Making a discovery is exciting for any company, but there is always more to the story when that discovery turns out to be one of major significance.
Rumble Resources (ASX: RTR) made such a discovery in 2021 at its Earaheedy project E69/3464 site, approximately 110 kilometres north-east of Wiluna in Western Australia.
Reverse circulation drilling at the time confirmed the project’s Chinook prospect as an important zinc-lead discovery, while highlighting its potential to become a large-scale, Tier 1 zinc-lead system.
‘We announced Chinook in April 2021, and we are now only 18 months on from that discovery,’ Rumble Resources Managing Director Shane Sikora says.
‘What we have discovered already, across two locations, is a globally significant combined zinc-lead mineralised footprint of 13 kilometres by two kilometres that is open in all directions, zinc sulphide dominant, and flat lying.
‘The shallow nature of that mineralisation lends itself to a potential low-cost, open pit mining scenario in a world-class mining jurisdiction of Western Australia.
‘To date, drilling has only partially tested less than 15 per cent of the prospective combined mineralised strike, underlining the possibility to delineate multiple further large-tonnage, shallow (open pit) deposits throughout the project – highlighting the provincial scale potential,’ says Sikora.
‘We believe it represents one of the largest zinc discoveries in recent history.’
Rumble Resources approached Earaheedy with an initial exploration target of around 40 million tonnes, which it has since increased to 100–120 million tonnes at 3.5 per cent to 4.5 per cent zinc-lead sulphides at open pit depths.
This places the project in the globally significant giant zinc deposit category, similar to the Hermosa zinc discovery made by Arizona Mining Inc. that was eventually sold for around A$2 billion to South32 in 2018.
Because zinc does not conduct like nickel or copper, ground electromagnetic geophysics are of little effect, which has meant that Rumble Resources has had to carry out more than 70,000 metres of drilling to define the zinc-lead grade envelopes to enable its technical team to understand what is controlling the mineralisation.
‘What we are seeing is a multitude of
multi-kilometre, high-grade feeders controlling the mineralisation,’ Sikora says.
‘Although our exploration target is in the 3.5–4.5 per cent range, we are now seeing kilometres at five per cent to eight per cent zones in these feeder zones.
‘We are also intersecting up to 20 per cent zinc-lead sulphide in those feeder zones, highlighting the potential for underground – which remains untested.’
These types of base metal systems generally form camps. The maths is simple: having tested less than 15 per cent of the prospective mineralised strike to date, the project has the potential to increase into the very rare supergiant category (greater than 300 million tonnes), which would make the Earaheedy project a multi-commodity cycle asset that would prick the ears of any major mining operation.
The company anticipates the release of a maiden resource in 2023.