• Electromagnetic survey identifies anomalies coincident with strong magnetic, gravity anomalies at Mallina gold project in the Pilbara
  • Two holes to be drilled as a platform for gathering high resolution DHEM data
  • Planning also underway for drilling to test Hemi-style gold targets


Peregrine is drilling two holes to improve understanding of a strong gravity and magnetic body at its Mallina gold project in WA’s Pilbara region after an extensive electromagnetic program identified coincident anomalies.

The 1,728km2 Mallina project, 120km northeast of De Grey’s enormous, play-opening Hemi deposit, was acquired by Peregrine Gold (ASX:PGD) in July 2021.

Most of the project is underlain by the same Mallina Formation that hosts the gold mineralised intrusions at Hemi.

There has been limited drilling and historical gold exploration over the project while geophysical data and some previous interpretation has been used to obtain an overall understanding of the geology of the area.

Peregrine started an airborne electromagnetic survey in July this year to identify potential mineralisation by identifying rock units to assist in interpreting lithology and structures.

Airborne electromagnetic (EM) surveys map the electrical conductivity below the Earth’s surface to a depth of several hundred metres – sometimes up to 2km below the surface in more favourable conditions.

This provides a detailed 3D picture – similar to a CT scan – that is used to map potential resources.

This survey only identified weakly conductive and subtle late-time anomalies with no clear high conductivity responses though the company noted that bedrock conductors at depth might not have been detected by airborne surveying.

It subsequently followed this survey with a ground based detailed moving loop EM survey to significantly improve the depth of investigation for conductive sulphides associated with a large 3500m by 2500m gravity anomaly.

The MLEM survey resulted in the identification of a discrete late-time anomaly that was followed by two fixed-loop EM lines to improve the MLEM anomaly resolution.


Following up on EM anomalies

This extensive EM program has identified anomalies are coincident with strong magnetic anomalies, strong gravity anomalies and anomalous copper-PGM geochemistry and logging in historical drill holes.

However, the company noted that the anomalies are not well constrained and are in an area with historical drilling.

As such, it decided to drill two holes into the gravity and magnetic body as a platform for gathering high resolution down-hole EM data to reconcile against drilling.


Drilling Hemi-style targets

Peregrine Gold
Hemi-style intrusion clusters on RTP magnetics at the Mallina project. Pic: Supplied (PGD).

Hemi-style intrusion clusters on RTP magnetics at the Mallina project. Pic: Supplied (PGD).

While DHEM surveying is underway, Peregrine plans to deploy the drill rig to test Hemi-style targets with additional holes subject to results from the DHEM survey.

“The confirmation of EM anomalism in close proximity to strong gravity, magnetic and historically reported geochemical anomalism is encouraging and requires immediate follow up with DHEM to better constrain the source,” technical director George Merhi said.

“We also look forward to testing our top ranked ‘Hemi’ style intrusive targets in the same campaign.

“The company will now commence the process of heritage surveys and lodging a POW to prepare for the maiden drill campaign.”



This article was developed in collaboration with Peregrine Gold, 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.