Magmatic Resources narrows in on copper-gold porphyry prize at Calais prospect

Magmatic Resources’ second diamond hole at its Calais prospect in NSW has intersected both gold and copper mineralisation.

Magmatic’s drilling has struck copper and gold in the quest for porphyry mineralisation. Pic: Getty Images

• Drilling at Magmatic Resource’s Myall project with Fortescue has intersected copper and gold mineralisation

• Encouraging results indicate that a potential copper-gold porphyry discovery might be present at the project’s Calais prospect

• Both companies will work closely on defining a follow-up work program at Calais

Special Report: Drilling carried out by Magmatic Resources and its farm-in partner Fortescue at the Myall project near Narromine, NSW, is closing in on a potential copper-gold porphyry discovery at the Calais prospect.

The drill program to test multiple regional conceptual targets based on geophysical and geochemical modelling by Fortescue (ASX:FMG) is being conducted under the farm-in agreement, which will see the mining giant earning up to 75% in the project by spending more than $14m over six years.

Drilling will also test and extend the geological model at the Corvette-Kingswood copper-gold maiden inferred resource of 110Mt at 0.33% copper equivalent, or 293,000t copper, 237,000oz gold and 2.8Moz arsenic.

Magmatic Resources (ASX:MAG), which is operating the project under the initial farm-in period of up to four years, is cheered by the second diamond hole at Calais returning multiple mineralised intersections including 11.7m grading 0.59g/t gold, 0.38% zinc, 2.9g/t silver, 1.8ppm molybdenum and 0.05% copper from a down-hole depth of 138m.

Hole FMD0508 also returned a deeper intersection of 8m at 0.23% copper and 0.04g/t gold from 255m.

These intersections sit within a broad magnetite-pyrite-chalcopyrite zone of 271.2m at 660ppm copper in intensely magnetite-epidote altered diorite and follow-up on a very encouraging first hole intercept of 10.8m at 0.39% copper and 0.07g/t gold from 42.8m in hole FMD0504.

Adding further interest, the drilling results are being returned from a prospect that is in a similar geological setting to Evolution Mining’s (ASX:EVN) Tier 1 Northparkes copper-gold mine 50 kilometres to the south, which has a resource of around 5.2Moz of gold and 4.4Mt of copper.

Evolution’s recent Major Tom and E51 near-mine discoveries, which add to the cluster of deposits at Northparkes, also boost Magmatic’s hopes that Calais, which sits just 15km from Corvette-Kingswood, will be the second of multiple discoveries to be found at Myall.

Calais so far has seen very little previous mineral exploration – it represents a strong target with a large search area and early drilling has delivered strong gold and copper mineralisation in the right rocks – all the early-stage ingredients for hosting a significant discovery.

Closing in on porphyry mineralisation

MAG believes the copper-gold intercepts in both holes are within the wallrock of a mineralised porphyry system and that the anomalous gold result in the second hole is potentially related to an epithermal overprint at the upper levels of a porphyry system.

It adds that FMD0508 is only the second deep hole at Calais where the controls on mineralisation are not well understood. The gold dominated intersection in hole FMD0508 is in addition to the copper dominated intersection in FMD0504 which together add to the potential scale of the system.

The company is now working with Fortescue to further understand the system and refine the geological framework of the Narromine Igneous Complex.

“The gold mineralisation intersected by recent drilling at Calais has continued to open up this second exploration front within the Myall FJVA Project and intersecting a gold-copper zone at this early stage is very encouraging,” managing director David Richardson said.

Cross section of the Calais prospect. Pic: Magmatic Resources

Myall project

The 244km2 Myall project covers the northern extension of the Junee-Narromine Volcanic Belt and hosts significant porphyry-associated copper-gold mineralisation.

In the two years prior to Fortescue’s entry in March 2024, work carried out extensive exploration in the Corvette-Kingswood prospect area that culminated in the definition of the maiden resource.

At the time of farm-in, which included Fortescue subscribing for ~75.95 million shares – 19.9% of MAG – worth ~$3.71m, the company said that partnering with the mining giant would enable significant advancement of both the Corvette-Kingswood prospect and other high potential targets within the project area.

These include the current Calais prospect, which was initially targeted based on broadly spaced copper-gold anomalous aircore holes and pathfinder geochemistry over a northwest trending magnetic high.

Results from the two holes are being reviewed by geologists from the two companies with Richardson saying they will work closely together on a follow-up program.

Farm-in agreement

Fortescue is earning an initial 51% in Myall by incurring $6m in expenditure on exploration over four years.

During this time, MAG will operate all exploration activities as directed by an exploration committee with two members from each company.

Once this initial period is over, Fortescue can take over as operator and earn the remaining 24% by spending another $8m in exploration expenditure over two years.

At the end of the farm-in period, funding reverts to a standard contribute or dilute joint venture. Should MAG’s interest in the JV fall below 10%, Fortescue will be entitled to purchase its remaining interest at 90% of the fair market value.Likewise, should MAG decide not to contribute to development of the project when a decision to mine is made, its partner has the pre-emptive right to purchase its JV interest for fair market value.

This article was developed in collaboration with Magmatic Resources, 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.