Mining Terms and Glossary
This page was last updated on May 2, 2025.
Complete List of Common Terms Used In Describing Underground Mines and Mining
A complete list of all mining terms can be found in "A Dictionary of Mining, Mineral and Related Terms," published by the U. S. Bureau of Mines in 1968.
(Link to "A Dictionary of Mining, Mineral and Related Terms" at Archive.org; PDF; 1288 pages; 629MB)
A "shaft" is a downward mine opening, starting at the surface, with some being an incline shaft.
A "raise" is a mining shaft, or a "winze," that is opened from below.
A "winze" is a mine opening similar to shaft, except its upper end does not reach the surface.
An "adit" is a horizontal tunnel opened from the surface, or side of a hill or wall of a canyon, with enough slope to provide for the natural drainage of water.
A "drift" is a horizontal mine opening that follows the mineral vein.
A "crosscut" is similar to a drift, but is perpendicular to the drift.
Abbreviated List of Common Terms Used In Describing Underground Mines and Mining
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
Adit - An opening driven horizontally into the side of a mountain or hill for providing access to a mineral deposit.
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.
Assay - A chemical test performed on a sample of ores or minerals to determine the amount of valuable metals contained.
Bedding - The arrangement of sedimentary rocks in layers.
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.
Breast - A working face in a mine, usually restricted to a stope.
Bullion - Metal formed into bars or ingots.
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.
Chute - An opening, usually constructed of timber and equipped with a gate, through which ore is drawn from a stope into mine cars.
Clay - A fine-grained material composed of hydrous aluminum silicates.
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.
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. Further treatment is required to recover the pure metal.
Conglomerate - A sedimentary rock consisting of rounded, water-worn pebbles or boulders cemented into a solid mass.
Continuous miner - A piece of mining equipment which produces a continuous flow of ore from the working face.
Converter - In copper smelting, a furnace used to separate copper metal from matte.
Country rock - Loosely used to describe the general mass of rock adjacent to an orebody. Also known as the host rock.
Crosscut - A horizontal opening driven from a shaft and (or near) right angles to the strike of a vein or other orebody, crossing a rock formation and used to connect ore veins.
Decline - A sloping underground opening for machine access from level to level or from surface; also called a ramp.
Development - Underground work carried out for the purpose of opening up a mineral deposit. Includes shaft sinking, crosscutting, drifting and raising.
Dip - The angle at which a vein, structure or rock bed is inclined from the horizontal as measured at right angles to the strike.
Disseminated ore - Ore carrying small particles of valuable minerals spread more or less uniformly through the host rock.
Drift - A horizontal underground opening that follows along the length of a vein or rock formation as opposed to a crosscut.
Dump - A pile of broken rock or ore on surface.
Dyke - A long and relatively thin body of igneous rock that, while in the molten state, intruded a fissure in older rocks.
Face - The end of a drift, crosscut or stope in which work is taking place.
Fault - A break in the Earth's crust caused by tectonic forces which have moved the rock on one side with respect to the other.
Flotation - A milling process in which valuable mineral particles are induced to become attached to bubbles and float as others sink.
Fold - Any bending or wrinkling of rock strata.
Footwall - The rock on the underside of a vein or ore structure.
Galena - Lead sulphide, the most common ore mineral of lead.
Gangue - The worthless minerals in an ore deposit.
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.
Gouge - Fine, putty-like material composed of ground-up rock found along a fault.
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.
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.
Hangingwall - The rock on the upper side of a vein or ore deposit.
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.
High grade - Rich ore. As a verb, it refers to selective mining of the best ore in a deposit.
Hoist - The machine used for raising and lowering the cage or other conveyance in a shaft.
Host rock - The rock surrounding an ore deposit.
Incline - Any entry to a mine that is neither vertical (like a shaft) nor horizontal (like an adit). An incline is a sloping passage used for accessing and transporting ore, personnel, and equipment, and can slope either up, or down.
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.
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.
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 meters or more apart.
Lode - A mineral deposit in solid rock.
Long ton - 2,240 lbs. A British or Imperial ton, equaling 160 stones (compared with a short or U.S. ton, which is 2,000 lbs.). (A metric ton is 1000 kilograms, or 2,205 pounds)
Matte - A product of a smelter, containing metal and some sulfur, which must be refined further to obtain pure metal.
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.
Mineral - A naturally occurring homogeneous substance having definite physical properties and chemical composition and, if formed under favorable conditions, a definite crystal form.
Muck - Ore or rock that has been broken by blasting.
Native metal - A metal occurring in nature in pure form, uncombined with other elements.
Nugget - A small mass of precious metal, found free in nature.
Open pit - A mine that is entirely on surface. Also referred to as open-cut or open-cast mine.
Ore - A mixture of ore minerals and gangue from which at least one of the metals can be extracted at a profit.
Orebody - A natural concentration of valuable material that can be extracted and sold at a profit.
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.
Oreshoot - The portion, or length, of a vein or other structure that carries sufficient valuable minerals to be extracted profitably.
Outcrop - An exposure of rock or mineral deposit that can be seen on surface, that is, not covered by soil or water.
Oxidation - A chemical reaction caused by exposure to oxygen that results in a change in the chemical composition of a mineral.
Porphyry copper - A deposit of disseminated copper minerals in or around a large body of intrusive rock.
Portal - The surface entrance to a tunnel or adit.
Pyrite - A yellow iron sulphide mineral, normally of little value. It is sometimes referred to as "fool's gold".
Pyrrhotite - A bronze-colored, magnetic iron sulphide mineral.
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.
Raise - A vertical or inclined underground working that has been excavated from the bottom upward.
Reclamation - The restoration of a site after mining or exploration activity is completed.
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.
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.
Shoot - A concentration of mineral values; that part of a vein or zone carrying values of ore grade.
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.
Skarn - Name for the metamorphic rocks surrounding an igneous intrusive where it comes in contact with a limestone or dolostone formation.
Skip - A self-dumping bucket used in a shaft for hoisting ore or rock.
Station - An enlargement of a shaft made for the storage and handling of equipment and for driving drifts at that elevation.
Stope - An excavation in a mine from which ore is, or has been, extracted.
Stratigraphy - Strictly, the description of bedded rock sequences; used loosely, the sequence of bedded rocks in a particular area.
Strike - The direction, or bearing from true north, of a vein or rock formation measured
on a horizontal surface.
Strip - To remove the overburden or waste rock overlying an orebody in preparation for mining by open pit methods.
Stripping ratio - The ratio of tonnes removed as waste relative to the number of tonnes of ore removed from an open-pit mine.
Strip mine - An open-pit mine, usually a coal mine, operated by removing overburden, excavating the coal seam, then returning the overburden.
Sublevel - A level or working horizon in a mine between main working levels.
Sulphide - A compound of sulfur and some other element.
Sulfur 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 - An underground excavation where water accumulates before being pumped to surface.
Syncline - A down-arching fold in bedded rocks.
Tailings - Material rejected from a mill after most of the recoverable valuable minerals have been extracted.
Tram - To haul cars of ore or waste in a mine.
Tunnel - A horizontal underground opening, open to the atmosphere at both ends.
Vein - A fissure, fault or crack in a rock filled by minerals that have traveled upwards from some deep source.
Vug - a small or open space inside of a rock; the interior crystal space of a geode is a vug.
Wall rocks - Rock units on either side of an orebody. The hangingwall and footwall rocks of an orebody.
Winze - An internal shaft with opening only inside the mine.
Zone - An area of distinct mineralization.
Zone of oxidation - The upper portion of an orebody that has been oxidized.
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