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Operations & financial report

Ore reserves

Ore reserves and mineral resources for Rio Tinto managed operations are reported in accordance with the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, December 2004 (the JORC Code) as required by the Australian Stock Exchange (ASX). Codes or guidelines similar to JORC with only minor regional variations have been adopted in South Africa, Canada, USA, Chile, UK, Ireland and Europe, Peru, and the Phillipines. Together these Codes represent current best practice for reporting ore reserves and mineral resources.

The JORC Code envisages the use of reasonable investment assumptions, including the use of projected long term commodity prices, in calculating reserve estimates. However, for US reporting, the US Securities and Exchange Commission (SEC) require historical price data to be used. For this reason, some reserves reported to the SEC on Form 20-F will differ from those reported below.

Ore reserve and mineral resource information in the tables below is based on information compiled by Competent Persons (as defined by JORC), or ‘recognised overseas mining professionals’ as defined by the ASX, most of whom are full time employees of Rio Tinto or related companies. Each has had a minimum of five years relevant estimation experience and is a member of a recognised professional body whose members are bound by a professional code of ethics. Each Competent Person consents to the inclusion in this report of information they have provided in the form and context in which it appears. A register of the names of the Competent Persons who are responsible for the estimates is maintained by the Company Secretaries in London and Melbourne and is available on request. Where operations are not managed by Rio Tinto the reserves are published as received from the managing company.

The ore reserve figures in the following tables are as of 31 December 2007. Summary data for year end 2006 are shown for comparison. Metric units are used throughout. The figures used to calculate Rio Tinto’s share of reserves are often more precise than the rounded numbers shown in the tables, hence small differences might result if the calculations are repeated using the tabulated figures.


  Type of mine
(a)		   Proved ore reserves at end 2007 Probable ore reserves at end 2007 Total ore reserves 2007
compared with 2006		   Rio Tinto share
    Tonnage Grade Tonnage Grade Tonnage Grade   Interest % Recoverable mineral
              2007 2006 2007 2006  
BAUXITE (b)     millions of tonnes %Al2O3 millions of tonnes %Al2O3 millions of tonnes millions of tonnes %Al2O3 %Al2O3     millions of tonnes
Reserves at operating mines                        
Gove (Australia) (c) O/P   78 49.4 65 49.0 143 - 49.2 -   100.0 143
Porto Trombetas (MRN) (Brazil) (c) O/P   149 51.3 18 50.1 166 - 51.2 -   12.0 20
Weipa (Australia) (c) O/P   149 53.2 1,074 53.7 1,224 1,193 53.6 53.7   100.0 1,224
Total                         1,387
                          Marketable product
BORATES (d)     millions of tonnes   millions of tonnes   millions of tonnes millions of tonnes         millions of tonnes
Reserves at operating mines                        
Rio Tinto Minerals – Boron (US) O/P   14.4   7.1   21.5 21.9       100.0 21.5
    Coal type
(f)		 Reserves Marketable Reserves Marketable Reserves Marketable coal quality Avg. % Yield to give mar-
ketable reserves		    
    Proved Probable Proved Probable Total Total       Marketable
reserves
      at end 2007 at end 2007 2007 2006 (g) (g)  
COAL (e)                          
Reserves at operating mines   millions of tonnes millions of tonnes millions of tonnes millions of tonnes millions of tonnes millions of tonnes Calorific value
MJ/kg		 Sulphur content
%		     millions of tonnes
Rio Tinto Energy America(US)                          
Antelope (US) O/C SC 325   325   325 359 20.59 0.24 100.0 100.0 325
Colowyo (US) (h) O/C SC 22 3 22 3 25 14 23.84 0.45 100.0 100.0 22
Cordero Rojo (US) O/C SC 241   241   241 285 19.54 0.30 100.0 100.0 241
Decker (US) O/C SC 12   12   12 18 22.10 0.39 100.0 50.0 12
Jacobs Ranch (US) O/C SC 379 4 379 4 383 418 20.35 0.43 100.0 100.0 383
Spring Creek (US) (i) O/C SC 295   295   295 199 21.75 0.33 100.0 100.0 295
Sub-total                         1,275
Rio Tinto Coal Australia                          
Bengalla (Australia) O/C SC 101 81 75 62 137 150 28.21 0.47 75 30.3 42
Blair Athol (Australia) O/C SC 42   37   37 42 26.91 0.30 89 71.2 26
Hail Creek (Australia) O/C MC 157 102 100 73 174 179 32.20 0.35 67 82.0 142
Hunter Valley Operations (Australia) O/C SC+MC 346 94 235 63 298 308 28.90 0.58 68 75.7 226
Kestrel (Australia) (j) U/G SC+MC 63 100 53 83 136 112 31.60 0.59 83 80.0 109
Mount Thorley Operations (Australia) O/C SC+MC 32 4 21 2 23 23 29.48 0.46 66 60.6 14
Tarong-Meandu (Australia) (k) O/C SC         - 29 - -   - -
Warkworth (Australia) O/C SC+MC 224 156 142 100 242 251 28.87 0.45 64 42.1 102
Sub-total                         661
Total reserves at operating mines                         1,936
Other undeveloped reserves(l)                          
Rio Tinto Coal Australia                          
Clermont (Australia) O/C SC 193 5 185 4 189 189 27.90 0.33 96 50.1 95
Mount Pleasant (Australia) O/C SC   459   350 350 350 26.73 0.51 76 75.7 265
Total undeveloped reserves                         360
  Type of mine
(a)		   Proved ore reserves at end 2007 Probable ore reserves at end 2007 Total ore reserves 2007
compared with 2006		 Average mill recovery
%		 Rio Tinto share
    Tonnage Grade Tonnage Grade Tonnage Grade   Recoverable
mineral
              2007 2006 2007 2006  
COPPER     millions of tonnes %Cu millions of tonnes %Cu millions of tonnes millions of tonnes %Cu %Cu     millions of tonnes
Reserves at operating mines                        
Bingham Canyon (US) O/P   337 0.55 276 0.45 612 641 0.51 0.53 86 100.0 2.680
Escondida (Chile) (m)                          
– sulphide O/P   626 1.24 1,078 1.08 1,704 1,832 1.14 1.15 86 30.0 5.002
– sulphide leach O/P   697 0.57 1,703 0.54 2,399 2,149 0.55 0.54 32 30.0 1.253
– oxide O/P   112 0.78 46 1.12 158 103 0.88 0.88 68 30.0 0.280
Grasberg (Indonesia) O/P+U/G   771 1.10 1,941 1.01 2,712 2,813 1.04 1.04 88 (n) 7.388
Northparkes (Australia)                          
– open pit and stockpiles O/P   0.7 0.69     0.7 3.8 0.69 0.67 85 80.0 0.003
– underground U/G       47 0.97 47 46 0.97 1.06 89 80.0 0.325
Palabora (South Africa) U/G   104 0.62     104 118 0.62 0.64 88 57.7 0.327
Total                         17.258
Reserves at development projects                        
Eagle (US) (o) U/G       3.2 3.04 3.2 - 3.04 - 95 100.0 0.092
Oyu Tolgoi (Mongolia) (p)                          
– Southern Oyu O/P   127 0.58 803 0.48 930 - 0.50 - 87 9.9 0.399
Total                         0.491
                          Recoverable
diamonds
DIAMONDS (b)     millions of tonnes carats per tonne millions of tonnes carats per tonne millions of tonnes millions of tonnes carats per tonne carats per tonne     millions of carats
Reserves at operating mines                  
Argyle (Australia) O/P+U/G   19 1.2 75 2.3 94 106 2.1 2.1   100.0 197.5
Diavik (Canada) O/P+U/G   9 3.4 13 3.6 22 25 3.5 3.3   60.0 46.2
Murowa (Zimbabwe) O/P       21 0.7 21 22 0.7 0.7   77.8 11.6
Total                     255.4
GOLD     millions of tonnes grammes per tonne millions of tonnes grammes per tonne millions of tonnes millions of tonnes grammes per tonne grammes per tonne     millions of ounces
Reserves at operating mines                  
Bingham Canyon (US) O/P   337 0.32 276 0.26 612 641 0.29 0.30 65 100.0 3.749
Cortez/Pipeline (US) (q) (y) O/P+U/G   14 4.36 116 2.53 130 126 2.73 1.85 81 40.0 3.709
Grasberg (Indonesia) O/P+U/G   771 1.09 1,941 0.82 2,712 2,813 0.90 0.90 69 (n) 13.672
Greens Creek (US) (y) U/G       7.7 3.68 7.7 7.0 3.68 3.86 68 70.3 0.437
Northparkes (Australia)                    
– open pit and stockpiles O/P   0.7 0.58     0.7 3.8 0.58 0.58 76 80.0 0.008
– underground U/G       47 0.40 47 46 0.40 0.46 73 80.0 0.357
Total                     21.932
Reserves at development project                  
Oyu Tolgoi (Mongolia) (p)                    
– Southern Oyu O/P   127 0.93 803 0.27 930 – 0.36 – 71 9.9 0.753

  Type of mine (a)   Proved ore reserves at end 2007 Probable ore reserves at end 2007 Total ore reserves 2007
compared with 2006		 Average mill recovery
%		 Rio Tinto share
    Tonnage Grade Tonnage Grade Tonnage Grade Interest
%		 Marketable
product
              2007 2006 2007 2006
IRON ORE (b)     millions of tonnes %Fe millions of tonnes %Fe millions of tonnes millions of tonnes %Fe %Fe     millions of tonnes
Reserves at operating mines                        
Channar (Australia)                          
– Brockman ore O/P   89 63.4 18 63.3 106 100 63.4 63.5   60.0 64
Corumbä (Brazil) O/P   104 66.9 107 67.0 210 214 67.0 67.2   100.0 210
Eastern Range (Australia)                          
– Brockman ore (r) O/P   81 63.2 30 63.2 111 91 63.2 62.9   54.0 60
Hamersley Iron (Australia)                          
– Brockman 2 (Brockman ore) O/P   18 62.7 8 62.6 25 30 62.7 62.6   100.0 25
– Brockman 4 (Brockman ore) O/P   336 62.4 233 62.1 570 552 62.3 62.2   100.0 570
– Hope Downs (Marra Mamba ore) O/P   32 61.9 312 61.4 344 344 61.4 61.6   50.0 172
– Marandoo (Marra Mamba ore) O/P   48 61.7 2 60.7 50 67 61.7 61.6   100.0 50
– Mt Tom Price (Brockman ore) O/P   59 64.2 67 64.6 125 127 64.4 64.6   100.0 125
– Mt Tom Price (Marra Mamba ore)O/P       33 61.2 33 35 61.2 61.2   100.0 33
– Paraburdoo (Brockman ore) (s) O/P   23 64.0 6 63.4 28 12 63.9 63.6   100.0 28
– Paraburdoo (Marra Mamba ore) (s)O/P       0.8 63.3 0.8 0.5 63.3 63.2   100.0 0.8
– Nammuldi (Marra Mamba ore) O/P   25 61.5 5 59.7 30 31 61.2 61.4   100.0 30
– Yandicoogina (Pisolite ore HG) (t) O/P   271 58.7 5 58.5 277 328 58.7 58.7   100.0 277
– Yandicoogina (Process Product) O/P   119 58.5     119 109 58.5 58.4   100.0 119
Iron Ore Company of Canada (u)                          
(Canada) O/P   406 65.0 131 65.0 538 416 65.0 65.0   58.7 316
Robe River (Australia)                          
– Pannawonica (Pisolite ore) O/P   264 57.3 40 56.6 304 345 57.2 57.2   53.0 161
– West Angelas (Marra Mamba ore) O/P   196 62.1 196 61.5 392 408 61.8 61.9   53.0 208
Total                         2,449
                          Recoverable metal
LEAD     millions of tonnes %Pb millions of tonnes %Pb millions of tonnes millions of tonnes %Pb %Pb     millions of tonnes
Reserves at operating mine                        
Greens Creek (US) (y) U/G       7.7 3.79 7.7 7.0 3.79 3.98 66 70.3 0.136
MOLYBDENUM     millions of tonnes %Mo millions of tonnes %Mo millions of tonnes millions of tonnes %Mo %Mo     millions of tonnes
Reserves at operating mine                        
Bingham Canyon (US) (v) O/P   337 0.047 276 0.042 612 641 0.045 0.047 62 100.0 0.172
NICKEL     millions of tonnes %Ni millions of tonnes %Ni millions of tonnes millions of tonnes %Ni %Ni     millions of tonnes
Reserves at project development                        
Eagle (US) (o) U/G       3.2 3.89 3.2 – 3.89 – 84 100.0 0.105
SILVER     millions of tonnes grammes per tonne millions of tonnes grammes per tonne millions of tonnes millions of tonnes grammes per tonne grammes per tonne     millions of ounces
Reserves at operating mines                        
Bingham Canyon (US) O/P   337 2.53 276 2.12 612 641 2.35 2.47 77 100.0 35.414
Grasberg (Indonesia) O/P+U/G   771 4.31 1,941 4.03 2,712 2,813 4.11 4.16 68 (n) 77.186
Greens Creek (US) (y) U/G       7.7 471 7.7 7.0 471 494 72 70.3 58.378
Total                         170.978
                          Marketable product
TALC (d)     millions of tonnes   millions of tonnes   millions of tonnes millions of tonnes         millions of tonnes
Reserves at operating mines                        
Rio Tinto Minerals – talc (w) O/P+U/G   25.7   7.8   33.5 28.8       100.0 33.5
(Europe/North America/Australia)                          

  Type of mine
(a)		   Proved ore reserves at end 2007 Probable ore reserves at end 2007 Total orereserves 2007
comparedwith 2006		 Average mill recovery
%		 Rio Tinto share 
    Tonnage Grade Tonnage Grade Tonnage Grade Interest
%		 Marketable
product 
              2007  2006 2007  2006
TITANIUM DIOXIDE FEEDSTOCK (d)   millions of tonnes   millions of tonnes   millions of tonnes millions of tonnes       millions of tonnes
Reserves at operating mines                   
QIT (Canada) O/P   30.0   23.5   53.5 52.7     100.0 53.5
RBM (South Africa) D/O   5.6   18.6   24.2 24.9     50.0 12.1
Total                      65.5
Reserves at development project                   
QMM (Madagascar) D/O   12.0   0.4   12.4 12.4     80.0 9.9
                      Recoverable metal
                     
URANIUM      millions of tonnes %U308  millions of tonnes %U308  millions of tonnes millions of tonnes %U308 %U308      millions of tonnes
Reserves at operating mines                   
Energy Resources of Australia                    
(Australia) – Ranger #3 O/P   25.2 0.137 6.9 0.217 32.1 35.6 0.155 0.143 86.90 68.4 0.030
Rössing (Namibia) (x) O/P   19.6 0.050 130.6 0.035 150.2 132.4 0.037 0.032 85.00 68.6 0.032
Total reserves at operating mines                    0.062
ZINC      millions of tonnes %Zn millionsof tonnes %Zn millions of tonnes millions of tonnes %Zn %Zn     millions of tonnes
Reserves at operating mine                   
Greens Creek (US) (y) U/G       7.7 10.18 7.7 7.0 10.18 10.39 76 70.3 0.419

Notes Expand
  1. Type of mine: O/P = open pit, O/C = open cut, U/G = underground, D/O = dredging operation.
  2. Reserves of iron ore, bauxite (as alumina) and diamonds are shown as recoverable reserves of saleable product after accounting for all mining and processing losses. Mill recoveries are therefore not shown.
  3. Rio Tinto acquired the operating assets of Alcan with effect from 24 October 2007. The Rio Tinto assets and the Alcan assets have been combined under the Rio Tinto Alcan name and reserves are presented here for the first time. The Weipa deposit now includes the reserve for Ely as this deposit is contiguous with Weipa.
  4. Reserves of industrial minerals are expressed in terms of marketable product, i.e. after all mining and processing losses. In the case of borates, the saleable product is B2O3.
  5. For coal, the yield factors shown reflect the impact of further processing, where necessary, to provide marketable coal.
  6. Coal type: SC = steam/thermal coal; MC = metallurgical/coking coal.
  7. Analyses of coal from the US were undertaken according to “American Standard Testing Methods” (ASTM) on an “As Received” moisture basis whereas the coals from Australia have been analysed on an “Air Dried” moisture basis according to Australian Standards (AS). MJ/kg = megajoules per kilogramme.
  8. Rio Tinto Energy America has a partnership interest in the Colowyo mine but, as it is responsible under a management agreement for the operation of the mine, all of Colowyo’s reserves are included in Rio Tinto’s share shown above. The increase in reserves results from the addition of reserves from the South Taylor area.
  9. Acquisition of additional leases increased the Spring Creek reserves.
  10. Approval of the Kestrel mine extension resulted in an increase in reserves by upgrading of resources from the Kestrel West area.
  11. Contracts have been signed for the sale of the Tarong Meandu properties with transfer being effected on 31 January 2008.
  12. The term ‘other undeveloped reserves´ is used here to describe material that is economically viable on the basis of technical and economic studies but for which mining and processing permits have yet to be requested or obtained. There is a reasonable, but not absolute, certainty that the necessary permits will be issued and that mining can proceed when required.
  13. Reporting for Escondida and Escondida Norte is combined for 2007. The increase in reserves results from updated geological models and the application of new economic parameters.
  14. Under the terms of a joint venture agreement between Rio Tinto and FCX, Rio Tinto is entitled to a direct 40 per cent share in reserves discovered after 31 December 1994 and it is this entitlement that is shown.
  15. Following completion of economic and technical studies at the Eagle project, resources were upgraded to reserves that are presented here for the first time.
  16. Whilst economic and technical studies continue at the Oyu Tolgoi deposits, reserves are presented here for the first time.
  17. The increase in grade at Cortez is due to the addition of higher grade material from resources together with production depletion of lower grade material.
  18. Life of mine studies at Eastern Range resulted in development of new pit designs that in turn increased the reserves.
  19. Life of mine studies at Paraburdoo resulted in transfer of resources that increased the reserves.
  20. The reduction in reserves at Yandicoogina is the result of production and economic studies.
  21. Reserves at IOC increased as a result of revised economic studies leading to an enlarging of the optimal pits.
  22. Molybdenum grades reflect reconciliation of model and plant grades.
  23. The increase in reserves at the talc operations results from updated models following increased drilling and the application of new economic parameters; this transferred resources to reserves.
  24. Economic and technical studies at Rössing resulted in revisions of pit shape thus increasing reserves.
  25. In February 2008 Rio Tinto entered into agreements to sell its interests in Greens Creek and Cortez.

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