Mining Related Terms
The following is a list of common mining terms. You may find these helpful when reading some of the
newspaper articles on this site when they are about the mines and mining.
Adit - A horizontal or nearly horizontal passage driven from the surface for the working or
de-watering of a mine. If driven through the hill or mountain to the surface on the opposite side, it would be a
Assay - To analyze the proportions of metals in an ore; to test an ore or mineral for
composition, purity, weight, or other properties of commercial interest.
Assayer - Person who analyzes ores and alloys, especially bullion, to determine the value and
properties of their precious metals.
Assay Office - A laboratory for examining ores, usually gold and silver ores, in order to
determine their economic value.
Assay Value - The quantity of an ore's valuable constituents, determined by multiplying its
assay grade or percentage of valuable constituents by its dimensions. The figure for precious metals is generally
given in troy ounces per ton of ore, or per assay ton.
Collar - In a mine shaft, the first wood frame of the shaft; sometimes used in reference to the
mouth or portal of the tunnel.
Cropping - Portions of a vein or other rock formation exposed at the surface.
Crosscut - In general, any drift driven across between any two openings for any mining
Drift - A horizontal opening in or near an ore-body and parallel to the course of the vein or
the long dimension of the ore-body.
Dump - A pile or heap of ore, coal, or waste at a mine.
Grubstake - In the Western United States, supplies or funds furnished to a mining prospector on
promise of a share in his discoveries. So called because the lender stakes or risks provisions so furnished.
Hanging Wall - The overlying side of an ore-body, fault, or mine working, especially the wall
rock above an inclined vein or fault.
Ledge - a projecting outcrop or vein, commonly of quartz, that is supposed to be mineralized;
also, any narrow zone of mineralized rock.
Level - A main underground roadway or passage driven along a level course to afford access to
stopes or workings and to provide ventilation and a haulage way for the removal of coal or ore. Levels are commonly
spaced at regular depth intervals and are either numbered from the surface or designated by their elevation below
the top of the shaft.
Lode - A mineral deposit consisting of a zone of veins, vein-lets, disseminations, or planar
breccias; a mineral deposit in consolidated rock as opposed to a placer deposit.
Milling - The grinding or crushing of ore. The term may include the operation of removing
valueless or harmful constituents and preparation for market.
Mining - The science, technique, and business of mineral discovery and exploitation. Strictly,
the word connotes underground work directed to severance and treatment of ore or associated rock. Practically, it
includes opencast work, quarrying, alluvial dredging, and combined operations, including surface and underground
attack and ore treatment.
Mining Camp - Colony of miners settled temporarily near a mine or a goldfield
Mining Claim - That portion of the public mineral lands that a miner, for mining purposes,
takes hold of and possesses in accordance with mining laws.
Mining District - A section of country usually designated by name, having described or
understood boundaries within which minerals are found and worked under rules and regulations prescribed by the
miners therein. There is no limit to its territorial extent and its boundaries may be changed if vested rights are
not thereby interfered with.
Mining Engineer - A person qualified by education, training, and experience in mining
Mining Lease - A legal contract for the right to work a mine and extract the mineral or other
valuable deposits from it under prescribed conditions of time, price, rental, or royalties.
Ore - The naturally occurring material from which a mineral or minerals of economic value can
be extracted profitably or to satisfy social or political objectives. The term is generally but not always used to
refer to metalliferous material, and is often modified by the names of the valuable constituent; e.g., iron ore.;
Outcrop - The part of a rock formation that appears at the surface of the ground.
Portal - The rock face at which tunnel driving is started.
Prospecting - The search for outcrops or surface exposure of mineral deposits.
Sampling - The gathering of specimens of ore or wall rock for appraisal of an ore-body. Since
the average of many samples may be used, representative sampling is crucial. The term is usually modified to
indicate the mode or locality; e.g., hand sampling, mine sampling, and channel sampling.
Shaft - A vertical or inclined excavation in rock for the purpose of providing access to an
ore-body. Usually equipped with a hoist at the top, which lowers and raises a conveyance for handling workers and
Shoot - A body of ore, usually of elongated form, extending downward or upward in a vein.
Sinking - The process by which a shaft is driven.
Stope - Any excavation in a mine, other than development workings, made for the purpose of
extracting ore. The outlines of the ore-body determine the outlines of the stope.
Stoping - The loosening and removal of ore in a mine either by working upward (overhead or
overhand) or downward (underhand).
Strike - Noun: The course or bearing of the outcrop of an inclined bed, vein, or fault plane on
a level surface; the direction of a horizontal line perpendicular to the direction of the dip. Verb: To find a vein
of ore. n. A valuable discovery.
Tunnel - A horizontal or nearly horizontal underground passage that is open at both ends. The
term is loosely applied in many cases to an adit. An adit, if continued through a hill, would be a tunnel. Any
level or drift in a mine open at one end, or which may serve for an adit. Often used as a synonym for adit; drift;
Vein - A mineral deposit, usually steeply inclined. Used to describe a body that is usually
smaller and has better defined walls than a lode.
Winze - A vertical opening driven downward connecting two levels in a mine. When one is
standing at the top of a completed connection the opening is referred to as a winze, while when standing at the
bottom, the opening is a raise, or rise.