Northam Platinum Holdings Limited · JSE:NPH

Northam Platinum — Technical Presentation (July 2005)

14 slides from Northam Platinum's technical presentation, Jul 1, 2005

  1. Slide 1: Technological solution to improvement in PGM recovery, upgrade ratio and Cr2O3 reduction of UG2 ore

    Technological solution to improvement in PGM recovery, upgrade ratio and Cr2O3 reduction of UG 2 ore Compiled by : D.S. Smit Northam Platinum Ltd South Africa Introduction ƒ MF 2 – concentrator @ 75 000 t / month ƒ Outokumpu tank cells ƒ PGM recovery not up to design specification ƒ Cr2O3 a problem

  2. Slide 2: Introduction; Pilot plant trials method

    Introduction ƒ Options investigated to reduce Cr2O3 : ƒ Depressant, frother, reduced mass pull ƒ Past experience suggested using a flotation column as re-recleaner to achieve the necessary selectivity ƒ Pilot plant was acquired and trials commenced using the column as re- recleaner 3 Pilot plant tri

  3. Slide 3: Pilot plant trials: method

    Pilot plant trials Method ƒ Operating parameters identified ƒ Air addition ƒ Pulp level ƒ Slurry feed rate ƒ Conditions set – parameter chosen ƒ Parameter varied across operating range ƒ Composite samples collected at each setting 5 Pilot plant trials Method ƒ Samples assayed : 315 composites ƒ Resu

  4. Slide 4: Plant configuration and metallurgical results

    Pilot plant trials Plant configuration Rod Mill Ball Mill Tails Secondary Roughers Primary Roughers Thickener After column Before column Column Re- Re-Cleaners Cleaners Final concentrate thickener 7 Pilot plant trials Plant metallurgical results obtained Comparison between normal plant operation and

  5. Slide 5: Plant results; internal vs external sparger comparison

    Pilot plant trials Plant metallurgical results obtained ƒ PGM recovery : + 0.98 % ƒ PGM upgrade ratio : + 51.2 % ƒ Cr2O3 in conc. : - 20.8 % ƒ PGM / Cr2O3 ratio : + 90.1 % * Internal sparger used 9 Pilot plant trials Comparison between internal and external sparger Column performance Comparison betw

  6. Slide 6: Column performance and conclusions

    Pilot plant trials Comparison between internal and external sparger Column performance ƒ PGM recovery : + 23.3 % ƒ PGM upgrade ratio : + 18.5 % ƒ Cr2O3 reduction : + 29.2 % ƒ PGM / Cr2O3 ratio : + 25.7 % * Data collected during Merensky trials 11 Pilot plant trials Conclusions ƒ Significant reductio

  7. Slide 7: Installation of external sparger column

    Installation of external sparger column Plant configuration Rod Mill Ball Mill Tails Secondary Roughers Primary Roughers Thickener After column Before column Column Re- Re-Cleaners Cleaners Final concentrate thickener 13 Installation of external sparger column Optimization – Method ƒ Parameters main

  8. Slide 8: Optimization: pulp level and air addition

    Installation of external sparger column Optimization Pulp level (Froth depth) Column performance at different Pulp levels (Figure 5) 100% 1.8 90% 1.6 80% C olumn PGM recovery, C r2 O 3 1.4 C olumn PGM upgrade ratio 70% 1.2 reduction (% ) 60% 1.0 50% 0.8 40% 0.6 30% 0.4 20% 10% 0.2 0% 0.0 100 400 700

  9. Slide 9: Optimization: mixing pressure and plant performance

    Installation of external sparger column Optimization Combined mixing pressure Column performance at different combined mixing pressures (Figure 7) 90% 6.0 80% 5.0 C olumn PGM recovery, C r2 O 3 C olumn PGM upgrade ratio 70% 60% 4.0 reduction (% ) 50% 3.0 40% 30% 2.0 20% 1.0 10% 0% 0.0 0.6 1.2 1.8 2.

  10. Slide 10: Plant performance: final concentrate Cr2O3

    Plant metallurgical performance - after Final concentrate % Cr2O3 UG 2 - Final concentrate % Cr2O3 (Figure 9) 6.0 Before After 5.0 % C r2 O 3 in final concentrate 4.0 3.0 2.0 1.0 0.0 Aug'03 Sep'03 Oct'03 Nov'03 Dec'03 Jan'04 Feb'04 Mar'04 Apr'04 May'04 Jun'04 Jul'04 Aug'04 Month Chrome in Conc. Grad

  11. Slide 11: Plant performance: recovery frequency and Cr2O3 reduction

    Plant metallurgical performance - after PGM recovery & upgrade ratio vs frequency UG 2 - Plant recovery > 81 % against PGM upgrade ratio & Frequency (Figure 12) 100 14 Before After 90 12 80 PGM recovery (% ) & PGM Frequency (days/month) 70 10 upgrade ratio 60 8 50 6 40 30 4 20 2 10 0 0 Nov'03 Dec'03

  12. Slide 12: Overall results and Cr2O3 penalties

    Plant metallurgical performance - after Results obtained – overall ƒ PGM recovery : + 2.0 % ƒ PGM upgrade ratio : + 9.0 % ƒ Cr2O3 in conc. : - 37.8 % ƒ PGM / Cr2O3 ratio : +76.3 % ƒ Plant throughput : + 9.5 % 23 Conclusions ƒ Typical Cr2O3 penalties payable : Cr2O3 in concentrate Smelting penalty (%

  13. Slide 13: Conclusions - Payback

    Conclusions - Payback Before After Comments Plant feed 100 000 100 000 @ 4.0 g/t 3PGE + Au Recovery 80.0 % 81.6 % Increase by 2 % Conc. Grade 340 g/t 375 g/t Improve by 10 % Cr2O3 in conc. 4.5 % 2.8 % Reduce by 38 % Penalty ZAR 50 000 ZAR 16 100 Per ton Cr2O3 in concentrate Additional ZAR 832 000 At

  14. Slide 14: Conclusions; Acknowledgements

    Conclusions Is this Northam proven technology the answer to Cr2O3 associated challenges in pyrometallurgical processes ? 27 Acknowledgements ƒ PrepQuip (Pty) Ltd ƒ Northam Platinum Ltd Contact details : D.M. Minnaar D.S. Smit Manager : Metallurgical operations Senior Metallurgist Northam Platinum Lt

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