Mining Glossary

The mining glossary provides a reference source for pgm mining terminology used on this site and elsewhere

A trading glossary is available in the PGM Prices section.

Terms appearing in italics are also defined within the glossary.

If you would like to suggest changes or additions to the glossary please contact us. Further information can also be found in the FAQs.

A - H | I - Q | R - Z

A-H

Adit: A passage driven into a mine from a hill or mountainside.

Alluvial deposits: Material, typically sands and gravels, transported by a river and deposited at points on the river's flood plain. These deposits can contain economically viable mineral resources. In the Kondyor and Koryak areas of eastern Russia alluvial deposits are mined for platinum group metals.

Bench: A ledge created in an open pit, which forms the surface for extraction. The size of the bench will reflect the strength of the rock, stability of adjacent slopes, pit economics and the machinery employed.

Black Economic Empowerment (BEE): A South African Government policy aimed at increasing the access that black South Africans have to "productive assets whilst simultaneously ensuring the productivity of those assets". BEE seeks "to promote new opportunities for and increase the levels of participation of black people in the ownership, management and control of economic activities". South African pgm mining companies have responded to the policy through a range of joint ventures and asset sales to BEE organisations.
Quotes from the Black Economic Empowerment Commission Report, 2001.

Bushveld Igneous Complex: Formed about 2,000 million years ago, the Bushveld Igneous Complex (BIC) is a well differentiated geological structure with an areal extent of some 450km east-west by 300km north-south. It has a series of distinct layers, three of which are currently mined for platinum group metals (pgm).

By-product: Material of some economic value produced in a process which is focused on extracting another material. For example palladium is produced as a by-product of platinum mining in South Africa.

Concentrating: The process of separating milled ore into two streams; one greatly enriched in the valuable mineral (concentrate) and another of waste material (tailings). Concentration is a vital economic step in the production process because it reduces the volume of material which must be transported to and processed in a smelter and refinery.

Decline: An inclined shaft used to transport workers, materials and ore to and from the underground working area in a mine.

Dense media separation (sink and float process): A pre-concentration process used by some pgm producers which separates relatively light and heavy particles by immersion in a liquid of an intermediate density.

Disseminated: Term applied to ore deposits consisting of fine grains of ore mineral dispersed through the host rock.

Froth flotation: A method of mineral concentration used in pgm production which separates the various minerals in the feed by utilising the differing surface properties of the minerals. The separation is achieved by passing air bubbles through the mineral pulp. By adjusting the chemistry of the pulp by using various reagents, valuable minerals can be made aerophilic (air-avid) and gangue minerals aerophobic (water avid). Separation occurs by the valuable minerals adhering to the air-bubbles which form the froth floating on the surface of the pulp.

Gangue: Material in the ore of no economic value.

Grade: The mass of desired metal(s) in a given mass of ore. Pgm-bearing ores are typically extremely low-grade. Grades are normally expressed as grams per tonne, equivalent to parts per million. Mining companies commonly quote combined 4-element grades, i.e. the combined mass of platinum, palladium, rhodium and gold per unit of ore. Combined six element grades are also quoted, which also include ruthenium and iridium.

Great Dyke: A pgm-bearing igneous body situated in Zimbabwe. A sinuous (4-11km wide), layered, mafic-ultramafic intrusion around 2,500 million years old which runs for 550km across the country (NNE - SSW). The Great Dyke consists of four geological complexes of which the Hartley complex is by far the largest (approximately 90km in length) and contains around 80% of Zimbabwe's pgm resource.

Head grade: The grade of the ore leaving the mine and entering the processing plant. Also termed mill head grade, which is the grade of ore as it enters the milling process.

I - Q

J-M Reef: A pgm-bearing horizon in a lenticular igneous intrusion located in Montana, USA. Formed approximately 2,700 million years ago, the J-M Reef extends for 45 km along strike and approximately 1.6 km downward and remains open at depth. The reef is worked at its eastern end by Stillwater Mining Company, which has also developed another mine, East Boulder, at the western end.

Joint venture: A contractual agreement between two or more parties for the purpose of executing a business undertaking. All parties agree to share in the profits and losses of the enterprise.

Merensky reef: A thin (0.3-3m) pgm-bearing horizon near the base of the Merensky zone in the Bushveld Igneous Complex. Chromite bands around 1cm thick mark the top and bottom of the reef and are enriched with platinum relative to the reef. Pgms are associated with nickel and copper sulphides and these base metals are also recovered. Nickel and copper concentrations are around 10 times higher than those in the UG2 horizon in the Bushveld.

Milling: The first stage of mineral processing. Crushed ore pieces from the mine are further mechanically reduced in size to maximise efficiency of the concentration process. In general two types of mills are used. Autogenous mills simply tumble the ore to achieve the desired grains size, whilst ball mills use an additional media, such as steel balls or rods, to aid milling.

Mining feasibility study: An assessment of the economic viability of a potential mining project. The study must consider all aspects of the project, including mine and processing plant design, waste disposal, environmental management and permitting. A feasibility study will only be undertaken after an extensive series of desk studies, exploration and trial mining and processing projects have been completed.

LHD (Load-Haul-Dump) vehicles: Vehicles used in some underground pgm mines to transport ore from the working areas to the main haulage system.

Open pit: A mine based on extraction from a surface excavation, which remains open to the surface for the life of the mine.

Ore: Rock from which metal or minerals can be extracted at a financial profit.

Ore mineral: A mineral which contains a metal or metals which can be extracted at a financial profit.

Platinum Group Elements/Platinum Group Metals (PGE/PGM): The six metallic elements platinum, palladium, rhodium, ruthenium, iridium and osmium.

Platreef: A pgm-bearing horizon occurring at the base of the northern (Potgietersrus) limb of the Bushveld Igneous Complex. The Platreef is far thicker (up to 200m) than the Merensky and UG2 horizons and has higher base metal grades. The richest mineralisation tends to be near the base of the intrusion and grades tend to be very irregular.

R - Z

Refining: see smelting.

SAMREC Code: The South African Mineral Resources Committee's code sets a required minimum standard for Public Reporting on exploration results, mineral resources, or mineral reserves in South Africa, prepared for the purpose of (a) informing investors or potential investors and their advisers or (b) satisfying regulatory requirements.

Shaft: A vertical or inclined conduit providing access from the surface to underground orebodies.

Smelting: Extracting metals from the ore concentrate by pyrometallurgical processes.

Stope: void created by extracting ore underground.

Stoping: activity of extracting ore underground.

Stripping Ratio: number of units of unpayable material (waste rock or overburden) which must be removed to expose one unit of ore in an open pit.

Tailings: fine grained remains of ore once most of the valuable material has been removed in the concentration process.

UG2 (Upper Group 2): A Chromitite layer in the Bushveld Igneous Complex which contains economically viable concentrations of pgm. The UG2 lies 130-300m below the Merensky reef in the intrusion and is typically 0.6 -1.3m thick. The UG2 has the highest concentration of sulphide minerals of all Chromitite layers in the Bushveld.