Iltani Achieves 13x Upgrade in Silver-Indium Ore Sorting Tests at Orient Project
Ore sorting test work confirms potential for pre-concentration at Orient
Iltani Resources has completed first-pass ore sorting test work at the Orient Silver-Indium Project in Herberton, North Queensland. The test work, conducted by TOMRA using X-ray Transmission (XRT) technology, demonstrated that the mineralisation is amenable to XRT ore sorting, establishing proof-of-concept for pre-concentration at the project. The company is now planning a seven-hole PQ diamond drilling program to generate samples for larger-scale bulk sorting test work.
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What is XRT ore sorting and why does it matter?
TOMRA’s X-ray Transmission (XRT) sorting technology discriminates material based on atomic density, identifying dense sulphide-bearing particles — specifically galena (lead sulphide) and sphalerite (zinc sulphide) — versus barren siliceous host rock. Sulphide minerals strongly absorb X-rays and appear as distinct dark particles in XRT images, enabling the sorter to separate valuable mineralisation from waste.
For investors, successful ore sorting can materially reduce upfront capital costs and ongoing operating costs for mining projects. By rejecting barren host rock before milling, ore sorting reduces milling throughput, energy consumption, and tailings storage requirements. This could potentially enable a smaller processing plant while maintaining metal units delivered to the concentrator, improving project economics at Orient.
High-grade sample achieves 2x upgrade with 58% mass rejection
The first test run processed a 13.5 kg high-grade RC chip sample screened to the 6–25 mm fraction. Single-stage sorting achieved a consistent upgrade factor of approximately 2x across all target metals while rejecting 58% of the screened feed mass as waste.
The production of a low-grade waste fraction indicated that most sulphide mineralisation reported to the product, minimising metal losses to the reject stream.
Key results from Run 01:
- Silver: 130 g/t in feed upgraded to 265 g/t in product (2.0x upgrade)
- Indium: 199 g/t in feed upgraded to 427 g/t in product (2.1x upgrade)
- Lead: 1.8% in feed upgraded to 3.6% in product (2.0x upgrade)
- Zinc: 4.3% in feed upgraded to 9.1% in product (2.1x upgrade)
Low-grade sample delivers exceptional 13.2x average upgrade
The second test run processed a 22.5 kg low-grade sample and achieved substantially higher upgrade factors, reflecting the lower feed grade of the sample. Mass rejection reached 96% relative to TOMRA feed, demonstrating the technology’s ability to dramatically concentrate low-grade mineralisation.
The successful sorting is attributed to the strong density contrast between sulphide mineralisation and siliceous host rock, combined with the coarse distribution of sulphides within the tested material.
| Metal | Feed Grade | Product Grade | Upgrade Factor |
|---|---|---|---|
| Silver | 26 g/t | 325 g/t | 12.5x |
| Indium | 27 g/t | 437 g/t | 16.1x |
| Lead | 0.6% | 7.3% | 12.7x |
| Zinc | 0.8% | 9.3% | 11.5x |
All reported mass rejection and upgrade factors are relative to the screened 6–25 mm TOMRA feed and are not representative of overall ROM ore sorting performance. The use of RC drill chips generated a significant fines fraction (<6 mm), which was not subjected to ore sorting in this first-pass test work. The contribution of the unsorted fines fraction will be evaluated during future bulk sorting and integrated flowsheet test work.
Managing Director outlines project benefits
Managing Director Donald Garner emphasised the potential project-level benefits of incorporating ore sorting technology at Orient.
Donald Garner, Managing Director
“TOMRA has completed first pass test results on samples from the Orient Silver-Indium Project. We selected a high-grade and a low grade sample (RC drill chips) so we could better understand if ore-sorting was viable at Orient, and the results clearly demonstrate that ore sorting works, and works well. Particularly impressive are the upgrades to the low grade sample, ranging from x11.5 (zinc grade) to x16.1 (indium grade). If we can use ore sorting technology to remove a significant proportion of waste prior to the milling circuit, this will have significant benefits for the Orient Silver-Indium Project. These include the potential to reduce upfront project capital cost (lower capacity processing plant, in particular the milling circuit and a smaller capacity tailings storage facility), lower operating costs (with less waste flowing through the plant) plus the potential to upgrade mineralised waste to higher-grade feed. Now we know ore sorting works, we can move onto the next stage of ore sorting test work, which will involve drilling PQ diameter diamond drillholes to generate sample required for a comprehensive ore sorting test work program.”
The results demonstrate that ore sorting works effectively at Orient. The company can now advance to the next phase of test work, which will involve drilling PQ diameter diamond holes to generate the sample required for a comprehensive ore sorting test work programme.
Next steps: PQ diamond drilling to support bulk sorting programme
Iltani is planning a seven-hole PQ (85 mm diameter) diamond drilling programme to generate samples for the next phase of test work. Crushing PQ core is anticipated to generate significantly less fines than RC chips, enabling a more representative assessment of ore sorting performance and overall ROM ore sorting outcomes.
The planned downstream activities include:
- Large-scale (~700 kg) XRT bulk sorting test work at TOMRA’s Sydney facility
- Evaluate sorting performance across multiple size fractions and mineralisation styles
- Conduct downstream comminution and flotation test work on sorted products and waste fractions
- Incorporate ore sorting results into future process flowsheet development and economic studies
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Orient Project hosts Australia’s largest known silver-indium deposit
The Orient Silver-Indium Project is Australia’s largest known silver-indium deposit, located approximately 120 km southwest of Cairns in the Herberton Mineral Field. Iltani has defined an initial Mineral Resource Estimate at a 60 g/t Ag Eq. cut-off of 34.2 Mt @ 31.3 g/t Ag, 16.9 g/t In, 0.74% Pb & 0.90% Zn (110.4 g/t Ag Eq.).
A larger Mineral Resource Estimate at a 30 g/t Ag Eq. cut-off totals 62.5 Mt @ 22.8 g/t Ag, 11.6 g/t In, 0.55% Pb & 0.67% Zn (81.5 g/t Ag Eq.).
In addition to the existing Mineral Resource Estimate, the company has identified an Exploration Target of 15.4 – 18.8 Mt @ 95 – 117 g/t Ag Eq., which Iltani intends to convert to Mineral Resources through further drilling.
The ore sorting proof-of-concept adds a potential processing pathway that could improve project economics for this substantial resource base. By reducing milling throughput and enabling a smaller processing plant, ore sorting could materially lower both capital and operating costs, enhancing the commercial viability of the Orient Silver-Indium Project.
Want to Track Further Progress at the Orient Silver-Indium Project?
Iltani Resources’ successful TOMRA test work has established a compelling proof-of-concept for ore sorting at Australia’s largest known silver-indium deposit. The next phase—PQ diamond drilling and bulk sorting trials—will determine whether this pre-concentration technology can materially reduce capital and operating costs across the project.
To stay informed on upcoming drilling results and the progression of Iltani’s ore sorting programme, visit the Iltani Resources investor centre for the latest announcements and technical updates.