- 1 barrel of oil
- 158.987 litres
- 1 kilogram
- 32.15 troy ounces; 2.2046 pounds
- 1 metric tonne
- 1,000 kilograms; 2,204.6 pounds
- 1 troy ounce
- 31.1 grams
Adit means a permanent horizontal underground tunnel leading from the surface to an ore body.
- Agitation leaching
Agitation leaching means a technological operation consisting of mixing slurry with the leaching agent in a tank agitated by impellers or rakes.
Assay means a chemical test performed on a sample of any material to determine the amount of valuable metals contained in the sample.
Autoclave means a lined stainless-steel vessel in which a technological operation of pressure oxidation takes place.
Backwardation means where the price of a forward or futures contract is trading below the spot price.
- Ball mill
Ball mill means a lined steel cylindrical vessel filled with steel balls in which a technological operation of grinding takes place. Size reduction is mostly achieved through balls impacting ore particles and particles abrading each other.
- Oil barrel
- Biological oxidation
Biological oxidation means a technological operation in which slurry is subjected to the activity of bacteria with the goal to destroy sulphide particles enveloping gold particles and make slurry amenable to cyanide leaching.
By-product means a secondary metal or mineral that is produced or recovered during mining and processing at a deposit. A by-product offers additional economic benefits to the project, but it is not necessary in order for the project to be economically efficient.
Carbon-in-column or CIC means a technological operation in which gold and silver dissolved in clean leach solution are absorbed onto activated carbon which is layered horizontally in vertical columns.
Carbon-in-leach or CIL means a technological operation in which slurry containing gold and silver is leached by cyanide in the presence of activated carbon. Gold is absorbed onto activated carbon in parallel with leaching.
Carbon-in-pulp or CIP means a technological operation in which slurry containing gold and silver is leached by cyanide initially without and subsequently in the presence of activated carbon. Gold absorption onto carbon starts only after preliminary leaching.
- Commonwealth of Independent States
Co-product means one of two metals that are produced at a deposit. The presence of the second co-product may allow for production at the mine to be economically efficient. A co-product is in contrast to a by-product.
- Cut-off grade
Concentrate means a semi-finished product of mineral processing (flotation or gravity separation) containing significantly more value per unit of weight than ore and subject to further processing for the production of metals or other substances in final useful form.
Contango means where the price of a forward or futures contract is trading above the expected spot price at contract maturity.
- Conventional flotation
Conventional flotation means flotation employing traditional equipment and reagents (as opposed to column flotation or inert atmosphere flotation or reverse flotation).
- Conventional rotary
Conventional rotary means a drilling method that produces rock chips similar to reverse circulation, except that the sample is collected using a single-walled drill pipe. Air or water circulates down through the centre of the drill pipe and returns chips to the surface around the outside of the pipe.
- Core drilling
Core drilling means a drilling method that uses a rotating barrel and an annular-shaped, diamond impregnated rock-cutting bit to produce cylindrical rock cores and lift such cores to the surface, where they may be collected, examined and assayed.
- Counter-current decantation
Counter-current decantation means a technological operation in which gold-and-silver bearing clear liquid is separated from the slurry through several stages of water addition (washing) and solid/liquid separation (thickening). Employed in the Merrill Crowe process.
Crushing means a technological operation in which the size of run-of-mine ore particles is reduced, sometimes in several stages, to make material amenable for further processing (grinding or heap leaching).
Cut-and-fill means a method of underground mining which requires purposeful backfilling of space emptied of ore. It is used where ore contains relatively high mineral values and ground conditions are less competent.
- Cut-off grade
Cut-off grade means the minimum grade at which mineralized material can be economically mined and processed (used in the calculation of ore reserves).
- Cyanide leaching
Cyanide leaching means leaching with cyanide as the leaching agent.
Decline means a permanent inclined underground tunnel leading from the surface to an ore body.
Desorption means a technological operation following CIP/CIL/CIC/RIL in which gold is washed away from its carrier particles (carbon resin) by the hot chemically active solution.
- Diamond core drilling
- <p>Diamond core drilling means a method of exploration in which rock samples from underground are retrieved as core (whole rock cylinders) for further examination and assaying.</p>
Dilution means the share (percentage) of material below the cut-off grade that is extracted together and irretrievably mixed with ore during mining. All other things being equal, higher dilution leads to lower grade in ore mined.
Dip means the angle between the ore body and the vertical. Also the vertical extent of an ore body or mineralisation.
Drift means a temporary horizontal underground tunnel along the strike of or parallel to an ore body.
Electrowinning means a technological operation following desorption in which gold from the desorbed solution is recovered onto a steel plate through electrolysis.
Exploration means activity ultimately aimed at discovery of ore reserves for exploitation. Consists of sample collection and analysis, including reconnaissance, geophysical and geochemical surveys, trenching, drilling, etc.
- Flash flotation
Flash flotation means fast flotation employed to recover coarse particles predominantly composed of metal-bearing minerals.
Flotation means a technological operation in which ore-bearing minerals are separated from gangue minerals in the slurry based on variance in the interaction of different minerals with water. Particles of valuable concentrate are carried upwards with froth and collected for further processing.
Freibergite means a complex sulfosalt mineral of silver, copper, iron, antimony and arsenic with formula (Ag,Cu,Fe)12(Sb,As)4S13.
- Future value
Gangue means barren minerals within ore or mineralisation.
Grade means the relative amount of metal in ore, expressed as grams per tonne for precious metals and as a percentage for most other metals.
- Grade control
Grade control means a complex of technological operations aimed at decreasing dilution.
- Gravity concentration
Gravity concentration means a technological operation in which ore-bearing minerals are separated from gangue minerals in the slurry based on variance in the specific gravity of different minerals. Heavier particles of valuable concentrate are carried downwards and collected for further processing.
Grinding means a technological operation in which the size of ore particle is reduced by impact, pressure or abrasion, to liberate valuable minerals for further processing.
HDPE means high-density polyethylene.
- Head grade
Head grade means the grade of ore coming into a processing plant.
- Heap leach
Heap leach means a technological operation in which crushed material is laid on a sloping, impervious pad where it is leached by cyanide solution to dissolve gold and/or silver. Metals are subsequently recovered from pregnant leach solution by CIC or the Merrill Crowe process.
- Heap leaching
In-fill means the collection of additional samples between existing samples, used to provide greater geological detail and to provide more closely-spaced assay data.
- In-fill drilling
in-fill drilling means a conventional method of detailed exploration on already defined resource of reserve, consisting of drilling on a denser grid to allow more precise estimation of ore body parameters and location.
An alloy of nickel, chromium, and iron that is highly resistant to high temperatures and corrosion.
- Indicated resource
Indicated resource means that part of a resource for which tonnage, grade and 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 resource
Inferred resource means that part of a resource for which tonnage, grade and 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, trenches, pits, workings and drill holes which may be limited or of uncertain quality and reliability.
Koz means thousand ounces.
Kt means thousand tonnes.
ktpa means a thousand tonnes per annum.
kv means kilovolts.
Leaching means the process of dissolving mineral values from solid into liquid phase of slurry.
LHD means a load haul dump being an underground front-end loader used to excavate ore and transport if over short distances.
- Longwall mining
Longwall mining means a mechanised or manual method in which long open voids (slots) left after ore extraction are left to subside and get filled with surrounding rock.
Losses Means the part of ore that cannot be extracted due to technical and economic constraints and is irretrievably lost for future use.
- Measured resource
Measured resource means that part of a 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 appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes. The locations are spaced closely enough to confirm geological and grade continuity.
- Merrill Crowe process
Merrill Crowe process means a technological operation for extraction of gold and/or silver after cyanide leaching. In the first step slurry containing gold and/or silver is separated into liquid and solid phases by washing the solids off in counter current decantation thickeners. In the second step pregnant leach solution (liquid phase of slurry) is filtered to remove impurities and de-aerated. Finally, gold and silver are deposited onto the solid bed of clay like material where they replace zinc particles which pass into a solution. Merrill Crowe is preferentially used for silver-rich ores.
mill means a colloquial term for a mineral processing plant. Also a type of processing equipment for size reduction (see «ball mill» and «SAG mill»).
Mineralisation means a rock containing valuable components, not necessarily in the quantities sufficient for economically justifiable extraction. Consists of ore minerals and gangue.
Moz means million ounces.
mt means metric tonnes.
Mtpa means million tonnes per annum.
MW means megawatts.
- Open-pit mine
Open-pit mine means a mine that is entirely on surface. Also referred to as open-cut or open-cast mine.
Ore means the part of mineralisation that can be mined and processed profitably.
- Ore body
Ore body means a spatially compact and geometrically connected location of ore.
- Ore processed
Ore processed means ore subjected to treatment in a mineral processing plant.
- Ore stacked
Ore stacked means the ore stacked for heap leach operations.
Ore mined means ore extracted from the ground for further processing.
- Oxidised ore
Oxidised ore means ore in which both ore minerals and gangue are fully or partially oxidised thus impacting its physical and chemical properties and influencing the choice of a processing technology.
Oz or oz means troy ounce (31.1035 g).
- POX or pressure oxidation
POX or pressure oxidation means a technological operation in which slurry is subjected to high pressure and high temperature in an autoclave with the goal to destroy sulphide particles enveloping gold particles and make slurry amenable to cyanide leaching.
Precipitate means the semi-finished product of mineral processing by Merrill Crowe process, normally containing very high concentrations of silver and/or gold.
Preg-robbing means a characteristic of gold-bearing ore denoting the presence of organic carbon matter which may lead to lower recovery in conventional cyanide leaching. Lower recovery is due to losses of gold absorbed into the above-mentioned organic carbon instead of absorbing into man-made carbon introduced to the slurry in CIP or CIL.
- Primary ore
Primary ore means unoxidised ore.
- Probable reserves
Probable reserves means the economically mineable part of an indicated (and in some cases measured) resource, which has a lower level of confidence than proved reserves but is of sufficient quality to serve as the basis for a decision on the development of the deposit.
Production means the amount of pure precious metals, measured in thousands of ounces for gold, millions of ounces for silver and tonnes for copper, produced following processing.
- Proved reserves
Proved reserves means the economically mineable part of a measured resource, which represents the highest confidence category of reserve estimate. The style of mineralisation or other factors could mean that proved reserves are not achievable in some deposits.
Raise means a temporary vertical underground tunnel along the strike of an ore body.
Ramp means a permanent inclined spiral-like underground tunnel connecting various horizontal levels of an underground mine.
Reclamation means the restoration of a site after mining or exploration activity is completed.
- Recovery or recovery rate
Recovery or recovery rate means the percentage of valuable metal in the ore that is recovered by metallurgical treatment in the final or semi-finished product.
Refining means the final stage of metal processing in which residual impurities are removed from semi-finished product (doré, precipitate) and LME-grade metal bars or ingots are produced.
Refractory means a characteristic of gold-bearing ore denoting impossibility of recovering gold from it by conventional cyanide leaching.
Reserves means the economically mineable part of a measured and/or indicated mineral resource. It takes into account mining dilution and losses. Appropriate assessments and 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. Reserves are subdivided in order of increasing confidence into probable reserves and proved reserves.
Resources means a concentration or occurrence of material of intrinsic economic interest in or on the earth’s crust in such form, quality and quantity that there are reasonable prospects for eventual economic extraction. The location, quantity, grade, geological characteristics and continuity of resources are known, estimated or interpreted from specific geological evidence and knowledge. Resources are sub-divided in order of increasing geological confidence, into inferred, indicated and measured categories.
- Reverse circulation
Reverse circulation means a drilling method that uses a rotating cutting bit within a double-walled drill pipe and produces rock chips rather than core. Air or water is circulated down to the bit between the inner and outer wall of the drill pipe. The chips are forced to the surface through the centre of the drill pipe and are collected, examined and assayed.
RIL means a technological operation in which slurry containing gold and silver is leached by cyanide in the presence of ion-exchange resin. Gold is absorbed into resin in parallel with leaching. RIL is used preferentially when ore displays preg-robbing characteristics.
Roasting means a technological operation in which slurry is subjected to high temperature in the presence of oxygen with the goal to burn sulphide particles enveloping gold particles and make slurry amenable to cyanide leaching.
- Run-of-mine ore
Run-of-mine ore means ore as mined in terms of grade, size, moisture, etc.
- SAG mill
SAG mill means a lined steel cylindrical vessel filled with steel balls in which a technological operation of grinding takes place. Size reduction is mostly achieved through balls impacting ore particles and particles impacting each other.
- Shrinkage stoping
Shrinkage stoping means a manual method of underground mining which leaves behind large voids emptied of ore. It is used where ground conditions are competent and ore body is relatively narrow.
Slurry means a mixture of finely ground ore particles with water.
- sq km
sq km means square kilometres.
One of the types of mineralisation, a complex system of structurally controlled or randomly oeirnted veins. Stockworks are common in many ore deposit types.
Stope means a large underground excavation entirely within an ore body, a unit of ore extraction.
Strike means a horizontal extension of an ore body or mineralisation.
Stripping means the mining of waste in an open pit mine.
- Sub-level open stoping
Sub-level open stoping means a mechanised method of underground mining which leaves behind large voids emptied of ore. It is used where ground conditions are competent and ore body is relatively wide.
- Sulphide ore
Sulphide ore means unoxidised ore in which the main ore minerals are sulphides.
Sulphosalts means oxidised silver minerals amenable to cyanidation and flotation.
Tailings means part of the original feed of a mineral processing plant that is considered devoid of value after processing.
- Tailings storage facility
Tailings storage facility means a man-made facility for safely depositing and storing tailings.
- Total cash cost
Toll-refining means refining at third party facilities for a certain fee with title not passing to the third party.
Ton means short or imperial ton (2,000 pounds).
Tonne means metric ton.
- Underground development
Underground development means excavation which is carried out to access ore and prepare it for extraction (mining).
Vein means a relatively narrow ore body with significant dip and strike dimensions and sharply defined boundaries.
Waste means barren rock that must be mined and removed to access ore in a mine.
- Waste mined
Waste mined means waste extracted from the ground.
XRF-separation means a technological operation in which every particle of crushed ore is examined by an X-ray and, dependent on response, separated into enriched ore and waste. Silver-rich ore has a different X-ray response pattern (intensity, wavelength) compared with barren material.