Forces related to the 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 or the state of being under strain.
• Tertiary – Lateral or panel openings in a mine, such as ramps or crosscuts.
• Thermal coal – Coal used primarily to generate heat as opposed to metallurgical coal which is converted to coke for steel production.
• 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 using a hollow drill steel with a vacuum applied at the base.
• 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.
• Tipple – 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 – A 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.
• Top – The roof of a mine.
• Torque wrench – A wrench that indicates the amount of torque exerted in tightening a roof bolt.
• Tractor – A battery-operated piece of equipment that pulls trailers, skids, or personnel carriers in a mine.
• 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 floor traders meet to buy or sell stocks.
• Tram – To haul cars of ore or waste in a mine or to refer to the motor in a cutting machine that supplies the power for moving the machine.
• Transfer – A vertical or inclined connection between two or more levels used as an ore pass.
• Transfer point – Location in the materials handling system where bulk material is transferred between conveyances.
• Transformation – The process of refining and smelting metal to achieve a purer state.
• 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.
• Trip – A train of mine cars.
• Troughing idlers – The idlers that support the loaded belt in a belt conveyor, forming a trough in the direction of travel.
• Tube mill – An apparatus consisting of a revolving cylinder about half-filled with  steel rods or balls for fine grinding of crushed ore.
• Tuff – Rock composed of fine volcanic ash.
• Tunnel – A horizontal, or near-horizontal, underground passage that is open to the surface at both ends.
• Tunnel boring machine – A machine used as an alternative to drilling and blasting, capable of excavating tunnels with a circular cross section through various types of rock and soil.

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, where coal is removed mechanically and transferred to the surface.
• Underground station — An enlargement of an entry, drift, or level at a shaft where cages stop to receive and discharge cars, personnel, and material, and where stationary electrical equipment is installed.
• 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 designed to make horizontal cuts in a coal face at any point between the bottom and top or to make shearing 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, often found in black pitch-like masses.
• Uranium – A radioactive, silvery-white, metallic element used as a fuel in nuclear reactors and in the manufacture of atomic bombs.

V

• Valuation – The act or process of determining the value or worth of something, often used in the context of appraising mineral properties.
• Vein – A fissure, fault, or crack in a rock filled by minerals that have traveled upwards from some deep source.
• Velocity – The rate of airflow measured in lineal feet per minute, important for underground mine ventilation.
• Vendor – A seller, in mining, often refers to a company that receives treasury shares as payment for property.
• Ventilation – The process of supplying fresh air to underground mines and removing stale or noxious gases.
• Violation – The act of breaking any state or federal mining law.
• Virgin – Descriptive of land or mineral deposits that have not been explored or worked upon.
• Visible gold – Gold that is easily seen in a rock specimen without magnification.
• Void – A general term for any empty space within rock, including pores, vesicles, or cavities.
• Volatile matter – Gaseous components released from coal when it is heated, consisting mostly of hydrocarbons.
• Volcanic rocks – Rocks formed from the solidification of magma that has either flowed or been ejected from a volcano.
• Volcanogenic – Pertaining to mineral deposits that have been formed by volcanic processes.
• Voting right – The entitlement of shareholders to vote on company matters, typically one vote per common share.
• Vug – A small cavity in rock, often lined with well-formed crystals, such as amethyst.

W

• Wall rocks – Rock units on either side of an orebody, specifically the hanging wall and footwall rocks.
• Warrant – An entitlement issued by a company that gives the holder the right to buy shares at a specific price before a certain date.
• Waste – Rock that is not mineable at a profit or has no value, which must be removed to access the ore.
•  Water Gauge (standard U-tube) — An instrument that measures differential pressures in inches of  water.
• Wedge – A technique for directing a diamond drill hole in a desired direction or a piece of wood used for tightening in timbering.
• Weight — The fracturing and lowering of the roof strata at the face due to mining operations.
• White damp — Carbon monoxide, a potentially fatal gas that may be present after an explosion or fire in a mine.
• Width — The thickness of a lode or vein measured at right angles to the dip.
• Windrows – Rows of material placed on the ground in mining operations to manage and segregate different types of extracted material.
• Winning — The process of excavating, loading, and removing coal or ore from the ground.
• Winze — A secondary or tertiary vertical or near-vertical opening sunk from inside a mine to connect with a lower level or to explore below a level.
• Wire rope — A steel wire rope used for winding in shafts and for haulages, designated by the number of strands and wires in each strand.
• Witness post – A claim post placed on a claim line in difficult terrain or near water where it cannot be placed at the corner of a claim.
• Working — The noise emitted by a coal seam under pressure, indicating the need for additional support.
• Working capital – The liquid resources a company has available for day-to-day operations, calculated as current assets minus current liabilities.
• Working face – The location in a mine where ore and waste are being extracted from the rock.
• Working place — The area in a mine from the last open crosscut to the face where mining is occurring.
• Working section — The part of a mine from the mining face to where the coal is loaded for transport to the surface.
• Workings — The complete system of mine openings for exploitation.
• Writeoffs – Amounts deducted from a company’s profit for depreciation or preproduction costs, reducing taxable profit but not representing an out-of-pocket expense.

X

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

Y

• Yield – The annual amount of dividend that a stock pays out, shown as a percentage of the stock’s present market price.

Z

• Zone – A specific area characterized by a particular set of minerals or geologic features.
• Zone of oxidation – The surface section of an ore deposit where chemical weathering has altered the original minerals.