Lefroy Exploration has intersected multiple intervals of altered eastern porphyry in new drilling at the Burns gold-copper prospect in WA.

The first hole of a new diamond drilling program at Lefroy’s (ASX:LEX) highly exciting prospect intersected the broadest interval of host diorite porphyry found to date at Burns.

The diamond hole, which was designed to twin a previous reverse circulation hole (LEFR260) to around 170m then investigate any downhole extension, intersected a 187.5m downhole interval of the eastern porphyry, before entering massive biotite chlorite altered basalt through to the end of the hole – 371m.

The interval contains three distinct variants of diorite porphyry, which Lefroy said indicated a multi-phase intrusive event, and had an estimated true width of 110m.

A number of mineralised zones were intersected, including:

  • From 117-169m, the twin position to LEFR260, a 52m interval of altered porphyry with some narrow basalt zones and a sulphide magnetite structure;
  • From 185-195m, a new 10m interval of porphyry with intense hematite alteration with disseminated pyrite and trace blebs of chalcopyrite, and;
  • From 216-266m, a new 50m interval of porphyry with weak red rock alteration and trace magnetite pyrite chalcopyrite alteration.

Lefroy said the core indicated and supported its initial interpretations of the prospect being a multi-stage mineral system.

LEFD004 interval 201-203m of altered diorite porphyry with chalcopyrite and magnesite. Pic: supplied

Assays from the hole are expected in June, with a further 13 holes planned under the current program for a total length of drilling expected to exceed 3000m.

The next hole, designed to test 50m vertically beneath mineralisation in LEFR260 using a prior RC drill hole as a drill collar, is now underway.

LEFR260 was hit early in 2021, with intersections including 38m at 7.63 grams per tonne gold and 0.56% copper from 134m to 172m (end of hole), including 27m at 10.1g/t gold and 0.74% copper from 141m.


Drill hole plan at the Burns prospect highlighting the Jan-Mar 2021 drill program (LEFR 259 to LEFR 286) planned diamond drill tails (blue open circles) relative to LEFR260 and the interpreted extent of the Eastern Porphyry. Pic: Supplied.




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.