The Lake Johnston project is located approximately 117km west of Norseman, on the Hyden-Norseman road. The project previously operated between 2001 and 2014, producing over 100kt nickel in concentrate with 1.5Mt at a grade of 3.5% Ni mined and processed from the Emily Ann mine and 10Mt at a grade of 0.6% Ni mined and processed from the Maggie Hays mine.
Lake Johnston includes a 1.5Mtpa processing facility and associated infrastructure, Maggie Hays underground resource totalling 3.5Mt @ 1.5% Ni for 52kt Ni metal and strong exploration targets for Ni, Li, Cu/Au. The project also has a 200 person camp and airstrip, plus mining, regulatory and environmental approvals in place.
NICKEL EXPLORATION
During 2023 the Company completed aircore (AC) and shallow reverse circulation (RC) drilling programs at Lake Johnston to progress several highly promising greenfields targets along the Western Ultramafic Unit (WUU) including Maggie Hays West. The former Maggie Hays nickel orebody and associated underground workings are hosted within the Central Ultramafic Unit (CUU) approximately 200m to the east of (directly below) Maggie Hays West.
At Maggie Hays West, a compelling greenfields nickel sulphide target has been defined with a coherent Ni-Cu-PGE regolith anomaly confirmed in shallow AC drilling over a strike of 1km. This anomaly sits over the overturned basal contact within the WUU. The best drill interval returned a best nickel intercept of 1.0m at 2.37% Ni, 347ppm Cu and 249ppb Pt+Pd in Hole PLJA176, within a 36m intercept of 0.99% Ni1.
1 refer to Poseidon Nickel Limited (ASX:POS) ASX Announcement “Exploration & Gold Tailings Update” dated 18 December 2023
COPPER-GOLD EXPLORATION
Gold exploration has historically been sporadic at Lake Johnston, with several gold in soil targets identified in the 1980’s and followed up by shallow drilling at the time. Since then, numerous generations of soil programs have been completed with a strong focus and an historical bias towards progressing only nickel targets.
Over 2024 the Company completed an assessment for other commodities at Lake Johnston which identified a number of copper-gold anomalies in the north-east area of the Lake Johnston tenement package (including Billy Ray and Norfolk). Infill and extensional soil sampling programs completed using the UltraFine+ technique confirmed and extended these anomalies.
The figure below presents gold results from all the soil programs conducted at Lake Johnston to date and highlights the extensive areas across the tenements that remain untested for gold or other commodities.
Billy Ray
A large, open and coherent copper-gold soil anomaly was confirmed at Billy Ray, measuring approximately 1.2km by 1.0km. The eastern extent of the anomaly representing the strongest copper-gold association with peak values of 71ppb Au and 141ppm Cu1 .
Previous drilling targeting the western ultramafic contact for nickel identified Cu-Au mineralisation in drillhole LJPD0032, with the best intersection grading 2.36% Cu and 2.26g/t Au from 149.62m 2. The eastern extent of the anomaly remains untested.
1 refer to Poseidon Nickel Limited (ASX:POS) ASX Announcement “Copper-Gold and Lithium Targets at Lake Johnston Enhanced” dated 8 October 2024
2 refer Poseidon Nickel Limited (ASX:POS) ASX Announcement “Update on Gold Exploration Programs” dated 30 July 2024
LITHIUM EXPLORATION
Recent soil sampling at Lake Johnston has identified two lithium targets, located in the northeast and southern areas of the tenement holding.
Wide spread soil sampling conducted in 2024 across the northern section of E63/2244 identified a large, coherent Li2O anomaly characterised by >100ppm Li2O. This anomaly extends south of previously reported composite rock chips, which returned high grades ranging from 2.80% up to 3.85% Li2O3 (refer Poseidon Nickel Limited (ASX:POS) ASX Announcement “High Grade Lithium Bearing Pegmatites Located at Lake Johnston” dated 23 May 2016).
The anomaly’s central core, defined by >200ppm Li₂O, spans approximately 0.95km by 2.3km and remains open to the west. Within this core zone, a peak value of 495ppm Li₂O was recorded, coinciding with elevated rubidium (117ppm Rb), caesium (31ppm Cs), and tin (9ppm Sn).
In the south, anomalous lithium values (>100ppm Li20) were identified with coincident rubidium (Rb) and caesium (Cs) anomalism over a strike length of 3km. Lithium levels in the soils are comparable to those recently reported by other companies exploring for lithium bearing pegmatites in the Lake Johnston region.
The company entered into a Farm-in Agreement with Mantis Resources Pty Ltd in 2023 to earn up to a 100% interest in exploration licences 63/2244 and 63/2256.
3 refer to Poseidon Nickel Limited (ASX:POS) ASX Announcement “High Grade Lithium Bearing Pegmatites Located at Lake Johnston” dated 23 May 2016