Mining Glossary

Term Definition
Anomaly An observed or measured deviation from normal geologic conditions, generally used to describe features that may suggest an ore deposit. Geochemical anomalies such as high arsenic content, or geophysical anomalies such as high magnetism, may signal the presence of mineralization.
Assay A chemical test performed on a sample of ores or minerals to determine the amount of valuable metals contained.
Base Metal A general term applied to relatively inexpensive metals, such as copper, zinc, lead.
Brownfields Areas where mineral deposits were previously discovered, near-mine project.
By-product Material of some economic value produced in a process which is focused on extracting another material.
Carbonate A salt of carbonic acid characterized by the presence of the carbonate ion, CO2−3.
Chalcocite An important copper ore mineral, copper sulfide (Cu2S). It is opaque and dark-gray to black with a metallic luster. It has a hardness of 2½ - 3 on the Mohs scale. It is a sulfide with an orthorhombic crystal system.
Chalcopyrite A copper iron sulfide mineral that crystallizes in the tetragonal system.
Concentrate Material produced from metalliferous ore by mineral processing or beneficiation; commonly based on sulphides of zinc, lead and copper. The raw ore is usually ground finely in various comminution operations and gangue (waste) is removed, thus concentrating the metal component. The concentrate is then transported to various physical or chemical processes called hydrometallurgy, pyrometallurgy smelters, and electrometallurgy where it is used to produce useful metals.
Copper cathode The negatively charged electrode in an eletrolytic cell. In electrolytic refining of copper, anodes of impure blister copper and cathodes of pure copper are placed in an electrified solution of copper sulphate and sulphuric acid. Copper dissolves from the anode and is redeposited at the cathode, leaving behind impurities. The result is a rectangular plate of copper, usually 99.99% pure, referred to as a copper cathode or simply cathode.
Core A solid, cylindrical sample of rock extracted from beneath the Earth's surface by drilling.
Crusher A machine for crushing rock or other materials. Among the various types of crushers are the ball mill, gyratory crusher, Handsel mill, hammer mill, jaw crusher, rod mill, rolls, stamp mill, and tube mill.
Cut-off grade Lowest grade or assay value of ore in a deposit that will recover mining costs; the cut-off grade determines the workable tonnage of an ore.
Deposit A mineral deposit is a mineralized mass that may be economically valuable, but whose characteristics require more detailed information. An ore body being mined may be called a deposit.
Diamond drilling A drilling method used to collect a small diameter core samples of rock from the orebody, geologists can analyse the core by chemical assay and conduct petrologic, structural and mineralogical studies of the rock.
Dilution The contamination of ore with waste rock.
Dip The angle at which a planar feature is inclined to the horizontal plane; it is measured in a vertical plane perpendicular to the strike of the feature.
Disseminated Ore deposits consisting of fine grains of ore mineral dispersed through the host rock.
Down-dip Located down the slope of a dipping plane or surface.
Down-hole electromagnetic (DHEM) An exploration method for conductive mineralisation, particularly in areas where the ability of surface EM to define a target is limited either by large depths or by interfering conductive bodies such as overburden, shallow sulphides and peripheral mineralised horizons. DHEM allowed explorers to widen the search radius of boreholes, when used in the search of massive sulphides.
Down-hole magnetometric resistivity (DHMMR) A pseudo-DC grounded dipole geophysical survey technique which allows absolute direction to a conductor from a borehole to be established. Anomalies produced by elongated block conductors are similar in shape and can be modelled in a similar way to gravity anomalies produced by block-shaped bodies having a density contrast. The anomalies are therefore simpler in shape than TEM anomalies and are easier to recognize in areas of geological complexity. The DHMMR technique is faster and more directional than down-hole TEM but has poorer resolution of conductor size and shape, and hence its ideal role is as a complement to down-hole TEM surveys.
Electromagnetic (EM) survey A geophysical survey method which measures the electromagnetic properties of rocks. The response vary according to the conductivity fo the ground. EM surveys can be used to help detect mineral deposits, especially base metal sulphides via detection of conductivity anomalies which can be generated around sulphide bodies in the subsurface. EM surveys can be carried out in the air, on the ground or within a drillhole.
Electrowinning The recovery of metals from solution by passing a current through the solution. Electrons from the current chemically reduce the mineral ions, to form a solid metal compound on the cathode. Also called electroextraction.
Environmental Impact Statement A document outlining the environmental effects of the project on the environment, prepared by the proponent of a project and presented to decision makers and the public.
Feasibility study An assessment of the economic viability of a potential mining project. The study must consider all aspects of the project, including mine and processing plant design, waste disposal, environmental management and permitting. A feasibility study will only be undertaken after an extensive series of desk studies, exploration and trial mining and processing projects have been completed.
FLTEM A Fixed Loop Transient Electromagnetic (FLTEM) geophysical survey.
Fold A geological fold occurs when one or a stack of originally flat and planar surfaces, such as sedimentary strata, are bent or curved as a result of permanent deformation.
Fresh rock The rock that shows no visible sign of weathering, rarely encountered in surface exposures.
Geophysics The study of the physical properties of rocks and minerals.
Gossan An intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Greenfields Uncharted territory, where mineral deposits are not already known to exist.
Heap leach The process to extract precious metals like gold, silver, copper and uranium from their ore by placing them on a pad (a base) in a heap and sprinkling a leaching solvent, such as cyanide or acids, over the heap.
High grade Rich ore. As a verb, it refers to selective mining of the best ore in a deposit.
Host rock The rock surrounding an ore deposit.
Indicated mineral resource A deposit in which tonnage, density; shape, physical characteristics, grade and mineral content can be estimated with a reasonable level of confidence. However, the continuity of the deposit is not verified.
Induced polarization (IP) A geophysical imaging technique used to identify the electrical chargeability of subsurface materials, such as ore. The method is similar to electrical resistivity tomography, in that an electric current is transmitted into the subsurface through two electrodes, and voltage is monitored through two other electrodes.
Inferred mineral resource A deposit which has been sampled (usually by drilling) to a point at which an estimate of its grade and tonnage is made at low confidence. Generally this is very approximate and subject to uncertainties.
JORC The Australasian Joint Ore Reserves Committee Code.
Lens A body of ore or rock or a deposit that is thick in the middle and thin at the edges, resembling a convex lens in cross-section.
Lode A deposit of metalliferous ore that fills or is embedded in a fissure in arock formation or a vein of ore that is deposited or embedded between layers of rock.
Measured mineral resource An economic deposit with a high level of geological confidence and confirmed geological continuity. The deposit has undergone enough sampling that a 'competent person' (which is defined by the JORC-code) has declared it to be an acceptable documented resource estimate.
Metallurgy The study of extracting metals from their ores.
Mineralization The process by which a mineral is introduced into a rock, resulting in a valuable or potentially valuable deposit.
Net Smelter Return (NSR) The net revenue that the owner of a mining property receives from the sale of the mine's metal/non-metal products less transportation insurance, refining and smelting costs.
Open pit mine A mine working or excavation open to the surface, also called open cut, open cast.
Optimum pit shell The pit shell contour, the shape of the pit which is the result of extracting the volume of material that provides the total maximum profit while satisfying the operational requirements of safe wall slopes.
Ore Rock from which metal or minerals can be extracted at a financial profit.
Ore shoot A long seam of mineral or metal bearing rock that can be profitable to extract.
Outcrop An exposure of rock or mineral deposit that can be seen on surface, that is, not covered by soil or water.
Oxide ores Oxide ores contain metals in oxidized forms. Unlike sulfide ores, oxides need much more energy to achieve melting. For this reason, the hydrometallurgical approach is generally used to refine these ores.
Plunge The vertical angle between the horizontal plane and the axis or line of maximum elongation of a feature.
Pre-collars A “pre-collar” hole is one that is started with reverse circulation drilling and then converted to core drilling when the reverse-circulation drill reaches its limit. Diamond ‘tails’ are drilled from the bottom of RC pre-collars to attain target depth, although some ‘shallower’ RC holes did achieve lode intersections.
Probable ore reserve The economically minable part of an indicated, and in some circumstances, a measured mineral resource.  The level of confidence is sufficient as a basis for decision on developing a deposit.
Proven ore reserve An economically minable part of a measured mineral resource and therefore holds the highest level of geological confidence. The deposit is also proved minable in terms of economic, mining, metallurgic, marketing, legal, social and governmental factors.
Reclamation The restoration of land and environmental values to a surface mine site after the mineral is extracted. The process includes restoring the land to its approximate original appearance by restoring topsoil and planting native grasses and ground covers.
Recovery The percentage of valuable metal in the ore that is recovered by metallurgical treatment.
Reserve Mineral deposits that are valuable and legally and economically and technically feasible to extract.
Resource Mineral deposits that are potentially valuable, and for which reasonable prospects exist for eventual economic extraction.
Reverse Circulation (RC) drilling A method of drilling which uses dual wall drill rods that consist of an outer drill rod with an inner tube. These hollow inner tubes allow the drill cuttings to be transported back to the surface in a continuous, steady flow. RC drilling is a fast and inexpensive method of drilling, particularly compared to diamond drilling.
SAG mill Semi-autogenous grinding (SAG). A method of grinding rock into fine powder whereby the grinding media consist of larger chunks of rocks and steel balls.
Sampling Selecting a fractional but representative part of a mineral deposit for analysis.
Sphalerite A mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides along with calcite, dolomite, and fluorite. Miners have also been known to refer to sphalerite as zinc blende, black-jack, and ruby jack.
Stoping The process of extracting the desired ore or other mineral from an underground mine, leaving behind an open space known as a stope. Stoping is used when the country rock is sufficiently strong not to collapse into the stope, although in most cases artificial support is also provided.
Strike The direction of the line that is formed by the intersection of the plane of the rock bed with a horizontal surface. Strike indicates the attitude or position of linear structural features such as faults, beds, joints, and folds.
Stringer A stringer lode is one in which the rock is so permeated by small veinlets that rather than mining the veins, the entire mass of ore and the enveined country rock is mined. It is so named because of the irregular branching of the veins into many anastomosing stringers, so that the ore is not separable from the country rock.
Sulfide A compound of sulfur and some other element.
Supergene Supergene processes or enrichment are those that occur relatively near the surface as opposed to deep hypogene processes. Supergene processes include the predominance of meteoric water circulation with concomitant oxidation and chemical weathering. The descending meteoric waters oxidize the primary (hypogene) sulfide ore minerals and redistribute the metallic ore elements. Supergene enrichment occurs at the base of the oxidized portion of an ore deposit. Metals that have been leached from the oxidized ore are carried downward by percolating groundwater, and react with hypogene sulfides at the supergene-hypogene boundary. The reaction produces secondary sulfides with metal contents higher than those of the primary ore. This is particularly noted in copper ore deposits where the copper sulfide minerals are deposited by the descending surface waters.
SX-EW Solvent extraction and electrowinning (SX/EW) is a two-stage hydrometallurgical process that first extracts and upgrades copper ions from low-grade leach solutions into a solvent containing a chemical that selectively reacts with and binds the copper in the solvent. The copper is extracted from the solvent with strong aqueous acid which then deposits pure copper onto cathodes using an electrolytic procedure (electrowinning).
Tailings Material rejected from a mill after the valuable minerals have been recovered.
Tenement A mineral claim provides an exclusive right to prospect for minerals within the claim area for 12 months, and to apply for a mining lease over all or a portion of the claim.
Transient electromagnetics A geophysical exploration technique in which electric and magnetic fields are induced by transient pulses of electric current and the subsequent decay response measured. Also known as time-domain electromagnetics / TDEM.  The methods are generally able to determine subsurface electrical properties, but are also sensitive to subsurface magnetic properties.
Transition rock A term formerly applied to the lowest uncrystalline stratified rocks (graywacke) supposed to contain no fossils, and so called because thought to have been formed when the earth was passing from an uninhabitable to a habitable state.
TSF Tailings storage facility (Tailing dam)
Underground workings The entire system of openings in an underground mine for the purpose of exploitation.
Volacaniclastic rocks All clastic sediments composed mainly of particles of volcanic origin, regardless of how the sediment formed.
Volcanic rocks Igneous rocks formed from magma that has flowed out or has been violently ejected from a volcano.
Volcanogenic Layered deposits formed when hot, sulphide laden fluids erupt through fractures in the sea floor. These are typically an important source of zinc, copper & lead.
Volcanogenic Massive Sulphide (VMS) Layered deposits containing varying amounts of pyrite, copper, lead and zinc sulfide minerals, along with baryte. Commonly, also gold and silver. VMS deposits form when hot fluids circulate through rocks of the seafloor, dissolving various metals, and then come into contact with cold seawater, causing the metals to precipitate as piles of tiny mineral grains. VMS ores are often located near “black smokers”, jets of superheated water shooting from the ocean floor. Some ancient VMS deposits are today found on continents or islands, having been lifted from the seafloor by tectonic action.
VTEM surveying Versatile Time Domain Electromagnetic is used to detect and discriminate between moderate to excellent conductors using a low base frequency and long pulse width.
Waste That rock or mineral which must be removed from a mine to keep the mining scheme practical, but which has no value.
Zone The section of a property or area with distinct mineralization.