Lefroy’s deep diamond hole to unlock the secrets of its enigmatic Burns gold-copper intrusion is already paying off with multiple new and unexpected diorite-porphyry intervals intersected.

The intervals, which occur within altered high magnesium basalt, include a 40 metre downhole zone from 400m to 440m of potassic-altered multi-phase diorite intrusions with chalcopyrite, pyrite + molybdenite, which support a broader western lateral extent to the Burns system.

Encouragingly for Lefroy Exploration (ASX:LEX), this indicates that the alteration zone is larger than previously interpreted with the contact of the main porphyry target-zone still to come given that the hole is less than halfway (570m down-hole) through its planned total depth of about 1,200m.

LEFD006 is co-funded by the Western Australian government under its Exploration Incentive Scheme and is part of a two-hole diamond program that seeks to find out just what makes Burns – a new and unique style of an intrusion-related gold-copper mineral system in the Eastern Goldfields region – tick.

“We are extremely pleased with the progress of hole LEFD006, and the geology observed to date,” managing director Wade Johnson said.

“We believe it is indicative of a mineralised hydrothermal Archaean age porphyry system with an alteration footprint that is broader than we have anticipated.

“We are looking forward to the next +500m of drilling that is planned to intersect the main body of porphyry and we eagerly await the completion of the hole to confirm the geological and mineralisation mode.”

Two sample batches representing the first 450m of the drillhole have already been submitted to the laboratory for priority gold, copper, and multi-element downhole analysis with assays expected in October.

Drilling observations and plans

The deep LEFD006 hole is designed to expand the continuity of the Burns mineralisation discovered to date on a vertical scale, test the lateral extent of the system by 250m to the west, provide geological and geochemical information to support ongoing research, and demonstrate that Burns is a new, large gold-copper intrusion hosted mineral system.

While drilling is still underway, observations to date appear to support the company’s objectives with the intersection of fracture-fill native copper from about 180m down-hole in fresh basalt down to a depth of 440m with vein and/or fracture-fill chalcopyrite, pyrite, chalcocite and molybdenite increasing the lateral extent of the copper mineralised Western Basalt zone by about 250m.

The unexpected interval of multiple cross-cutting diorite porphyry intrusives from about 400m to 440m is also separate from the main (deeper) porphyry target and has created an additional target for follow-up drilling.

LEFD006 will be followed by a second diamond hole – drilled to a depth of just 450m, which will test an interpreted shallowly plunging high-grade gold-copper zone within the broader gold-copper-silver-molybdenum porphyry-hosted mineral system at Burns.



This article was developed in collaboration with Lefroy Exploration, 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.