Development of PhotonAssay Technology for Rapid Assay of Gold and Other Elements in Mineral Ores. Dr James Tickner Chrysos Corporation

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1 Development of PhotonAssay Technology for Rapid Assay of Gold and Other Elements in Mineral Ores Dr James Tickner Chrysos Corporation

2 Outline The need for an improved gold analysis technique The PhotonAssay method History of previous implementations Technical development challenges Sensitivity and accuracy Footprint Sample preparation Safety and licencing Accreditation, QA/QC Implementation Assay bureau facility + relocatable field assay units Additional elements 2 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

Conventional gold assay Fire-assay has been the

alternatives: Aqua regia digest Cyanidation

Usually > 24 hours Small sample mass (10-50 g)

requirements Hazardous process 3 Development of

3 Conventional gold assay Fire-assay has been the standard method for many centuries Existing alternatives: Aqua regia digest Cyanidation Neutron activation analysis g Turn-around time Usually > 24 hours Small sample mass (10-50 g) Extensive sample prep Skilled labour requirements Hazardous process 3 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

4 PhotonAssay method Few minutes per sample with little or no sample preparation Irradiate samples using high-energy accelerator Detect signal from activated gold atoms Sealed samples loaded into analyser The PhotonAssay process Samples available for further testing or disposal as required 4 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

PhotonAssay analysis characteristics True bulk analysis of large samples (500 g approximately) Highly penetrating X-rays pass through entire sample Analysis is independent of physical, chemical or

5 PhotonAssay analysis characteristics True bulk analysis of large samples (500 g approximately) Highly penetrating X-rays pass through entire sample Analysis is independent of physical, chemical or mineralogical form of sample Assay measures mass of gold in sample Reported as concentration based on sample mass No direct interference from other elements Highly elevated levels of U, Th and Ba raise detection limit, but this can be detected and reported for individual samples Method can be extended to additional elements 5 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

6 Applications of rapid turn-around assay Fast turnaround for mine planning and scheduling in pit Assay-supported blending between pit and processing Stockpile sampling Mine ROM Crushing Stockpile Grinding Exploration Real-time monitoring pre/post blasting All samples retained for QC + additional testing Gold Room Multi-stage concentration Smelting Product Tailings disposal + water recovery Buyer/seller assays Process monitoring to optimise concentrator recovery 6 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

7 History and development challenges History Discovery of basic physics of the X-ray activation process (1940s-1950s) Identification of X-ray activation as method for gold analysis (1960s) Establishment of assay lab(s) in the former Soviet Union (1970s-1990s) Limited subsequent commercial development Why? Challenges Improving sensitivity and accuracy Reducing equipment footprint and simplifying installation Understanding sample preparation needs Safety and compliance with licencing requirements Accreditation (JORC, NATA), quality assurance and quality control Cost effectiveness for end users 7 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

8 Sensitivity and accuracy 15-year R&D program undertaken by the CSIRO Patented reference foil method includes reusable standard with every sample Each assay tied directly back to certified reference materials Absolute accuracy of 1% or better on high-grade ores Optimised design of X-ray source and detector systems improves sensitivity Detection range of 0.03 ppm to percent levels (>10,000 ppm) Reduced interference from elements such as U, Th and Ba 8 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

Performance Parameter Results to date (lab prototype) Final system (under construction) Throughput* 6 samples/h 80 samples/h Det. limit (3s)* 60-75 ppb < 30 ppb Accuracy @ 0.1 ppm 35% (0.

9 Performance Parameter Results to date (lab prototype) Final system (under construction) Throughput* 6 samples/h 80 samples/h Det. limit (3s)* ppb < 30 ppb 0.1 ppm 35% (0.035 ppm) 15% (0.015 ppm) 0.3 ppm 15% (0.045 ppm) 7% (0.020 ppm) >1 ppm Better than 5% Better than 3% >30 ppm < 1-2% < 1% * Throughput/sensitivity can be traded Standard precision, 1 sigma errors 9 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

Equipment footprint Traditional model: operating in

relocatable equipment developed in partnership with

container format No requirement for operators to enter

meet national & international safety standards 10

10 Equipment footprint Traditional model: operating in massive concrete bunker PhotonAssay: compact, relocatable equipment developed in partnership with Nuctech Company Ltd Deployment in standard 20 container format No requirement for operators to enter containers Radiation levels at accessible surfaces meet national & international safety standards 10 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

11 Sample preparation Traditional sample preparation geared to g fire-assay aliquot Using 500 g sample significantly reduces preparation requirements Current expectation is that a crush to minus 1-2 mm and split will be sufficient No intrinsic difficulties with particle size or moisture content Significant opportunities for highly heterogenous ores: multi-kg assay + error information Assay results for multi-kg as-received RC samples assayed to extinction 11 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

12 Safety and operator requirements Infeed 6 m approx X-ray source Operator controls Outfeed Electronic X-ray source: no power, no radiation Equipment packaged as black box. No operator access during routine use Fully automated sample handling. Operator loads and unloads samples from outside unit Radiation levels, interlocks etc in compliance with state and national regulations Samples can be safely handled, stored or disposed of after analysis Local radiation safety officer (RSO) required 12 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

13 Accreditation and QA/QC NATA (National Association of Testing Authorities, Australia) Work with existing NATA-accredited facility to undertake validation and develop new procedure specification JORC (Joint Ore Reserves Committee) Establish scientific reliability of PhotonAssay method through validation and reporting Quality assurance/quality control Reference foil method ties analysis directly back to CRMs Digital recording of all process steps All samples can be retained in original form 13 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

14 Bureau and on-site units Bureau unit Designed for fixed lab operations fire assay replacement High throughput (80+ samples/hour) Flexible X-ray source to cover broad element suite On-site unit Designed for rapid turn-around analysis for planning and control Reduced power requirements and footprint Throughput of 20+ samples/hour Operating model Both units operate on fee-per-assay lease model Pricing competitive with conventional assay 14 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

15 Other elements Fully demonstrated Experimental validation Sensitivity measurements Theoretically accessible 15 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

16 Summary Rapid, non-destructive analysis of gold in bulk mineral samples Focus on meeting practical industry needs: Ease of deployment Safety Accreditation Cost effective Applications Replacement for conventional assay methods On-site: mine planning, grade control, process monitoring 16 Development of PhotonAssay Technology for Assay of Gold in Mineral Ores James Tickner

17 Dr James Tickner Chief Technology Officer T +61 (0) E james.tickner@chrysos.com.au W chrysos.com.au Thank you

18 Dr James Tickner Chief Technology Officer T +61 (0) E james.tickner@chrysos.com.au W chrysos.com.au Thank you

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