Facing the challenges of new low-grade orebodies with new economic circuit designs

1. Facing the challenges of new low-grade orebodies with new economic circuit designs Malcolm Powell JKMRC - Queensland

2. Flexibility to create value Driven by uncertainty & variability • Modify process to respond to uncertainty (S. Begg) • Vary processing routes to respond to known variability (Powell) Embrace uncertainty to develop a new range of economic/business options The variability of what comes your way will drive flexible processing

3. DRIVERS Comminution 36±10% mining energy Ballantyne 2011 Energy Water Massive low-grade ore bodies Increasing demand Grade price Gold Copper

4. A new mining era – a ‘New mining industry’ • Considerably more challenging orebodies • rapid expansion by exploiting previously uneconomic deposits • Rapidly increasing production costs cannot be sustained by continually increasing commodity prices • illustrated by the recent downturn in the industry

5. Reduction in grade • processing of 50 to 100% more ore same amount of metal • + finer grain structure - finer grinding more challenging recovery tweaking current technologies and relying on economies of scale will not turn the industry around Switch to considerably more efficient processing Transform processing capability

6. Current approach Throughput Collapse the rich orebody information to a standard single figure used in machine selection and circuit design Production prediction linked to conventional circuits average product size equipment gigantism Current approach is to extract less metal from more ore

7. Conventional design - locked in history RISK is underperformance for the new orebodies Conventional circuits operated at historic inefficiencies Geometallurgical Modelling – at great cost and effort – No Upside

8. Upside The value-add of seeking upside In variability there is a lot of upside yet we choose to smooth and ignore blending and daily operation Limit New average Process output average lost opportunity in daily operation

9. Feed quality - extremely variable Conditional simulation • Grade: 0 - 3 • Competence 0.5 -1 • Size (F80) 40 – 130 mm Product requirement • 40 – 100 µm Specific energy requirement • 11 – 33 kWh/t • Process fixed at 20±2 kWh/t ! kWh/t • Time 10 yrs

10. Future approach - Utilise variability Utilise the properties of the orebody – variability revolutionising our processing techniques Our new mantra: ‘Selective mass mining’ with flexible processing It is time to extract more metal from less ore

11. Future approach Circuits designed to respond to variation in: • grade • competence • feed size distribution • liberation size by processing to varying: • target grind size • recovery options • cut-off grades Considerable, worthwhile challenge to ensure sustainability of our industry

12. FlexiCircuits “FlexiCircuits leverage ore variability to maximise resource utilisation” Providing a range of alternative processing routes for a rock. Investigate processing options that provide extra capacity through sophistication rather than scale smart ore characterisation economic modelling innovative processing plant design

13. Novel Flexible Circuits A choice of processing routes • respond to a wide variability in ore properties and throughput requirements • Shift workload • slash processing costs and energy utilisation • Blast control • Reduced milling requirement • Progressive upgrade • while enhancing overall recovery • Higher feed grades to flotation • Alternative recovery routes

14. Spot the HPGR Enabling Technology Novel processing routes Novel or new application of equipment Devise and test the potential new processes Requires Ability to model equipment and circuit performance with confidence Circuit Simulation Circuit response Individual machinery is useless

15. Examples applied to novel flexible circuit design

16. Uneconomic ore-body to viable Ore body knowledge Ore body knowledge Smart blasting Waste rejection Tag & load Gyratory Bulk grade detector Waste stockpile splitter 60mm screen Bulk sorter Flotation Low-grade SP Delayed processing Pebble crusher cyclone Split stockpile screen Ball mill

17. From uneconomic to viable 2 to 1 processing reduction 2x40 ft SAG, 2x26ft ball mill 1x42ft SAG 1x28ft ball mill

18. Model Cells Contain processing parameters Ore body knowledge • Know what is coming your way & plan when Courtesy CSIRO Courtesy CRC Ore

19. Utilise variability – e.g. Blast Engineering by Grade Coarse low grade Fine High Grade Ore Coarse Waste Coarse Low Grade

20. Ore body knowledge + flexible flowsheets Know what is coming your way Grade detector Smart tag Process route Deferred stockpile Grade detector Fine waste rejection • No grinding media • 60% total energy • Stable product • + 3% recovery • +25% metal production • Upside • 40% capacity AG→SAG • Reduced RISK Making an orebody viable

21. Hybrid Circuit - HPGR - AG • > water recovery • < viscosity issues RoM 5000tph RoM2000tph Dry Clay clumps Dry fluidised bed separator LG circuit / heap leach / waste 50mm 20mm • 70% energy • Stable product • Higher recovery • Reduced RISK Cone crush HPGR Feed 2200tph Waste sorting HPGR Rejects Wet Screen-1mm 3-product cyclone 5mm 600 tph Middlings ball Mill SAG Coarse flotation Pump Sump concentrate Tailings

22. High quality ore body knowledge • Model feed as average • little advantage in complex circuit • Model variability of feed • advantages of hybrid flexible circuit over SABC circuit • response to ore variability • Multi-component simulation with advanced models Tuning variable processing to the variable processing regimes critical to advanced circuit development

23. Hybrid + Stirred Mill P80? Grade splitter Fine grinding P80? sorter P80? Multi-comp crusher 3-prod cyclone, multi-comp P80? P80? Multi-comp HPGR P80? Middlings Grade-by-size P80? P80? Coarse flotation Bimodal feed, multi-component SAG Coarse recovery

24. Uptake • Characterise ore • Base properties • Apply to variable circuits • Model & Simulate • Multi-component • dynamic • Pilot • larger capacity • process options • Control • Dynamic simulation • test on large pilot plant (10 tph) • Engineer • Physical layout • Turning concepts into reality

25. Equipment suppliers & Engineering companies Transform complexity into elegance

26. New Mining Industry Exploiting lower grade and less favourable ore bodies → Doubling comminution energy and processing equipment →Unviable Geomet • higher resolution of ore body knowledge • tracks ore variability • linked to flexible processing incorporating ore upgrade options Transform currently uneconomic resources into viable and reliable reserves

27. Flexible circuits – Go Hybrid Design & build with today’s technology, while allowing the uptake of tomorrow’s technology for tomorrow’s challenges. Ensure: Continued licence to operate Sustained profitability in the long-term P.S. Invest in research, not mills

28. Considerable team effort • Rio de Janeiro • CMRCape Town Hacettepe Chalmers TU Braunschweig

29. Future value Resource definition (Geomet) Feeding into Flexible processing options Providing Increased recovery Greater resource value Process Drivers Geological model Utilising Variability Fresh & feasible Conditional simulation Transform processing