Deep Mill Level Zone, PT Freeport Indonesia From Feasibility to Production. May 2016

Transcription

1 Deep Mill Level Zone, PT Freeport Indonesia From Feasibility to Production May 2016

2 Contents Location and Topography Geology and History Reserves and Strategic Timing Timeline/Mine Overview Conveyor Decline Redesign Caving Update Conclusions 2

3 East Ertsberg Skarn System Geology & History 3

4 Grasberg Minerals District & Reserves Tonnes Grades Payable Metal Plan View Cu Au Cu Au (millions) (%) (g/t) (Bn lbs) (MM Ozs) Grasberg & Grasberg Block Cave 962 Kucing Liar 1.03% Kucing Liar % DMLZ Big Gossan % Deep MLZ % Big Deep Ore Zone 115 Gossan 0.56% DOZ 2.0 Underground Total 1, % Grasberg Open Pit % N N District Total 2, % Kucing Liar Spur Portals (at Ridge Camp) Kucing Liar Big Gossan Spur Big Gossan Common Infrastructure 2,500 m elev Grasberg open pit Grasberg Block Cave Amole 2,900 m elev MLA Grasberg BC Spur DMLZ Spur DOZ DMLZ

5 5 Deep MLZ - Timeline Prefeasibility Study Completed Trade-off Studies & Value Engineering DMLZ Spur Started (AB Adits) Feasibility Study Completed Conveyor & Service Decline Started Mine Development & Construction Undercutting (August) First Drawbell (September) Production Ramp-Up 80,000tpd

6 Surface (3020 ml) Deep MLZ Mine Overview Primary Exhaust Fans (DOZ & DMLZ) View Looking West To Ridge Camp AB Adits (2500 ml) Vent Raises (530 m long) DOZ (3100 ml) DMLZ (2590 ml)

7 Deep MLZ Mine Overview Advanced Undercutting 1,900 Drawpoints Drawbell spacing 30m x 20m 580,000 m 2 footprint Two 1.6m x 2.3m 1000kw gyratory crushers Conveyors km 1.83m 15% Ventilation: 5 x 2200kW mixed flow fans 2300 m 3 /s Surface Control Room P20 Grizzly LP20 Chute Remote Loading Grizzly P20 Remote Breaker DMLZ Crusher 60 t Truck 7

8 Major Project Impacts Primary access from Rail to Rubber Tyre in AB Fixed facility re-design Conveyor decline redesign/high pressure water Rail to trucks for ore handling Herringbone to El Teniente Reduced grizzly excavation Improved truck chutes Water and H 2 S gas intersects on Northern fringe redesign fringe area Raisebore failure - 530m x 6m dia. Multiple undercut sequence revisions Others 8

9 9 Major Project Impacts Conveyor Declines Re-Route Re-Design Surface (3020 ml) DOZ (3100 ml) Water Intersect Original Design DMLZ (2590 ml)

10 Major Project Impacts Conveyor Declines Probe holes drilled ahead of the decline Main concern was the Wanagon fault crossing Both core and drift had no issues at the fault crossing Probe holes intersected water just before the planned transfer station Additional holes identified several narrow zones of broken and very wet ground near the conveyor transfer It was felt to be a manageable problem We were committed to the conveyor designs, engineering and procurement Development proceeded Diamond Drill Hole: ~ 20 LPS Plan View of Conveyor Routing and Geology Cv514 Wanagon Fault Conveyor Transfer 10

11 Major Project Impacts Conveyor Declines Additional diamond drill holes intersected more water/poor ground The geological contact was re-defined and not to an advantageous location The conveyor face intersected a zone of high pressure and high volume water Estimated at 180 l/s at 34 bar This coincided with a labour action and the declines flooded Recovery was slow and after re-entry it was decided to abandon and re-design The engineering and operations teams worked rapidly on the new concept 11

12 Final Remediation Keyed in place concrete plug with grouting gallery (x2) 12

13 Major Project Impacts Conveyor Declines Surface (3020 ml) Wrong side DOZ (3100 ml) DMLZ (2590 ml) Original Design 13

14 Caving Update Drawbelling: 15 open Undercut area: 12,500 m2 HR: 28m Airgap: 10-15m (two holes) Constructed D/P s: 180 Three chutes installed Some initial issues on drawbell design and execution 14

15 Conclusions The DMLZ mine is critical in the transition from open pit to underground Early start allowed for some time contingency and reduced risk DMLZ: 7 years to initial caving; 7 years to sustained full production Flexible approach delivered by the Engineering and Operations teams Good collaboration, rapid response and some heated debates The feasibility plan was adhered to in concept but significant changes were discussed and applied as required Mitigating schedule risk was a priority Caving has started so the work is just beginning 15

16 Questions? 16