Glossary

This is a selected glossary of commonly used terms in the mining and minerals processing industry.

If you can't find the term you're after, please e-mail us.

Adit
A horizontal, or near horizontal passage, driven from the surface for the working of the mine.

Anode
Generally refers to impure copper cast into a special shape for incorporating into an electrolytic refinery for the final purification process.

Aquifer
An underground geological zone which is able to store or conduct water in reasonably large quantities.

Assay
The testing of a sample of ore to determine the content of valuable minerals.

Autogenous (AG) grinding
A secondary grinding system where material is tumbled in a revolving cylinder with no steel rods or balls taking part in the operation.

Back
The roof or upper part in any underground mining cavity.

Ball mill
A horizontal rotating steel cylinder which grinds ore to fine particles. The grinding is carried out by the pounding and rolling of a charge of steel balls carried within the cylinder.

Base metals
Commercial metal such as copper, lead or zinc. The term was coined to describe a metal 'inferior' to precious metals such as gold and silver.

Benching
A method of working small quarries or opencast pits in steps or benches.

Biological oxygen demand
Potential for microorganisms in decomposing organic matter to consume oxygen in water. Biological Oxygen Demand readings provide a measure of the effects of organic pollution on receiving waters.

Blast
The ignition of a heavy explosive charge, particularly a large one in opencast or quarry work.

Blast furnace
A furnace in which solid fuel is burned with an air blast to smelt ore in a continuous operation.

Borehole
A hole drilled into the ground at any angle to secure geological information.

Breccia
Rock made of highly angular, course fragments.

Bullion
Gold or silver bars produced at the refineries, or impure gold or silver obtained by smelting, or silver and gold alloy in bars.

By-product
A secondary or additional mineral or mineral product.

Cathode
Unmelted flat plate produced by electrolytic refining process of anode copper.

Coal
A combustible rock of organic origin composed mainly of carbon, hydrogen and oxygen with lesser amounts of nitrogen, sulphur and other elements. Coal is formed from accumulated vegetable matter that has been altered by decay and by various amounts of heat and pressure.

Coal preparation plant
A plant for the cleaning and sizing of the raw coal before it is loaded into railway wagons or road vehicles.

Coke
A porous solid composed mainly of carbon and ash.

Concentrate
An intermediate powdery material derived from the flotation process containing minerals plus various quantities of sulphur, iron and other impurities.

Concentrator
A mill or plant in which minerals are separated from waste rock, usually containing grinding mills where the ore is ground and flotation cells where the mineral concentrate is extracted.

Continuous miner
A large, heavy mining machine that can cut and load the coal.

Converter
A brick-lined, cylindrical vessel in the smelter for processing molten copper matte from the reverberatory furnace; the impurities, principally iron and sulphur, are removed by blowing air through the molten bath; the result is blister copper (97% purity).

Conveyor
An endless belt or chain for transporting coal, or other material, from one point to another.

Copper (Cu)
A native metal found in hydrothermal and metasomatic deposits, in the cavities of basic igneous rocks, and in the zones of oxidisation of copper veins.

Crosscut
An underground passage cutting through the orebody essentially at right angles to the dip and strike of the orebody.

Crusher
Apparatus in which ore is broken into progressively smaller pieces. Used for reducing coal, ore or rock. It may be used for preparing the feed to grinding mills.

Cyanide (HCN)
It is used in the recovery of gold and silver and also as a flotation reagent in the treatment of base metal ores.

Decibel
A unit of relative measure used to compare levels of sound intensity.

Development
The process of preparing an orebody for mining; sinking a shaft and driving haulage tunnels for the underground mine, or removing the overburden for an open-cut mine; installing crushers, concentrators, transportation, power and water lines, offices, shops, warehouses and community support services.

Dip
The angle at which the orebody is inclined from the horizontal.

Dore silver
Silver contained in unrefined precious metal.

Dragline
A crane-like, caterpillar-mounted, excavator with a bucket suspended on a long light boom, which is dragged by a steel rope towards the machine. It can dig material well below the level at which it stands and is usually able to dump the spoil in a levelled condition.

Drill
To cut or bore a hole in coal, ore or rock for blasting, exploration or other purpose.

Drive
An underground passage for exploration, development or working of an orebody. It may be taken along the orebody or parallel to it.

Dross
The scum that forms on the surface of molten metals.

Dump truck
A heavy-duty truck used for coal transport and dirt disposal.

Ecosystem
An ecosystem is composed of air, land, water and living organisms (often including humans) and the interactions between them. An ecosystem is dynamic in space and time and no ecosystem is closed with respect to exchanges of organisms, matter and energy.

Electrolytic
The process where copper anodes are immersed in a Coppercell containing an acidified copper sulphate refining solution with cathode starter blanks. As electrical current is passed between them, deposits of 99.99% pure copper collect on the cathodes.

Environmental efficiency
A measure of the relative amount of pollution or resource use required to produce a unit of product or service. To improve efficiency, more outputs must be produced while consuming less resources (such as raw water) and generating less waste.

Exploration
The process of locating and proving that a mineral occurrence is an orebody and that it is large enough, and contains enough mineral, to be mined profitably.

Face
The surface exposed by excavation; a working place from which coal or mineral is extracted.

Fauna
Animal life.

Feed
The crude ore introduced to a treatment plant or grinding mill.

Final voids
The openings which remain after the extraction of ore and/or waste rock.

Fines
In general, the smallest particles of coal or mineral in any classification process or sample of the run-of-mine material.

Flora
Plant life.

Flotation
The process of mixing ground ore with water chemical reagents and air to separate mineral particles from waste rock. The mineral particles stick to the air bubbles and float to the surface. The froth is collected and dewatered to produce concentrate for smelting or further processing.

Fluosolids roaster
A furnace in which copper concentrates are roasted to eliminate sulphur. Heat is provided by the burning sulphur.

Footwall
Opposite wall from the hanging wall; the wall on the lower side of an inclined orebody.

Fusion
The process or operation of melting or rendering liquid by heat.

Galena (PbS)
Naturally occurring lead sulphide; frequently associated with silver. When pure, galena contains 86% lead.

Geology
The science which investigates the physical history of the earth.

Gold (Au)
The element gold occurs very widely diffused in nature, chiefly in the free state, but invariably alloyed with silver or copper, and occasionally with other metals.

Grade (of ore)
The classification of an ore according to the desired or worthless material in it or according to value.

Greenhouse gas equivalents
The calculated quantity of carbon dioxide emitted by the creation of energy, combustion of diesel, and use of explosives, as well as the amount of carbon dioxide that would have the equivalent greenhouse gas effects as the amount of methane (and other gases) released.

Hanging wall
The wall on the upper side of an inclined orebody.

Head grade
The average grade of ore fed into the concentrator/mill.

Hoist
A winding engine installed at the top of the shaft of a mine and used for raising mineral, lowering supplies and the transport of workmen.

Incline
A sloping tunnel; a shaft not vertical.

In-situ
In its original state.

Longwall mining
A form of underground coal mining whereby the seam is removed in one operation by means of a mechanical shearer which cuts along a long working face or 'wall', hence the name.

Matte
A mixture of sulphur, iron and copper tapped from the reverberatory furnace in the smelter.

Metal
The final form of material derived from the processing of concentrate.

Metalliferous
Containing metal or metals of the heavier type.

Methane
The most common gas found in coal mines, it is flammable, tasteless, colourless, non-poisonous and odourless.

Milling
The grinding or crushing of ore.

Open cut mining
A form of mining designed to extract minerals that lie near the surface. Waste or overburden is removed to expose the minerals for mining. Rock covering the minerals is blasted and removed by large draglines or electric shovels and trucks.

Ore
A mixture of minerals, host rock and waste material which is expected to be economically mineable.

Ore reserves
Refers to that part of an orebody that has been planned for extraction. Classification is according to level of geological and mining confidence. 'Proved Ore Reserve' is the highest level, followed by 'Probable Ore Reserve'.

Orebody
A mass of ore of any shape, which may include low-grade and waste as well as valuable minerals, but is separate in form and character from the surrounding country rock.

Outcrop
That part of a geological formation or structure that appears at the surface of the Earth.

Overburden
The surface waste or worthless rock overlying a flat or moderately inclined economic deposit.

Oxide ore
Ore containing minerals which have been altered by oxidation or weathering.

Pass
An opening in a mine through which ore is delivered from a higher to a lower level.

pH
A relative measure of the acidity of a solution using a scale of 1-14. It is used to indicate whether a solution is acidic (below 7), neutral (7) or alkaline (above 7).

Precious metals
Metals such as gold and silver which are valued for other than ordinary industrial uses.

Preparation plant (see Coal preparation plant)

Pulp
A slime consisting of finely crushed ore and water. The material may be treated by cyaniding.

Pyrite (FeS2)
Sulphide of iron. A common ore containing about 53% sulphur and 46.7% iron. Commonly occurring in mineral deposits, its chief use is for the manufacture of sulphuric acid for which purpose it is roasted to obtain the sulphur as sulphur dioxide in the gaseous state.

Raise
A vertical or inclined opening, or passageway, driven to connect one mine working space with another at a higher level.

Reagent
A chemical or solution used to produce a desired chemical reaction; a substance used in assaying or in flotation.

Recovery
The amount of mineral separated and recovered in a mill, and expressed as a percentage of that calculated to be the original ore.

Rehabilitation
A process whereby previously mined or disturbed areas are returned to a stable, non polluting landform usually through recontouring and seeding.

Reserves (see Ore reserves)

Respirator
A piece of safety equipment worn by miners which covers the nose and mouth to prevent the wearer inhaling excessive quantities of dust.

Reverberatory furnace
A type of smelter where concentrates are melted, slag drawn off, and molten metal-bearing matte tapped for further processing.

Rod mill
A rotating, horizontal, steel cylinder in which steel rods grind the crushed ore.

Roof bolting
A system of roof support in underground mines.

Royalty
Amounts of money paid by a company operating a mining company to the actual owner of the mineral rights. The amount may be based on tonnes produced or by a percentage of revenue or profits.

Run-of-mine
Used to describe ore produced from a mine for sale or further processing to extract valuable minerals.

Run-of-mine coal (or ROM)
The raw coal as it is delivered by the mine cars, skips or conveyors and prior to treatment of any sort.

Seam
A stratified deposit, usually of coal.

Semi-autogenous (SAG) grinding
A grinding system material is ground by tumbling in a revolving cylinder using a proportion of steel rods or balls taking part in the operation.

Shaft
A vertical or steeply inclined excavation or opening from the surface (usually) down through the strata to the coal or mineral to be developed.

Shot
A single explosive charge fired in coal, stone or ore.

Shotfiring
The firing of an explosive charge in a drilled hole to break the material to a suitable size for loading.

Silver (Ag)
A white metal commonly found associated with lead ores. Also found in the oxidised zones of ore deposits and in hydrothermal veins.

Sinter plant
A plant in which sintering is carried out.

Sintering
The heating of a mass of fine particles (eg. lead concentrates) below the melting point, causing agglomeration to form larger particles.

Skimming
The removal of the top layer of soil or of irregularities in the ground surface at new mine sites.

Skip
A guided steel hoppit used in vertical or inclined shafts for winding coal or mineral. It can also be adapted to carry people.

Skip winding
A system of winding in vertical or steeply inclined shafts, in which shafts replace cages.

Slag
Waste material from the smelting process. The black, lava-like material is primarily iron and silica.

Slurry
The fine carbonaceous discharge from a colliery washery.

Smelting
The process of extracting a metal from its ores by heating; the chemical reduction of the oxide of the metal with carbon in a furnace. Earth and other impurities, separating as lighter and more fusible slags, can readily be removed from the reduced metal.

Sphalerite (ZnS)
Naturally occurring zinc ore (zinc sulphide).

Spoil heap
The pile of dirt produced by mining operations and stacked at the surface of a mine either in conical heaps or in layered deposits.

Stacker reclaimer
Mechanical device that stores and retrieves stockpiled materials such as coal and concentrate.

Stockpile
An accumulation of ore or mineral formed to create a reserve for loading.

Stoker
A mechanical appliance for feeding coal, coke or other fuel into a boiler or furnace.

Stope
Any excavation in an underground mine, other than development workings, made for the purpose of extracting ore.

Strike
The course or bearing of the outcrop of an inclined bed or structure on a level surface. It is perpendicular to the direction of the dip.

Subsidence
The lowering of the strata, including the surface, due to underground excavations.

Sulphide ore
Material containing economically extractable concentrations of valuable metal in sulphide form.

Tailings
The finely ground residue or waste material contained in the ore remaining after floating off the mineral-bearing concentrate.

Trenching
The digging of shallow trenches to expose a coal seam or vein for inspection or sampling.

Ventilation
The provision of an adequate flow of fresh air along all roadways, workings and service points underground.

Washery/Wash plant
A coal cleaning plant in which water or other liquid is used to remove dirt by differences in density.

Water table
The upper limit or surface of the groundwater which follows approximately the profile of the land-surface.

Winder
The engine at the top of a shaft which rotates the winding drum and thus hoists and lowers the cage or skip by means of a winding rope.

Winze
An underground opening similar to a shaft but not starting at the surface.

Zinc (Zn)
A bluish-white brittle metal. Occurs naturally in soil, water and foods. Second only to iron as a metal found in the human body.