Development of an Innovative Copper Flowsheet at Phu Kham. M F Young and I Crnkovic

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1 Development of an Innovative Copper Flowsheet at Phu Kham M F Young and I Crnkovic

2 Phu Kham Location in Laos

3 Phu Kham Plant Layout Plant Layout showing Primary Grinding Rougher Flotation IsaMill Regrinding

4 Phu Kham Flowsheet GYRATORY CRUSHER SAG MILL No.1 BALL MILL MILL CYCLONES COARSE ORE STOCKPILE ROUGHER FLOTATION CELLS ROUGHER CONCENTRATE CYCLONES 1st CLEANER FLOTATION CELLS TAILINGS DAM PROCESS WATER ISAMILL 2nd CLEANER FLOTATION CELLS CONCENTRATE THICKENER 3rd CLEANER FLOTATION CELLS CONCENTRATE TANK CONCENTRATE FILTER CONCENTRATE STOCKPILE

5 Phu Kham Flowsheet 12.8 Mt/a of copper-gold bearing ore from the open pit Plant Feed Grades are 0.75% Cu and 0.33g/t of Au and 3.8g/t of Ag Concentrate quality is +25% Cu, 7 g/t of Au and 60g/t of Ag Primary Grinding Circuit contains 34 ft 18 ft (13MW) SAG mill 24 ft 39 ft (13 MW) ball mill Regrinding Circuit contains M10,000 (2.6MW) IsaMill Ore has fine locking of copper and gangue minerals Ore requires regrinding rougher concentrate to 38 microns to make good quality final copper concentrate

6 Cleaner Feed Performance IsaMill currently grinds from 90 microns to 38 microns Cleaner feed performance at 38 microns and 25 microns Laboratory Flotation Tests 40 Cleaner Grade-Recovery Profile For Cu-Afternoon Test 30 Cum Cu Grade No Regrind (PM) With Regrind (PM) Cum Cu Recovery

7 New Phu Kham Flowsheet Cleaning Circuit was overloaded at times Fine grinding to improve concentrate quality, slowed flotation rate and increase frothing issues in the cleaner circuit, decreasing the performance of the cleaner circuit Jameson Cell with froth washing was installed at the head of the cleaner circuit to increase cleaning capacity This new circuit allowed final concentrate to be produced from the IsaMill regrind product in one flotation cell and remove more than half the load from the existing cleaning circuit

8 New Phu Kham Flowsheet GYRATORY CRUSHER SAG MILL No.1 BALL MILL MILL CYCLONES COARSE ORE STOCKPILE ROUGHER FLOTATION CELLS ROUGHER CONCENTRATE CYCLONES 1st CLEANER FLOTATION CELLS TAILINGS DAM PROCESS WATER ISAMILL JAMESON CELL 2nd CLEANER FLOTATION CELLS CONCENTRATE THICKENER 3rd CLEANER FLOTATION CELLS CONCENTRATE TANK CONCENTRATE FILTER CONCENTRATE STOCKPILE

9 Layout of IsaMill and Jameson Cell

10 Jameson Cell Flotation at Phu Kham

11 Phu Kham Jameson Cell Grade-Recovery Curve Performance IsaMill Cyclone Overflow P80=20 microns IsaMill Discharge P80=38 microns Feed (Rougher Conc) Grade = 3-5% Cu Cu grade (%) Cyclone overflow only Cyclone oveflow + IsaMill discharge % 55% 60% 65% 70% 75% 80% 85% 90% 95% Cu recovery (%)

12 Jameson Cell Size by Size Recovery on IsaMill Cyclone Overflow Stream Phu Kham Jameson Cell Size-By-Size Recovery % Cu CYC OF 1 Cu CYC OF % 80.00% 70.00% 60.00% Recovery % 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% Size Fraction

13 New Cleaning Circuit Results Jameson Cell was initially commissioned on the regrind cyclone overflow Cyclone Overflow was fine (P80=20 microns) and well liberated Jameson Cell produced 25.5% to 27.5% Cu grade at 75% to 90% Cu recovery on this stream Jameson Cell produced high recovery in all size fractions for this stream Jameson Cell then treated cyclone overflow plus IsaMill discharge Jameson Cell still produced high grade copper concentrate at 26% to 29% Cu grade at 55% to 60% copper recovery The recovery of the coarser size fraction was lower due to the locking and lower liberation in the size fractions

14 Redox Measurements in Plant Low Eh reduces the copper mineral flotation performance

15 Impact of Inert Grinding - Chalcopyrite The Effect of Eh Mt Isa Cu Ore The critical importance of the grinding environment on fine particle recovery in flotation - Stephen Grano

16 Cleaner Feed Performance The Effect of Aeration in Laboratory Float 30 Cu Grade-Recovery Curve-C1F Cu Grade % C1F Without Aeration C1F With Aeration RCOF Cu Recovery %

17 IsaMill Discharge Performance The Effect of Aeration in Laboratory Float 25 Grade Recovery Curves (Total Cu) IMD IMD Without Aeration IMD With Aeration

18 HYPERSPARGE Supersonic Gas Injection Solenoid Control Valve and flexible connection hose Compact Ball Valve for Secure Isolation Fine Bubble Generation Able to generate much finer bubbles for fast gas transfer rates Sturdy Barrel Union Connection for rapid maintenance Failsafe In Line Check Valve to prevent Slurry Spills HyperSparge kl a High Pressure sparge Spool Piece and High Pressure Seal for safe Insertion and removal Supersonic Gas Injection Nozzle for high intensity mass transfer Low Pressure Ring sparge Gas Flow

19 HyperSparge installed in IsaMill Discharge line

20 Phu Kham Effect of Aeration Plant Surveys Phu Kham Jameson Cell Performance Before and After Aeration Before Hypersparge After Hypersparge Grade % Cu % 45% 50% 55% 60% 65% 70% 75% 80% Recovery % Cu

21 Phu Kham Effect of Aeration Plant Surveys Phu Kham Jameson Cell Size-By-Size Recovery Before HyperSparge After HyperSparge % 90.00% 80.00% 70.00% Recovery % 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% Size Fraction

22 Summary IsaMill regrinds rougher concentrate to 38 micron to improve the final copper concentrate quality Cleaner feed performance at 38 microns is 25-28% Cu in final concentrate and regrinding 25 microns can produce +30% Cu in final concentrate Jameson Cell installation was an innovative flowsheet change to removed load from cleaning circuit and increased plant capacity and decrease cleaner circuit frothing issues Aeration of Cleaner feed has improve performance and fines recovery and selectivity Jameson Cell has allowed the IsaMill to operate at Increase power to improve the circuit performance.