Exploration & Mining Glossary

Devonian - A geological time period of 60.3 million years ranging from 358.9 million years ago (Mya) to 419.2 Mya.

DHEM (Geophysics) - An exploration method for conductive mineralisation, particularly in areas where the ability of surface EM to define a target is limited either by large depths or by interfering conductive bodies such as overburden, shallow sulphides and peripheral mineralised horizons. DHEM allowed explorers to widen the search radius of boreholes, when used in the search of massive sulphides.

Diamond drilling - A drilling method used to collect a small diameter core samples of rock from the orebody, geologists can analyse the core by chemical assay and conduct petrologic, structural and mineralogical studies of the rock.

Dilution - The contamination of ore with waste rock.

Dip - The angle at which a planar feature is inclined to the horizontal plane; it is measured in a vertical plane perpendicular to the strike of the feature.

Disseminated - Ore deposits consisting of fine grains of ore mineral dispersed through the host rock.

Down-dip - Located down the slope of a dipping plane or surface.

Electromagnetics (EM) (Geophysics) - A geophysical survey method which measures the electromagnetic properties of rocks. The response vary according to the conductivity of the ground. EM surveys can be used to help detect mineral deposits, especially base metal sulphides via detection of conductivity anomalies which can be generated around sulphide bodies in the subsurface. EM surveys can be carried out in the air, on the ground or within a drillhole.

Exploration (mineral) - The sequence of searching for economic mineral/mineral assemblages in an area. It ranges from early stage exploration, the reconnaissance for a new mineral prospect to late stage exploration which involves infrastructure and mine development.

Extension (geological) - Structural features formed by the stretching of the lithosphere (the rigid outer part of the earth, consisting of the crust and upper mantle). Peel Mining context: The Cobar Basin was opened by transtensional NE-SW extension.