Mining Glossary

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A horizontal passage from the surface into a mine. Sometimes called a tunnel.


A geological feature, especially in the subsurface, distinguished by geological, geophysical, or geochemical means, which is different from the general surroundings and is often of potential economic value, and usually suggests the possibility of a mineral deposit.


Pertaining to clay or clay minerals; e.g. "argillic alteration" in which certain minerals of a rock are converted to minerals of the clay group.


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.


The process of refilling an excavation, a mine opening, or the space around a foundation.

Base Metal

Any of the more common and more chemically active metals, e.g. lead, copper.

The principal metal of an alloy, e.g. the copper in brass.


A course-grained clastic rock, composed of angular broken rock fragments held together by a mineral cement or in a fine-grained matrix. The fragments have sharp edges and unworn corners.

Capital Assets

Assets, purchased as a long term investment for generating profit, such as buildings, plant and machinery and fixtures etc.


A mineral compound characterized by a fundamental anionic structure.

A sediment formed by the organic or inorganic precipitation from aqueous solution of carbonates of calcium, magnesium, or iron; e.g. limestone and dolomite

Cash Operating Cost

Includes site costs for all mining (excluding deferred stripping costs), processing and administration, but are exclusive of royalties, production taxes, depreciation, reclamation, financing costs, capital costs and exploration costs.

Channel Width

The total thickness of all reef bands, including internal waste mined as one unit.


A system of forces or stresses that tends to decrease the volume or to shorten a substance, or the change of volume produced by such a system of forces.


The valuable fraction of an ore that is left after worthless material is removed in processing.

Contained Gold

The total gold content of the orebody (tons multiplied by grade), irrespective of economic potential and without deduction for mining and processing losses prior to recovery.

Contained Ounces

Represents ounces in the ground without the reduction of ounces not recovered by the applicable metallurgical process.

Core Hole

Any hole drilled for the purpose of obtaining cores.

Cut & Fill

A stoping method in which the ore is excavated by successive flat or inclined slices, working upward from the level. However, after each slice is blasted down, all broken ore is removed, and the stope is filled with waste (backfill) up to within a few feet of the back before the next slice is taken out. This leaves just enough room left being between the top of the waste pile and the back of the stope to provide working space. The term cut-and-fill stoping implies a definite and characteristic sequence of operations: breaking a slice of ore from the back; removing the broken ore; and introducing filling.

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 estimate.


The preparation of a mining property or area so that an orebody can be analyzed and its tonnage and quality estimates have been made; ore essentially ready for mining.

Diamond Drilling

A variety of rotary drilling in which diamond bits are used as the rock-cutting tool. It is a common method of prospecting for mineral deposits, esp. in development work where core samples are desired.


An igneous rock formed by the solidification of molten material.

Fault Zone

A fault that is expressed as a zone of numerous small fractures or of breccia or fault gouge. A fault zone may be as wide as hundreds of meters.


Man-made deposits of natural earth materials (e.g. rock, soil, gravel) and waste materials (e.g. tailings or spoil from dredging), used to fill an enclosed space such as an old stope or chamber in a mine.


A process by which some mineral particles are induced to become attached to bubbles and float, and other particles to sink, so that the valuable minerals are concentrated and separated from the worthless gangue.

Gold Equivalent

Gold equivalent ounces include silver ounces produced and sold, converted to a gold equivalent based on a ratio of the average spot market price for the commodities for each year.


The amount of valuable mineral in each ton of ore, expressed as troy ounces per ton or grams per tonne for precious metals and as a percentage for other metals.

Gravity Circuit

A method by which mineral particles are separated with the aid of water or air, according to the differences in their specific gravities.


Size reduction of ore into fine particles to prepare it for processing; comminution.

Heap Leach Pad

A large impermeable foundation or pad used as a base for ore during heap leaching.


One hectare = 2.47 acres.

Host Rock

The rock surrounding an ore deposit.


Of or pertaining to hot water, to the action of hot water, or to the products of this action, such as a mineral deposit precipitated from a hot aqueous solution, with or without demonstrable association with igneous processes; also, said of the solution itself.


Said of a rock that does not permit the passage of fluids under the pressure conditions ordinarily found in the subsurface.

In Situ Deposit

Reserves still in the ground

Indicated Mineral Resource

An Indication Mineral Resource is that part of a Mineral Resource for which quantity, grade or quality, densities, shape and physical characteristics, can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough for geological and grade continuity to be reasonably assumed.

Inferred Mineral Resource

An Inferred Mineral Resource is that part of a Mineral Resource for which quantity and grade or quality can be estimated on the basis of geological evidence and limited sampling and reasonably assumed, but not verified, geological and grade continuity. The estimate is based on limited information and sampling gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes.

Infill Drilling

Diamond drilling at shorter intervals between existing holes, used to provide greater geological detail and to help establish reserve estimates.


That portion included between two points in a borehole, as between the point where the hole first encounters a specific rock or mineral body and where the hole enters a different or underlying rock formation.


One kilometer = 0.62 miles.


The separation, selective removal, or dissolving-out of soluble constituents from a rock or orebody by the natural action of percolating water, or the extraction of soluble metals or salts from an ore by means of slowly percolating solutions.

Life Of Mine

Number of years that the operation is planning to mine and treat ore, and is taken from the current mine plan.


A mineral deposit consisting of a zone of veins, veinlets, disseminations, or planar breccias; a mineral deposit in consolidated rock as opposed to a placer deposit.

Long-Hole Open Stope

A method of mining involving the drilling of holes up to 90 feet long into an orebody and then blasting a slice of rock which falls into an open space. The broken rock is extracted and the resulting open chamber is not filled with supporting material.

Measured Mineral Resource

A Measured Mineral Resource is that part of a Mineral Resource for which quantity, grade or quality, densities, shape, physical characteristics are so well established that they can be estimated with confidence sufficient to allow the appropriate application of technical and economic parameters, to support production planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough to confirm both geological and grade continuity.

Metallurgical Plant

A processing plant erected to treat ore and extract gold


The science and art of separating metals and metallic minerals from their ores by mechanical and chemical processes; the preparation of more metalliferous materials from raw ore.


One meter = 3.28 feet.


A plant where ore is ground fine and undergoes physical or chemical treatment to extract the valuable metals.

Mill Head Grade

The grade of ore as it comes from a mine and goes to a mill.

Milling Circuit

The combination of various processes and systems which concentrate the valuable minerals.


An excavation beneath the surface of the ground from which mineral matter of value is extracted.

Mineral Deposit

A mineralized body which has been delineated by appropriately spaced drilling and/or underground sampling to support a sufficient tonnage and average grade of metal. This material or deposit does not qualify as a reserve until a comprehensive evaluation, based on costs, grade, recoveries and other factors, demonstrates economic feasibility. Consequently, although the potential exists, there is no assurance that this mineral deposit will ever become an ore reserve.

Mineral Resource

A mineral resource is a concentration or occurrence of material of economic interest in or on the earth's crust in such form, quality and quantity that there are reasonable and realistic prospects for eventual economic extraction. The location, quantity, grade, continuity and other geological characteristics of a mineral resource are known, estimated from specific geological evidence and knowledge, or interpreted from a well-constrained and portrayed geological model. Mineral resources are subdivided, in order of increasing geological confidence, into inferred, indicated and measured categories. The mineral resources are inclusive of those resources which have been modified to produce ore reserves.


The process or processes by which mineral or minerals are introduced into a rock, resulting in a valuable or potentially valuable deposit.

Mineralized Material

Mineralized material is the projection of mineralization in rock based on geological evidence and assumed continuity. It may or may not be supported by sampling but is supported by geological, geochemical, geophysical or other data. This material may or may not have economically recoverable mineralization.

Mining Claim

That portion of public mineral lands which a party has staked or marked out in accordance with federal, provincial or state mining laws to acquire the right to explore for and exploit the minerals under the surface.

Net Smelter Return

A royalty based on a percentage of gold produced with settlement made either in kind or in currency based on the spot gold sale proceeds received less the cost of refining at an off-site refinery.


Rock, generally containing metallic or non-metallic minerals that can be mined and processed at a profit. Also, the mineral(s) thus extracted.

Ore Shoot

An elongated pipelike, ribbonlike, or chimneylike mass of ore within a deposit (usually a vein), representing the more valuable part of the deposit.

Ore Slurry

The fine carbonaceous discharge from a mine washery. All washeries produce some slurry, which must be treated to separate the solids from the water in order to have a clear effluent for reuse or discharge.


A sufficiently large amount of ore that can be mined economically.


Used in imperial statistics. A kilogram is equal to 32.1507 ounces. A troy ounce is equal to 31.1035 grams.


Barren rock material, either loose or consolidated overlying a mineral deposit, which must be removed prior to mining.

Oxide Ore

Mineralized rock in which some of the original minerals have been oxidized. Oxidation tends to make the ore more porous and permits a more complete permeation of cyanide solutions so that minute particles of gold in the interior of the minerals will be readily dissolved

Oxidized Zone

An area of mineral deposits modified by surface waters, e.g. sulfides altered to oxides and carbonates.


A process established under the U.S. General Mining Law of 1872 which permits the conversion of mining claims on federal lands into full fee ownership, provided certain conditions are met.


Pertaining to a rock or soil having a texture that permits passage of liquids or gases under the pressure ordinarily found in earth materials.

Probable Ore

Material for which tonnage and grade are computed partly from specific measurements, samples or production data and partly from projection for a reasonable distance on geological evidence; and for which the sites available for inspection, measurement and sampling are too widely or otherwise inappropriately spaced to outline the material completely or to establish its grade throughout.

Proven Ore

Material for which tonnage and grade are computed from dimensions revealed in outcrops, trenches, underground workings or drill holes; grade is computed from the results of adequate sampling; and the sites for inspection, sampling and measurement are so spaced and the geological character so well-defined that size, shape and mineral content are established.


A common, pale-bronze or brass-yellow, isometric mineral. It is dimorphous with marcasite, and often contains small amounts of other metals. Pyrite has a brilliant metallic luster and an absence of cleavage, and has been mistaken for gold. Pyrite is the most wide-spread and abundant of the sulfide minerals and occurs in all kinds of rocks, such as in nodules in sedimentary rocks and coal seams or as a common vein material associated with many different minerals.


Crystalline silica, an important rock-forming mineral. It is, next to feldspar, the commonest mineral, occurring either in transparent hexagonal crystals (colorless, or colored by impurities) or in crystalline or cryptocrystalline masses. Quartz is the commonest gangue mineral of ore deposits, forms the major proportion of most sands, and has a widespread distribution in igneous, metamorphic, and sedimentary rocks.

A general term for a variety of non-crystalline or cryptocrystalline minerals having the same chemical composition as that of quartz, such as chalcedony, agate, and opal.


A granoblastic metamorphic rock consisting mainly of quartz and formed by recrystallization of sandstone or chert by either regional or thermal metamorphism.

A very hard but un-metamorphosed sandstone, consisting chiefly of quartz grains that have been so completely and solidly cemented with secondary silica that the rock braks across or though the grains rather than around them. The cement grows in optical and crystallographic continuity around each quartz grain, thereby tightly interlocking the grains as the original pore spaces are filled.


The process by which lands disturbed as a result of mining activity are reclaimed back to a beneficial land use. Reclamation activity includes the removal of buildings, equipment, machinery and other physical remnants of mining, closure of tailings impoundments, leach pads and other mine features, and contouring, covering and re-vegetation of waste rock piles and other disturbed areas.

Recovered Grade

Actual metal content of ore determined after processing.


A term used in process metallurgy to indicate the proportion of valuable material obtained in the processing of an ore. It is generally stated as a percentage of valuable metal in the ore that is recovered compared to the total valuable metal present in the ore.

Recovery Rate

A term used in process metallurgy to indicate the proportion of valuable material obtained in the processing of an ore. It is generally stated as a percentage of the material recovered compared to the total material present.


The final stage of metal production in which impurities are removed from the molten metal.

Refractory Material

Gold mineralized material in which the gold is not amenable to recover by conventional cyanide methods without any pretreatment. The refractory nature can be either silica or sulphide encapsulation of the gold or the presence of naturally occurring carbons which reduce gold recovery. Material of this nature is difficult or expensive to recover its valuable constituents.


The process of reclaiming land disturbed by mining to allow an appropriate post-mining use and address among other issues, ground and surface water, topsoil, final slope gradient, waste handling and re-vegetation issues.


The quantity of mineral that is calculated to lie within given boundaries. It is described as total (or gross), workable, or probable working, depending on the application of certain arbitrary limits in respect of deposit thickness, depth, quality, geological conditions, and contemporary economic factors. Proved, probable, and possible reserves are other terms used in general mining practice.


That part of a mineral deposit which could be economically and legally extracted or produced at the time of the reserve determination. Reserves are customarily stated in terms of ore when dealing with metalliferous minerals. There are two categories of reserves: Proven Ore & Probable Ore.


A Mineral Resource is a concentration or occurrence of natural, solid, inorganic or fossilized organic material in or on the Earth's crust in such form and quantity and of such a grade or quality that it has reasonable prospects for economic extraction. The location, quantity, grade, geological characteristics and continuity of a Mineral Resource are known, estimated or interpreted from specific geological evidence and knowledge.


A group of extrusive, igneous rocks.

Rod & Tube Mills

These are types of circular grinding mills used to break the ore down into fine particles in preparation for dissolving out the gold by means of cyanide.


Solid fragmental material that originates from weathering of rocks and is transported or deposited by air, water, or ice, or that accumulates by other natural agents, such as chemical precipitation from solution or secretion by organisms, and that forms in layers on the Earth's surface at ordinary temperatures in a loose, unconsolidated form; e.g., sand, gravel, silt, mud, alluvium.

Sedimentary Rock

Rocks formed from material derived generally by erosion of other rocks and laid down by a chemical or mechanical process i.e., limestone, shale and sandstone


A vertical passageway to an underground mine for moving personnel, equipment, supplies and material including ore and waste rock.

Sheeted Veins

A group of closely spaced, distinct parallel fractures filled with mineral matter and separated by layers of barren rock.


A mixture of crushed and finely ground solids with water.


A metallurgical operation in which metal is separated from impurities by a process that includes fusion.


Broken ore heaped on surface or prepared areas underground, pending treatment or shipment.


A mineral deposit consisting of a three-dimensional network of planar to irregular veinlets spaced closely enough that the whole mass can be mined.


An area in an underground mine where ore is mined.


The process of mining the orebody on the plane of the reef.

Stoping Width

The sum of the channel width and external waste widths.


A bed or layer of rock; strata, more than one layer.

Strike Fault

A fault whose strike is parallel to the strike of the strata.

Strike Length

The longest horizontal dimension of an orebody or zone of mineralization.

Stripping Ratio

The ratio of the number of tonnes of waste material removed to the number of tonnes of ore removed, used in connection with open pit mining.

Sulphide Ore

A sub-group of refractory ore - mineralized rock in which much of the gold is encapsulated in sulphides and is not readily amenable to dissolution by cyanide solutions - associated with sulphide minerals (primarily pyrite) that have not been oxidized. Some sulphide ore may require autoclaving or roasting prior to cyanidation.


Formed contemporaneously with the deposition of the sediment.


The material that remains after all metals considered economic have been removed from ore during milling.

Tailings Dam

A natural or man-made area suitable for depositing the material that remains after the treatment of ore.

Thermal Regeneration

The process of heating activated carbon granules typically to 750 degrees Celsius to restore the properties of carbon for the next gold extraction cycle.


A vessel or apparatus for reducing the proportion of water in a pulp by means of sedimentation.

Thrusting Event

A period of structural compression in geological time with the generation of low-angle thrust faults.


Used in imperial statistics. Equal to 2,000 pounds. Referred to as a short ton.


Quantities where the ton or tonne is an appropriate unit of measure. Typically used to measure resources and reserves of gold-bearing material in situ or quantities of ore and waste material mined, transported or milled.


Used in metric statistics. Equal to 2,205 pounds.

Total Cash Cost

Total cash production costs calculated in accordance with the Gold Institute Standard includes direct mining expenses, mine development adjustments, refining and transportation costs, by-product credits, royalties and production taxes.

Total Production Cost

Total production costs comprise total cash production cost plus depreciation, depletion and reclamation provisions.

Troy Ounce

(Used in imperial statistics) Equal to 31,10348 grams.


Material that contains insufficient mineralization for consideration for future treatment and, as such, is discarded.

Zinc Precipitation

Zinc precipitation is the chemical reaction using zinc dust that converts gold solution to a solid form for smelting into unrefined gold bars.