Special Report: De Grey’s drilling has firmed up the continuity and consistency of gold mineralisation at the Brolga zone within its ground-breaking Hemi discovery in WA.

A metallurgical diamond hole returned results of 14.7m at 1.1 grams per tonne (g/t) gold from 40m, 70.2m at 1.5g/t gold from 109.5m and 12m at 1.1g/t gold from 175.1m.

Notably, the main 70.2m intersection correlates well with previously reported results in reverse circulation drilling on the same section such as 72m at 1.6g/t gold.

De Grey Mining (ASX:DEG) says the consistency of gold mineralisation at Brolga is encouraging and important for increasing resource confidence.

Additionally, an extensional drilling hole on the western fringe of the Brolga has returned a combined intersection of 86m at 0.9g/t gold, demonstrating that the mineralising system remains open to the west.

“The infill drilling diamond drilling at Brolga has provided strong support and confidence in the consistency and continuity of gold mineralisation previously intersected in RC drilling in this large mineralised system,” managing director Glenn Jardine said.

“Extensional RC drilling shows that the system remains open to the south and west. RC drilling is in progress to the south and west of Brolga between Brolga and Brolga South and between Brolga and Falcon.

“Potential remains to identify near surface gold mineralisation capable of shallow open pit mining.”

The areas between Brolga and Brolga South and between Brolga and Falcon have not previously been drilled with RC holes.

De Grey is also carrying out extensional drilling at the Falcon deposit and to the northwest of the Crow deposit in the immediate vicinity of Hemi.

De Grey drilling brolga gold
Drill results and near surface mineralisation extensions at Brolga. Pic: Supplied

Hemi drilling

The ongoing infill drilling program is designed to provide sufficient drill density to enable a significant portion of the maiden resource estimate to meet JORC 2012 indicated classification, which provides enough information on geology and grade continuity to support mine planning.

Intercepts received to date continue to show broad zones of consistent gold mineralisation and strong correlations between adjacent holes.

This will continue into early 2021 throughout the various zones in parallel with extensional drilling.

Samples from metallurgical drilling from the Aquila, Crow and Falcon zones have been sent for analyses to provide spatial and grade variability across each of the zones for the ongoing and comprehensive metallurgical variability testwork program.

Metallurgical testwork is being linked to multi-element assay results, geochemical analysis and mineralogy across each zone at Hemi to allow domains for oxide, transition and fresh mineralisation to be determined.

This will also allow a geo-metallurgical model for the deposits to be formed.


This article was developed in collaboration with De Grey Mining, a Stockhead advertiser at the time of publishing.

This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.