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Terms
Agitation leach tests
A basic means of assessing the Heap Leach recovery of metals of interest by agitating the crushed sample in the solution for a given time.
Andesite
Fine grained igneous extrusive rock, mineralogical equivalent of Diorite.
Argillites
Fine grained sediment comprised mainly of clay minerals an fine quartz.
Arsenopyrite
A common sulphosalt FeAsS.
Assay
assessment of valuable metals content
Azurite
Secondary mineral in the oxidized zone of copper ore deposits: Cu3(CO3)2(OH)2.
Base metals
A term which covers the metals copper, lead, zinc, and tin.
Basement
A term to describe the older and deeper parts of the Earth's crust consisting of dense and solid crytaline rocktypes.
Batholith
A large intrusive mass of igneous rock.
Batter
Term relating to the slope angle of an individual bench face; to 'batter back' effectively makes the overall pit slope angle shallower.
Bornite
Disseminated in igneous intrusions and a primary and secondary mineral in copper ore veins: Cu5FeS4.
Breccia
A rock made up of large sharp fragments of rock in a groundmess of finer grained sediment or vein material.
Calcareous
Describing rocks which contain much calcium carbonate (calcite).
Chalcocite
Secondary mineral in or near the oxidized zone of copper sulphide deposits: Cu2S.
Chalcopyrite
Common in sulphide veins and disseminated in igneous rocks: CuFeS2.
Chlorite
Hydrothermal alteration product of tuffs, andesites and sediments: Na(Al,Mg)12(Si,Al)16O36(OH)25(H2O)2.
Column leach tests
A means of assessing the Heap Leach recovery of metals of interest and the dynamics of this over time using large samples in tall perspex cylinders.
Continental margin
At the edge of the Earth's major crustal plates ie where continental masses meet oceanic crust.
Copper recovery
Copper that is recovered from metallurgical processing expressed a percentage of copper that is mined.
Copper sulphide
The most common form of hypogene copper mineralisation, commonly chalcopyrite.
Core samples
Rock samples collected by diamond core drilling.
Covellite
Commonly found in zones of secondary enricment above copper ore deposits: CuS.
Cretaceous
The geological period between 136 Ma and 64 Ma ago.
Crushing
Reduction in size of mined rocks by mechanical action, generally to the size of one or two centimetres.
Cut-off Grade
The lowest grade of mineralised material considered economic, used in the calculation of ore reserves. Also used in reserve estimation, meaning all material higher than the given grade
Dacite
A fine grained igneous intermediate in composition between Rhyolite and Andesite.
Diatreme
The underground part of a volcanic vent usually representing an explosive eruption.
Diorite
A coarse grained igneous rock consisting of alkali feldspar, some pyroxene and or amphibole with a little quartz : appx. 55-60 per cent. SiO2.
Disseminated
Evenly distributed grains of mineralisation.
Dykes
Steep dipping to vertical sheets of igneous rock which have exploited existing fractures.
Electrowinning
A means of finally collecting the chemical element(s) of interest from solution by electroplating onto cathodes.
Environmental
baseline study A study which quantifies existing conditions such as fauna and flora diversity, water and air quality and local habitation.
Epithermal
Pertains to hydrothermal processes which are distant from the heat source and subsequently are of low temperature (100-200*C).
Feldspars
The most common family of aluminosilicate minerals, the most common varieties being potassic, sodic and calcic.
Feasibility Study
An extensive technical and financial study to assess the commercial viability of a project
Flotation plant
A means of separating one type of mineral from another after milling, commonly separating sulphide minerals from silicate minerals.
g/t
Common unit of grade: grammes of precious metal per tonne of mineralised rock.
Grade
Relative quantity or the percentage of ore mineral content in an ore body. See also cut-off grade
Gabbro
A coarse grained igneous rock consisting of calcic feldspar, pyroxene and commonly hornblende and/or olivine: appx. 45-50 per cent. SiO2.
Galena
Found in lead sulphide ore veins, and disseminated in igneous and sedimentary rocks: PbS.
Gneisse
Coarse grained banded rocks resulting from extreme metamorphism.
Granitic
Pertaining to coarse grained igneous rocks which consist mainly of quartz, alkali feldspar and sometimes mica: appx. 65-75 per cent. SiO2.
Granodiorite
A coarse grained rock intermediate in composition between granite and diorite: appx. 65 per cent. SiO2.
Heap leaching
A means of dissolving the chemical of interest out of the mined rock by spraying solvent onto a large pile of crushed material and collecting the solvent for further treatment.
High-sulphidation
A term used to describe those types of epithermal systems with sulphide minerals and advanced argillic alteration characterised by quartz and alunite.
Hydrothermal alteration
Chemical and mineralogical change brought about by superheated aqueous solutions from igneous sources.
Hypogene
A general term pertaining to mineralisation originating within the Earth, often by ascending fluids.
Ignimbrites
A type of tuff which was so hot when deposited that the mineral grains are partially welded together.
Illite
Common clay mineral type, an alteration product of micas and alkali feldspars.
Induced polarization
A type of geopyhsical investigation which is designed to locate sulphide mineralisation.
Intrusion
A general term describing a mass of igneous rock which solidified before reaching surface.
Jarosite
Secondary mineral, forming under conditions of weathering in arid climates: KFe(SO4)2(OH)6.
Jurassic
The geological period between 195 Ma and 135 Ma ago.
Kaolinite
A clay mineral which is usually the result of argillic alteration of feldspars.
Landsat TM imagery
The use of satelite images generated by various sensors and cameras, commonly employed in mineral exploration.
Leach pads
Piles of broken material on an impermeable lining over which leaching solution is sprayed and collected in a heap leach operation.
Leach ponds
Collection ponds for leach solution from leach pads in a heap leach operation.
Leaching
Removal of a chemical element from a mineral by dissolving and transporting in a liquid.
Limestone
A deep marine sedimentary rock comprised of fine grains of shell material --- comprised mostly of calcium carbonate.
Lower Cretaceous
The geological period between 136 Ma and 100 Ma ago.
Low-sulphidation
A term used to describe those types of epithermal systems with sulphosalt minerals and native metals with silicic and argillic alteration characterised by quartz, sericite and adularia.
Magnetometry
A type of geopyhsical investigation which is designed to locate iron-rich mineralisation.
Malachite
Secondary mineral in the oxidized zones of copper ore deposits: Cu2(CO3)(OH)2.
Mantle
Molten rock found beneath the Earth's crust at a depth of between 35 km and 2,900 km.
Manto
Generally flat lying zones of mineralisation, often replacement bodies confined to bedding planes.
Mesothermal
Pertains to hydrothermal processes which are fairly close to the heat source and subsequently are of intermediate temperature (200-300*C).
Metallogenic Belt
A linear geological trend containing metallic mineralisation
Metallurgical processing
The means by which the minerals and/or metals of interest in the ore are separated and concentrated into a saleable form.
Metallurgical testwork
Laboratory based tests which examine methods of concentrating minerals and/or metals of interest.
Metamorphic
A type or rock which has been subjected to high heat and/or pressure resulting in deformation and mineralogical changes.
Meta-sedimentary
A general term describing sedimentary rocks which have been subjected to metamorphism.
Milling
A means of further reducing partical size after crushing resulting in a sandy or silty fineness.
Mineralisation
The process by which minerals are introduced into a rock. More generally, a term applied to accumulations of economic or related minerals in quantities ranging anomalous to economically recoverable
Mineral Resource
is a concentration or occurrence of material of intrinsic economic interest in or on the Earth's crust in such form that there are reasonable prospects for eventual 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. Mineral resources are sub-divided, in order of increasing confidence, into Inferred, Indicated and Measured categories
Miocene
The geological epoch between 25 Ma and 5 Ma ago, part of the Tertiary period.
Molybdenite
The most common ore of molybdenum, found in hydrothermal veins and copper porphyries: MoS2.
Monzonite
Coarse grained igneous rock with equal amounts of alkali and calcic feldspar, some olivine and pyroxene and little or no quartz.
Oceanic subduction
The process of oceanic crust being forced down into the mantle as it meets continental crust at a continental margin.
Open-pit
an open excavation for the purpose of mining ore
Open-pit mining
Extraction of mineralised rock from a pit without use of underground tunnels.
Ore
rock that can be mined and processed at a profit
Orebody
a solid mass of ore
Ore Reserve
is the economically mineable part of a Measured or Indicated Mineral Resource. It includes diluting materials and allowances for losses which may occur when the material is mined. Appropriate assessments, which may include feasibility studies, have been carried out, and include consideration of and modification by realistically assumed mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors. These assessments demonstrate at the time of reporting that extraction could reasonably be justified. Ore reserves are sub-divided in order of increasing confidence into Probable and Proven
Ounce
troy ounce; unit of weight equal to 31.1035g
Palaeozoic
The geological era between 590 Ma and 250 Ma ago.
Pervasive limonite
The result of oxidation of iron sulphides and silicates to a rusty material, often termed 'gossan'.
Phyllic alteration
Hydrothermal alteration resulting in chemical and mineralogical change of silicates to a sericite mica domintaed assemblage (also sericitic alteratrion).
Phyllite
A cleaved metamorphic rock due to a high mica content, less well cleaved than slate.
PIMA
Portable Infrared Mineral Analyser --- used to quantify alteration types during field mapping.
Plutonic igneous rock
Mantle material which has risen up and solidified before reaching the Earth's surface.
Polymetallic
Pertaining to mineralisation, indicates the presence of many metals in economically attractive concentrations.
Porphyry
An igneous rock which contains large crystals (phenocrysts) usually of feldspar.
Porphyry copper
A type of copper mineralisation commonly exploited, usually being very large tonnages mineralisation with relatively low grades of copper and often molybdenum, gold and silver.
Potassic alteration
Chemical and mineralogical changes by hydrothermal fluids, characterised by potassium feldspar, sericite and sometimes biotite.
Precambrian
The geological eon running from the solidification of the Earth's crust 4,500 Ma ago to 590 Ma ago.
Precious metals
A general term relating to high value metals which occur in relatively small concentrations in the Earth's crust.
Pressure acid leach
A process in which sulphide minerals are dissolved in acid at high pressure and high temperature by means of an autoclave.
Propylitic halo
A peripheral zone where minerals have been chemically changed, characterised by chlorite, sericite, quartz and carbonate minerals.
Pyrite
A common sulphide found in sedimentary, magmatic, metamorphic, and hydrothermal environments: FeS2.
Pyrrhotite
A common sulphide found in magmatic, metamorphic, and hydrothermal environments: Fe(1-x)S.
Quartz
A very common mineral in sedimentary, magmatic, metamorphic, and hydrothermal environments : SiO2.
Quartz monzonite
A monzonite with a small amount of quartz.
Quartzite
A metamorphic rock comprised of recrystallised quartz.
Refining
Purification of metal products to meet particular specifications.
Reserves
Proven: measured mineral resources, where technical economic studies show that extraction is justifiable at the time of the determination and under specific economic conditions
Probable: Measured and/or indicated mineral resources which are not yet proven, but where technical economic studies show that extraction is justifiable at the time of the determination and under specific economic conditions
Resource
Measured: a mineral resource intersected and tested by drill holes, underground openings or other sampling procedures at location which are spaced closely enough to confirm continuity and where geoscientific data are reliably known. A measured mineral resource estimate will be based on a substantial amount of reliable data, interpretation and evaluation of which allows a clear determination to be made of shapes, sizes, densities and grades
Indicated: a mineral resource sampled by drill holes, underground openings or other sampling procedures at locations too widely spaced to ensure continuity but close enough to give a reasonable indication of continuity and where geoscientific data are known with a reasonable degree of reliability. An indicated resource estimate will be based on more data, and therefore will be more reliable, than an inferred resource estimate
Inferred: A mineral resource inferred from geoscientific evidence, underground openings or other sampling procedures where the lack of data is such that continuity cannot be predicted with confidence and where geoscientific data may not be known with a reasonable level of reliability
Rhyolite
The fine grained equivalent of granite.
Rolling bottle tests
A basic means of assessing the Heap Leach recovery of metals of interest by rollong the crushed sample in the solution for a given time.
Scoping study
a compilation of data used to assess the potential economics of a mining project
Sediment
A broad term generally used to describe rocks which are made up of other rocks which were eroded and transported over the Earth's surface.
Sericite
A type of mica.
Shear
Large scale geological fault zone often with considerable movement and deformation.
Silicification
Introduction of quartz and other forms of silica usually from hydrothermal fluids.
Sill
Shallow dipping to horizontal sheets of igneous rock which have exploited existing fractures.
Siltstone
A sedimentary rock, often bedded, with a grainsize of 1/16 mm to 1/256 mm.
Skarn A body of rock which is the result of an igneous intrusion coming into contact with limestone or calcareous sediment.
Smelting
The winning of metal or amalgam from burning sulphide minerals at high temperature.
Solvent extraction
A means of partitioning and concentrating dissolved chemical element(s) of interest into a liquid which is easy to separate from the original solvent.
Sphalerite
Found in sulphide ore veins in all rock classes: (Zn,Fe)S.
Stacker conveyors
A system of moveable conveyor belts designed to deposit broken marterial over a wide area.
Stibnite
Typically found in low temperature (epithermal) veins: Sb2S3.
Stocks
Masses of plutonic igneous rock, smaller than batholiths and often representing the near surface parts of a batholith.
Stockwork
A nest or swarm of small veins in many orientations occupying a mass of rock.
Supergene enrichment
Concentration of chemical elements usually beneath and as a result of near-surface leaching.
SX/EW
solvent-extraction/electro-winning process producing copper metal from a leach solution
Tertiary
The geological period running from 65 Ma ago to 2 Ma ago.
Tourmaline
A cyclosilicate mineral family, often seen as radiating masses of needles: eg. NaFeAl6(BO3)3Si6O18(OH)4.
Transition zone
A continuous zone which represents the gradual change from one distinct style of mineralisation to another.
Tuff
A type of pyroclastic rock which is derived from the collapse of volcanic ash clouds.
Upper Jurassic
The geological period running from 162 Ma ago to 135 Ma ago.
Valley fill
A method of depositing broken material into a valley feature so as to result in a horizonal top surface and a graded downhill edge.
Vein
A fracture which has been filled by minerals which have crystallised from mineralised fluids.
Volcanic
A subtype of igneous rock which has been extruded and cooled at the Earth's surface usually found as a lava flow.
Volcanoclastic Sediment
comprised mainly of eroded volcanic material.
Volcanogenic massive sulphide A recognised type of base metal ore deposit derived from submarine hydrothermal vent sediments.
Vuggy
A term to describe the existence of many holes in the rock which are often crystal lined.
Weathering
Action of climatic conditions such as rainfall and heat on near-surface rocks resulting in chemical changes and the breakdown of original mineral grains.
Abbreviations
Ag silver
Au gold
Cu copper
g/t grammes per tonne
IRR internal rate of return
km kilometre
Kozs thousand ounces
Kt thousand tonnes
lb pound
m metre
m3 cubic metres
mm millimetre
Moz million ounces
Mt million tonnes
Mtpa million tonnes per annum
NPV net present value
oz Troy ounce
tpa tonnes per annum
tpd tonnes per day
tpy tonnes per year
VMS volcanogenic massive sulphide
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