Yanacocha GOLD MILL

7/28/2019 Yanacocha GOLD MILL

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July 13, 2005

YANACOCHA GOLD MILL


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July 13, 2005

PROJECT IS STRATEGICALLY IMPORTANT TO

YANACOHA OPERATION

Project is economically attractive.

Ores are becoming more complex. Gold

Mill is an alternative process to treat these

materials.

Gold Mill Facility provides the basefacilities and skills for future complex ores

at Yanacocha.


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July 13, 2005

RESOURCE SUMMARY FOR GOLD MILL

Total Tonnes

41.5 million tonnes

Average Ore Grade

Au 3.92 g/t Ag 24.37 g/t

Contained Ounces Au 5.2 Moz Ag 32.5 Moz

Recoverable Ounces

Au 4.15 Moz Ag 14.2 Moz

Deep Transition Reserves Ounces (Contained)

Au 980 Koz


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July 13, 2005

PROCESS

Stockpile

Agglomeration

Primary Crusher

Counter Current

Decantation (CCD)

Acidification, Volatilization,

Re-adsorption (AVR)

Sulfidization, Acidification,

Recirculation & Thickening (SART)

Leach Circuit

24 Hrs

Electrical

Substation

Area

Grinding

circuit

Video


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July 13, 2005

GOLD MILL PROCESS FLOWSHEET

Crusher Feed Bin

Jaw

Crusher

Stockpile Feed Conveyor

Crushed Ore Stockpile

(11 hr S torage)

Mill Feed Conveyor

SAG Mill (625tph)Ball Mill

(11.5MW)

Cyclones

Linear Trash

Screen

Sump & Pumps

Pre-Leach

Thickener

Process Water Tank

Lime &

Cyanide

Tailings Disposal atLa Quinua Leach Pad

Flocculant

NaHS &

H2SO4

Flocculant

Flocculant

Lime

Carbon Treatment

At La QuinuaH2SO4

NaOH

Recovered NaCN

To Mill Circuit

Flocculant

CONCENTRATE SALES

Feeder & Vibrating

Grizzly

EXISTING ATAGGLOMERATOR

Leach Circuit

(6 Tanks @ 24 hrs)

Dilution Water

SART Precip Thickener

SART NeutralizationTanks (4 Stages)

GypsumThickener

Gypsum

Recycle

Carbon

Return

Stripping Columns

(5 Installed)

Adsorption Columns

(5 Installed)

Stripped Solution Tank

Barren

Solution

La Quinua Carbon

Adsorption Circuit

Barren Solution

To Leach Pad

CCD Wash Solution

(LQ Barren)

Barren Solution

To CCD Wash

CARBON COLUMNSAVR CIRCUIT

SART CIRCUIT

GOLD LEACH

PRIMARY CRUSHER

(Existing)

Lime &

Cyanide

CCD CIRCUIT

5 Stages

Precip Filter and

Bagging Plant Gypsum Recycle

To Mill

SAG & BALL

MILLING

CRUSHED ORE STOCKPILE

Flocculant

PRE-LEACH

THICKENER


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July 13, 2005

CRUSHING

Use existing agglomeration Crusher

1500 TPH

~9.5 h/d operation

Feed Stockpile

~11 hours live capacity in stockpile

Consumables

Power and Steel liners


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July 13, 2005

MILLING

New SAG and Ball Mill

D-26 Krebbs Hydrocyclones

Classify ground ore (80% -75 m)

Consumables

Power, steel balls, mill liners


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July 13, 2005

PRE-LEACH THICKENING

Objective

Recover process water for grinding circuit

Thicken pulp for subsequent leaching to

optimize leach residence time

Consumables Flocculent, anti-scalent, and power


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July 13, 2005

GOLD LEACH

Slurry is mixed in large agitated tanks

with the objectives:

Leach gold and silver from ore copper is

leached as a by-product

Consumables

Power, cyanide, lime, low pressure air


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July 13, 2005

CCD THICKENING AND WASHING

Purpose

Solids/liquid separation to produce metal/cyanide rich

solution for recovery of gold, silver, copper andcyanide

Solids routed to mill sands

5 Stages of Thickeners- 28 30 metersdiameter

Approx 600 m3/h of wash solution 1.2:1 was

ratio for >99% solute recovery

Final thickener is also a high density mill sands

thickener deeper cone

J l 13 2005


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July 13, 2005

SART SOLUTION TREATMENT

Sulfidization, Acidification, Recycle, and

Thickening.

1st CCD thickener overflow is treated in aSART process to remove Cu and Ag

Precipitation of (WAD) metal cyanide

complexes Ag, Cu, Zn

Cu and Ag sulfides sold as a concentrate

Neutralization with lime for gypsum removal Au recovery via 7 stage CIC

J l 13 2005


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July 13, 2005

SART SOLUTION TREATMENT

Batu Hijau Copper Sulfide

Precipitation Filter Press

Copper Sulfide product

July 13 2005


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July 13, 2005

CARBON ELUTION / REGENERATION

Will be performed in existing plants at La Quinua

Final Au recovery in existing Merrill Crowe

plant/refinery at Yanacocha NorteObjective

Acid wash carbonate and organic material from

carbon Concentrate gold from carbon to an enriched solution

Regenerate carbon activity

Return sized barren carbon to leach circuitConsumables

Carbon, power, caustic, cyanide, anti-scalent, diesel

fuel, hydrochloric acid

July 13 2005


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July 13, 2005

AVR CYANIDE RECOVERY

Acidification, Volatilization, and Recovery

Excess cyanide used in the mill will berecovered and reused in the mill to maintain

cyanide balance

Only in years where transition ores containinghigh copper values are treated

Solution contacted with air in packed bed towers HCN is stripped from the solution to the gas phase

Recycled cyanide is returned to the mill.

July 13 2005


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July 13, 2005

NEW REAGENT FACILITIES

Cyanide

Lime

Caustic Soda

Carbon

FlocculantDiesel Fuel

Anti-Scalent

Sulfuric Acid

July 13 2005


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July 13, 2005

MILL SANDS DISPOSAL

High compression thickened mill sands.

Dispose mill sands on the south section of theLQ pad.

Mill sands disposal area has same foundation

preparation and liner system as La Quinuaheap leach.

Heap leach and mill sands drainage systems

are continuous.Continuos monitoring program.

July 13 2005


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July 13, 2005

MILL SANDS CROSS SECTION

LA QUINUA PAD

July 13, 2005


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July 13, 2005

PROJECT MILESTONE DATES

Submit AFE March 2005

Start EIS Workshops March 2005

Submit EIS January 2006

Start Detail Engineering Plant. November 2005

Start Bulk Earthworks Const. August 2006

EIS Approval January 2007

Start Mechanical/Elect. Const. March 2007

Mechanically complete November 2007

Startup Plant January 2008

July 13, 2005


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Ju y 3, 005

IMPORTANT RISKS

Manageable Risks

Expenditure schedule controlled by social

acceptance/permit progress.

Other Risks Considered Political (Elections).

Social acceptance.

Metal prices.

Reagents & Consumable prices.

Escalation.

Documents

Yanacocha GOLD MILL