Acid

An igneous rock containing greater than 63% SiO2.

Ag

The chemical symbol for silver.

Agglomeration

A method of concentrating valuable minerals based on their adhesion properties.

Al

The chemical symbol for aluminum.

Alkaline

Pertaining to igneous rocks containing feldspathoids and/or alkali amphiboles or pyroxenes.

Alteration

Changes in the chemical or mineralogical composition of a rock, generally produced by weathering or hydrothermal solutions.

Alunite

A mineral with the composition KAl2 (SO4)2 (OH)6, and an important alteration product in high-sulphidation epithermal systems.

Andesite

A fine-grained dark coloured volcanic rock.

Anomalous

Samples that differ significantly from all the others in a group of population.

Anomaly

A departure from the expected or normal; 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.

Argillic

Altered to clay. ‘Argillic alteration’ is the process  in which certain minerals are converted to minerals of the clay group.

Arsenopyrite

A tin-white or steel-grey orthothrombic mineral, FeAsS that occurs in crystalline rocks and especially in lead and silver veins. It is the principle of arsenic.

As

The chemical symbol for arsenic:

Assay

To analyze the proportion of metals in an ore or mineral for composition, purity, weight, or other properties of commercial interest. The analysis of minerals, rocks and mine products to determine and quantify their constituent parts.

Au

The chemical symbol for gold.

Auriferous

Containing gold.

Ba

The chemical symbol for barium.

Background

In geochemical prospecting, the range in values representing the normal concentration of a given element in a material under investigation such as a rock, soil, plants and water.

Ball Mill

A large steel cylinder containing steel balls into which crushed ore is fed. The ball mill is rotated, causing the balls to cascade and grind the ore.

Banded iron formation

Banded ore

Batholith

Bauxite

Bedding

Bench

Horizontal steps/increments mined as an open pit progresses deeper.

Bi

The chemical symbol for bismuth.

BLEG

Bulk Leach Extractable Gold - a method of sampling which improves the reliability of sampling for finer gold fractions.

A large-production low-cost method of mining, in which the greater part of the bottom area of a block of ore is undercut, the supporting pillars are blasted away, and the ore caves are removed. As the block caves and settles, the cover follows.

Bonanza grade

A miner’s term for a high-grade orebody or a rich part of a deposit. A mine is said to be in ‘bonanza’ when it is operating profitably. (Spanish for ‘prosperity, success’)

Bornite

A common mineral and important ore of copper, copper iron sulfide, Cu5FeS4, of reddish-brown color that tarnishes to an irridiscent blue or dark purplish color when it is fractured and exposed to the air; “peacock ore”; an ore of copper.

Breccia

A coarse-grained clastic rock composed of broken, angular fragments held together by a natural mineral cement or enclosed in a fine-grained matrix.

Bulk samples

A large volume sample commonly taken for metallurgical testing or trial mining purposes.

Bull market

Term used to describe financial market conditions when share prices are going up.

By-product

A secondary metal or mineral product recovered in the milling process such as copper and silver.

C

The chemical symbol for carbon.

Ca

The chemical symbol for calcium.

Cadastral survey

Caldera

Carboniferous

The Mississippian and Pennsylvanian periods combined, ranging in geologic time from about 345 to about 280 million years ago, and the corresponding system of rocks.

Carbon-in-leach

A recovery process in which a slurry of gold ore, carbon granules and cyanide are mixed together. The cyanide dissolves the gold content and the gold is absorbed on the carbon; the carbon is subsequently separated from the slurry for further gold removal. 

Carbon-in-pulp

A method of recovering gold and silver from pregnant cyanide solutions by adsorbing the precious metals to granules of activated carbon, which are typically ground up coconut shells.

Carbonate

A mineral compound characterized by a fundamental anionic structure of CO3-2; a sediment formed of the carbonates of calcium, magnesium and/or iron; e.g. limestone and dolomite. A mineral containing the carbonate radical.

Carbonation

A process of chemical weathering involving the transformation of minerals containing calcium, magnesium, potassium, sodium, and iron into carbonates or bicarbonates of these metals by carbon dioxide contained in water. Introduction of carbon dioxide into fluid.

Carboniferous

The Mississippian and Pennsylvanian periods combined, ranging in geologic time from about 345 to about 280 million years ago; also the corresponding system of rocks.

Cartography

The science and art of constructing maps and charts, from surveying of the ground to the final printing of the map.

Heavy metal pipe, lowered into a bore hole during or after drilling and cemented into place to prevent the sides of the hole from caving, prevent loss of drilling mud or other fluids into porous formations, and prevent unwanted fluids from entering into the hole.

Cd

The chemical symbol for cadmium.

Cenozoic

The latest of the four eras into which geologic time is divided; it extends from the close of the Mezosoic Era, about 65 million years ago to present. The Cenozoic is subdivided into Tertiary and Quarternary periods, or on a different basis into Paleogene and Neogene periods.

Chalcopyrite

A bright brass-yellow tetragonal copper-iron sulphide mineral (CuFeS2). It is generally found massive and constitutes the most important ore of copper.

Channel sample

A rock sample usually selected across the face of a rock body or vein to provide an average value.

Chalcedony

The group name for cryptocrystalline varieties of silica composed of minute crystals of quartz with submicroscopic pores.

Chimney

A cylindrical, more or less vertical ore body; a chimney-shaped column of rock rising above the face of a steep slope; or a conduit through which magma reaches the earth’s surface.

Chip sample

Chlorite

A representative of a group of greenish silicate clay minerals.

Circulation

Clast

Clastic

Pertaining to a sediment or rock composed chiefly of fragments derived from pre-existing rocks or minerals.

Cl

The chemical symbol for clorine.

Co

The chemical symbol for cobalt.

Colluvium

A general term applied to loose and incoherent deposits, usually at the foot of a slope or cliff and brought there chiefly by gravity. Talus and cliff debris are included in such deposits.

Concentrate

A very fine, powder-like product containing the valuable ore mineral from which most of the waste mineral has been eliminated.

Contact

The surface between two types or ages of rock.

Contact deposit

 A mineral deposit that occurs at the contact of two unlike rock types, esp. at the contact between a sedimentary and an igneous rock.

Contact metamorphism

Reconstitution of rocks that takes place at or near their contact with a body of igneous rocks and is genetically related to its intrusion.

Contact metasomatism

A mass change in the composition of rocks in contact with an invading magma. ‘Fluid’ constituents from the magma are carried out to combine with some of the courtry-rock constituents to form a new suite of minerals.

Contact mineral

A mineral formed by contact metamorphism.

Continental crust

The crustal rocks that underlie the continenetsand range in thickness from about 35 km to as much as 60 km under mountain ranges. 

Conventional rotary drilling

Produces rock chips similar to reverse circulation except that the sample is collected through a single-walled drill pipe.

Core Drilling

The process of obtaining cylindrical rock samples by means of annular-shaped rock-cutting bits rotated by a borehole-drilling machine.

Core sample

A cylinder sample generally 1-5" in diameter drilled out of an area to determine the geologic and chemical analysis of the overburden and mineral present.

Country rock

The rock enclosing or traversed by a mineral deposit; e.g. a vein system or by an igneous intrusion.

Covellite

An indigo-blue hexagonal mineral. (CuS) It is a common secondary mineral and represents an ore of copper.

Craton

An old and stable part of the continental crust that has survived the merging and splitting of continents and supercontinents for at least 500 million years in geologic time. Cratons are generally found in the interiors of continents and are characteristically composed of ancient crystalline basement crust of lightweight felsic igneous rock such as granite. They have a thick crust and deep roots that extend into the mantle beneath to depths of 200 km. The extensive central cratons of continents may consist of both shields and platforms, and the crystalline basement. A shield is that part of a craton in which the usually Precambrian basement rocks crop out extensively at the surface. In contrast, the platform of the basement is overlain by horizontal or subhorizontal sediments.

Cretaceous

The final period of the Mezosoic era (after the Jurassic and before the Tertiary) thought to have covered the period of geologic time between 135 to 65 million years ago, and the corresponding system of rocks.

Crosscut

A small passageway driven between the entry and its parallel air course or air courses for ventilation purposes. Also, a tunnel driven from one seam to another through or across the intervening measures; sometimes called "crosscut tunnel", or "breakthrough". In vein mining, an entry perpendicular to the vein that intersects the vein or the ore bearing structure at an angle.

A fault that strikes diagonally or perpendicularly to the strike of the associated strata or to the general structural trend.

Crushing and grinding

The process by which ore is broken into small pieces to prepare it for further processing.

Crust

The outermost layer of the earth which represents less than 0.1% of the earth’s total volume.

Crustified

Said of a vein in which the mineral filling is deposited in layers on the wall rock.

Cryogenic

An informal designation for a period in geologic history when large bodies of ice formed at or near the poles and the climate was generally suitable for the growth of continental glaciers.

Cu

The chemical symbol for copper.

Cut-and-fill

A method of stoping in which ore is removed in slices, or lifts, and then the excavation is filled with rock or other waste material (backfill), before the subsequent slice is extracted.

Cut-off grade

The lowest grade of mineralized material that qualifies as ore in a given deposit; ie. material of the lowest assay value that is included in an ore estimate.

Cyanidation

A method of extracting gold or silver by dissolving it in a weak cyanide solution.

Dacite

A fine grained volcanic rock, the extrusive equivalent of granodiorite.

Deformation

A general term for the process of folding, faulting, shearing, compression, or extension of rocks as a result of various earth forces.

Deglaciation

The uncovering of an area from beneath glacier ice as a result of melting.

Deposit

A naturally occurring accumulation of minerals that may be considered economically valuable.

Deposition

The laying down of rock-forming material by any natural agent, e.g. the mechanical settling of sediment from suspension in water or the precipitation of mineral matter from suspension in solution, e.g.  of quartz in veins.

Detrital

Pertaining to or formed from detritus; esp. said of minerals occurring in sedimentary rocks, which were drived form pre-exisitng rocks either within or outside the basin of deposition.

Developed reserves

Ore that has been exposed on three sides and for which tonnage and quality estimates have been made; ore essentially ready for mining.

Development

Preparation of a mining property so that an orebody can be analyzed and its tonnage and quality estimated. Development is an intermediary stage between exploration and mining.

Deviation

The departure of a drilled hole from being straight. Deviation may be undesireable or intentional.

Devonian

A period of the Paleozoic era (after the Silurian and before the Mississippian) thought to have covered the span of time between 400 and 345 million years ago, and the corresponding system of rocks.

Diamond bit

A rotary-drilling bit studded with diamonds (usually bort) used for drilling and coring in extremely hard rock.

Diamond drilling

A variety of rotary-type rock 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 and generally retrieved in long cylindrical sections, two cm or more in diameter. 

The effect of waste or low-grade ore being included unavoidably in the mined ore, lowering the recovered grade.

Diorite

A group of plutonic rocks intermediate in composition between acidic and basic; characteristically composed of hornblende, oligoclase or andesine, and sometimes a little quartz.

Dip

Inclination of a geological feature/rock from the horizontal (perpendicular to strike); the angle that a stratum or any planar feature makes with the horizontal, measured perpendicular to the strike and in the vertical plane.

Said of an ore deposit formed at an incredible distance; e.g. tens of kilometers away from the volcanic source from which its constituents have been derived.

Disseminated

Fine grained material scattered evenly throughout the rock.

Cash or stock awarded to preferred and common shareholders at the discretion of the company's board of directors.

Dolomite

A common rock-forming mineral CaMg(O3)2, that is white to light-colored and has perfect rhombohedral cleavage; a sedimentary rock of which more than 50% by weight consists of the mineral dolomite. Most dolomite is associated and often interbedded with limestone.

Doré                      

Unrefined gold and silver bullion bars, which will be further, refined to almost pure metal.

A carefully formulated heavy suspension, usually in water but sometimes in oil, used in rotary drilling. It commonly consists of bentonitic clays, chemical additives, and weighting materials such as barite. It is pumped continuously down the drill pipe, out through openings in the drill bit, and back up in the annulus between the pipe and the walls of the hole to a surface pit where it is screened and reintroduced through the mud pump. The mud lubricates and cools the bit; carries the cuttings up from the bottom; and prevents blowouts and cave-ins by plastering friable or porous formations and maintaining a hydrostatic pressure in the borehole offsetting pressures of fluids that may exist in the formation.

Said of a rock that is able to sustain, under a given set of conditions, 5-10% deformation before fracturing or faulting.

Due Diligence

The process of investigation into the details of a potential investment, such as an examination of operations and management and the verification of material facts.

Duricrust

A hard crust on the surface or a layer in the upper horizons of a soil in a semi-arid climate, formed by the accumulation of soluble minerals deposited by mineral-bearing waters that move upward by capillary action and evaporate during the dry season.

Dike

A sub-vertical tabular igneous intrusion which cuts across the bedding of adjacent rocks or other massive or planar structures in the country rock.

Eluvial

Said of an incoherent ore deposit, resulting from rock decomposition or disintegration in place. It may have slumped or washed downslope but has not been transported by a stream; pertaining to eluvium; a residual accumulation of rock debris produced in place by the decomposition or disintegration of rock material through the process of weathering.

Engineering geology

Application of the geological sciences to engineering practice, to assure that the geologic factors affecting the location, design, and construction of engineering works are recognized and adequartely provided for.

Environmental geology

The application of geologic principles and knowledge to problems created by man’s occupancy and exploitation of the physical environment.

Environmental impact statement

A document prepared by industry or a political entity on the environmental impact of its proposals for legislation and other major actions significantly affecting the quality of the human environment.

Epidote

A green monoclinic mineral Ca2(A,Fe)3Si3O12, common in low-grade metamorphic rocks derived from limestone.

Epigenetic

Said of a mineral deposit of origin later than or subsequent to that of the enclosing rocks; said of a sedimentary mineral, texture, or structure formed after deposition of the sediment.

Pertaining to mineral veins and ore deposits formed from warm waters at shallow depth, at temperatures ranging from 50-200°C, and generally at some distance from the magmatic source. Pertaining to mineral veins and ore deposits formed from warm waters at shallow depth, at temperatures ranging from 50-200°C, and generally at some distance from the magmatic source. Said of a hydrothermal mineral deposit formed within about 1 km of the earth’s surface and in the low temperature range of formed at low temperatures (50-200 °C) near the Earth’s surface (<1500 m).Bottom of Form

50-200 °C, occurring mainly as veins near the Earth’s surface (<1500 m) and generally at some distance from the magmatic source.

Epoch

An interval of geologic time longer than an age and shorter than a period, during which the rocks of a series were formed; also an informal term used to designate a short interval of geologic time, e.g. glacial epoch.

Erosion

The wearing away of any part of the Earth’s surface by natural agencies.

Exploration

Prospecting, sampling, mapping, diamond-drilling and other work involved in searching for deposits of useful mineral ore and fossil fuels; and establishing the nature of a known mineral deposit preparatory to development.

The aspect, appearance, and characteristics of a rock unit, usually reflecting the conditions of its origin; esp. as differentiating it adjacent or associated units.

Fault

A fracture in a rock along which the opposite sides have been relatively displaced parallel to the plane of the movement.

Fe

The chemical symbol for iron.

Feasibility Study

A detailed study of the economics of a project based on technical calculations and specific mine designs undertaken to a sufficiently high degree of confidence to justify a decision on construction.

Feldspar

A silicate mineral group, most important group of rock-forming minerals being essential constituents of igneous rocks, present in most metamorphic rocks and in many sedimentary rocks. Feldspars are the most widespread of any mineral group and constitute 60% of the earth’s crust and can be white, grey or pink.

Felsic

Term applied to an igneous rock having an abundance of light colored minerals; also applied to those rocks (quartz, feldspars, feldsparthoids, muscovite) as a group.

Ferruginous

Pertaining to or containing iron, for example a sandstone that is cemented with iron oxide. Also said of a rock having a red or rusty color due to the presence of ferric-oxide.

Fire assay  

The assaying of metallic ores, usually of gold and silver, by methods requiring furnace heat.

Fissure vein

A type of mineral deposit of veinlike shape, with clearly defined walls rather than extensive host-rock replacement.

Float

A general term for isolated, displaced fragments of a rock that are often found in the soil on a slope or hillside below an outcropping or vein.

Flotation

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 uneconomic or valueless gangue or waste.

Fold

A bend or placation in bedding, foliation, cleavage, or other planar features in rocks. A fold is usually a product of deformation but the definition does not specify manner of origin.

Foliation

A planar arrangement of textural or structural features in any type of rock; esp. the planar structure that results from flattening of the constituent grains of a metamorphic rock.

Fool’s gold

A popular term for pyrites resembling gold in color; specif. pyrite and chalcopyrite.

Footwall

The mass of rock beneath a fault, orebody, or mine working; esp. the wall rock beneath an inclined vein or fault.

g/t

Grammes per tonne.

Gabbro

A group of dark-colored, basic intrusive igneous rocks composed principally of labradorite or bytownite and augite, with or without olivine and orthopyroxene. It is the approximate intrusive equivalent of basalt. Appatitie and magnetite or ilmenite are common accessory minerals.

Galena

A gray metallic mineral, PbS. It has perfect cubic cleavage, is soft and very heavy, and is the principal ore of lead. Galena commonly contains lead, zinc and silver.

Gangue

The valueless rock or mineral aggregates in an ore; that part of an ore that is not economically desireable but cannot be avoided in mining. It is separated from the ore minerals during concentration.

Geochemical anomaly

A concentration of one or more elements in a rock, sediment, soil, water or vegetation that differs significantly from the normal concentrations.

Geochemical exploration

The search for economic mineral or petroleum deposits by detection of abnormal concentrations of elements or hydrocarbons in surficial materials or organisms, usually by techniques that may be applied in the field.

Geochemistry

The study of the distribution and amounts of the chemical elements in minerals, ores, rocks, soils, water, and the atmosphere, and their circulation in nature, on the basis of the properties of their atoms and ions. A major concern of geochemistry is the synoptic evaluation of the abundance of the elements in the earth’s crust and in the major classes of rocks and minerals.

Recording geological information.

Geologist

One who is trained in and works in any of the geological sciences; a specialist in geology.

Geophysical surveys

A scientific exploration technique which uses surface methods to measure the physical properties of the subsurface in order to detect or infer the presence and position of concentrations of ore minerals by use of seismic, gravitational, magnetic, electrical and electromagnetics to measure the physical properties of rocks, and in particular, to detect the measurable physical differences between rocks that contain ore deposits or hydrocarbons and those without, in order to define anomalies for further testing.

Geophysicist

One who studies the physical properties of the earth, or applies physical measurements to geological problems; a specialist in geophyiscs.

Gibbsite

A mineral, Al(OH)3 that is the principal constituent in bauxites.

GIS

Geographical Information System -- a system of computerized hardware, software and procedures to facilitate the management, manipulation, analysis, modelling, representation and display of geo-referenced data.

Glacial boulder

A large rock fragment that has been transported by a glacier.

Glacial epoch

Any part of geologic time, from Precabrian onward, in which glaciers covered a much larger total area than those of the present day; specif. the latest of the glacial epochs, known as the Pleistocene Epoch.

Glacier milk

A stream of turbid, whitish meltwater containing rock flour in suspension.

Gneiss

A foliated rock formed by regional metamorphism, in which bands or lenticles of granular minerals alternate with bands or lenticles of minerals with flaky or elongate prismatic habit. Generally less than 50% of the minerals show preferred parallel structure. Although gneiss is commonly feldspar and quartz-rich, mineral composition is not an essential factor in its definition.

Goethite

A yellow, red, or brown mineral, FeO(OH) that is the commonest constituent of much limonite and occurs, esp. as a weathering product in gossans.

Gold

A soft yellow mineral, the native metallic element Au. Specific gravity of pure gold is 19.3. It is often alloyed with silver, copper, or other metals, and is found in nuggets and grains in gravels, and in veins associated with quartz.

Gondwana

The late Paleozoic supercontinent of the southern hemisphere, named by Suess for the Gondwana System of India. The present-day southern continents are believed to be fragments that have separated from each other by continental displacement and drift.

Gossan

An iron-bearing weathered product overlying a sulfide deposit. It is formed by the oxidation of sulfides and the leaching-out of the sulfur and most metals, leaving hydrated iron oxides and rarely sulfates.

Grab sample

A sample of rock or sediment taken more or less indiscriminately at any place.

Grade

The amount of metal in each ton of ore, expressed as troy ounces per ton or grams per tonne for precious metals and as a percentage for most other metals.
Cut-off grade: the minimum metal grade at which an orebody can be economically mined (used in the calculation of ore reserves).
Mill-head grade: metal content of mined ore going into a mill for processing.
Recovered grade: actual metal content of ore determined after processing.
Reserve grade: estimated metal content of an orebody, based on reserve calculations.

A medium to coarse grained plutonic igneous rock usually light coloured and consisting largely of quartz and feldspar.

Granodiorite

A group of coarse-grained plutonic rocks intermediate in composition between quartz diorite and quartz monsonite, containing quartz, oligoclase or andesine, and potassium feldspar, with biotite, hornblende, or more rarely pyroxene, as the mafic components.

Grass-roots

The earliest phase of geological exploration and knowledge gathering.

Greenstone

A field term for any compact dark-green altered or metamorphosed basic igneous rock that owes its color to chlorite, actinolite or epidote.

Greenstone belt

Greenstone belts are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that occur within Archaean and Proterozoic cratons between granite and gneiss bodies. The name comes from the green hue imparted by the color of the metamorphic minerals within the mafic rocks. Chlorite, actinolite and other green amphiboles are the typical green minerals. A greenstone belt is typically several dozen to several thousand kilometres long and although composed of a great variety of individual rock units, is considered a 'stratigraphic grouping' in its own right, at least on continental scales. A greenstone belt forms a tectonic marker far more distinct than the much more voluminous and homogeneous granites. The vast majority of greenstones are interpreted as altered basalts and other volcanic or sedimentary rocks; basically metamorphosed volcanic belts. Greenstone belts are primarily formed of volcanic rocks, dominated by basalt, with minor sedimentary rocks inter-leaving the volcanic formations. Through time, the degree of sediment contained within greenstone belts has risen, and the amount of ultramafic rock (either as intrusive ultramafic to mafic layered intrusions or as volcanic komatiite) has decreased. Greenstones, aside from containing basalts, also give rise to several types of metamorphic rocks which are used synonymously with 'metabasalt' etc; greenschist, whiteschist and blueschist are all terms spawned from study of greenstone belts. The belts often contain ore deposits of gold, silver, copper, zinc and lead.

Greenstone belt distribution

Archaean greenstones are found in the Slave craton, northern Canada, Pilbara craton and Yilgarn Craton, Western Australia, Gawler Craton in South Australia. Examples are found in South and Eastern Africa, namely the Kaapvaal craton and also in the cratonic core of Madagascar, as well as in West Africa and Brazil, northern Scandinavia and the Kola Peninsula. The belts often contain ore deposits of gold, silver, copper, zinc and lead. The Abitibi greenstone belt in Ontario and Quebec is one of the largest Archean greenstone belts in the world and hosts numerous gold deposits. One of the best known greenstone belts in the world is the South African Barberton greenstone belt, where gold was first discovered in South Africa. Some of the major greenstone belts of the world are:
Abitibi greenstone belt (Quebec/Ontario, Canada)
Barberton greenstone belt (South Africa)
Bird River greenstone belt (Manitoba, Canada)
Flin Flon greenstone belt (Manitoba/Saskatchewan, Canada)
Isua greenstone belt (Southwestern Greenland)
Pietersberg greenstone belt (South Africa)
Taishan greenstone belt (Southeast Asia)
Temagami greenstone belt (Ontario, Canada)
Guinea greenstone belt (West Africa)
Ashanti greenstone belt (Birimian/Proterozoic) (Ghana, West Africa)

Greenschist

A schistose metamorphic rock whose green color is due to the presence of chlorite, epidote, or actinolite.

The Hadean is the geologic eon before the Archean. It started at Earth's formation in geologic time thought to be about 4.6 billion years ago (4600 Ma), and ended roughly 3.8 billion years ago at the start of the Archaean, though the latter date varies according to different sources. The name "Hadean" derives from Hades, Greek for "Underworld", referring to the conditions on Earth at the time. The term was coined originally to label the period before the earliest-known rocks. An almost synonymous term is the "Priscoan period". Other older texts simply refer to the eon as the Pre-Archean.

Hanging Wall

The overlying side of an orebody, fault or mine working; esp. the wall rock above an inclined vein or fault.

Heap leaching

 A process whereby gold is extracted by “heaping” broken ore on sloping impermeable pads and continually applying to the heaps a weak cyanide solution which dissolves the contained gold. The gold-laden solution is then collected for gold recovery.

H

The chemical symbol for hydrogen.

Hectare

Hematite

Hg

The chemical symbol for mercury.

High grade

 Said of an ore with a relatively high ore-mineral content; rich ore.  As a verb, it refers to selective mining of the best ore in a deposit.

High-sulphidation

A style of gold mineralisation which is typically found proximal to volcanic centers and is characterised by alunite-kaolinite and vuggy silica alteration.

Holocene

An epoch of the Quarternary period, from the end of the Pleistocene, approximately 8 thousand years ago, to the present time, and the corresponding series of rocks and deposits.

Hornblende

The commonest mineral of the amphibole group, (Ca,Na)2-3(Mg,Fe+2,Fe+3,Al)5 (Al,Si)8O22(OH)2. Hornblende is commonly black, and occurs in distinct monoclinic crystals or in columnar, fibrous, or granular forms. It is a primary constituent of many acid and intermediate igneous rocks and less commonly of basic igneous rocks. It is a common metamorphic mineral.

Hydraulic mining

The extraction of desired earth material by means of strong jets of water; e.g. washing gold-bearing gravel into sluices, or phosphatic gravel or high silica sand into sumps for removal.

Hydrothermal

Refers in the broad sense to the processes associated with alteration and mineralization by a hot mineralizing fluid (water).

Hydrothermal deposit

A mineral deposit formed by precipitation of ore and gangue minerals in fractures, faults, breccias, openings, or other spaces, by replacement or open space filling from watery fluids ranging in temperature from 50-700 degrees C but generally below 400 degrees C, and ranging in pressure from 1 to 3 kilobars..

Hydrothermal alteration

Alteration of rocks or minerals by the reaction of hydrothermal water with pre-existing solid phases.

I

The chemical symbol for iodine.

Ilmenite

An iron-black opaque rhombohedral mineral FeTiO3. It is the principal ore of titanium. Ilmenite is a common accessory mineral in the basic igneous rocks, esp. gabbros and norites, and is also concentrated in mineral sands.

In

The chemical symbol for indium.

Industrial mineral

Any rock, mineral, or other naturally occurring substance of economic value, exclusive of metallic ores, mineral fuels and gemstones; one of the non-metallics.

Inferred Mineral Resource

The part of a Mineral Resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a low level of confidence. It is inferred from geological evidence and reasonably assumed, but not verified as to geological and/or 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.  

In-fill

Any method of drilling intervals between existing holes, used to provide greater geological detail and to help establish reserve estimates.
Geotechnical infill: diamond drilling targeted and utilized specifically for the collection of information used for mine stability purposes.

In-situ

In place; in its natural position; said specif. of a rock, soil, or fossil when in the situation in which it was originally formed or deposited.

Intrusion

The process of emplacement of magma in older pre-exisitng rock; magmatic activity. Aslo the body of igneous rock so formed.

Iron

A heavy magnetic malleable and ductile chemically active mineral, the native metallic element Fe. Native iron is rare in terrastrial rocks but common in meteorites. In combination with other elements, iron occurs in a wide range of ores and in most igneous rocks. It is the most widely used of the metals.

Iron ore

Ferruginous rock containing one of more minerals from which metallic iron may be profitably extracted. The chief ores of iron consist mainly of the oxides (Fe2O3), goethite FeO(OH), magnetite (Fe3O4) and the carbonate, siderite (FeCO3).

Itabirite

A laminated, metamorphosed oxide-facies iron formation, in which the original chert or jasper bands have been recrystallized into megascopically distinguishable grains of quartz and the iron is present as thin layers of hematite, magnetite, or martite.

A device for concentrating minerals. Crushed ore is fed into a box containing water whose level is rapidly raised and lowered by action of a piston causing heavier minerals to sink to the bottom from which they are drawn off.

JORC

the Australasian Code for Reporting of Mineral Resources and Ore Reserves which sets out the minimum standards, recommendations and guidelines for Public Reporting of exploration results, Mineral Resources and Ore Reserves in Australasia.

Jurassic

The second period of the Mesozoic era (after the Triassic and before the Cretaceous) thought to have covered the span of time between 190 and 135 million years ago, and the corresponding system of rocks.

K

The chemical symbol for Potassium

Kaolinite

A group of clay minerals formed by weathering or hydrothermal alteration of feldspars and other aluminous silicate minerals.

Karat

The proportion of pure gold in an alloy. Pure or fine gold is 24 karat; 10 karat gold is 10/24 pure, or 10 parts of pure gold by weight mixed with 14 parts of other metals. Not to be confused with carat.

K-feldspar

Potassium feldspar.

Kimberlite

An alkaline peridotite containing abundant phenocrysts of olivine (commonly altered to serpentine or carbonate) and phlogopite (commonly chloritized), in a fine-grained groundmass of calcite, second-generation olivine, and phlogopite; with accessory ilmenite, serpentine, chlorite, magnetite, and perovskite. The name is derived from Kimberley South Africa where the rock contains diamonds. Not all kimberlites are diamondiferous.

Lamprophyre

A group of dike rocks in which dark minerals occur both as phenocrysts and in the groundmass and light minerals occur in the groundmass. Essential constituentsa re biotite, hornblende, pyroxene, and feldspar or feldsparthoids. Most lamprophyres are highly altered. They are commonly associated with carbonatites and in some cases have been found to be diamond-bearing.

Landsat TM

Multispectral data from satellite remote-sensing imagery that provides landscape patterns reflecting geologic structures, types of rocks, and vegetation.

Laterite

A highly weathered red subsoil or material rich in secondary oxides of iron, aluminum, or both, nearly devoid of bases and primary silicates, and commonly with quartz and kaolinite. It develops in hot and wet tropical areas or forested warm to temperate climate, and is a residual product of long lasting weathering of the underlying parent rock. The iron oxides goethite and hematite cause the red-brown color of laterites. Laterite covers have mostly a thickness of a few meters but occasionally they can be much thicker.

Leaching

The dissolution of soluble constituents from a rock or orebody by the natural action of percolating water or solutions; e.g. the separation of gold by treatment with a cyanide solution.

Lead

A soft heavy malleable isometric mineral, the native element Pb. Lead rarely occurs in the native form, being found mostly in combinations, esp. galena.

Leonardian

Upper series of the Lower Permian era of North America.

Light colored; applied to igneous rocks containing less than 30% mafic minerals.

Limestone

A sedimentary rock composed almost entirely of calcium carbonate (CaCO3).

Limonite

An amorphous hydrated iron oxide, one of the chief constituents of gossan. Limonite is a minor ore of iron.

Lineament

A linear topographical feature.

Lithology

The description of rocks, especially in hand specimens and outcrops, on the basis of such characteristics as color, mineralogic composition and grain size.

Lode

A mineral deposit consisting of a zone of veins, veinlets or disseminations; also a mineral deposit in solid rock as compared to a placer deposit.

Logging

The act or process of making or recording a log. The technique or method by which subsurface formations are characterized relative to depth by measurements or observations on the rocks of a borehole; mapping and recording the observed geologic features and orientation of drill core.

Low-sulphidation

A style of gold mineralisation which is typically found distal to volcanic centers and is characterised by adularia-sericite alteration and quartz veins.

M

Metre.

M

Million.

Ma

Million years before present.

Mafic

Said of an igneous rock composed chiefly of dark, ferromagnesian minerals; also said of those minerals.

Magma

Naturally occurring molten rock material, generated within the earth and capable of intrusion and extrusion, from which igneous rocks have been derived through solidification and related proceses. It may or may not contain suspended solids such as crystals and rock fragments.

Magma chamber

A reservoir of magma in the shallow part of the lithosphere (to a few km or tens of km) from which volcanic materials are derived; the magma has ascended into the crust from an unknown source.

Magnetite

A black, isometric, strongly magnetic, opaque mineral of the spinel group (Fe,Mg)Fe2O4. It often contains titanium oxide, and it constitutes an important ore of iron. Magnetite is a very common and widely distributed accessory mineral in rocks of all kinds and also occurs as a heavy mineral in sands.

Malachite

A bright green mineral, Cu2CO3(OH)2. It is a minor ore of copper and a common secondary mineral, associated with azurite in the oxidized zone of copper-sulfide deposits.

Massive sulfide deposit

Any mass of unusually abundant metallic sulfide minerals, e.g. a kuroko deposit.

Matrix

The groundmass of an igneous rock; the finer-grained material enclosing the larger grains in a sediment or sedimentary rock.

Measured Mineral Resource

The portion of a Mineral Resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a high level of confidence. It is based on detailed and reliable exploration, sampling and testing information gathered through workings and drill holes. The locations are spaced closely enough to confirm geological and/or grade continuity.
A concentration or occurrence of diamonds, natural solid inorganic material, or natural solid fossilized organic material including base and precious metals, coal, and industrial minerals 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.

Melanocratic

Dark colored; applied to igneous rocks containing more than 60% mafic minerals.

Mercury

A heavy, silver-white to tin-white hexagonal mineral, the native element Hg. It is the only metal that is liquid at ordinary temperatures. Native mercury is found as minute globules disseminated through cinnabar (the principal ore of mercury) or deposited from the waters of certain hotsprings, but it is unimportant as a source of the metal. It usually contains small amounts of silver. Mercury combines with most metals to form alloys or amalgams. It is highly toxic if breathed or ingested. Also referred to as ‘Quicksilver’.

Mesothermal

Said of a hydrothermal mineral deposit formed at considerable depth and in the termperature range of 200-300 degrees C.

Mesozoic

An era of geologic time spanning from 250 to 65 million years ago, including the Triassic, Jurassic and Cretaceous periods.

Metallogenic province

A belt of rocks, often structurally controlled, that are host to a specific selection of metals. An area characterized by a particular assemblage of mineral deposits, or by one or more characteristic types of mineralization. A metallogenic province may have had more than one episode of mineralization, or metallogenic epoch.

Metallogeny

The study of the genesis of mineral deposits, with emphasis on their relationship in space and time to regional petrographic and tectonic features of the earth’s crust.

The science and art of separating metals from their ores and preparing them for use, as by smelting and refining.

Metamorphism

Altering in composition, texture, or internal structure by processes involving pressure, heat and/or the introduction of new chemical substances. The mineralogical, chemical, and structural adjustment of solid rocks to physical and chemical conditions imposed at depth below the surface zones of weathering and cementation, which differ from the conditions under which the rocks originated.

Mg

The chemical symbol for magnesium.

Mill

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

Milling ore

Mine

Mineralogy

Miocene

An epoch of the early Tertiary Period, after the Oligene and before the Pliocene, extending in geologic time from 23.3 to 5.2 million years ago; also the corresponding worldwide series of rocks. It is considered to be a period when the Tertiary is designated as an era.

Mineral deposit

A mass of naturally occurring mineral material, e.g. metal ores or nonmetallic minerals, usually of economic value without regard to mode of origin.

Mineral Resource

A concentration or occurrence of material of intrinsic economic interest in or on the earth’s crust in such a form and quantity that there are reasonable prospects for eventual economic extraction.

Mineral Reserve

The economically mineable part of a Measured or Indicated Mineral Resource demonstrated by at least a Preliminary Feasibility Study. This Study must include adequate information on mining, processing, metallurgical, economical, and other relevant factors that demonstrate, at the time of reporting, that economic extraction can be justified. A Mineral Reserve includes diluting materials and allowances for losses that may occur when the material is mined.

Mineralization

The concentration and process of metals and their chemical compounds introduced within a body of rock.

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 engineering

Miocene

Mississippi Valley-type deposit

Mn

The chemical symbol for manganese.

Mo

The chemical symbol for molybdenum.

Mobilization

Any process that renders a solid rock sufficiently plastic to permit it to flow or to permit geochemical migration of the mobile components; any process that redistributes and concentrates the valuable constituents of a rock into an actual or potential ore deposit.

Molybdenite

A lead-grey hexagonal mineral, MoS2. It is the principal ore of molybdenum. Molybdenite generally occurs in foliated masses or scales, and is found in pegmatite dikes and quartz veins or disseminated in porphyry; it resembles graphite in appearance and to the touch but has a bluer color.

Mother Lode

A main mineralized unit that may not be economically valuable in itself but to which workable veins are related; e.g. the Mother Lode of California; an ore deposit from which a placer is derived.

MT

Abbreviation for  Metric Tonne;  a measure of mass equivalent to 1,000 kilograms or 2204 pounds.

N

The chemical symbol for nitrogen.

Na

The chemical symbol for sodium.

Ni

The chemical symbol for nickel.

NI 43-101

National Instrument 43-101 (NI 43-101) is a mineral resource classification and is a national instrument for the Standards of Disclosure for Mineral Projects with the Canadian Securities Administrators. The NI is a strict guideline for how public Canadian companies can disclose scientific and technical information about mineral projects. The instrument requires that a "qualified person" be attributed to the information. A qualified person is defined as:
an engineer or geoscientist with at least 5 years experience in the mineral resources field
a subject matter expert in the mineral resources field and has a professional association

O

The chemical symbol for oxygen.

Open pit

A method of mining in which the ore is extracted from a surface excavation open to the sky.

Ore

Mineral bearing rock that contains one or more metallic and non-metallic minerals, at least one of which can be mined and treated profitably under current or immediately foreseeable economic conditions.

Orebody

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

Orogenic belt

A linear or arcuate zone in the Earth’s crust characterised by deformed and metamorphosed rocks, usually associated with large plutonic intrusions in the deeper levels of the belt.

Ortho-

In petrology, a prefix that, when used with the name of a metamorphic rock, indicates that it was derived from an igneous rock.

Outcrop

That part of a geologic formation or structure that appears at the surface of the earth; also bedrock that is covered by alluvium or appears exposed and visible at the earth’s surface.

Overburden

Loose or consolidated rock material that overlies a mineral deposit and must be removed prior to mining.

Oxidation

The process of combining with oxygen; e.g. the oxidation of Zn given ZnO.

Oxide

Soft, weathered rock formed by the process of weathering near the surface.

Oxide ore

 Mineralized rock in which some of the original minerals have been oxidized. Oxidation tends to make the ore more amenable to cyanide solutions so that minute particles of gold will be readily dissolved.

Oz

Troy ounce (equal to 31.1034768 grammes).

P

The chemical symbol for phosphorus.

Paleozoic

An era of geologic time, from the end of the Precambrian to the beginning of the Mesozoic, thought to be from about 570 to about 225 million years ago.

Paleochannel

An old or ancient stream or riverbed.

Pangea

A supercontinent thought to have existed in geologic time from about 300 to about 200 million years ago and included most of the continental crust of the earth. The presenet continents were derived from it by fragmentation, via an intermediate stage of Laurasia on the north and Gondwana on the south.

Pay streak

That portion of a vein which carries the profitable ore.

Pb

The chemical symbol for lead.

Pd

The chemical symbol for palladium.

Peacock ore

Informal name for an irridiscent copper mineral having a lustrous, tarnished surface exhibiting variegated colors, such as chalcopyrite and esp. bornite. Syn. ‘Peacock copper’.

Pegmatite

An exceptionally coarse-grained igneous rock, with interlocking crystals, usually found as irregular dikes, lenses, or veins, esp. at the margins of batholiths. Most grains are one cm or more in diameter. The composition of pegmatites is generally that of granite; it may be simple or complex, and may include rare minerals rich in such elements as lithium, boron, fluorine, niobium, tantalum, uranium, and rare earths. Pegmatites represent the last and most hydrous portion of a magma to crystallize and hence contain high concentrations of minerals that are present only in trace amounts in granitic rocks.

Permian

The last period of the Paleozoic era (after the Pennsylvanian) thought to have covered in geological time the span from 280 to 225 million years ago; and the corresponding system of rocks. The Permian is sometimes considered part of the Carboniferous and Triassic.

Petrography

That branch of geology dealing with the description and systematic classification of rocks, esp. igneous and metamorphic rocks and, esp. by means of microscopic examination of thin sections.

Phenocryst

One of the relatively large and ordinarily conspicuous crystals of the earliest generation in a porphyritic igneous rock.

Pinch-out

The termination or end of a stratum or vein that narrows or thins progressively in a given direction until it disappears and the rocks it once separated are in contact.

Pipe

The vertical conduit below a volcano, through which the magmatic materials passed. It is usually filled with breccias and may be mineralized; also used to describe a cylindrical, more or less vertical ore body.

Placer

A surficial mineral deposit formed by mechanical concentration of mineral particles from weathered debris. The mineral concentrated is usually a heavy mineral such as gold, cassiterite or rutile.

Placer mining

The extraction and concentration of heavy metals or minerals from placer deposits by various methods generally using water; cf: hydraulic mining.

Plate tectonics

A theory of global tectonics in which the lithosphere is divided into a number of plates whose pattern of horizontal movement is that of torsionally rigid bodies that interact with one another at their boundaries, causing seismic and tectonic activity along these boundaries.

Platinum Group Elements

Pliocene

An epoch of the Tertiary period, after the Miocene and before the Pleistocene; also the corresponding series of rocks. It is considered to be a period when the Tertiary is designated to an era.

Plunge

The inclination of a fold axis or other linear feature, measuring in the vertical plane. It is mainly used in the geometry of folds.

Pluton

An igneous intrusion, a body of rock formed by metasomatic replacement; the term originally signified only deep-seated or plutonic bodies of granitoid texture.

Plutonic rock

A rock formed at considerable depth by crystallization of magma and/or by chemical alteration. It is characteristically medium to coarse grained of granitoid texture.

Polygenetic

Resulting from more than one process of formation, derived from more than one source, or originating or developing at various places and times, e;g. said of a mountain range resulting from several orogenic occurrences. Also said of a conglomerate composed of materials from several sources.

Polymetallic

Porphyry

An igneous rock in which relatively large crystals (phenocrysts) constitute 25% or more of the volume and are set in a fine-grained groundmass. Can also be used in conjunction with a mineral name where the phenocrysts are of the named mineral e.g. quartz porphyry.

Potential ore

As yet undiscovered mineral deposits; or a known mineral deposit for which recovery is not yet economically feasible.

Potash

Potassium carbonate, K2CO3. A term loosely used for potassium oxide, potassium hydroxide, or even for potassium in such informal expressions as potash feldspar or potash spar.

Precipitation

The process of separating mineral constituents from a solution by evaporation; or from magma to form igneous rocks.

Pre-Feasibility Study

A geological, technical and economic study to determine whether a deposit can be exploited.

Petrography

That branch of geology dealing with the description and systematic classification of rocks, especially igneous and metamorphic rocks and especially by means of microscopic examination of thin sections.

Petrology

That branch of geology dealing with the origin, occurrence, structure and history of rocks; especially igneous and metamorphic rocks. Petrology is broader in scope than petrography.

Porphyry copper deposit

A large body of rock, typically porphyry, that contains diseminated chalcopyrite and other sulfide minerals. Such deposits are mined in bulk on a large scale, generally in open pits, for copper and by-product molybdenum. Most deposits are 3-8 km across and of low grade (less than 1% Cu). Super gene enrichment has been very important at most deposits, as without it the grade would be too low to premit mining.

Precambrian

All geological time and its corresponding rocks before the beginning of the Paleozoic; it is equivalent to about 90% of geologic time and covers the period of time from the formation of the Earth estimated at 4500 million years ago to about 590 million years ago.

Prospect

An area of ground that is a potential site of mineral deposits, based on preliminary exploration, and considered worthy of further investigation with respect to mineral potential. A prospect is different from a mine in that it is non-producing.

Prospector

An individual engaged in prospecting for valuable mineral deposits, generally working alone or in a small group, and on foot with simple tools or portable detectors. The term implies an individual searching on his own behalf, rather than an employee of a mining company.

Proterozoic

The more recent of two great divides of the Precambrian. Syn Algonkain.

Pu

The chemical symbol for plutonium

Pyrite

A common yellow iron sulphide mineral (FeS2). Pyrite has a brilliant metallic luster and an absence of cleavage, and has often been mistaken for gold (which is softer and heavier). Pyrite is the most widespread and abundant of the sulfide minerals and occurs in all kinds of rocks. It is sometimes mined for associated gold and copper.

Pyroclastic

Fragmented clastic rock materials formed by volcanic explosion or aerial expulsion from a volcanic vent.

Pyrope

Pyrrhotite

Quartz

A crystalline silica and important rock forming mineral (SiO2). Next to feldspar, it is the most common mineral on the earth occurring either in hexagonal crystals 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. It has a vitreous luster and a hardness of 7 on the Mohs scale.

Quartzite

A metamorphic rock consisting mainly of quartz, formed by recrystallization of sandstone by regional or thermal metamorphism.

Quaternary

The most recent period of geologic time, the second period of the Cenozoic era following the Tertiary, and the corresponding system of rocks. It began two to three million years ago and extends to the present. It consists of two grossly unequal epoch: the Pleistocene, up to about 8,000 years ago, and the Holocene since that time.

QuickBird

A high resolution (0.6m per pixel) true-colour satellite image data.

Rare Earth Elements

Oxides of a series of 15 metallic elements, from lanthanum (atomic number 57) to lutetium (71), and of three other elements: yttrium, thorium, and scandium. These elements are not especially rare in the earth’s crust, but concentrations are. The rare earths are constituents of certain minerals, esp. monazite, bastnaesite, and xenotime.

Re

The chemical symbol for rhenium.

Reverse Circulation (RC)

A type of hydraulic drilling process that produces rock chips rather than core whereby fluid is circulated down the outside of the rods and returned to the surface with drill cuttings inside the rods.The chips are forced by air to surface through a double-walled drill pipe and are collected for examination.

Reclamation

Reconnaissance

 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 revegetation of waste rock piles and other disturbed areas.
A general exploratory examination or survey of the main geological features of a region, usually preliminary to a more detailed survey. In mineral exploration it often includes stream sediment sampling and initial geological mapping to determine if further mineral exploration of an area is warranted.

Recovery

 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.

Refining

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

Replacement

The progressive substitution of one mineral for another.

Rhyolite

One of a group of extrusive igneous rocks commonly showing flow textures, the extrusive equivalent of a granite.

Room-and-Pillar

A system of mining in which the ore is mined in rooms separated by pillars of undisturbed rock left for roof support.

Royalty

An amount of money paid at regular intervals by the lessee or operator of an exploration or mining property to the owner of the ground. Generally, it will be based on a certain amount per tonne or a percentage of the total production or profits. The landowner’s share of the value of minerals produced on a property is generally free of expenses of development and production.

S

The chemical symbol for sulphur.

Saprolite

Soft, thoroughly decomposed and porous rock, often rich in clay, formed by the in-place chemical weathering of igneous, metamorphic, or sedimentary rocks. Saprolite is especially common in humid and tropical climates. It is usually reddish brown or grayish white and contains those structures (such as cross-stratification) that were present in the original unweathered rock from which it formed. Saprolites contain predominantly quartz and a high percentage of kaolinite with other clay minerals which are formed by chemical decomposition of primary minerals, mainly feldspars. More intense weathering conditions, exceeding the saprolite stage, give rise to a continuous transition to laterite soils.

Sb

The chemical symbol for antimony.

Schist

A strongly foliated crystalline rock, formed by dynamic metamorphism, that has well developed parallel orientation of more than 50% of the minerals present, esp. those of lamellar or elongate prismatic habit, e.g. mica and hornblende.

Schistosity

The foliation in schist or other coarse grained, crystalline rock due to the parallel arrangement of mineral grains of the platy or prismatic types, usually mica, and is considered by some to be a type of cleavage.

Secondary mineral

A mineral formed later than the rock enclosing it, usually at the expense of an earlier-formed primary mineral, as a result of weathering, metamorphism or solution.

Sedimentary rock

A layered rock resulting from the consolidation of sediment, eg. A clastic rock such as sandstone, a chemical rock such as rock salt, or an organic rock such as coal.

Sericite

A fine grained white stretched micaceous mineral often the product of alteration processes.

Shaft

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

Shear

The deformation of an object in which parallel planes remain parallel but are shifted in a direction parallel to themselves.

Siliceous

Containing abundant silica.

Silicification

The introduction of, or replacement by, silica into a non-siliceous rock, especially in the form of fine-grained quartz, chalcedony or opal, via silica saturated groundwater or fluids of igneous origin.

Skarn

 The term is generally reserved for rocks composed mostly of lime-bearing silicates, derived from nearly pure limestones and dolomites into which large amounts of Si, Al, Fe, and Mg have been introduced; the name for the metamorphic rocks surrounding an igneous intrusive where it comes in contact with a limestone or dolostone formation.

Sn

The chemical symbol for tin.

Specific gravity

The ratio of the weight of a given volume of a substance to the weight of an equal volume of water (i.e. its density).

Stockpile

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

Stockwork

A mineral deposit in the form of a branching network of small irregular veins.

Stope

An excavated area in an underground mine where ore is mined. Stoping refers to the extraction of ore in an underground mine by working laterally in a series of levels in the plane of the vein.

Strata

Stratigraphy

Strike

The direction taken by a structural surface such as a fault or bedding plane as it intersects the horizontal.

Strike length

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

Stringer

A mineral veinlet or filament, usually one of a number, occurring in a discontinuous subparallel pattern in host rock.

Sulphide

A mineral compound characterized by the linkage of sulfur with a metal, such as galena, PbS, or pyrite FeS2. Metalliferous minerals formed with sulphur and often iron.

Sulfide enrichment

Sulfide enrichment The enrichment of a deposit by replacement of one sulfide by another of higher value, as pyrite by chalcopyrite.

Sulfide zone

That part of a sulfide deposit that has not ben oxidized by near-surface waters; a zone in which supergene enrichment has occurred.

Supergene Enrichment

The near-surface proceeses of mineral deposition in which oxidation produces acidic solutions that leach metals, carry them downward, and reciprocate them; thus enriching sulfide materials already present. Supergene enrichment, also referred to as downward or secondary enrichment, has been important in upgrading porphyry copper deposits to the status of ore.

Syngenetic

Said of a mineral deposit formed at the same time, and by the same processes, as the enclosing rocks. Also said of a primary structure, such as a ripple mark, formed contemporaneously with the deposition of the sediment in which it occurs.

t

Metric tonne.

Ta

The chemical symbol for tantalum.

Tailings

The material that remains after all economically and technically recoverable precious metals have been removed from the ore during processing.

Tectonics

A branch of geology dealing with the broad achictecture of the outer part of the earth, primarily the major structural or deformational features and forces and their relations, origin, and historical evolution.  Plate tectonics is a theory of of global tectonics in which the lithosphere is divided into a number of plates whose pattern of horizontal movement is that of torsionally rigid bodies that interact with one another at their boundaries, causing seismic and tectonic activity along these boundaries.

Tertiary

The first period of the Cenozoic era (after the Cretaceous of the Mesozoic era and before the Quarternary) thought to have covered the geologic span of time between 65 million and 2 million years ago; also the corresponding system of rocks. It is divided into five epochs: the Paleocene, Eocene, Oligocene, Miocene, and Pliocene.

Ti

The chemical symbol for titanium.

Topography

The general configuarion of a land surface, including its relief and the position of its natural and man-made features.

Trace element

An element that is not essential in the mineral but it is found in small quantities in its structure or absorbed on its surfaces.

Transported

Said of material that has been carried by natural agents from its former site to another place on or near the earth’s surface.

Trenching

A means of exposing and sampling near-surface geology by digging a trench.

Triassic

A period of geological time thought to have covered the span of time between 225 and 190 million years ago. The first period of the Mesozoic era (after the Permian of the Paleozoic era and before the Jurassic).

Tuff

A rock formed from volcanic ash fall deposits; a general term for all consolidated pyroclastic rocks.

Twin drilling

Drilling at the same locations as holes already drilled to verify the results of existing drill holes.

U

The chemical element for uranium.

Ultramafic

Said of an igneous rock composed of mafic (dark) minerals, e.g. monomineralic rocks composed of hypersthenes, augite, or olivine.

Value

In economic geology, the valuable constituents of an ore; their percentage in an ore body, or assay grade; their quantity in an ore body or assay value.

Vein

An epigenetic mineral filling in the openings of fissures, faults, fractures, joints, or other cracks, in tabular or sheetlike form, often with associated replacement of the host rock; and often filled by minerals that have traveled upwards from some deep source.

Visible gold

Native gold which is discernible, in a hand specimen, to the unaided eye.

Void

Cavities within rocks resulting from extraction of material.

Volcanic

Pertaining to igneous rocks which have been erupted from volcanoes.

Volcaniclastic

Pertaining to fragmental rocks containing volcanic material in any proportion without regard to origin.

W

The chemical symbol for tungsten.

A ‘dirty’ sandstone that consists of a mixture of poorly sorted mineral and rock fragments in an abundant matrix of clay and fine silt; spec. an impure sandstone containing more than 10% argillaceous matrix. A clastic sedimentary rock in which the grains are almost evenly distributed among the several size grades; e.g. a sandstone consisting of sediment ‘poured in’ to a basin of deposition at a comparatively rapid rate without much selection or reworking; a shortened term of greywacke.

Waste rock

In mining, rock that must be broken and disposed of in order to gain access to and excavate the ore; valueless rock that must be removed or set aside in mining.

Weathering

The destructive processes by which rocks are changed on exposure to atmospheric agents at or near the earth’s surface, with little or no transport of the loosened or altered material; specifically the physical disintegration and chemical decomposition of rock that produces an in-situ mantle of waste and prepares sediments for transportation. Degradation of rocks at the Earth’s surface by climatic forces.

Whole-rock analysis

A procedure in which a portion of rock, rather than individual minerals, is examined.

Wolframite

The principle ore of tungsten. (Fe,Mn)WO4.

Zn

The chemical symbol for zinc.