Lefroy Lake Johnston Project

AC drilling reinforces nickel prospectivity at Lefroy’s Lake Johnston Bullseye target

Lefroy Exploration Limited (ASX: LEX) announced that the results from the 22-hole, early stage, aircore drilling program at the Bullseye nickel target within the Company’s Lake Johnston Project in WA has reinforced the prospectivity of the target area, with promising shallow nickel intersections in ultramafic rocks.

Standout intersections included 27m at 0.40% Ni & 0.02% Co from 16m including 12m at 0.46% Ni & 0.02% Co from 16m; and 18m at 0.32% Ni & 0.01% Co from 8m.

LEX said that the reinterpretation of the recent and previous drilling with geophysical data suggests the broad magnetic feature may represent a buried ultramafic intrusion that has potential to host nickel sulphide mineralisation.

The Company reported that it has applied for an additional Exploration Licence to adjoin the Bullseye prospect and strengthen its land position in the Lake Johnston area.

LEX said that the planning of the next phase of exploration activity is underway. This will include aircore drilling and ground geophysical surveys to further map the extent of the ultramafic rocks.

AC drilling at Bullseye target

The company had completed a 22-hole, early stage, aircore drilling program at the Bullseye nickel target within the Lake Johnston Project in December 2020 to follow up previous shallow nickel drill intercepts and to gain a better appreciation of the underlying geology associated with a large ovoid shaped aeromagnetic anomaly designated Bullseye.

Significant results from the 1997 program at Bullseye target had included 18m at 0.46% Ni from 20m in RTRB16 including 4m at 0.58% Ni from 24m; 9m at 0.48% Ni from 4m in RTRB 24 including 4m at 0.68% Ni from 8m; 16m at 0.24% Ni from 12m in RTRB 13; and 16m at 0.26% Ni from 12m in RTRB 12.

Shallow nickel intersections

The company announced that the AC drilling identified shallow nickel intersections in ultramafic rocks and reinforced the prospectivity of the target area.

Significant results included 27m at 0.40% Ni & 0.02% Co from 16m in hole LKJA005 including 12m at 0.46% Ni & 0.02% Co from 16m; 8m at 0.72% Ni & 0.09% Co from 8m in hole LKJA018 including 4m at 1.04% Ni & 0.15% Co from 8m; and 18m at 0.32% Ni & 0.01% Co from 8m in hole LKJA020.

All standout Ni results from Bullseye Aircore Drilling program are as shown below.

Extensive ultramafic rocks

LEX said that the interpretation by the Company of the recent and past drill information with geophysical datasets suggests that the ultramafic rocks are more extensive than earlier interpretations. The ovoid shaped Bullseye magnetic anomaly has an approximate 4km x2km footprint with only a very limited portion having been evaluated by drilling to date.

The Company said that it interprets that the magnetic anomaly is due to ultramafic rocks which are, related to a mafic or ultramafic intrusion.

Mafic-Ultramafic Intrusions can be hosts for substantial Ni-Cu sulphide mineralisation occurring as basal accumulations in embayments on or near the basal margins of the intrusion. The Bullseye area has had little if any drilling focused on a magmatic intrusion model and is considered to be under explored.

Application for new EL E63/2673

The company said that the recognition of an alternative geological model at Bullseye combined with the strengthened Ni prospectivity supported its decision to apply for an Exploration Licence (E63/2673) adjoining the Bullseye tenement (E63/1723).

This new tenement also covers the east-west dolerite dyke interpreted by the Company to be related to the Bullseye anomaly.

Further work

LEX said that the next stage of exploration at Bullseye will involve further aircore drilling to scope out and confirm the extent of the ultramafic rocks interpreted from geophysical data. In tandem with that activity additional geophysical (gravity & magnetics) surveys will be designed to assist with drill targeting. This work is expected to commence in the September quarter of 2021.

The company said that the completion of that phase of exploration will then provide a base to design and undertake ground EM surveys over confirmed ultramafic and or mafic rocks to seek conductors that may represent accumulations of Ni -Cu sulphide mineralisation.

Management statements

Lefroy Exploration Managing Director Wade Johnson said: “We are excited by the results generated from our maiden drill program at the Bullseye target in our Lake Johnston project. It is especially pleasing to deliver promising results after targeting the area based on the coincident magnetic feature and previous nickel intercepts from drilling in 1997 that was never followed up.

Bullseye adds to the growing pipeline of early-stage generative drill targets at Lake Johnston. We will schedule more drilling in Q3/21 at Bullseye to map out the prospective ultramafic rocks in our search for Ni sulphide mineralisation.”

Image Source: Lefroy Exploration Limited

Written By Jonathan Norris
Jonathan is a founder of Mining.com.au and has been covering the resources industry since 2018. With over 17 years experience in print, broadcast and online media, Jonathan has seen first hand the transformative effect of online niche media.