Australian Critical Minerals says one extended drill hole at its Flint project in Peru has strengthened the case for a near-surface epithermal system and a deeper concealed porphyry target. The interpretation remains conceptual, with no economic-grade intersections or mineral resource reported.
- FL_DDH002 intersected advanced argillic alteration and elevated epithermal pathfinder elements from surface to 54 metres
- Deeper phyllic alteration contained more than 10% pyrite with anomalous molybdenum and copper
- Two conductive lithocap targets measure up to 1,000 by 500 metres and 800 by 400 metres
- Flint’s broader alteration system covers 4.8 square kilometres
- ACM is planning mapping, geochemistry, magnetic, IP and follow-up drilling work
Drilling Extends Flint’s Porphyry Concept
Australian Critical Minerals Limited (ASX:ACM) has found geological and geochemical signs pointing in two directions at its Flint project in northern Peru: a shallow high-sulphidation epithermal system and a possible porphyry system concealed at depth. The evidence comes from assay, hyperspectral logging and geological interpretation of FL_DDH002, which ACM extended to 656.7 metres after observing alteration deemed encouraging by its geologists.
The hole cut advanced argillic alteration from surface to 54 metres, accompanied by elevated arsenic, antimony, tellurium and thallium, as well as silver at parts-per-billion levels. Below that zone, the alteration shifted through propylitic and phyllic styles, with the deeper interval carrying more than 10% pyrite, a peak molybdenum reading of 23 parts per million and copper values typically ranging from 75 to 131 parts per million in the propylitic-to-phyllic zone.
Two Conductive Lithocaps Become Drill Targets
ACM’s interpretation becomes more ambitious beyond the drill hole itself. An integrated review by Global Ore Discovery identified two large conductive targets in the company’s existing AMT geophysical model: Lithocap Target 1, measuring approximately 1,000 by 500 metres, and Lithocap Target 2, measuring about 800 by 400 metres.
The company says these conductors could represent upper-level, relatively metal-poor alteration zones overlying porphyry copper-molybdenum-gold mineralisation. A porphyry index derived from historic rock-chip samples produced a stronger anomaly over Target 1, a lower-order anomaly near Target 2 and a down-hole vector in FL_DDH002. ACM interprets that combination as evidence the hole may have been drilled through the outer halo of a concealed porphyry system beneath Target 1.
No Economic Intersections Yet
That interpretation is an exploration model, not a discovery of a defined orebody. ACM explicitly reports no economic assay intervals, and the geometry and true widths of any mineralisation remain undetermined. The porphyry index is a relative targeting tool rather than a measure of copper, gold or other metal grade, and does not establish a deposit’s presence, size, depth or economic significance.
The Phase 1 program comprised four diamond holes totalling 1,773.3 metres. Taken together with earlier work, ACM says the Flint alteration system now covers 4.8 square kilometres, although the southern high-sulphidation target area remains largely untested by modern systematic exploration.
Mapping and Geophysics Before More Drilling
ACM’s next step is a target-refinement campaign rather than an immediate declaration of a resource. The company plans WorldView-3 satellite alteration mapping, drone magnetics, low-detection-limit soil and rock-chip sampling, TerraSpec alteration analysis and deep-penetrating induced-polarisation surveys. Areas where those datasets overlap with the AMT conductors are expected to receive priority for future drill testing.
The attraction for shareholders is clear: FL_DDH002 has expanded the geological story from a surface epithermal target to a potentially much larger porphyry-epithermal system. The unresolved question is whether the planned work can turn broad alteration, conductors and trace-element vectors into a coherent drill target carrying economic metal grades.
Bottom Line?
ACM has upgraded Flint’s exploration model, but the next value test is whether layered geophysics and geochemistry can locate a mineralised centre rather than another alteration halo.
Questions in the middle?
- Will follow-up IP and magnetic surveys identify a coherent intrusive centre beneath Lithocap Target 1 or Target 2?
- Can future drilling demonstrate economic copper, gold or silver grades within the deeper porphyry concept?
- How much of the 4.8-square-kilometre alteration system remains prospective once the southern target area is systematically tested?