De Grey Mining upgrades WA Mallina gold resource to over 10Moz

Tue 31 May 22, 3:15pm (AEST)
A collection of gold nuggets against a black background with one specimen in the foreground
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Key Points

  • De Grey Mining has upgraded the global resource estimate for its WA Mallina project to over 10Moz
  • Measured resources sit at 0.3Moz
  • Drilling to continue into June 2023; De Grey ultimately targeting an open pit mine operation in the Northern Pilbara

De Grey Mining (ASX:DEG) has updated its Mallina Gold Project resource statement for 2022, with the Hemi target upgraded 25% to 8.5M ounces of gold (indicated and inferred) and the Global Mallina Gold Project estimate increased to 10.6Moz. 

Global Measured and Indicated Resources have grown 80% in turn to 6.9Moz. Breaking down the Hemi target estimate; 68% of that gross figure is indicated at 139Mt @ 1.3 grams of gold per tonne for 5.8Moz and the remaining 32% classified as inferred for 74Mt @ 1.1g/t totalling 2.7Moz. 

All indicated resources fall within the Open Pit classification to 370m depth, the company notes, with 38Mt @ 1.3g/t at Diucon totalling 1.6Moz and 26Mt @ 1.1g/t for 0.95Moz at Eagle. 

The Global resource estimate at over 10Moz includes measured, indicated and inferred, with measured resources reflecting 5Mt @ 1.7g/t for 0.3Moz.

(Source: De Grey) A 3D render of mineralisation dimensions at the Hemi target
(Source: De Grey) A 3D render of mineralisation dimensions at the Hemi target

10 rigs active on-site

De Grey calculates the inferred resource discovery cost is $10/oz and highlights an additional conversion cost to indicated resources of $7/oz, both figures below the industry average. 

A total of 10 rigs are conducting ongoing exploration drilling to test for further discoveries within the Greater Hemi corridor and adjacent target areas of interest. 

Over the next twelve months, De Grey's geo team will now "pivot back to resource growth at Hemi and high priority untested targets within the Greater Hemi region” with drilling continuing into June 2023.

The estimates are to form part of an upcoming pre-feasibility study; a number of geotechnical and environmental surveys remain ongoing as part of the larger PFS. 

De Grey aiming for an open pit operation

All in all, De Grey's resource estimate comes by way of 323 diamond drill holes for 83,993m and 949 RC drill holes for over 230,000m between February 2020 and April 2022. 

The company is ultimately targeting an open pit mining operation.  

The Mallina Gold Project is located southwest of Port Hedland in the northern Pilbara region of WA, proximate to nearby highways and port facilities, as well as gas pipelines and 220kV transmission infrastructure. 

The Hemi project was first targeted following aircore drilling in November 2019 and further supported by February 2020 RC drill runs. 

Gold mineralisation at Hemi is thought to persist through a number of geological substrates present at the location.

De Grey's three month charts versus the materials index
De Grey's three month charts versus the materials index


Written By

Jonathon Davidson

Finance Writer

Jonathon is a journalism graduate and avid market watcher with exposure to governance, NGO and mining environments. He was most recently hired as an oil and gas specialist for a trade publication. Email Jon at [email protected].

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