Geometallurgy: 'No Surprises' when Mining and Processing Olympic Dam Ore

Transcription

1 Geometallurgy: 'No Surprises' when Mining and Processing Olympic Dam Ore SA Explorers Conference 30 November 2007 Kathy Ehrig Principal Geometallurgist ()

2 Disclaimer The views expressed here contain information derived from publicly available sources that have not been independently verified. No representation or warranty is made as to the accuracy, completeness or reliability of the information. Any forward looking information in this presentation has been prepared on the basis of a number of assumptions which may prove to be incorrect. This presentation should not be relied upon as a recommendation or forecast by BHP Billiton. Nothing in this release should be construed as either an offer to sell or a solicitation of an offer to buy or sell shares in any jurisdiction. Page 2 30 November 2007

3 Geometallurgy: 'No Surprises when Mining and Processing Olympic Dam Ore Selection Phase Drilling Olympic Dam Resource Update Geometallurgy Program Update Page 3 30 November 2007

4 Olympic Dam Fe-oxide Cu-U-Au-Ag Deposit fresh Roxby Downs Granite weakly brecciated/altered Roxby Downs Granite hematite breccias Page 4 30 November 2007

5 Selection Phase Drilling (Jul 2005 Dec 2007) RC (m) Diamond (m) Surface ~210,000 ~396,000 UG - Expansion - ~18,000 UG - Operation - ~186,000 Total Drilled ~210,000 ~600,000 Page 5 30 November 2007

6 Olympic Dam Mineral Resource 2007* Tonnes (Mt) Cu (%) U 3 O 8 (kg/t) Au (g/t) Ag (g/t) Measured Measured Indicated Indicated Inferred Inferred Total Total *The above 2007 data have been previously released and are extracted from the BHP Billiton Annual Report The information contained in this statement relates to the Mineral Resource estimation for the Olympic Dam Deposit is based on information compiled by S O Connell who is a member of the Australasian Institute of Mining and Metallurgy and S Hayward who is a Member of the Australian Institute of Geoscientists, both are full time employees of BHP Billiton. S O Connell and S Hayward both have sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and the activity which they are undertaking to qualify as Competent Persons as defined in the 2004 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. Shane O Connell and Stuart Hayward consent to the inclusion in the statement of the matters based on their information in the form and context in which it appears. Page 6 30 November 2007

7 World Copper Deposits World Copper Deposits EL TENIENTE CHUQUICAMATA ANDINA OLYMPIC DAM ESCONDIDA GRASBERG NORILSK LUBIN COLLAHUASI OYU TOLGOI Copper Metal (millions of tonnes) Sources: Company Annual Reports and press releases (as at September 2007). Compiled by Richard Schodde Page 7 30 November 2007

8 World Uranium Deposits World Uranium Deposits OLYMPIC DAM ELKONSKY GORSK MCARTHUR RIVER ROSSING INKAI JABILUKA CIGAR LAKE MYNKUDUK STRELTSOVSKOYE IMOURAREN Uranium Oxide (millions of tonnes) Sources: Company Annual Reports and press releases (as at September 2007). Compiled by Richard Schodde Page 8 30 November 2007

9 World Gold Deposits World Gold Deposits >1, Page 9 30 November Gold Metal (millions of ounces) WITWATERSRAND CAMP MURUNTAU GRASBERG (Copper) PEBBLE (Copper) OLYMPIC DAM (Copper) NATALKA SUKHOI LOG LIHIR CARLIN - NEWMONT OYU TOLGOI (Copper) Sources: Company Annual Reports and press releases (as at September 2007). Compiled by Richard Schodde

10 Size and High Grade 160 Copper Metal (millions of tonnes) % 2.36% 0.71% 1.39% 0.64% Cu Equivalent Cu Only 0.89% 2.6% 0.78% 0.79% 4.87% 0 Norilsk Olympic Dam El Teniente Grasberg Chuquicamata Escondida Lubin Andina / Los Bronces Collahuasi Tenke Fungurume Page November 2007 Based on 2003 published resource figures, June 2007 Olympic Dam Resource, and Brook Hunt data Commodity Price assumptions : (June 2004 US$ numbers) $0.85/lb Cu, $3.25/lb Ni, $7/lb Co, $3/lb Mo, $18/lb U3O8, $300/oz Au, $400/oz PGE and $5/oz Ag, with adjustments for recoveries and treatment & refining charges

11 Reportable Resource vs Total Model >90% Total Mineralisation Page November 2007 Within Pit

12 Major Rock Types within the Olympic Dam Breccia Complex Continuum of rock types : RD Granite barren hm-qtz breccias increasing intensity of Fe-oxide alteration/mineralisation increasing number of brecciation events chemical basis for rock type categories decr. granitic component GRN (GRNB) Page November 2007 GRNL GRNH HEMH (HEM) HEMQ

13 Felsic, mafic, and ultramafic dikes and volcaniclastics Page November 2007

14 Major Rock Types, Density, and Iron Relationship 'Southern Mine Areas' (Mine Area E Drilling to Aug04) HEM >= 55% Fe Fe (wt%) HEMH 35-<55% Fe GRNL 20-<35% Fe GRNH 5-<20% Fe Density (g/cm3) GRNB <5% Fe Page November 2007

15 Geometallurgy Program Update Mining and processing Olympic Dam ores has shown that simple, and quantifiable, relationships exist between in situ ore chemistry, mineralogy, and metallurgical properties. chemistry mineralogy metallurgical properties The Geometallurgy Program is structured to define and quantify the links between chemistry, mineralogy and metallurgical properties. Ore Characterisation Program Metallurgical Testing Program Page November 2007

16 Ore Characterisation Program chemistry mineralogy 6000 x 15m composites of ¼ cut NQ diamond core (QA/QC 2%). Samples selected from drill holes located on ~150x150m spaced grid over the entire length of hole. Composites crushed to -1.7mm, rotary spilt into ~3kg charges, head sample selected, another charge screened down to -38µm. Head sample: measure all elements which may impact on metal extraction µm fraction: assay and quantitative mineralogy via MLA Page November 2007

17 Metallurgical Testing Program (GEOMET and Design) chemistry mineralogy metallurgical properties 20 HQ diamond drill holes for metallurgical testing which represent all possible ore types. 500 x 15m drill core composites selected to represent likely ore types with Cu > 0.2wt% (inc. 50 QA/QC samples). Comminution: SMCC, BWI, Abrasion Index, and JKDW tests. Kinetic rougher and cleaner flotation and locked cycle tests. Uranium leach and acid consumption tests. Settling/Rheology Tests Quantitative mineralogy (via QEMSCAN) and detailed chemical analysis on size fractions of flotation concentrates, flotation tailings, tailings leach residues, and concentrate leach residues. Page November 2007

18 Geometallurgy Program Outcomes Validation of prediction of mineralogy from routine drill core assays. Recovery = ƒ(mineralogy, grade, ore texture, process conditions) Mill Throughput Cu-Flotation Recovery Uranium Recovery Acid Consumption Settling/Rheology Characteristics Smelter Feed (i.e. concentrate grade, tonnages, mineralogy) Each resource block (~8 30x30x15m) has detailed chemistry, mineralogy, and predicted throughput/recovery. Page November 2007

19 Thoughts to Conclude Designing for averages does not produce average results. Representative samples aren t, but representative distributions are 100 Density Distribution in 15 yr Pit 90 % Cumulative Frequency Density (g/cm 3 ) Cu>0.15% Cu>0.5% Cu>1.0% d d d d d d d >0.15% Cu >0.5% Cu >1.0% Cu Page November 2007