Development & Construction Update of the Grasberg Block Cave

MineMay 2016

2

• Describe Designs, Development Status and Construction Status for the Grasberg Block Cave Mine (GBC)

• Overview of Grasberg Mining District• Summary Overview of Grasberg Block Cave Mine

• Caving Plan Overview

• Mine Design and Facilities Overview

• Backbone Systems

• Development and Construction Status

• Conclusions/Questions

Contents

3

Grasberg (Ertsberg) District Location

4

District Orebody & Access Overview

GBC Terminal:

5

6

Grasberg Block Cave MineKey Facts

AB Adits 2500 m

Vent & Conveyor Drifts

Mill 3000 m

Extraction Level: 2830 m

1 kilometer

962 Mt @ 1.03% Cu, 0.78 g/t Au Cutoff grade ca. 0.60% EqCu 18 bn lbs copper; 16 mm ozs gold

(payable)

2,416 drawpoints El Teniente (Diagonal) Layout 700,000 m2 footprint 30m x 20m drawbells

Mining Rate: 160 ktpd Primary Mine Access via 6-km AB Adits

Gravity Drainage

Service Shaft for men & materials Rail Haulage to a 3-Crusher Complex

Incline conveyors to surface

Intake/Exhaust Adits

7

• 1995: Initial GBC reserve established• 2003: Prefeasibility Study completed• 2004: Initiate AB Adit Access Development• 2006: Initiate GVD (Vent Declines); Upper Access Development

• Initiate Feasibility Study• 2008: Feasibility Study Completed• 2011: Initiate Shaft-Sinking (2016 Commissioning)• 2012: Commission Main Fan #1• 2015: Commence fixed facility construction• 2016: Commence extraction level construction• 2017: Commission Crushing & Conveying System; Commission Rail System• Early 2018: Initiate Undercutting & Drawpoint Production• 2024: Full Production

Project History and Plan

8

Summary of GBC Mine Layout

9

GBC Mine General Layout

GRS Final Pit

GBC

CrushersPumpsInterlevel Ramp

AB Adit

3000 Amole Adits

Hoistroom

BatchPlant

ServiceShaft

2535 GBC Terminal

Interlevel Ramp2850 Undercut Level

2830 Extraction Level2810 Vent/Service Level2760 Haulage Level

2710 Drainage Level

10

GBC Mine General Arrangement

11

Caving

12

Current Undercutting Sequence

PB1N

PB1S

PB1E

PB2N

PB2S

PB3C

PB3N

PB3S

PB4C

PB4N

PB4S

PB5N

200 m

N

1

2

3

1

2

3

4

5

6

7

8

9

10

PB2C

13

Advanced Undercutting System Average column height >450m Caving Initiated in year 2018

- Caving @ hydraulic radius = 33 8 drawbells per month maximum opening rate

- 4 per month in one cave front (2,400 m2)- 6 per month when only one cave front available

0.28m (11”) per day maximum draw rates Initiate undercutting in two production blocks

- “Crinkle-cut” style undercutting- Accelerate production ramp-up- Maximize early metal production

GBC Feasibility - Caving

14

Production Forecast

15

Infrastructure

16

GBC Service Shaft

Primary mode of transportation for men & materials

- 353m long, 8.5m diameter concrete-lined

- Hoist: 4.88m diameter double-drum modified Blair

- 38.4 tonne payload- Cage: double deck, 300 miner

capacity- Not for ore or waste delivery- Commissioning 2016

17

GBC Service Shaft

• Working Levels• Hoistroom/Shaft Collar – 2875m El.• Undercut/Batch Plant – 2850m El.• Extraction Level – 2830m El.• Rail Haulage Level – 2760m El.• AB Terminal – 2535m El.

• Major Materials Desinations• Undercut (Batchplant), Extraction

• Most Personnel to:• Extraction Level, Haulage Level

• All Men/Materials delivered via AB Terminal

18

GBC Service Shaft

Galloway on the AB Terminal Level

19

GBC Service Shaft: Hoistroom

20

GBC Fixed Facilities

Underground Facilities:

Maintenance and Repair Shops for Rubber Tire Equip

Rail Shop

Warehouses and Offices

3 Fuel bays

Bus Terminals and Light Vehicle Parking

3 Lunchrooms

3 Mosques and 3 Chapels

1 Wastewater Treatment Facility

AB Terminal 2535 m

Service Shaft

Extraction Lvl 2830 m

Haulage Lvl 2760 m

200 meters

21

GBC Extraction Level

200 meters

Rubber Tire Shop

Material Handling Area

Mine Offices

Fuel and Lube Station

Lunchroom & Ancillary Facilities

Mine Warehouse

Shop Warehouse

Construction Laydown Area

Shop Lunchroom

22

250 m3/day concrete / shotcrete Dual streams Cement silos with 2-day supply Direct-dump aggregate and sand bins Commissioned 2014

Underground Batch Plant

23

Manage projected inflows to the cave from surface & groundwater sources Provide process water for the concentrator 1,260 L/sec capacity with standby of 315 L/s Dedicated Drainage Level: fail safe overflow system via AB tunnels Lower and Upper Pumping Stations ~150m head each Excavation of stations complete in 2016; commissioning in 2017

GBC Pumping System

24

GBC Pumping System: Lower Pump Station

GIW 10x 600 hp centrifugal slurry pumps

Drainage Level sumpsAccumulators

25

Total Flow = 6.6 million cfm (3,100 m3/s) @ Full Production (2024)- 4 primary intake drifts & 4 primary exhaust drifts (6.8 mW x 9.0mH)- Vent on Demand Systems required

Four x 5,000 kW Howden Mixed Flow Main Fans- 4.05m diameter; 5,000 kW; 710 rpm; 775 m3/s

Fan #1 Commissioned 2012; Fan #2 commissioned 2014; Fan #3 2017

Ventilation

26

Rail Haulage: Ore Delivery

Automated Rail System- 1435 mm (standard) gauge

- Overhead Catenary System on main lines

- 40t Schalke electric locomotives (11-12 trains plus one spare)- 20 x 20m3 NMT bottom-dump cars

- 120 loading chutes in full layout

- NMT Unloading Station x 3 delivers ore to 1400-tonne bins / crusher

- Communication-Based Train Controls System: Midroc / Bombardier

27

Ore Flow Schematic

Primary Crushing Plants (3)- 1,000 kW 63x89 Gyratory

Crushers (Krupp)

- 1,400–tonne coarse ore bin

- Apron feeder – above crusher

- Metal detectors & magnets

- Discharge conveyor

- Dual conveyor systems

Construction in progress - Commissioning in 2017

28

GBC Oreflow Construction April 2016

Apron Feeder

Conveyor601 Tail

O/H Crane Crusher

Eccentric

29

Detailed Engineering Ongoing- GBC Ventilation on Demand (VOD) - Ongoing Geotechnical Studies & Caving Design Optimisation- GBC Rail and Ancillary Support Facilities

Construction in Progress to be Completed by end-2017- GBC Service Shaft- GBC Rail System- GBC Fan #3- GBC Ore Flow- GBC Pumping System- GBC Fixed Facilities- GBC Extraction Level infrastructure – lintels, rock-breakers/grizzly's, ore passes and roadways

Current EPCM Activities

30

2016 Q2 Schedule – Development to start of Production –Jan 2018

31

Thank You