Hatch Water PRM10

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SAL OR DESALSEAWATER SUPPLY OPTIONS FOR THE MINING INDUSTRYRaymond Philippe Hatch Ingenieros y Consultores Ltda, Chile

Characteristics Chilean Mining Projects North Chile (desert), water scarcity High volumes (500 -10000 m3/h) Project altitude (1500 4500 masl) Distance to ocean (80-200 km) Copper mining (Copper/moly, copper/gold) Copper flotation Greenfield Technology conversion from oxides to sulphides processing

Seawater use in Mining South America Desalinated seawater Escondida, BHP, Chile Cerro Lindo, Milpo, Peru Candelaria, Freeport, Chile (Execution fase)

Salt water (seawater/ saline well water) Michilla, Chile Las Luces, Chile Mantos de la Luna, Chile Lipesed (Chile) Esperanza, Chile (start-up) Several projects (Study fase)

Mantos de la Luna

Michilla

Las Luces

Lipesed

Batu Hijau (Indonesia)

Texada (Canada)

All existing direct salt seawater usage is in mining projects at short distance and relatively low altitudes Simple and economical conveyance systems Water conveyance costs do not require process optimization (recirculation, thickened tailings)

Components Seawater supply systemMinesite Altitude (masl) Pretreatment

Desal plant

Pumping Stations

Intake/ Outfall

Electrical Supply

Distance (m)

Seawater ConveyanceAspects: Pipeline length Project altitude Pumping stations Water quality In general (new projects Chile): CAPEX: Conveyance system >>> Desalination Plant OPEX: Conveyance system >>> desalination

Decision Seawater Saline - desalinated Is not (should not be): CAPEX desalinated = CAPEX Saline + CAPEX desal plant(eventual corrosion compensation)

Trade-off based on SWOT analysis (qualitative)Depending on the project location, water supply may represent up to 15 - 30% of CAPEX of the overall project

Salt vs desalinated seawaterPossible impact differences in: Seawater intake (outfall) Pretreatment Desalination plant Conveyance system Mineral Processing Product differences Environment Financing options

Salt vs desalinated seawater Conveyance differences Gravity (Difference 3%) Viscosity (Difference 5 %) Corrosion Materials selection pipes + pumps Pipe thickness (bare steel,corrosion compensation) Corrosion velocity (mpy, mm/y) Oxidation Chloride pitting choose correct testprocedures

Internal pipe protection (liners, coating)

Seawater Differences@15C TDS Cl SO4 mg/l mg/l mg/l Saline 36000 20175 2590 Desalinated 205 119 4

BOD5Viscosity

mg/lm2/s.106

variable1.184