Bacterial Oxidation (BIOX)

A process in which a combination of three bacteria are used to break down the sulphide mineral matrix in the ore being treated, thus freeing occluded gold for subsequent cyanidation. The bacteria attach themselves to the metal sulphide surfaces in the ore, resulting in the accelerated oxidation of the sulphides. During the bacterial oxidation process, elements like iron, sulphur and arsenic are dissolved.

Ball mill

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

Carbon in leach (CIL)

A method of recovering gold and silver, in which a slurry of gold/silver-bearing ore, carbon, and cyanide are mixed together. The cyanide dissolves the gold, which is subsequently absorbed by the activated carbon whose base is usually ground coconut shells.

Carbon in pulp (CIP)

A technique in which granular activated carbon particles much larger than the ground ore particles are added to a cyanide pulp which is already impregnated with the gold particles. The activated carbon and pulp are agitated together to enable the solubilised precious metals to become adsorbed onto the activated carbon.

Crushing

Breaking of ore from the size delivered from the mine into smaller and more uniform fragments to be then fed to grinding mills or to a leach pad.

Doré

The final, saleable product of a gold mine. Usually consisting of gold and silver.

Drilling

Core: 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. Reverse circulation: 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. Conventional rotary: 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. In-fill: the collection of additional samples between existing samples, used to provide greater geological detail and to provide more closely-spaced assay data.Exploration Prospecting, sampling, mapping, diamond drilling and other work involved in searching for ore.

Flotation

A milling process in which valuable mineral particles are induced to become attached to bubbles and float as others sink.

Grade

The amount of metal in each tonne of ore, expressed as troy ounces per tonne or grams per tonne for precious metals and as a percentage for most other metals.

Grinding (milling)

Powdering or pulverising of ore, by pressure or abrasion, to liberate valuable minerals for further metallurgical processing.

g/t

Gram per tonne.

Indicated resource

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

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

Thousand ounces.

Kt

Thousand tonnes.

Measured resource

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.

Metric conversion

grams x 31.10348 = troy ounces; grams per tonne x 34.28600 = troy ounces per short ton; tonnes x 0.00045 = pounds; tonnes x 0.90718 = tons; metres x 0.30480 = feet; kilometres x 1.60930 = miles; hectares x 0.40468 = acres; Fahrenheit (F-32) x 5/9 = Celsius

Mill

A plant in which ore is treated and metals are recovered or prepared for smelting; also a revolving drum used for the grinding of ores in preparation for treatment.

Moz

Million ounces.

Mt

Million tonnes.

Open pit mine

A mine that is entirely on the surface. Also referred to as open-cut or opencast mine.

Ore

A mixture of ore minerals and gangue from which at least one of the metals can be extracted at a profit.

Oz or oz

Troy ounce (31.1035g).

Probable reserves

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.

Proved resources

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.

Reclamation

The restoration of a site after mining or exploration activity is complete.

Recovery rate

The percentage of valuable metal in the ore that is recovered by metallurgical treatment.

Refining

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

Reserves

The economically mineable part of a measured and/or indicated mineral resource. It includes diluting materials and allowances for losses, which may occur when the material is mined. 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 sub-divided in order of increasing confidence into probable reserves and proved reserves.

Resources

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.

Tailings

Material rejected from a mill after most of the recoverable valuable minerals have been extracted.

Tailings storage facility

A natural or man-made confined area suitable for depositing the material that remains after the treatment of ore.

Tonne

Metric ton.

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