Rumble Resources Ltd (ASX:RTR) has delivered zinc recoveries and grades described as "exceptional" from initial flotation tests at the Earaheedy Project in Western Australia.
The company is highly encouraged by high zinc recoveries of up to 90% zinc in cleaner concentrates with a coarse primary grind size of 150 microns.
In addition, Rumble returned zinc concentrate grades of 59% with no significant deleterious elements, supporting a very marketable product.
Notably, these recoveries and concentrate grades are at the higher end of global benchmarks when compared to current zinc developers and producers.
As a result, Rumble sees considerable potential for additional metallurgical optimisation test-work and value add beneficiation studies planned for 2023.
What’s more, the company has brought forward its maiden mineral resource estimate (MRE) to the first half of 2023.
“Clean and highly marketable bulk concentrate”
Rumble managing director Shane Sikora said: “This is an exciting step forward for the project.
“The metallurgical test-work carried out on the zinc sulphide dominant mineralisation has returned exceptional recoveries and grades via a simple and straightforward flotation process delivering a clean and highly marketable bulk concentrate.
“It compares favourably to current zinc producers and is positioned in the higher end of globally reported benchmarks.
“Furthermore, these recoveries have been achieved at coarse grind sizes with an uncomplicated reagent scheme supporting a simple and conventional process flowsheet that will potentially result in much lower capital and operating costs to those typically observed in many zinc operations of this scale.
“Work continues on the maiden JORC-compliant mineral resource estimate (MRE) for the Earaheedy Project which we are now aiming to announce in the first half of 2023.
“This maiden MRE, in combination with the excellent metallurgy, open-pittable depths, provincial scale and being located in a Tier-1 mining jurisdiction will assist to establish the Earaheedy Project as a world-class zinc deposit and future producer of this critical future-facing commodity.”
Forward plan
The outcomes from this initial sighter metallurgy were 'exceptional', delivering a potentially marketable product via a simple conventional flowsheet with many potential cost (operating and capital) and environmental benefits.
Further work is now planned to test more variability samples to confirm the flowsheet, and conditions and improve performance further including:
- Testing a coarser primary grind.
- Improved flotation performance with the use of alternative collectors.
- Investigations into the nature of any mineral loss to the flotation tail.
- Further comminution test-work will be performed along with locked cycle flotation tests once the final optimisation test work is completed. The locked cycle work will provide details of penalty and other payment elements not yet analysed from these sighter stages of investigation.
- Value-adding beneficiation work (dense media separation and/or ore sorting) will commence once the required volumes of material have arrived from the site and a suitable composite prepared in 2023.
On the exploration front, RC drilling is targeting further high-grade feeder zones (eg, Chikamin Feeder Fault) and is ongoing within and outside the Sweetwater Trend.
Rumble is planning further RC and diamond drilling to test the many potential high-grade east-west and northwest-southeast feeder structures that have been recently outlined via lithostructural mapping and geophysical interpretation over the project.
Further assessment has kicked off to generate targets to test the newly defined high-grade copper-silver dominant polymetallic fault system with angled holes that will form part of upcoming planned drill programs.
An independent technical study to determine the optimum drill spacing for a maiden resource is nearing completion, with a maiden JORC mineral resource estimate (MRE) due to be reported in the first half of 2023.