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Glossary

A

AEM
Airborne electromagnetic survey
Ag
The chemical symbol for silver
Alluvial
Deposited by the action of running water in a stream
Alteration
Changes in the composition of a rock, generally chemical or mineralogical, brought about by weathering or hydrothermal activity
Arsenopyrite
A sulphide mineral of arsenic and iron (Fe AsS)
Assay
The chemical test of rock samples to determine their mineral content
Au
Chemical symbol for gold

B

Below Collar
A distance below the surface elevation of a drill hole collar or shaft
Bench
The equivalent of a level in an underground mine most noticeable as the step-like features in an open-pit wall. The open-pit bench height is calculated to match the rock strength, pit economics and capabilities of the open-pit machinery. Typical bench heights in open-pit mines range from 10 to 20 metres.
Birimian
Geological Time Era, about 2.1 billion years ago in which a suite of rocks characteristic to West Africa formed
Boudinage
A structure common in strongly deformed sedimentary and metamorphic rock, in which an original continuous competent layer or bed between less competent layers has been stretched, thinned and broken at regular intervals into bodies resembling boudins or sausages
Breccia/Brecciation
Rock type, formed from recrystallised fragments of other rocks

C

Capex
Capital expenditure
Carbon-In-Leach (CIL)
Similar to the CIP plant except the gold is leached and absorbed onto carbon granules in the same circuit. The carbon granules are separated and eluted in the same way as for CIP.
Carbon-In-Pulp (CIP)
Gold is leached conventionally from a slurry of gold ore with cyanide in agitated tanks. The leached slurry passed into the CIP circuit where carbon granules are mixed with the slurry and gold is absorbed onto the carbon. The granules are separated from the slurry and treated in an elution circuit to remove to gold
Cash Costs
Cash costs include site costs for all mining (excluding deferred development costs), processing and administration, but are exclusive of royalties, production taxes, amortisation and rehabilitation, as well as corporate administration, capital and exploration costs.
Channel Width
The total thickness of all reef bands including internal waste.
Concentrating
This is the process of separating milled ore into a waste stream (tailings) and a valuable mineral stream (concentrate) by the flotation operation. The valuable minerals in the concentrate contain almost all the base metal and precious metal minerals; these minerals are treated further by the smelting and refining process to obtain the pure metals (Cu, Ni and Platinum Group Metals).
Craton
A part of the earth’s crust that has attained stability and has been little deformed for a long time
Cut-off grade
The lowest grade material that can be included in a potentially economic intersection without dropping the overall grade below a specified level, referred to as the minimum mining grade. Lowest grade of mineralised material that qualifies as ore.

D

Diamond drilling
A rock drilling method using a rotary diamond bit which is attached to long hollow rods. The drill cuts a cylindrical core of solid rock, recovered for geological and metallurgical examination, and assay purposes
Dyke
A tabular igneous intrusion that cuts across the planar structures of the surrounding rock
Dilution
Mixing of ore grade material with non-ore grade/waste material in the mining process
Dip
The angle that a structural surface, a bedding or fault plane, makes with the horizontal, measured perpendicular to the strike of the structure
Drill-core
The sample of rock obtained by diamond drilling

F

Fault
A fracture in rock along which there has been an observable amount of displacement
Feasibility study
A definitive engineering study addressing the economic viability of bringing a deposit to the production stage; taking into consideration all associated costs, revenues and risks. The study is used to support the search for project financing.
Footwall
The underlying side of an orebody

G

g/t
Grams per metric tonne
Geophysical surveys
A survey method used primarily in the mining industry as an exploration tool, applying the methods of physics and engineering to the earth’s surface. Exploration by observation of seismic of electrical phenomena and the earth’s gravitational or magnetic fields, using specialized instrumentation
GIS
A geographical information system is a computerised relational database for spatial information
Grade
The amount of valuable element in each ton of ore, expressed as troy ounces per ton for precious metals and as a percentage for other metals
Cut-off grade is the minimum metal grade at which an ore body can be economically mined
Millhead grade is the metal content of mined ore going into a mill for processing
Recovered grade is actual metal content of ore determined after processing
Reserve grade is estimated metal content of an ore body, based on reserve calculations
Grade also “yield”
Gold recovered per unit of rock milled or treated. Normally measured as grams of gold per ton of rock
Grain
The smallest unit of mass in the three English systems (avoirdupois, troy and apothecaries’ weights) used in the UK and USA, equal to 0,0648g. It was reputedly the weight of a grain of wheat. One pound avoirdupois equals 7 000 grains; one pound troy apothecaries weight equals 5 760 grains
Gram
Metric unit of mass; one thousandth of a kilogram
Granite
A medium to coarse grained igneous intrusive rock in which quartz constitutes 10 to 50 percent of the felsic components
Granitoid
An igneous rock type

H

Hanging Wall
The overlying side of an orebody
Head Grade
The gold contained in material passing through the mill in grams per tonne or troy ounces per short ton milled
Heap leaching
A process whereby metals are extracted by heaping broken ore on an impermeable pad, and repeatedly spraying with solutions which percolate through the heap, dissolving a high percentage of the metal content. The resulting mineral solution is then collected for metal recovery generally by electro-winning
Heap/dump leaching
A process whereby gold is extracted by “heaping” broken ore on sloping impermeable pads and repeatedly spraying the heaps with a weak cyanide solution which dissolves the gold content. The gold-laden solution is collected for gold recovery
Hedging
Generally refers to any precaution against risk. In the context of gold mines refer specifically to measures to reduce the risk of gold price fluctuations - particularly a fall in the gold price. Hedging has almost become standard practice to “insure” funding over the duration of large capital expenditure programs. Hedging the gold price is done by forward contracts and options and has developed into quite an art form.
Hydrothermal
Process of injection of heated or hot acqucous-rich solutions into existing rocks

I

Igneous
Formed by the solidification of hot mobile material termed magma
Indicated Mineral Resource
is that part of a Mineral Resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a reasonable level of confidence. It is based on exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes. The locations are too widely or inappropriately spaced to confirm geological and/or grade continuity but are spaced closely enough for continuity to be assumed
Inferred Mineral Resource
is that part of a Mineral Resource for which tonnage, grade and mineral content can be estimated with a low level of confidence. It is inferred from geological evidence and assumed but not verified geological and/or grade continuity. It is based on information gathered through appropriate techniques from locations such as outcrops, tenches, pits, workings and drill holes that may be limited or of uncertain quality and reliability
In-Situ
The original, natural state of the orebody before mining or processing of the ore takes place
Intrusion
The process of emplacement of magma (naturally occurring molten rock material generated within the earth) in pre-existing rock
IP Survey
Induced polarisation survey

K

K
Chemical symbol for potassium
Kriging
An interpolation method that minimises the estimation error in the determination of mineral resources

L

Leaching
The dissolving of elements and minerals out of ore
Lenticular
Resembling in shape the cross section of a lens
Lower Proterozoic
Era or geological time between 2.5 x 109 and 1.8 and 109 years before the present

M

m
Metre
Measured Resource
That 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
Meta-morphosed
The mineralogical and structural adjustment of solid rocks to physical and chemical conditions which have been imposed at depth below the surface zones of weathering and cementation
Metallurgy
The science and art of separating metals from their ores by mechanical and chemical processes
Metasediment
A sedimentary rock that has undergone metamorphism
Metavolcanic
A rock which was volcanically extruded onto the surface and subsequently altered mineralogically by a combination of heat and pressure. (Metamorphism)
Meta-volcanics
Metamorphosed volcanic rocks
Mill
A plant where ore is ground fine and undergoes physical or chemical treatment to extract the valuable metals
Milling
Process to reduce broken ore to a size where concentrating can be undertaken
Mineral
A naturally formed chemical element of compound having a definite chemical composition and, usually, a characteristic crystal form
Mineral Reserve
is the economically mineable material derived from a measured and/or indicated Mineral Resource. It is inclusive of diluting materials and allows for losses that may occur when the material is mined. Appropriate assessments, which may include feasibility studies, have been carried out, including 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 is justifiable. Mineral Reserves are subdivided in order of increasing confidence into Probable Mineral Reserves and Proved Mineral Reserves
Mineral Resource
is a concentration or occurrence of material of economic interest in or on the Earth’s crust in such form and quantity that there are reasonable and realistic prospects for eventual economic extraction. The location, quantity, grade, continuity and other geological characteristics of a Mineral Resource are known, estimated from specific geological evidence and knowledge, or interpreted from a well constrained and portrayed geological model. Mineral resources are subdivided, in order of increasing confidence in respect of geoscientific evidence, into Inferred, Indicated and Measured categories
Mineral Resources
Any mineral deposit in such form and quantity that mining of the mineral may be feasible. The location, grade, quality and quantity of ore are estimated from specific geological evidence. Mineral resources are subdivided based upon the confidence of estimated qualities of that resource
Mining Area
The area for which a mining authorisation /permission to mine has been granted
Moz
Million troy ounces
Mt
Million metric tons

O

Open-pit
Open cut; mine worked at surface
Ore
Rock which contains a mineral or a concentration of minerals and/or metals which can be mined for a profit
Ore reserve
That part of a “Resource” which feasibility studies have shown “could be recovered economically under conditions realistically assumed at the time of reporting”
Orebody
Mostly solid and fairly continuous mass of mineralisation estimated to be economically mineable
Overburden
Uneconomic material which overlies a bed of useful material; barren rock material overlying a mineral deposit
Oxidised Ore
Ore that has decomposed by exposure to surface and near-surface elements
oz
Ounce
Oz/ton
Ounce of a particular element per short ton of rock

P

Pluton
An igneous intrusion
ppm
Parts of a particular element per million parts of rock or soil
Pre-feasibility study
The initial stage of the feasibility study in which the accuracy of the factors involved such as costs and revenues is +- 25%. Should the pre-feasibility study be positive, then the company would move to the final feasibility study
Probable Mineral Reserve
This is the economically mineable material derived from a Measured and/or Indicated Mineral Resource. It is estimated with a lower level of confidence than a Proved Mineral Reserve. It is inclusive of diluting materials and allows for losses that may occur when the material is mined. Appropriate assessments, which may include feasibility studies, have been carried out, including 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.
Probable Ore Reserve
The economically mineable part of an Indicated, and in some circumstances, Measured 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
Proved Mineral Reserve
The economically mineable material derived from a Measured Mineral Resource. It is estimated with a high level of confidence. It is inclusive of diluting materials and allows for losses that may occur when the material is mined. Appropriate assessments, which may include feasibility studies, have been carried out, including 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 is reasonably justified.
Proven Ore Reserve
The economically mineable part of a Measured Mineral Resource. It includes diluting material 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 justifiedv

Q

Quartz
Crystalline silica; silicon dioxide
Quartzite
A very hard, often metamorphosed, sandstone consisting chiefly of tightly cemented quartz grains

R

RC
Reverse circulation drilling
Reclamation
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
Recovery Rate
A term used in process metallurgy to indicate the proportion of valuable material obtained in the processing of an ore. It is generally stated as a percentage of the material recovered compared with the total material present
Reef
A gold-bearing quartz vein
Reef
Ore of economic interest
Refining
The final stage of metal production in which impurities are removed from the molten metal
Regolith
Fragmental and unconsolidated rock material overlying bedrock
Resource definitions
The mineral resources and mineral reserves of the Group are classified, verified and reported in accordance with statutory, stock exchange and industry/professional guidelines. The classifications are based on the SAMREC Code.
Reverse circulation drilling (RC)
A drilling method using a tricone bit, during which rock cuttings are pushed to the surface through an outer tube by liquid and/or air pressure moving through an inner tube
Reverse fault
A thrust fault with a dip of 45″ or less in which the hanging wall appears to have moved upward relative to the footwall
ROM
Run of Mine - equivalent to normal feed ore from mining operations

S

Sandstone
A medium-grained sedimentary rock composed of abundant fragments of sand size set in a fine-grained matrix of silt or clay
Saprolite
Weathered rock with distinguishable features/minerals of original rock
Schist
A strongly foliated crystalline rock formed by dynamic metamorphism
Sedimentary
Sourced from erosion of other rock
Shale
A fine-grained detrital sedimentary rock formed by the consolidation of clay, silt or mud and characterized by finely stratified structure
Shear zone
A tabular zone of rock that has been crushed and brecciated by many parallel fractures due to shear strain
Smelting
A metallurgical operation in which metal is separated from impurities by a process that includes fusion
Spot gold price
Refers to the open market gold price that we all hear on the radio or see in the morning paper. A spot price is the opposite of a contractual or fixed price, which remains constant over a certain agreed period
Sterilization
Drilling carried out to ensure there is no hidden mineralisation below of permanent infrastrucutre (also known as condemnation drilling)
Strike
The direction or trend that a structural surface, e.g. a bedding or fault plane, takes as it intersects the horizontal
Stringer
A mineral veinlet (typically less than 1cm wide), or filament occurring in a discontinuous pattern in the host rock
Stripping Ratio
The number of units of unpayable material which is to be mined in order to expose one unit of ore
Sulphide
A compound of sulphur with metallic element
Syncline
A concave upward fold, the core of which contains the stratigraphically younger rocks

T

T (t)
Tonne
Tailings
Finely ground rock material that remains once all economically-valuable metals are removed
Tailings Grade
The metal content of the tailings produced by the milling and concentrating process - when compared to head grade is a measure of the efficiency of the extraction process
Termitary
Geochemical sampling of residual surficial material (mounds) produced by termites
Ton
(Used in imperial statistics)

A short tone equal to 2 000 pounds
Tonne
(Used in metric statistics)

Equal to 1 000 kilograms
Tourmaline
A mineral commonly found as an accessory in intermediate to felsic igneous rocks, metamorphic rocks and certain sedimentary rocks
TPM
Metric tonnes per month
Transport
The moving of broken rock to the shaft and the transport of men and materials to the working faces
Trend
The regional strike of a geological feature
Troy ounce
(Used in imperial statistics)

Equal to 31 10348 grams
Troy system
A system of units used for precious metals and gems. The pound troy (0.37kg) consists of 12 ounces (each of 120 carats) or 5 760 grains (each equal to 65 mg)

U

U
Chemical symbol for uranium
Unoxidised Ore
Ore that has not undergone changes/degradation due to the weathering process close to surface

V

Vein
A thin sheetlike crosscutting body of hydrothermal mineralization, principally quartz

W

Weathering
The destructive process constituting that part of erosion whereby earthy and rocky materials on exposure to atmospheric agents at or near the earth’s surface are changed in character with little or no transport of the loosened or altered material
Whittle
An optimisation computer program used for open pit mine design
Wireframe
Outline of an orebody based on varying parameters