Lefroy (ASX:LEX) intersects large-scale gold-copper at Burns

Highlights

• Lefroy has completed the deepest hole to date at Burns with a final depth of 1245.8m.
• Hole LEFD006 intersected 195m of mineralised interval of diorite-porphyry and has established four key geological domains.
• Drilling is in progress on the second hole, LEFD007, with a planned depth of 500m.

Greenfield mineral explorer Lefroy Exploration Limited (ASX:LEX) is progressing well on the two-hole drilling campaign at its Eastern Lefroy Gold Project. The holes are drilled at the Burns Au-Cu intrusion-related mineral system.

The first hole, LEFD006, has been completed after reaching a total depth of 1245.8m. The drilling at Burns demonstrates a broader scale of alteration zonation and the extent of multiphase porphyry intrusions, which extend to at least 1000m below the surface, as per an ASX update released on 1 September 2022.

The company is currently progressing on the second hole, LEFD007a, drilled at a distance of 240m to the south of LEFD006. The hole was drilled to a depth of 231m of the total planned depth of 500m. 

Image source: © 2022 Kalkine Media®

To know more about the project, click here.

Burns is a unique intrusion-related gold, copper, molybdenum, and silver mineral system. It is hosted by rocks from the Archean epoch in WA’s Eastern Goldfields Province. Through this deep drilling campaign, Lefroy is aiming to improve the understanding of the system’s scale and genesis.

Lefroy believes that the gold-copper mineralisation near Kalgoorlie is a new and unique form of gold-copper mineralisation. It is hosted by numerous diorite-porphyry intrusives and high-magnesium basalt.

The drilling program

Lefroy commenced the drilling campaign on 12 July 2022 with the first hole, LEFD006, and drilled it to a depth of 1245.8m. The hole was aimed at investigating the Burns Au-Cu mineralised diorite porphyry host rock to a target (vertical) depth of 1000m.

The hole was designed with the following objectives:

Image source: © 2022 Kalkine Media®

During the first 570 meters, LEFD006 encountered a significant downhole interval containing primarily high-Mg basalt. The basalt interval has mineralisation, which includes native copper that fills fractures as well as chalcopyrite, pyrite, chalcocite, and molybdenite in veins and/or fracture fill.

This interval of altered basalt has increased the lateral extent of the copper-mineralised Western Basalt zone by roughly 250m to the west. The alteration assemblage is consistent with an intrusion-related system and supports a sizable hydrothermal alteration cell.

At 510m and 710m interval, four texturally distinct and variably changed diorite porphyry units were intersected. This is significant as the interval contains the Burns Alkalic Porphyry (BAP) unit, which LEX interprets as a control on copper and gold mineralisation.

A large zone of sheared, calcite-veined, biotite-altered basalt was intersected between 710 and 905 meters. This 195m downhole interval consists of numerous large and variable pyrite porphyry units.

The interval, 905-1034m, intersected a new zone of sulphide-altered-fine-grained sediment (siltstone) and porphyry.

Drill intercepts with mineralised section (Image source: LEX update)

Samples from the drilled hole are sent to a laboratory for gold, copper and a multi-element analysis. The 400m-480m interval that returned significant chalcopyrite has been prioritised for an analysis with results expected later this month.

The second diamond drill hole, LEFD007a, is currently underway and is at 231.07m downhole. The drill hole has a target depth of 500m and is designed to intersect the down-plunge extent of a modelled high-grade Au Cu zone defined by holes LEFR260 & 320.

As of 29 August, LEFD007a had intersected a 177.2m section of western basalt, which is the same unit as the top of LEFD006. LEFD007a is expected to be completed in early September and assay results are expected in November.