SMELTER START UP OF NEW ISA FURNACE AND

SMELTER START UP OF NEW ISA FURNACE AND PROGRESS TO DATE Mopani Copper Mines

SMELTING AT MUFULIRA - DEVELOPMENTS 1937 2 x Reverbs, 4 x PS Converters 1956 3 x Reverbs, 5 PS Converters, 4 Anode Furnaces, 2 Casting Wheels 1972 36 MVA Electric Furnace, 1 x Reverb, 6 x PS Converters, 4 x Anode Furnaces, 2 x Casting Wheels, 1 x Holding Furnace 1991 -2006 36 MVA Electric Furnace, 4 PS Converters 4 Anode Furnaces, 2 Casting Wheels 2006 -Present Isasmelt Furnace, 12 MVA Slag cleaning furnace 5 x PS Converters, 2 x 400 tonnes Anode furnace, 1 x twin casting wheel(commissioned in March 2009)

PROJECT MOTIVATION (PHASE 1) Potential to treat > 420, 000 tpa (ie toll) New mines being developed in the region Improve environmental performance From no SO 2 capture to 50% Avoid ~6 m shutdown to rebuild old Electric Furnace Old furnace at the end of its life. Old Electric Furnace failed during Isasmelt commissioning Exporting concentrates difficult due to transport constraints

PROJECT DESCRIPTION (PHASE 1) Isasmelt furnace 850, 000 Matte Settling Electric Furnace (MSEF) 850, 000 tpd (MECS) Oxygen Plant 650 tpa (equivalent) capacity (SMS Demag) Acid Plant (Isasmelt offgas only) 1150 tpa tpd (Air Products) Fastest Isasmelt project 28 months from license agreement to feed on.

PROJECT DESCRIPTION Equipment Legend Smelter Upgrade- Phase 1 MCM Concentrators Concentrate Purchased concentrate, coal and fluxes Concentrate storage Sulphuric Acid Plant (1150 tpd) Diesel Cons, reverts, flux, coal Smelter Upgrade- Phase 2 Offgas to Atmosphere Offgas Coke Discard slag to Dump Isasmelt furnace (850, 000 tpa) Oxygen Plant (650 tpd) Reverts Tail gas to Atmosphere Matte, Slag Matte Settling Electric Furnace Matte Slag Offgas to Atmosphere PS Converters ) 4 to 5 (upgrade from Blister Fire Refining and Casting (install 2 x 400 t AFs, 80 tph casting wheel ) Anode Copper to Refinery

Post-combustion air (N 2, O 2) Oxygen (O 2) Air (N 2, O 2) Offgas (CO 2, SO 2, H 2 O, N 2) Diesel / Fuel Oil Slag box ISASMELT CONCEPT Concentrates (Cu. Fe. S 2, Cu 2 S, Cu. CO 3. (OH)X, Fe. S 2, Si. O 2, and others. . . ) Flux (Si. O 2, Ca. CO 3) Coal (C, CH 4) Slag Coating Water (H 2 O) Smelting reactions Cu. Fe. S 2 + O 2 Cu-Fe-S + Fe. O + SO 2 (Fe. S + 3 Fe 3 O 4 10 Fe. O + SO 2) ISASMELT Lance Fe. S 2 + 5/2 O 2 ISASMELT Furnace Matte-Settling Electric Furnace Matte + Slag Fe. O + 2 SO 2 2 Fe. O + Si. O 2 2 Fe. O. Si. O 2 Slag Matte Granulation water

PLANT DESCRIPTION - FEED PREPARATION Feed materials: Concentrates (Mopani and toll) Reverts (<25 mm) Silica flux (sand) Limestone flux (not normally used) Coal (5 -20 mm) Isasmelt ESP dust WHB dust (mixed with reverts) Feed materials stored in separate stockpiles

PLANT DESCRIPTION - FEED PREPARATION Feed materials reclaimed by front end loader Conveyed to storage bins: Concentrate (4 x 150 t) Flux (2 x 80 t) Reverts (1 x 180 t) Coal (1 x 50 t) Don’t mix up feed materials!

PLANT DESCRIPTION - FEED PREPARATION Feed bin building s) in b o 4 (t 12 V C (to 3 3 1 CV ce) a n r u f

PLANT DESCRIPTION - FEED PREPARATION Feed materials are accurately measured (± 2%) and controlled by the PWCS. Feed rate is controlled by variable speed drives. Flexible system allows quick blend changes. Reverts, Coal and Flux bins have 2 conveyors to measure accurately at low rates.

PLANT DESCRIPTION - FEED PREPARATION Cons feeders (x 4) Flux, Reverts and Coal feeders

PLANT DESCRIPTION - FEED PREPARATION Combined feed on CV 131 Paddle mixer installed, but normally bypassed Furnace feed conveyor (CV 701) Retractable and reversible to prevent heat damage (fires) Conveyor always runs unless retracted. Otherwise the belt will catch on fire from furnace radiant heat Coal reduction bin (furnace reductions) Reversible to bypass the furnace For weigher calibrations For unsuitable feed materials

PLANT DESCRIPTION – ISASMELT FURNACE Furnace refractory: 13. 3 m tall 4. 4 m internal diameter 450 mm Cr-Mg (in most areas) 100 mm insulation brick Roof Boiler tubes (part of WHB) Openings: 13. 3 m Feed chute Lance Holding burner Offgas Copper blocks Splash block Tapping blocks (inner and outer) 4. 4 m

PLANT DESCRIPTION – ISASMELT FURNACE Feed chute Lance port Holding burner port WHB Splash block

PLANT DESCRIPTION – ISASMELT FURNACE Feed chute Slag box (Lance port) Holding burner port

PLANT DESCRIPTION – ISASMELT FURNACE Feed chute Lance port Holding burner port Isasmelt furnace

PLANT DESCRIPTION – ISASMELT LANCE Lance 18. 1 m long 350 mm body 300 mm tip Single swirler Internal air and tip pressure pipes Changed after ~ 7 days Process Typical flow 5 Nm 3/s (regardless of feed rate) 50 – 80% O 2 Process air from dedicated blower Oxygen (95%+ O 2) from oxygen plant (650 tpd)

PLANT DESCRIPTION – ISASMELT TAPPING Tapping machine rails Bend section Head section

Shaft 1 Shaft 2 PLANT DESCRIPTION – OFFGAS offgas cooled using a Waste Heat Boiler (WHB) Furnace roof (inlet ~1, 200 o. C) Cooling screen and Transition piece Shaft 1 Shaft 2 (inlet ~600 o. C) Transition piece Gas cooler (inlet ~400 o. C) To ESP Cooling screen Furnace roof Gas cooler sprays

PLANT DESCRIPTION – OFFGAS ESP 3 field ESP. 3 perpendicular (to gas flow) drag link conveyors. Dust is pneumatically conveyed to feed system, and is directly recycled. Induced Draft (ID) Fan Single ID Fan. Precise control of furnace draft Variable speed drive. Inlet damper.

PLANT DESCRIPTION – MSEF General Tapping 4 Matte tap holes (2 mud gun drills) 2 Slag tap holes (manual tapping) Large pit for granulated slag Reclaim slag with a grab crane Feed materials 12 MVA, 3 in line Electric Furnace 1092 mm Soderberg electrodes 2 Return Slag Launders (PS Converter slag) 1 Isasmelt Launder 8 charge bins (coke and reverts) Offgas Naturally ventilated Cooled by dilution air Discharged without treatment

MATTE SETTLING ELECTRIC FURNACE

OPERATING CONDITIONS Concentrates Mufulira Nkana Kansanshi Blend (41%Cu, 12%Fe, 21%S, 12% Si. O 2) (32%Cu, 22%Fe, 29%S, 7% Si. O 2) (28%Cu, 27%Fe, 32%S, 5% Si. O 2) (32%Cu, 22%Fe, 29%S, 7% Si. O 2) (concentrate only) Furnace feed 70 -115 tph (Design 113 tph) 30 -32%Cu in blended concentrate (excluding reverts) 7 -9% Moisture (no water additions) 0 -6 tph Silica 1 -4. 5 tph Coal (typically 2 -3 tph) 0 -25 tph Reverts Paddle mixer not used

OPERATING CONDITIONS Lance 50 -80% O 2 5 Nm 3/s Total lance flow (design 7 Nm 3/s) Minimum lance air ~1. 2 Nm 3/s 35 lph diesel (average during smelting) Products 1170 -1190 o. C 56 -58% Cu in matte 0. 8 Si. O 2: Fe 8% Fe 3 O 4 in slag MSEF Products Matte 58 -60% Cu (1180 o. C) Slag 0. 7% Cu (1250 o. C)

CONCENTRATE TREATMENT FROM START UP

REVERTS TREATMENT FROM STARTUP

PLANT AVAILABILITY No venting Rebrick O 2 plant compressor Circ pumps, grab, electrodes Power failure, SAP Pumps Isasmelt roof leak

ISASMELT REBRICK General 22 month campaign duration 105 mm minimum brick thickness (~3 m) Air cooling of shell during 2 nd year (offtake side of furnace) Low wear above the splash block Unusually symmetrical wear Wear control Brick monitoring thermocouples (important) and thermal imaging (not very important, just looking for hotspots) High wear during the first 7 months (high temps, poor slag chemistry) Wear rates controlled for remainder of campaign Good match between physical measurements and calculations Post combustion control very important for refractory above the splash block Injecting air through the holding burner damages refractory, and probably the splash block

ISASMELT REBRICK – WEAR PROFILE

ISASMELT REBRICK

SPLASH BLOCK PERFORMANCE Design Performance Single piece, cast in Monel tubes 4 cooling water passages (no air) Copper anchors on the bottom and front face of block 4 thermocouples (3 in block, 1 between block and refractory) Temperature (copper) control by manipulating cooling water flow 22 months without leaks or apparent damage (apart from anchors) Cooling water flow does vary (occasionally) to control copper temperature (uncertain if it makes any difference to block’s life) Post combustion air injection via the holding burner heats the top surface of the block (all slag melts leaving a bare block) 2 nd Campaign Design Anchors added to the top of the block

SPLASH BLOCK PERFORMANCE

MSEF REBRICK General Expected refractory life was 5 -10 years After 2 years side walls required replacement (partial) Roof required replacement due to furnace explosions Wear control Brick monitoring thermocouples were initially installed (SMS Design) 3 separate brick monitoring locations spontaneously leaked Remaining openings were closed with refractory and a steel Additional thermocouples were not installed mid campaign due to cooling jacket design (steel cooling jacket behind working lining)

MSEF REBRICK – WEAR PROFILE

MSEF PERFORMANCE Charging Input launders directed towards dead corners resulting in launder blockages Burners required to prevent launder blockages Accretions No accretions on the side walls (no refractory protection) Bottom accretions of up to 1 metre Accretions largest in non active areas of the furnace Regular pig iron additions required to control accretions

MSEF PERFORMANCE Matte tapping Initial tapping arrangement (4 tapholes, 1 ladle at a time) was a major production constraint, matte bogie installed to minimise tapping delays Matte taphole inserts (Cr-Mg, installed in outer tapping block) require replacement every 4 days. Therefore only 3 working tapholes Matte tapholes can not be closed manually 2 nd mud gun installed to prevent run aways Taphole design being improved (eliminating outer tapping block inserts) Tapholes require deep repair every 1 -2 months (requires a 24 hour shutdown)

MSEF PERFORMANCE Refractory Disappointing performance Low grade brick used by SMS Demag (400 mm RHI ESD) Unable to monitor brick wear, operating parameters not optimised Technical focus on other areas (due to many other problems) 2 nd Campaign Isasmelt style brick monitoring implemented for 2 nd campaign Improved process control Higher grade bricks (RHI FG) Consider jacket design change if wear rate can’t be controlled Target refractory life is >= 2 Isasmelt campaigns

PROBLEMS – ESP DAMAGE < February 07 ESP Rebuild ESP exit temp intermittently > inlet temperature (believed to be instrumentation problems) ESP inspections (external) did not identify problem Shutdown February 2007 to inspect and repair ESP (ESP could not maintain KVs) ESP internals found to be beyond repair Acid plant not commissioned at this stage September – November 07 (US$1. 4 M) ESP bypassed for rebuild Additional dust load to gas cleaning plant required daily shutdowns to remove dust from scrubbers Post Rebuild No further damage ESP’s performance improved, but still struggles to hold KVs at times

PROBLEMS – ESP DAMAGE

PROBLEMS – POST COMBUSTION Symptoms Factors ESP Exit temperature increases Sulphur formation in gas cleaning plant Coal rate (high rates increase problems) Post combustion air Excessive dust in ESP (high dust levels in hoppers cause problems) Consequences Potential damage to ESP (none since Nov 2007) Damage to gas cleaning pumps (very sensitive to S)

PROBLEMS – POST COMBUSTION Detection SAP Gas Cooling Tower pump discharge pressure increases (indicates weak acid coolers are blocking) ESP exit temperature increases Glass rod test (least reliable) Prevention Implemented post combustion air flow smelting interlock Implemented ESP d. T interlock (Outlet temp – Inlet temp) Installing CO, O 2, NO monitor at WHB exit (in progress) Post combustion fan operates at maximum rate, so additional post combustion air is provide by increasing furnace draft (not very efficient)

PROBLEMS – POST COMBUSTION

PROBLEMS – WHB LEAK (MAY 07) Problem Cause Gas cooler spray malfunctioned Water impingement on tubes causing thinning Damage and repairs Large water leak in the WHB’s 2 nd shaft 6 tubes replaced Repair time 5 days (poor welding technique) Actions Implemented logic to detect failure (using existing instruments) Modified spray design (sprays heads were dissolving) Regular thickness testing of tubes around sprays

PROBLEMS – WHB LEAK (MAY 07)

PROBLEMS – WHB ROOF LEAK (DEC 07) Problem Cause Furnace roof leak (bottom of roof) Consultant’s report indicated localised overheating, however cause is unknown Damage and repairs 1 tube replaced Lost time - 6. 5 days (including reheating furnace)

PROBLEMS – WHB ROOF LEAK (DEC 07)

PROBLEMS –ROOF DAMAGE (MAY 08) Problem Cause Holding burner hoist rope failed, dropping holding burner Web ripped off tube causing small leak Leak noticed about 10 hours after hoist failure Damage and repair Furnace roof leak (top of roof) Tube welded Web not reattached (concerned about differential expansion causing leaks) Furnace partially cooled Lost time ~19 hours (including furnace recovery) Actions Holding burner carriage stopper relocated (was too low) Minor repairs to roof during rebrick (tubes were not straightened) Hoist replaced (original rope was under designed)

PROBLEMS –ROOF DAMAGE (MAY 08)

PROBLEMS – WHB CAPACITY Problem WHB design exit temperature Actual exit temperature 700 o. C 400 -500 o. C (under typical operating conditions) Design condensing capacity 35 tph Required condensing capacity ~50 tph (for design conditions) Demin capacity 5 tph It is not possible to operate under design conditions Availability would be limited to ~33% Cause (probable) Fouling on the hot side of the boiler tubes much less than design, resulting in higher than design heat transfer Very clean (Pb, Zn, As) concentrates

PROBLEMS – WHB CAPACITY

PROBLEMS – WHB CAPACITY Mitigation Increased demin storage from 10 to 70 m 3 Decrease lance flow from 7 to 5 Nm 3/s Concentrate blend requires less coal than design (very lucky) Additional 10 MW condenser was installed.

SMELTER PROJECTS HFO Conversion Currently using diesel for the holding burner, lance and launder burners Commissioning of HFO on the holding burner is in progress. Aisle debottlenecking 3 x 55 tonne Main Aisle Cranes Mechanical punching machines are being commissioned.

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