Definitions for the language of the gold mining industry

Autogenous grinding

The process of grinding ore in a rotating cylinder using large pieces of the ore insteadof conventional steel balls or rods.


The ceiling or roof of an underground opening.


Waste material used to fill the void created by mining an orebody.

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.

Banded iron formation

A bedded deposit of iron minerals.


An extrusive volcanic rock composed primarily of plagioclase, pyroxene and some olivine.

Base camp

Centre of operations from which exploration activity is conducted.

Base metal

Any non-precious metal (eg. copper, lead, zinc, nickel, etc.).

Basement rocks

The underlying or older rock mass. Often refers to rocks of Precambrian age which may be covered by younger rocks.

Basic rocks

Igneous rocks that are relatively low in silica and composed mostly of dark-coloured minerals.


A large mass of igneous rock extending to great depth with its upper portion dome-like in shape. Similar, smaller masses of igneous rocks are known as bosses or plugs.


A rock made up of hydrous aluminum oxides; the most common aluminum ore.


A measure of volume representing a cubic metre of insitu rock.


The arrangement of sedimentary rocks in layers.


To concentrate or enrich; often applied to the preparation of iron ore for smelting.


A clay with great ability to absorb water and which swells accordingly.


A process for recovering metals from low grade ores by dissolving them in solution, the dissolution being aided by bacterial action.


A platy magnesium-iron mica, common in igneous rocks.


Geological time era, about 2.1 billion years ago.


The cutting end of a drill frequently made of an extremely hard material such as industrial diamonds or tungsten carbide.


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