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Presentation Outline
• project scope, location and background
• process plant overview
• plant capacity and design basis
• general design approach
• process plant design
• plant start-up
Project Scope
The Constancia project consists of a large-scale porphyry copper deposit in southern Peru at 4,200 masl including:
• open pit mine.
• process plant for recovery of copper and molybdenum concentrates.
• tailings management facility.
• associated infrastructure including power supply, water supply, workshops and accommodation camp.
The project was built for a cost of approximately US$1.75 B.
Project Location Figura– Mapa de Ubicación del Área del Proyecto / Figure 1
Constancia
Project
630 km south-east of Lima; 110 km south of Cusco, Peru.
Project Background
• Sept 2009 – GRDMinproc (now AMEC) completes DFS.
• 2010 – Norsemont contracts Ausenco to complete a Feasibility Study Optimisation Review.
• Feb 2011 – Ausenco completes Technical Report (with input from SRK and Knight Piesold).
• 2011 – HudBay acquires Norsemont (and Constancia Project).
• 2011 – Ausenco commences engineering work for permitting and FEED phase.
• 2012 – Beneficiation concession permit received in June 2012.
Project Background
• 2012 – Hudbay’s board approves construction in August 2012.
• 2014 – copper concentrate production commences Dec 2014.
• 2015 – commercial production achieved April 2015.
Mineralogy and Major Ore Types
• majority of mineralisation associated with potassic alteration and quartz veining (occurring as chalcopyrite-bornite-pyrite mineralisation in Type A and B veinlets).
• high-grade hypogene copper mineralisation found in Type A stockwork.
• pyrite/chalcopyrite ratio is relatively low ranging from 1:1 to 2:1.
• occurrence of molybdenite generally increases with depth and is associated with Type B veinlets.
• oxide mineralisation occurs locally – shallow and volumetrically small.
• supergene enrichment occurs immediately below the oxide cap.
• transition (mixed) mineralisation present over a limited interval where supergene and hypogene mineralisation co-exist.
Mineralogy and Major Ore Types
Abundance of major ore types:
Ore Type Relative Abundance (%)
Hypogene 63
Supergene 20
Skarn 1 6
Skarn 2 / High Zn 11
Process Plant Overview
Key unit processes:
• primary crusher
• stockpile and reclaim
• grinding and pebble recycle
• copper flotation and regrind
• copper concentrate thickening
• copper concentrate filtration and load out
• tailings thickener
• molybdenum flotation
• molybdenum concentrate handling
• reagents and services
Design Basis Summary – Throughput
Plant throughput:
• plant capacity 25.3 Mt/y
• plant capacity 38,000 t/d (per line)
• plant capacity 76,000 t/d (total)
Note: The Constancia plant is capable of treating up to approximately 86,000 t/d (28.8 Mt/y at 91.3% availability) subject to ore competency and SAG mill feed size with throughput expected to average 80,000 t/d.
Design Basis Summary – Operating Availability
Operating availability:
• crusher operating hours: 6,132 h/y (70%)
• grinding / flotation operating hours: 8,000 h/y (91.3%)
• concentrate filter operating hours: 7,200 h/y (82.2%)
Design Basis Summary – Nominal Grade and Recovery
Product Nominal Concentrate
Grade Nominal Recovery
Copper Concentrate 26% Cu 90%
Moly Concentrate 45% Mo 55%
Average feed grades: 0.39% Cu; 105 g/t Mo Average annual copper production: 82,000 t (contained metal in conc)
General Design Approach
• use of natural ground contours
• minimise height of structures
• minimise use of fully enclosed buildings
• use of tower crane (construction & operations)
• compact plant footprint
• location of sub-stations and MCCs
Key objective – capital efficient design (minimise capital and operating cost without compromising safety, operability and maintainability).
Primary Crusher
Primary crusher criteria:
• crushing work index CWi = 20 kWh/t (design)
• 4,125 t/h (nominal) / 6,000 t/h (design)
• dump pocket designed for 250 t haul trucks (2 points for direct tipping).
• single primary gyratory crusher (FLSmidth 1600 x 3000 TSU 1,000 kW).
• top service machine serviced by overhead crane.
• drive-in ramps for clean out of dump pocket and discharge vault.
Stockpile / Reclaim
Stockpile criteria:
• single open conical stockpile
• stockpile capacity (live) = 16 h
• stockpile capacity (total) = 200,000 t
• reclaim feeder rate (each) = 1,600 t/h
• dual reclaim lines (2 apron feeders per line)
• free draining tunnels
• common ventilation system.
Grinding
P75 values (above) for each ore type used in the absence of any other relationship linking ore properties to the block model.
Ore Type Axb Value BMWi
(kWh/t) SG
DWi (kWh/t)
Percentile P75 P50 P75 P75 P75
Hypogene 38 42.5 15.9 2.54 7.3
Supergene 77 90 12.8 2.47 3.7
Skarn 76 120 11.5 3.73 3.8
Ore competency and hardness criteria:
Grinding
Parallel grinding circuits using dual geared drive systems selected due to:
• higher installed SAG mill power (available with geared mills) achieved required maximum throughput.
• maintenance issues associated with GMD mills in the 5 years prior to 2011.
• de-risking plant start up with parallel grinding lines.
• less complex systems for maintenance.
• lower or equivalent capital cost.
Grinding
Comparison of single GMD and dual geared SAG mill system costs:
Item GMD System Geared System
Mill and motor cost (US$M) 39 32
Installed cost (US$M) 61 50
Reclaim and SAG feed system (US$M) 15 20
Approximate total cost (US$M) 76 70
Grinding
• two parallel SAG / ball mill grinding lines with pebble recycle circuits (SAB):
o SAG mills: 10.97 Ø x 7.3 m EGL, 16 MW (dual pinion)
o ball mills: 7.92 Ø x 12.36 m EGL, 16 MW (dual pinion)
o Warman 650 cyclone feed pump (2 MW)
o Krebs gMax26 hydrocyclones
• nominal feed rate(per line) = 1,584 t/h
• product size P80 = 106 micron
• pebble crushers required in Year 6 (harder ore)
Grinding Services
• overhead crane (service cyclones and add ball mill balls).
• drive-on ramp to grinding mill floor.
• drive-in sumps for clean up.
• mill feed chute transporter (RME).
• separate SAG mill and ball mill liner handlers (RME).
• dedicated reline hoists and bolt hammers for SAG and ball mills.
Copper Flotation
Copper flotation circuit consists of:
• two parallel lines of mechanical rougher flotation.
• rougher concentrate regrind.
• three stage cleaner circuit comprising:
o mechanical first cleaner flotation.
o mechanical cleaner scavenger flotation (in open circuit).
o mechanical second cleaner flotation.
o column second cleaner (two in parallel).
Copper Flotation Overview
Parameter Units Value
Rougher mass recovery % 9
Rougher stage recovery % Cu 94
Cleaner 1 stage recovery % Cu 85
Cleaner-scavenger stage recovery % Cu 92
Cleaner 2 stage recovery % Cu 80
Cleaner 3 stage recovery % Cu 80
Cleaner 3 concentrate grade % Cu 26
Copper Rougher Flotation
Rougher flotation criteria:
• design residence time = 25 min.
• design pulp density = 36% solids.
• mass recovery = 9% (average grade).
• two parallel lines of 7 x Outotec e300 cells.
• forced air tank cells, dual level control dart valves per cell.
• 250 kW direct drive via Moventas gearbox.
Copper Rougher Regrind
Rougher regrind criteria:
• product size P80 = 25 micron
• agitated surge tank capacity = 20 min
• specific energy = 8 kWh/t
• Krebs gMax15 hydrocyclones
• single M10,000 Isamill (3 MW) in open circuit
• layout allows for second regrind mill (future) if required
Copper Cleaner Flotation
First cleaner flotation criteria:
• cleaner residence time = 12.5 min.
• cleaner scavenger residence time = 15 min.
• 4 x Outotec e130 cleaners.
• 5 x Outotec e130 cleaner scavengers.
• forced air tank cells, dual level control dart valves per cell.
• 160 kW direct drive via Moventas gearbox.
Copper Cleaner Flotation
Second cleaner flotation criteria:
• Second cleaner residence time = 8 min.
• 3 x Outotec e130 cleaners.
• forced air tank cells, dual level control dart valves per cell.
• 160 kW direct drive via Moventas gearbox.
Copper Cleaner Flotation
Third cleaner criteria:
• superficial gas velocity 1.5 cm/sec
• carrying capacity = 2 t/m2/h.
• wash water bias ratio = 0.2
• two CPT columns 4.87 m Ø x 12 m high.
• cavitation air sparge system.
Copper Flotation Services
Copper flotation services:
• Outotec Courier OSA system (9 streams).
• LP air blowers to tank cells.
• dedicated compressors to column cells.
• flotation plant serviced by tower crane.
• maintenance stands for servicing cell mechanisms.
Bulk Concentrate Thickening
Bulk Cu-Mo concentrate thickened (to remove residual reagents ahead of moly flotation).
• unit settling area rate = 0.2 t/m2/h.
• underflow pulp density = 60% solids.
• 24 m Ø HRT concentrate thickener (hydraulic drive).
• froth skimmer fitted to recover fine concentrate.
• thickener overflow treated in Jameson flotation cell to minimise loss of Mo fines.
Copper Concentrate Thickening
Final copper concentrate (moly tail) thickened and filtered.
• unit settling area rate = 0.2 t/m2/h.
• underflow pulp density = 60% solids.
• 24 m Ø HRT concentrate thickener (hydraulic drive).
• froth skimmer fitted to recover fine concentrate
• separate flocculant preparation facility for concentrate thickeners
Copper Concentrate Filter
Key criteria:
• filter feed tank capacity = 24 hours.
• filter feed capacity = 97 t/h.
• two Larox PF 108/144 M60 160 filters.
• dedicated compressors/receivers for filter pressing and drying air.
Copper Concentrate Loadout
Key criteria:
• 7 days covered storage capacity.
• direct discharge to bunkers.
• truck wheel wash.
• weighbridge.
Tailings Thickening
Key criteria:
• unit settling area rate = 0.75 t/m2/h.
• 75 m Ø HRT thickener (hydraulic drive).
• final tailings thickened (50-55% solids) and pumped to TSF.
• dedicated flocculant preparation facility.
• single duty set (5 x Weir Warman 20/18) tailings pumps.
• layout allows for future standby pump set.
• single tailings 750 mm diameter pipeline (HDPE-lined steel).
Molybdenum Plant
Key criteria:
• rougher feed density 30% solids.
• cleaner feed density 15% solids.
• flotation capacity to accommodate high recirculating loads.
• Mo concentrate grade 45% Mo.
• Mo circuit recovery 85.7% (overall recovery = 60%).
Molybdenum Flotation
• two stage rougher conditioning (dilution, pH and Eh control)
• mechanical rougher flotation (FLSmidth inert gas cells).
• five stage cleaner circuit comprising:
o first cleaner conditioning (pH and Eh control)
o mechanical first cleaner flotation.
o mechanical cleaner scavenger flotation (open circuit).
o second cleaner conditioning (pH and Eh control)
o mechanical second cleaner flotation.
o mechanical third cleaner flotation.
o mechanical fourth cleaner flotation.
o Jameson cell fifth cleaner flotation.
Molybdenum Flotation
Parameter Units Value
Rougher mass recovery % 10
Rougher stage recovery % Mo 95
Cleaner 1 stage recovery % Mo 90
Cleaner-scavenger stage recovery % Mo 85
Cleaner 2 stage recovery % Mo 60
Cleaner 3 stage recovery % Mo 50
Cleaner 4 stage recovery % Mo 40
Cleaner 5 stage recovery % Mo 40
Cleaner 5 concentrate grade % Mo 45
Molybdenum Flotation
• mechanical roughers 6 x Wemco No 164 (28 m3) inert gas cells.
• mechanical first cleaner 5 x Wemco No 144 (14 m3) inert gas cells.
• mechanical cleaner scavenger 4 x Wemco No 144 (14 m3) inert gas cells.
• mechanical second cleaner 4 x Wemco No 144 (14 m3) inert gas cells.
• mechanical third cleaner 5 x Wemco No 120 (9 m3) inert gas cells.
• mechanical fourth cleaner 4 x Wemco No 84 (4 m3) inert gas cells
• Jameson cell fifth cleaner Z1200/1.
Molybdenum Flotation
• enclosed conditioning tanks, hoppers and flotation cells vented to a caustic gas scrubber (H2S)
• Outotec Courier OSA system (5 stream)
• liquid carbon dioxide and evaporator (pH adjustment)
• supplementary inert gas (nitrogen) used to deplete O2
• moly flotation plant serviced by mobile crane
Molybdenum Concentrate Dewatering
Final Mo concentrate thickened, filtered, dried and bagged.
• filter feed tank 24 h capacity.
• concentrate thickener (HRT) 4 m diameter.
• Larox PF 4.7/6.3 filter press with dedicated compressor.
• filter moisture < 15%.
Molybdenum Concentrate Dewatering
• Metso D1216-5 Holoflite dryer (1 t/h).
• product moisture 5%
• wet gas scrubber with SO2 gas sensor.
• product storage bin capacity 24 h.
• bag loader capacity 4 st/h.
Molybdenum Services
• NaHS scrubber for flotation circuit and NaHS storage tanks.
• Nitrogen purge to inert gas flotation cells.
• H2S sensor on exhaust stack.
• H2S and O2 sensors located at NaHS addition points and various locations around the plant.
Reagents and Consumables
Copper Plant:
• lime slurry (quicklime slaker)
• primary collector (Cytec A-3302)
• frother (Cytec AF-65)
• flocculant (tailings)
• flocculant (concentrate)
• grinding media (SAG, ball, regrind mills and lime slaker)
Reagents and Consumables
Molybdenum Plant:
• NaHS depressant
• promoter (diesel + emulsifying agent)
• carbon dioxide (liquid storage and evaporator) pH modifier
• nitrogen gas (PSA unit)
• flocculant (concentrate)
Plant Water Services
• process water
• raw water / fire water
• potable water
• gland seal water
• cooling water
• molybdenum process water
Air Services
• dedicated HP air compressors for : o primary crusher o column cells (one per column) o concentrate filters (drying and
pressing) o molybdenum filter o tailings filters (7 duty / 1 standby) o quicklime unloading.
• all other HP air supplied from plant air system (two duty / one standby).
• LP blowers for copper flotation air (two duty / one standby).
Project Start Up
Key milestone dates:
• 24 Oct 2014 – First ore crushed.
• 16 Dec 2014 – First ore milled through Line 2 (L2).
• 27 Dec 2014 – First copper concentrate produced.
• 24 Jan 2015 – L2 grinding off-line due to bearing damage.
• 1 Feb 2015 – start-up of L1 grinding circuit.
• 16 Mar 2015 – L2 grinding resumed operation.
• 29 Mar 2015 – 3 consecutive days at design throughput.
Plant Start-Up Performance
“Since the end of the second quarter, daily throughput has averaged approximately 80,000 tonnes and copper recoveries
have averaged approximately 75%”, Q2 Management Discussion and Analysis (29 July 2015).