Mars becomes top Stellar porphyry target

PolarX Ltd. Oct. 1 announced that drilling has tapped encouraging porphyry copper mineralization at the Stellar project, part of the Australia-based explorer's Alaska Range property.

This Stellar copper, however, was not encountered at Saturn, the primary target of porphyry exploration at Alaska Range. Instead, this mineralization was identified in core from the first hole drilled at Mars, another porphyry target at the opposite end of a 7.5-mile- (12 kilometers) long mineralized corridor that runs across the project.

This corridor runs northwest from the Saturn porphyry target, through the high-grade Zackly copper-gold skarn deposit and on to Mars.

Earlier this year, Lundin Mining Corp. entered into a strategic partnership to explore the porphyry potential at Stellar, a project PolarX acquired from Millrock Resources Inc.

The deal with Lundin excluded a block of claims in the middle of Stellar that covers Zackly, which is allowing PolarX to explore expansions of the skarn deposit independently of the A$4.3 million of exploration being funded by Lundin and managed by PolarX.

The five‐person Stellar exploration committee – three from Lundin Mining and two from PolarX – decided to test Mars this year and the top 300 meters of the very first hole cut porphyry‐style veins containing visible iron, copper and molybdenum sulfides in altered volcanic rocks.

"Visual confirmation of porphyry‐style veins containing chalcopyrite and molybdenite in the first hole at Mars is extremely encouraging," said PolarX Managing Director Frazer Tabeart.

Adding to the excitement is the potential size of a deposit at Mars.

Infill soil and rock chip sampling carried out by PolarX during its 2018 program confirmed a 2,000- by 1,500-meter area of anomalous copper, gold, molybdenum and arsenic mineralization previously identified with broadly spaced sampling at Mars.

Within this larger soil anomaly, the sampling outlined a 1,500- by 800-meter with soil samples topping 250 parts per million copper and 5 ppm molybdenum. The best 2018 samples from this area returned 1,775 ppm copper and 24.2 ppm molybdenum.

The first hole ever drilled at Mars, 19MAR001, cut roughly 300 meters of porphyry-style mineralization starting at a depth of about 5.3 meters.

Assays are pending from this hole.

"Given the large size of the co‐incident copper‐gold‐molybdenum geochemical anomaly and the geophysical anomalies at Mars, this has the potential to be a very large mineralized system and clearly warrants considerable follow‐up drilling," said Tabeart. "We look forward to further results from this very exciting prospect."

At the opposite end of the corridor, PolarX and Lundin are still testing for similar mineralization at Saturn, a large magnetic anomaly masked by a thick layer of glacial sediments deposited on top.

The geological and geophysical evidence for a buried porphyry at Saturn, however, is compelling.

Saturn is roughly 3,000 meters east of the high‐grade copper-gold mineralization encountered at the Zackly skarn.

Porphyry and skarn deposits are often mineralized by the same fluids.

Skarns are formed when mineralized fluids come in contact with carbonate-rich rocks, which causes the metals to precipitate out and form a particularly high-grade mineralized body.

This is the case with Zackly, which hosts 3.4 million metric tons of inferred resource averaging 1.2 percent (90.4 million pounds) copper, 2 grams per metric ton (213,000 oz) gold and 14 g/t (1.5 million oz) silver, according to an Australian Joint Ore Reserves Committee- (JORC) resource calculated in 2017.

Saturn, on the other hand, potentially represents a porphyry deposit that could have served as a fluid source for the east‐west trend of skarn mineralization and alteration discovered at Zackly.

Porphyries, such as the one being sought at Saturn and Mars, are often enormous bulk tonnage copper deposits formed at the center of the mineralizing event that created the skarn.

Porphyry deposits currently account for more than half of global copper production and are an increasingly important source of this useful metal. In addition to copper, porphyries tend to carry gold, molybdenum, silver, rhenium and other metals.

Previous drilling east of Zackly has encountered increased grade, thickness and intensity of alteration as it gets closer to the magnetic anomaly at Saturn – indicating that the mineralized fluids come from this direction.

The five holes drilled at Saturn so far, however, have not found the porphyry sought.

PolarX said the geological, geochemical and other evidence suggest this porphyry body may be deeper and east of current drilling and a detailed analysis of this evidence will be completed to refine targets for further testing.

A gravity survey to help identify buried intrusions is underway at Saturn.

–SHANE LASLEY