Definitions for the language of the gold mining industry

Step-out drilling

Holes drilled to intersect a mineralisation horizon or structure along strike or down dip.


Broken ore heaped on surface, pending treatment.


An excavation in a mine from which ore is, or has been, extracted.


Strictly, the description of bedded rock sequences; used loosely, the sequence of bedded rocks in a particular area.


A diagnostic characteristic of minerals, where scratching a sample on a piece of unglazed porcelain leaves powder of a characteristic colour.


The direction, or bearing from true north, of a vein or rock formation measure on a horizontal surface.

Strike length

The direction and length of a geological plane.


A narrow vein or irregular filament of a mineral or minerals traversing a rock mass.

Strip ratio

Ratio of waste material to ore material in an open pit mine.


The process of removing overburden to expose ore.


A level or working horizon in a mine between main working levels.


A mineral characterised by the linkages of sulfur with a metal or semi-metal, such as pyrite or iron sulfide. Also a zone in which sulfide minerals occur.

Sulphide dust explosions

An underground mining hazard involving the spontaneous combustion of airborne dust containing sulphide minerals.


An excavation where water accumulates before being pumped to surface.

Sustainable development

Industrial development that does not detract from the potential of the natural environment to provide benefits to future generations.


An intrusive igneous rock composed chiefly of orthoclase.


A down-arching fold in bedded rocks.


A term used to describe when mineralisation in a deposit was formed relative to the host rocks in which it is found. In this case, the mineralisation was formed at the same time as the host rocks. (The opposite is epigenetic.)


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

Tailings facility

A low-lying depression used to confine tailings, the prime function of which is to allow enough time for heavy metals to settle out or for cyanide to be destroyed before water is discharged into the local watershed.


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