Maximus Resources Ltd (ASX:MXR) has kicked off a large-scale ground-based survey at its Central nickel prospect, a key target just 25 kilometres from BHP Group Ltd’s nickel concentrator in Western Australia’s Kambalda nickel district.
The junior gold and nickel explorer’s Central target covers roughly 5 kilometres of highly prospective stratigraphy, situated between the historical, high-grade Andrews Shaft and 1A nickel mines, and has seen very limited drilling.
As a result, Maximus’ geophysical survey aims to define prospective nickel sulphide mineralisation zones across several under-explored ultramafic corridors within the Central prospect.
The geophysics program is supported by Maximus’ recent two tranche placement that raised $12 million to support future exploration.
“An exciting step forward”
Maximus Resources managing director Tim Whither said: “The commencement of the major electromagnetic (EM) survey across the highly prospective Central nickel target is an exciting step forward for the company’s dual commodity strategy.
“This is the first time in almost 20 years that modern high-powered ground EM surveys have been undertaken across the Central nickel prospect, which is amazing considering the highly-prospective stratigraphy located between two significant historic high-grade nickel mines; Andrews Shaft and 1A.
“The team has secured the use of GAP Geophysics’ latest SQUID EM technology, which is preferred for its superior detection and resolution capability, coupled with a powerful transmitter for deeper detection.
“The high-powered survey is expected to provide high-quality data, to be used for planning and optimising future drill programs to test for highly prized Kambalda nickel sulphides.”
Central nickel target
Maximus’ Central prospect is one of several high-priority targets within its Kambalda tenements, which features an approximate 16-kilometre contiguous ultramafic belt.
Because of previously fragmented ownership and an emphasis on gold discovery, the targets represent a key opportunity for nickel sulphide discovery in one of the world’s best nickel districts.
A geological review has pinpointed a suite of underexplored and prospective structural and stratigraphic positions that need to be explored with geophysical tools.
As a result, Maximus hopes its survey will support a targeted drill program at Central in the future.
Two prospective horizons
The company has recognised two folded ultramafic branches at Central that have since been dubbed the eastern and the western limb, representing two prospective horizons for Kambalda-style nickel sulphide mineralisation.
Estrella Resources’ nearby 1A nickel mine is situated on the eastern limb, while the Andrews Shaft nickel mine is located on the western arm.
The 1A mine was developed between 1990 and 1993, while production estimates indicate that 112,000 tonnes of resource, grading at 3.8% nickel, was mined between 1990 and 1992.
To the west, the Andrews Shaft was active between 1974 and 1979 but ultimately closed due to low nickel prices.
The mine was developed down to 360 metres deep and across roughly 320 metres of strike, with the orebody reported at around 2 metres wide.
Historical production from Andrews Shaft was estimated to hit roughly 310,000 tonnes at 2.5% nickel for around 7,800 tonnes of nickel metal.
Along the eastern limb of the Central target, very little reported drilling has been reported, except for immediately next to the 1A nickel mine.
Meanwhile, exploration across the western limb has been dominated by wide-spaced reconnaissance rotary air blast drilling.
This reached a maximum depth of roughly 45 metres, returning anomalous drill intersections of 4 metres at 0.8% nickel from 28 metres and 4 metres at 0.6% nickel from 40 metres.
The Ground EM survey will also incorporate Andrews Shaft West prospect, which is an additional prospective ultramafic corridor immediately west of the Central prospect and directly north of the Wattle Dam Gold Mine.
An internal review highlights shallow wide-spaced rotary air blast drilling across this area, with anomalous nickel intersections including 8 metres at 0.5% nickel from 8 metres and 16 metres at 0.5% nickel from 8 metres.
Fixed loop electromagnetic survey
The upcoming fixed loom electromagnetic survey, spanning roughly 10 square kilometres, will include 20 x 2.5-kilometre lines.
Nine fixed loops will be used to explore the four targeted ultramafic horizons and evaluate the geology as much as 500 metres deep.
Due to the size of the targeted area, the FLEM survey is expected to be completed over a three-week period with geophysical interpretations expected to be completed in the following weeks.
Maximus chose to employ ground-based electromagnetic geophysics because of the conductive response of sulphide minerals, with massive and semi-massive nickel mineralisation exhibiting strong conductive signatures in contrast to their surrounding geology.
Due to the high demand for geophysical services in Western Australia, the company delayed the Central program to use the specialised Superconducting Quantum Interference Device (SQUID) equipment, which recently arrived in Australia.