Oxiana Limited Mineral Resource Explanatory Notes As at June 30, 2007 Tables of Contents Sepon Copper Resource Statement: June 30, 2007...................................................................2 Sepon Gold Resource Statement: June 30, 2007.....................................................................27 Golden Grove Mineral Resources Statement: June 30, 2007 .................................................101 Prominent Hill Resource Statement: July 31, 2007.................................................................107 Martabe Mineral Resources Statement: December 31, 2007..................................................112 Wiluna Nickel Laterite Statement: June 30, 2005....................................................................115 OXIANA LIMITED │ Respect – Action – Performance – Openness │ WWW.OXIANA.COM.AU Level 9, 31 Queen Street T: +61 3 8623 2200 E: [email protected] Melbourne, Victoria 3000 F: +61 3 8623 2222 ABN: 40 005 482 824 ASX OXR Oxiana Limited 2007 Mineral Resource Explanatory Notes Sepon Copper Resource Statement: June 30, 2007 Resource Statement 1.1 Scope This June 2007 Sepon Cu Resource Statement includes the Supergene and Primary Copper Resources for the following deposits within the Sepon Project in Laos: Khanong (KHN), Thengkham North (TKN), Thengkham South (TKS), Phabing (PHB) Lane Xang Minerals Ltd (LXML) is the manager of, and 90% equity holder in the Sepon Project with the Government of the Lao People’s Democratic Republic holding the remaining 10% equity. The estimates are derived from block models as follows: KHN is an update of the 2006 ordinary kriged (OK) block model and includes data from additional resource and grade control drillholes. The 2007 TKN ordinary kriged block model replaces the 2006 ordinary kriged (OK) block model following significant infill and extension resource drilling. TKS is the 2007 ordinary kriged block model and replaces the 2004 multiple indicator kriged (MIK) block model after a phase of infill resource drilling. A further program of significant infill and extensional drilling is currently in progress at TKS and an updated estimate of this resource is planned for 2008. The ordinary kriged resource estimate of mineralisation at Phabing is a new estimate for 2007 and represents additional Inferred supergene resources in the Sepon District. Section 1 of this statement presents the copper resources categorised by the style of mineralisation, being either supergene or primary (tables 1-3). The competent persons’ statements for each of the estimates are included at Sections 2 to 5 where the total resources for each Copper Deposit are tabulated. 1.2 Mineral Resource Categories and Tabulation Supergene and primary resource estimates are classified in the categories specified in the 2004 JORC Code and reported at several appropriate cut-off grades that approximate those employed at the operating Khanong mine. Resources are included in Tables 1-3. 1.3 Contributing Experts The following identifies the key personnel involved in the estimation of the Sepon Copper Resources. A full listing of all involved can be seen in Sections 2 to 5 where details of the estimates are documented: Page 2 Oxiana Limited 2007 Mineral Resource Explanatory Notes KHN – All grade control data was sourced and validated by LXML geologists. Geological interpretations and geostatistical analyses were performed by Duncan Hackman of Hackman and Associates Pty Ltd (HA). Geostatistical analysis was conducted by Arnold van der Heyden of Hellman and Schofield Pty Ltd (HS) and grade interpolations were performed by HA. TKN – Drillhole data was sourced, validated and the geological interpretation and domaining were undertaken by LXML geologists and Kerrin Allwood of Geomodelling Pty Ltd (GM). Geostatisitical analysis, resource modelling and grade interpolation were conducted by Mark Sweeney and Tracie Burrows of AMC Consultants (AMC). TKS – Drillhole data was sourced and validated by LXML geologists and Kerrin Allwood of Geomodelling Pty Ltd (GM). Geological interpretation, domaining of the data and grade interpolation was performed by GM. Geostatisitical analysis was conducted by Steve Hyland of Ravensgate Pty Ltd (RG). PHB – Drillhole data was sourced and validated by LXML geologists. Geological interpretation and domaining for grade estimation was conducted by LXML geologists and Jared Broome (Oxiana Limited). Grade interpolation was undertaken by Jared Broome. Compliance with the JORC Code This statement of mineral resources complies with the 2004 Australasian Code for the Reporting of Resources and Reserves (2004 JORC Code). Sections 2 to 5 of this statement describes the factors considered in estimating and assigning resource categories under the code, following the format of Table 1 of the 2004 JORC Code. Comparisons between the 2007 and 2006 estimates for the deposits are also documented along with risks identified in the resource estimate. The Competent Persons (as defined in the 2004 JORC Code) endorsing these statements of mineral resources are, for: KHN – Duncan Hackman (HA), who has over 22 years experience as a geologist in mining and exploration, which includes fifteen years experience in resource estimation and six years experience in supergene copper deposits. TKN & TKS - Paul Quigley (LXML) who has over 19 years experience as a geologist in mining and exploration, which includes 11 years experience in resource estimation and 7 years experience in sediment-hosted gold deposits. He also has substantial knowledge of the matters relating to supergene copper estimation, mine production, and reconciliation, and as such is responsible for data integrity, geological interpretation and resource classification. PHB – Jared Broome and Antony Manini (Oxiana Limited). Jared Broome has over 15 years experience as a geologist in mining and exploration, which includes 12 years experience in resource estimation. Antony Manini has over 25 years experience as a geologist in mining and exploration, which includes over 10 years experience in supergene copper deposits. Resource Tables Tables 1 to 3 list the copper resources at Sepon as of the 30th June 2007. Page 3 Oxiana Limited 2007 Mineral Resource Explanatory Notes Table 1: June 2007 Sepon Copper Mineral Resource Estimate: KHN, TKN, TKS, PHB & Stockpiles at 0.5 % Cu cut-off grade Greater than 0.5% Cu Cut Resource SUPERGENE MINERALISATION PRIMARY MINERALISATION Deposit Classification (JORC 2004) Mt Cu (%) Au (g/t) Ag (g/t) Cu (kt) Au (kOz) Ag (kOz) Mt Cu (%) Au (g/t) Ag (g/t) Cu (kt) Au (kOz) Ag (kOz) KHANONG Measured 16.6 3.31 0.20 20.5 547 108 10,931 2.0 1.73 0.19 6.7 35 13 435 Indicated 4.5 4.98 0.22 21.2 222 31 3,030 1.2 1.67 0.24 6.9 20 9 268 Inferred 4.4 2.84 0.25 10.0 124 35 1,404 7.2 1.18 0.06 5.6 85 13 1,311 Meas+Ind+Inf 25.4 3.52 0.21 18.8 893 174 15,366 10.4 1.34 0.11 6.0 140 35 2,014 THENGKHAM Measured - - - - - - - - - - - - - - NORTH Indicated 3.5 4.20 0.34 21.2 147 39 2,377 - - - - - - - Inferred 6.9 1.14 0.30 8.1 79 68 1,812 1.2 1.06 0.23 8.7 13 9 347 Meas+Ind+Inf 10.4 2.17 0.32 12.5 226 106 4,190 1.2 1.06 0.23 8.7 13 9 347 THENGKHAM Measured - - - - - - - - - - - - - - SOUTH Indicated - - - - - - - - - - - - - - Inferred 10.7 1.39 0.19 - 149 66 - 4.5 0.81 0.16 - 36 23 - Meas+Ind+Inf 10.7 1.39 0.19 - 149 66 - 4.5 0.81 0.16 - 36 23 - PHABING Measured - - - - - - - - - - - - - - Indicated - - - - - - - - - - - - - - Inferred 2.0 3.37 0.16 2.0 68 10 129 - - - - - - - Meas+Ind+Inf 2.0 3.37 0.16 2.0 68 10 129 - - - - - - - STOCKPILES Measured 2.9 2.15 - - 61 - - - - - - - - - Indicated - - - - - - - - - - - - - - Inferred - - - - - - - - - - - - - - Meas+Ind+Inf 2.9 2.15 - - 61 - - - - - - - - - TOTAL Measured 19.4 3.13 0.20 20.5 608 108 10,931 2.0 1.73 0.19 6.7 35 13 435 Indicated 7.9 4.64 0.27 21.2 368 70 5,408 1.2 1.67 0.24 6.9 20 9 268 Inferred 24.0 1.75 0.23 7.8 421 179 3,345 12.9 1.04 0.11 6.1 134 46 1,658 Meas+Ind+Inf 51.4 2.72 0.23 16.2 1,398 356 19,684 16.1 1.17 0.13 6.3 189 68 2,361 Decimal Places do not imply precision. Page 4 Oxiana Limited 2007 Mineral Resource Explanatory Notes Table 2: June 2007 Sepon Copper Mineral Resource Estimate: KHN, TKN, TKS, PHB & Stockpiles at 1.0 % Cu cut-off grade Greater than 1.0% Cu Cut Resource SUPERGENE MINERALISATION PRIMARY MINERALISATION Deposit Classification (JORC 2004) Mt Cu (%) Au (g/t) Ag (g/t) Cu (kt) Au (kOz) Ag (kOz) Mt Cu (%) Au (g/t) Ag (g/t) Cu (kt) Au (kOz) Ag (kOz) KHANONG Measured 11.6 4.43 0.19 25.0 512 71 9,278 1.4 2.20 0.22 6.6 30 10 294 Indicated 3.3 6.46 0.21 25.1 214 23 2,667 0.8 2.08 0.26 7.4 17 7 198 Inferred 3.1 3.67 0.25 12.0 115 25 1,214 2.9 1.89 0.11 7.8 55 10 735 Meas+Ind+Inf 18.0 4.67 0.21 22.7 841 119 13,159 5.1 2.00 0.16 7.4 103 27 1,227 THENGKHAM Measured - - - - - - - - - - - - - - NORTH Indicated 3.4 4.32 0.35 21.3 146 38 2,309 - - - - - - - Inferred 1.8 2.49 0.32 13.0 45 19 763 0.6 1.48 0.26 10.2 9 5 190 Meas+Ind+Inf 5.2 3.68 0.34 18.4 191 56 3,071 0.6 1.48 0.26 10.2 9 5 190 THENGKHAM Measured - - - - - - - - - - - - - - SOUTH Indicated - - - - - - - - - - - - - - Inferred 4.0 2.67 0.18 - 108 24 - 0.7 1.39 0.17 - 10 4 - Meas+Ind+Inf 4.0 2.67 0.18 - 108 24 - 0.7 1.39 0.17 - 10 4 - PHABING Measured - - - - - - - - - - - - - - Indicated - - - - - - - - - - - - - - Inferred 1.9 3.54 0.16 2.0 67 10 123 - - - - - - - Meas+Ind+Inf 1.9 3.54 0.16 2.0 67 10 123 - - - - - - - STOCKPILES Measured 2.3 2.47 - - 58 - - - - - - - - - Indicated - - - - - - - - - - - - - - Inferred - - - - - - - - - - - - - - Meas+Ind+Inf 2.3 2.47 - - 58 - - - - - - - - - TOTAL Measured 11.6 4.43 0.19 25.0 512 71 9,278 1.4 2.20 0.22 6.6 30 10 294 Indicated 6.7 5.38 0.28 23.2 359 60 4,975 0.8 2.08 0.26 7.4 17 7 198 Inferred 10.9 3.08 0.22 6.0 336 77 2,100 4.2 1.75 0.14 6.8 74 19 924 Meas+Ind+Inf 29.1 4.14 0.22 17.5 1,208 209 16,354 6.4 1.89 0.17 6.8 122 36 1,417 Decimal Places do not imply precision.