Porphyry deposits are known for their large volumes and recent core drilling has provided more evidence that this is very much true of Alma’s Briggs copper project in central Queensland.
The 441.5m intersection grading 0.21% copper confirmed the presence of copper sulphide mineralisation from the base of cover at 8m along the entire remaining down-hole length of hole 22BRD0013.
Numerous higher-grade zones – including 46m at 0.36% copper from 34m and 44m at 0.34% copper from 202m – are evident over several intervals that coincide with intrusive boundaries, a feature which is also observed at the Briggs Central resource about 750m to the south and which could assist future exploration target higher-grade zones.
What’s even more important for Alma Metals (ASX:ALM) is that the results confirm that the mineralised porphyry is substantially larger than previously interpreted and remains open in all directions.
This has the potential to reap big rewards for the company as porphyry deposits account for some 60% of the world’s copper and feature easy mining volumes that more than make up for their low grades.
And just to add a little more fuel to the first, drilling of hole 22BRD0013 was terminated in mineralisation – 3.5m at 0.34% copper – due to issues with the rig, making it likely that there was probably at least a bit more mineralisation to find.
Drilling is now underway on 22BRD0014, the second hole into the Northern Porphyry target.
This has intersected similar fine-grained visible copper sulphide mineralisation along much of its length to its current depth of about 386m.
Copper drilling
The current drill program is designed to test the validity of the Exploration Target at the Northern Porphyry and Briggs Central areas.
Spoiler: It’s starting to look pretty good given the assays from 22BRD0013 and visual observations of copper sulphides in 22BRD0014.
Once drilling of the second hole on the Northern Porphyry target is completed, the rig will move to Briggs Central to complete further drilling aimed at increasing the size of the current Inferred resource of 143Mt at 0.29% copper.
This work is being funded by Alma under an earn-in joint venture agreement that could see it earn up to 70% in the project from owner Canterbury Resources (ASX:CBY).
This article was developed in collaboration with Alma Metals, 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.