Adit |
a tunnel driven horizontally into a hillside to provide access to a mineral deposit |
Agitation leaching |
leaching of gold from the host rock by agitating the ground ore in a cyanide solution |
Archean |
a term usually applied to the oldest Precambrian rocks |
Argillite |
a rock derived either from siltstone, claystone, or shale that has undergone a higher degree of hardening through heat, cementation or pressure than exists in those rocks |
Autoclave system |
oxidation system in which high temperatures and pressures are applied to convert refractory sulphide mineralization into amenable oxide ore. |
Backfill |
material used to fill the space in a mine after ore has been extracted |
Ball mill |
a mill using metal balls as the grinding medium |
Boudin |
structure arising from tensional forces. It develops by stretching of a competent bed along bedding planes giving rise to tension cracks. Appearance is that of a string of sausages. |
Carbon-in-leach |
a process very similar to carbon-in-pulp. In the carbon-in-leach process, the leaching and absorbing of gold onto carbon take place in the same tank |
Carbon-in-pulp |
a process to recover gold from a cyanide leach slurry. Coarse, activated carbon particles are moved counter-current to the slurry, absorbing the gold. Loaded carbon is removed by screening, and the gold is recovered from the carbon by stripping in a caustic cyanide solution followed by electrolysis or by zinc precipitation |
Cash cost |
includes production costs, royalties, marketing and refining charges, together with all administration expenses at the joint venture level |
Commercial production |
production for accounting purposes |
Cut-and-fill |
a mining method which involves excavating a stope, then filling it with waste material to provide support |
Cut-off grade |
the lowest grade of mineralized material considered economic; used in the calculation of the ore reserves in a given deposit |
Cyanidation |
a method of extracting gold grains from crushed or ground ore by dissolving them in a weak solution of sodium or calcium cyanide: also known as leaching |
Decline ramp |
an inclined haulage road |
Dip |
the angle at which a vein, structure or rock bed is inclined from the horizontal, measured at right angles to the strike |
Disseminated ore |
ore carrying small particles of valuable minerals, spread more or less uniformly through the gangue matter; distinct from massive ore, wherein the valuable minerals occur in almost solid form with very little waste mineral included |
Doré |
impure mixture of metallic gold and silver produced through the smelting of gold and silver
concentrate, sand or precipitate. Typical impurities include base metals |
Epithermal |
hydrothermal deposits formed at low temperature and pressure |
Flotation |
a process for concentrating materials based on the selective adhesion of certain minerals to air bubbles in a mixture of water and ground-up ore. When the right chemicals are added to a frothy water bath of ore that has been ground to the consistency of talcum powder, the minerals will float to the surface. The metal-rich flotation concentrate is then skimmed off the surface |
Footwall |
the mass of rock beneath a geological structure such as an orebody or fault |
Formation |
the ordinary unit of geologic mapping consisting of a large and persistent stratum of rock |
Gold equivalent |
silver expressed in equivalent ounces of gold using a conversion ratio dependent on prevailing gold and silver prices |
Gravity separation |
recovery of gold from crushed rock or gravel using gold’s high specific gravity to separate it from lighter material |
Grinding media |
material used to finely grind ore material to a size which allows recovery of the desired contained material |
Hangingwall |
the mass of rock overlying a geological structure such as an orebody or fault |
Hedging |
an arrangement which effectively offsets a price or exchange risk inherent in another transaction or arrangement |
In-fill drilling |
drilling within a group of previously drilled holes to provide a closer spaced pattern to define more accurately the parameters of the orebody |
Leaching |
the process in which a soluble metallic compound is extracted from ore by dissolving the metals in a solvent; see cyanidation |
Level |
a horizontal opening in a mine; levels are usually established at regular intervals |
Merrill-Crowe |
a precipitation process to recover precious metals using zinc dust to treat a de-oxygenated precious metals-cyanide solution |
Mineralized zone |
any mass of host rock in which minerals of potential commercial value occur |
Net smelter return |
an interest in a mining property held by the vendor on the net revenue generated from the sale of metal produced by the mine |
Operating cost |
cash cost plus depreciation and amortization |
Ore |
material that contains one or more minerals, at least one of which can be recovered at a profit |
Ounces |
troy ounces of a fineness of 999.9 parts per 1,000 parts, equal to 31.1034 grams |
Oxidized ore |
the alteration of metalliferous minerals by weathering and the action of surface waters and their conversion, partly or wholly into oxides, carbonates or sulfates |
Phyllite |
scaly minerals, micas, chlorites and clays; a term more recently applied to minerals with a layered crystal structure |
Porphyry |
rocks containing conspicuous phenocrysts in a fine-grained or aphanitic groundmass |
Precipitate |
a mixture of mineral particles filtered from solutions as a result of a chemical reaction |
Proterozoic |
the younger of two Precambrian systems or eras |
Pyroclastic |
produced by explosive or aerial ejection of material from a volcanic vent |
Pyroclastic deposits |
deposits made up mainly of rock material that has been expelled aerially from a volcanic vent |
Reagent |
a chemical used in the mineral recovery process |
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, 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 |
Reserves |
that part of a mineral deposit which could be economically and legally extracted or produced at the time of the reserve determination. Reserves are customarily stated in terms of ore when dealing with metalliferous minerals. There are three categories of reserves:
Proven ore – material for which tonnage and grade are computed from dimensions revealed in outcrops, trenches, underground workings or drill holes; grade is computed from the results of adequate sampling; and the sites for inspection, sampling and measurement are so spaced and the geological character so well-defined that size, shape and mineral content are established.
Probable ore – material for which tonnage and grade are computed partly from specific measurements, samples or production data and partly from projection for a reasonable distance on geological evidence; and for which the sites available for inspection, measurement and sampling are too widely or otherwise inappropriately spaced to outline the material completely or to establish its grade throughout.
Possible ore – material for which quantitative estimates are based largely on broad knowledge of the geological characteristics of the deposit and for which there are few samples or measurements.
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Resource |
mineralization based on geological evidence and assumed continuity. May or may not be supported by samples but is supported by geological, geochemical, geophysical or other data |
Rod mill |
a mill using metal rods as the grinding mechanism |
Room and pillar |
a method of mining flat-lying deposits in which the mined-out ore or “rooms” are separated by pillars of approximately the same size |
Run of mine ore |
uncrushed ore in its natural state just as it is when blasted |
Semi-autogenous mill |
a mill in which rock is reduced to smaller particles partially by grinding against other pieces of rock |
Shaft |
a vertical passageway to an underground mine for moving personnel, equipment, supplies and material including ore and waste rock |
Skarn |
the metamorphic rocks surrounding an igneous intrusive where the latter has come in contact with limestone or dolomite rocks |
Spot price |
current delivery price of a commodity traded in the spot market, also called the cash price |
Stope |
the working area in a mine from which ore is extracted |
Stratigraphic |
pertaining to the composition, sequence and correlation of stratified rocks |
Strike |
the direction, or course or bearing, of a vein of rock formation measured on a level surface |
Stripping ratio |
the ratio of the amount of waste material which must be removed in an open pit to allow one ton of ore to be mined |
Sulphides |
compounds of sulphur with other metallic elements |
Tailings |
material rejected from a mill after the valuable minerals have been recovered |
Tertiary |
the earlier of the two geologic periods in the Cenozoic era |
Triassic |
the earliest of the three geologic periods comprised in the Mesozoic era |
Vertical crater retreat (VCR) |
a method of mining ore underground in which holes drilled between sublevels are blasted in successive horizontal slices from bottom to top |
Water management |
the process whereby the groundwater table in the mining area is lowered by pumping water from wells, and the water is conveyed and used or recharged to the groundwater system through infiltration, reinjection or irrigation return |