The Future is Nuclear 2005 Annual Report
U
Reserves and Resources

Note Regarding Reserves and Resources

Reserves and resources reported herein have been estimated as at December 31, 2005 in accordance with definitions adopted by the Canadian Institute of Mining, Metallurgy and Petroleum and incorporated into National Instrument 43-101 (see definitions below). Estimates of uranium reserves and resources were prepared by or under the supervision of the qualified persons identified at “Uranium Reserves and Resources.” Estimates of gold reserves and resources were prepared by or under supervision of the qualified person identified at “Gold Reserves and Resources.” The amount of reported resources does not include those amounts identified as reserves.

Cameco reports its reserves and resources in accordance with National Instrument 43-101, as required by Canadian securities regulatory authorities. For United States reporting purposes, Industry Guide 7 under the Securities Exchange Act of 1934 (as interpreted by the staff of the US Securities and Exchange Commission) applies different standards in order to classify mineralization as a reserve. Accordingly, for US reporting purposes, as at December 31, 2005, the mineralization at the Ruth uranium in situ leach project in Wyoming is classified as mineralized material. In addition, for US reporting purposes, all mineral resources must be considered as mineralized material.

For the purpose of estimating uranium reserves in accordance with National Instrument 43-101 of the Canadian securities regulatory authorities, a uranium price of $22.70 (US) was used. For the purpose of estimating reserves in accordance with United States Securities and Exchange Commission’s Industry Guide 7 for US reporting purposes, a uranium price of $19.60 (US) was used. Estimated uranium reserves are the same using either uranium price, except for the Ruth uranium in situ leach project in Wyoming which, for US reporting purposes, is classified as mineralized material.

For the purpose of estimating gold reserves in accordance with National Instrument 43-101 of the Canadian securities regulatory authorities and in accordance with United States Securities and Exchange Commission’s Industry Guide 7 for US reporting purposes, reserves were calculated with cut-off grades based on a gold price of $400 (US) per ounce.

Mineral resources are not mineral reserves and do not have demonstrated economic viability, but do have reasonable prospects for economic extraction. Measured and indicated mineral resources are sufficiently well defined to allow geological and grade continuity to be reasonably assumed and permit the application of technical and economic parameters in assessing the economic viability of the resources. Inferred resources are estimated on limited information not sufficient to verify geological and grade continuity or to allow technical and economic parameters to be applied. Inferred resources are too speculative geologically to have economic considerations applied to enable them to be categorized as mineral reserves. There is no certainty that mineral resources will be upgraded to mineral reserves through continued exploration.

Although the company has carefully prepared and verified the mineral reserve figures presented in this annual report, such figures are estimates, which are, in part, based on forward-looking information, and no assurance can be given that the indicated levels of uranium and gold will be produced. See “Risk Factors” and “Note Regarding Forward-Looking Statements” in Cameco’s annual information form available at cameco.com and sedar.com.

Definitions

A mineral resource is a concentration or occurrence of diamonds, natural solid inorganic material, or natural solid fossilized organic material in or on the Earth’s crust in such form and quantity and of such a grade including base and precious metals, coal and industrial materials, or quality that it has reasonable prospects for economic extraction. The location, quantity, grade, geological characteristics and continuity of a mineral resource are known, estimated or interpreted from specific geological evidence and knowledge. Mineral resources are subdivided, in order of increasing geological confidence, into inferred, indicated and measured categories.

An inferred mineral resource is that part of a mineral resource for which quantity and grade or quality can be estimated on the basis of geological evidence and limited sampling and reasonably assumed, but not verified, geological and grade continuity. The estimate is based on limited information and sampling gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes.

An indicated mineral resource is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics, can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough for geological and grade continuity to be reasonably assumed.

A measured mineral resource is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics are so well established that they can be estimated with confidence sufficient to allow the appropriate application of technical and economic parameters, to support production planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough to confirm both geological and grade continuity.

A mineral reserve is the economically mineable part of a measured or indicated mineral resource demonstrated by at least a preliminary feasibility study. This study must include adequate information on mining, processing, metallurgical, economic and other relevant factors that demonstrate, at the time of reporting, that economic extraction can be justified. A mineral reserve includes diluting materials and allowances for losses that may occur when the material is mined. Mineral reserves are subdivided in order of increasing confidence into probable mineral reserves and proven mineral reserves.

A probable mineral reserve is the economically mineable part of an indicated and, in some circumstances, a measured mineral resource demonstrated by at least a preliminary feasibility study. This study must include adequate information on mining, processing, metallurgical, economic and other relevant factors that demonstrate, at the time of reporting, that economic extraction can be justified.

A proven mineral reserve is the economically mineable part of a measured mineral resource demonstrated by at least a preliminary feasibility study. This study must include adequate information on mining, processing, metallurgical, economic and other relevant factors that demonstrate, at the time of reporting, that economic extraction can be justified.

Uranium Reserves and Resources

The disclosure in this annual report of scientific and technical information regarding Cameco’s uranium properties, including reserve and resource estimates and the description of the geology, were prepared by or under the supervision of the following qualified persons:

Qualified Persons Properties
Alain Gaston Mainville, geologist and professional geoscientist, manager, mining resources and methods at Cameco McArthur River, Rabbit Lake, Key Lake, Dawn Lake, and Millennium
Raymond Jean-François Chauvet, geological engineer and professional geoscientist, former director, mining resources and methods at Cameco. Cigar Lake and Inkai
Steve Lunsford, registered professional geologist Wyoming, chief geologist at Power Resources, Inc. Crow Butte, Gas Hills-Peach, Highland, North Butte/Brown Ranch, Northwest Unit, Reynolds Ranch, Ruby Ranch, Ruth, Shirley Basin and Smith Ranch

The qualified persons as a group, beneficially own, directly or indirectly, less than 1% of the issued and outstanding common shares of Cameco.

Canadian Securities Administrators’ National Instrument 43-101 requires mining companies to disclose reserves and resources using the subcategories of proven reserves, probable reserves, measured resources, indicated resources and inferred resources. Cameco reports reserves and resources separately. (See “Note Regarding Reserves and Resources”).

Cameco reports all its mineral reserves as quantity of contained ore supporting the mining plans and includes an estimate of the metallurgical recovery for each of its properties. Metallurgical recovery is a term used in the mining industry to indicate the proportion of valuable material physically recovered by the metallurgical extraction process. The estimated recoverable amount of a commodity is obtained by multiplying the reserves “Content” by the “Estimated Metallurgical Recovery Percentage.”

Uranium Reserves

The following table shows the estimated uranium reserves as at December 31, 2005 on a property basis and Cameco’s share.

RESERVES1, 5 PROVEN
(100% basis)
PROBABLE
(100% basis)
PROPERTY* Tonnes % Grade U3O8 Content lbs U3O8 Tonnes Grade % U3O8 Content lbs U3O8
Cigar Lake 497.0 20.67 226.3 54.0 4.41 5.2
Crow Butte 816.4 0.39 6.8 195.6 0.24 1.0
Gas Hills - Peach 6,851.0 0.14 19.7
Highland 672.8 0.12 1.8 1,016.6 0.12 2.7
Inkai 22,700.0 0.07 35.4 63,700.0 0.06 79.0
Key Lake 61.9 0.52 0.7
McArthur River 363.4 24.38 195.3 363.6 24.17 193.8
North Butte/            
Brown Ranch 3,874.6 0.10 8.5
Rabbit Lake 176.7 0.80 3.1 206.4 1.73 7.9
Ruby Ranch 2,832.2 0.09 5.5
Ruth3 853.7 0.10 1.7
Smith Ranch 1,368.8 0.09 2.8 3,143.1 0.12 8.3
Total4 26,657.0 472.2 83,090.8 333.3


RESERVES1, 5 - CONTINUED TOTAL RESERVES
(100% basis)
 
PROPERTY* Tonnes Grade % U3O8 Content lbs U3O8 Cameco’s Share lbs U3O8 Estimated Metallurgical Recovery % Mining Method 2
Cigar Lake 551.0 19.06 231.5 115.8 99 UG
Crow Butte 1,012.0 0.35 7.8 7.8 85 ISL
Gas Hills - Peach 6,851.0 0.14 19.7 19.7 65 ISL
Highland 1,689.3 0.12 4.5 4.5 80 ISL
Inkai 86,400.0 0.06 114.4 68.6 80 ISL
Key Lake 61.9 0.52 0.7 0.6 99 OP
McArthur River 727.0 24.28 389.1 271.6 99 UG
North Butte/            
Brown Ranch 3,874.6 0.10 8.5 8.5 80 ISL
Rabbit Lake 383.1 1.30 11.0 11.0 97 UG
Ruby Ranch 2,832.2 0.09 5.5 5.5 80 ISL
Ruth3 853.7 0.10 1.7 1.7 80 ISL
Smith Ranch 4,512.0 0.11 11.1 11.1 80 ISL
Total4 109,747.8 805.5 526.4
*tonnes in thousands; pounds in millions

Notes:
1 Cameco reports reserves and resources separately.
2 Mining Method: OP – Open Pit; UG – Underground; ISL – In Situ Leaching.
3 For United States reporting purposes, Industry Guide 7 under the Securities and Exchange Act of 1934, as interpreted by the staff of the U.S. Securities and Exchange Commission, applies different standards to classify mineralization as a reserve.  Accordingly, for US reporting purposes as of December 31, 2005, the mineralization at the Ruth uranium in situ leach project in Wyoming is classified as mineralized material.
4 Totals may not add, due to rounding.
5 For the purpose of estimating reserves in accordance with National Instrument 43-101, a uranium price of $22.70 (US) per pound U3O8 was used.  For the purpose of estimating reserves in accordance with US Securities Commission Industry Guide 7 for US reporting purposes, a uranium price of $19.60 (US) was used.  Estimated uranium reserves are the same using either uranium price except for the Ruth uranium in situ leach project in Wyoming, which is classified for US reporting purposes as mineralized material.
In addition to the above reserves, Cameco has contractual committed supplies, including supplies under the HEU Commercial Agreement, of approximately 59 million pounds of uranium from January 1, 2006 until the end of 2013.

Uranium Measured and Indicated Resources

Cautionary note to investors concerning estimates of measured and indicated resources:

This section uses the terms “measured resources” and “indicated resources”. US investors are advised that while those terms are recognized and required by Canadian securities regulatory authorities, the US Securities and Exchange Commission does not recognize them. Investors are cautioned not to assume that any part or all of the mineral deposit in these categories will ever be converted into proven or probable reserves.

The following table shows the estimated uranium measured and indicated resources as at December 31, 2005 on a property basis and Cameco’s share.

RESOURCES1 MEASURED
(100% basis)
INDICATED
(100% basis)
PROPERTY* Tonnes Grade % U3O8 Content lbs U3O8 Tonnes Grade % U3O8 Content lbs U3O8
Crow Butte 1,475.8 0.25 8.1
Dawn Lake 347.0 1.69 12.9
Gas Hills – Peach 2,013.0 0.09 3.3 1,153.0 0.08 2.3
Highland 782.3 0.10 1.7 47.0 0.09 0.1
Inkai 11,033.0 0.06 14.2
McArthur River 40.9 10.21 9.2 39.8 8.39 7.4
Millennium 449.0 4.63 45.8
North Butte/Brown Ranch 1,008.8 0.08 1.9 3,923.6 0.07 6.3
Northwest Unit 4,000.7 0.04 2.3
Rabbit Lake 456.3 0.74 7.5
Reynolds Ranch 3,073.5 0.07 4.5 5,245.3 0.06 7.0
Ruby Ranch 156.0 0.18 0.6 108.0 0.06 0.1
Ruth 99.8 0.10 0.2 125.2 0.07 0.2
Shirley Basin 89.1 0.15 0.3 1,635.9 0.11 4.1
Smith Ranch 30.8 0.20 0.1 2,406.4 0.09 5.0
Total3 7,294.3 21.8 32,445.9 123.3


RESOURCES1 - CONTINUED MEASURED AND INDICATED
(100% basis)
   
PROPERTY* Tonnes Grade % U3O8 Content lbs U3O8 Cameco’s Share lbs U3O8 Mining Method 2
Crow Butte 1,475.8 0.25 8.1 8.1 ISL   
Dawn Lake 347.0 1.69 12.9 7.4 OP&UG  
Gas Hills – Peach 3,166.1 0.08 5.6 5.6 ISL  
Highland 829.3 0.10 1.8 1.8 ISL  
Inkai 11,033.0 0.06 14.2 8.5 ISL  
McArthur River 80.7 9.33 16.6 11.6 UG  
Millennium 449.0 4.63 45.8 19.2 UG  
North Butte/Brown Ranch 4,932.3 0.07 8.2 8.2 ISL  
Northwest Unit 4,000.7 0.04 2.3 2.3 ISL  
Rabbit Lake 456.3 0.74 7.5 7.5 UG  
Reynolds Ranch 8,318.8 0.06 11.5 11.5 ISL  
Ruby Ranch 264.0 0.12 0.7 0.7 ISL  
Ruth 225.0 0.07 0.4 0.4 ISL  
Shirley Basin 1,725.0 0.12 4.4 4.4 ISL  
Smith Ranch 2,437.2 0.09 5.1 5.1 ISL  
Total3 39,740.2 145.1 102.2  
*tonnes in thousands; pounds in millions
Notes:
1 Cameco reports reserves and resources separately. The amount of reported resources does not include those amounts identified as reserves.
2 Mining Method: OP – Open Pit; UG – Underground; ISL – In Situ Leaching.
3 Totals may not add, due to rounding.


Uranium Inferred Resources

Cautionary note to investors concerning estimates of inferred resources:

This section uses the term “inferred resources”. US investors are advised that while this term is recognized and required by Canadian securities regulatory authorities, the US Securities and Exchange Commission does not recognize it. “Inferred resources” have a great amount of uncertainty as to their existence and great amount of uncertainty as to their economic and legal feasibility. It cannot be assumed that all or any part of an inferred resource will ever be upgraded to a higher category. Under Canadian securities regulations, estimates of inferred resources may not form the basis of feasibility or prefeasibility studies. Investors are cautioned not to assume that part or all of an inferred resource exists or is economically or legally mineable.

The following table shows the estimated uranium inferred resources as at December 31, 2005 on a property basis and Cameco’s share.

  INFERRED RESOURCES1  
  (100% basis)   
PROPERTY* Tonnes Grade % U3O8 Content lbs U3O8 Cameco’s Share lbs U3O8 Mining Method 2
Cigar Lake 317.0 16.92 118.2 59.1 UG   
Crow Butte 2,802.1 0.16 10.1 10.1 ISL  
Gas Hills-Peach 656.8 0.07 0.8 0.8 ISL  
Highland 587.6 0.15 2.0 2.0 ISL  
Inkai 253,918.0 0.05 268.0 160.8 ISL  
McArthur River 584.6 7.35 94.8 66.2 UG  
Millennium 280.0 1.81 11.2 4.7 UG  
North Butte/Brown Ranch 618.5 0.07 1.0 1.0 ISL  
Northwest Unit 627.8 0.04 0.5 0.5 ISL  
Rabbit Lake 104.7 1.60 3.7 3.7 UG  
Reynolds Ranch 5,333.3 0.04 4.9 4.9 ISL  
Ruby Ranch 60.8 0.15 0.2 0.2 ISL  
Ruth 210.5 0.07 0.4 0.4 ISL  
Shirley Basin 506.8 0.10 1.1 1.1 ISL  
Smith Ranch 595.7 0.07 0.9 0.9 ISL  
Total3 267,204.1 517.8 316.4  
*tonnes in thousands; pounds in millions
Notes:
1 Cameco reports reserves and resources separately. The amount of reported resources does not include those amounts identified as reserves.
2 Mining Method: OP – Open Pit; UG – Underground; ISL – In Situ Leaching.
3 Totals may not add, due to rounding.


Uranium Reserves Reconciliation

The following reconciliation of Cameco’s share of uranium reserves reflects the changes in reserves during 2005. The 2005 additions and deletions result from additional information provided by mining and milling, analysis of drilling results, change in mining plans, re-estimation and reclassification.

Cameco’s share of proven and probable uranium reserves has decreased by 26.9 million pounds, from 553.4 million pounds at the end of 2004 to 526.5 million pounds at the end of 2005. The majority of the decrease was attributable to mine production during 2005.

Another change in 2005 was the reclassification of a significant portion of McArthur River reserves from proven to probable. Currently, McArthur River mine uses only raise boring to extract ore. As expected from the start of mining, other mining methods may be used to maintain or expand production. In 2005, Cameco determined that the boxhole boring method would be better suited for the upper zone #4 at McArthur River, because it would allow for development from a preferred location.

Until Cameco has fully developed and tested the boxhole boring method, there is uncertainty in the estimated productivity. As a result, Cameco has reclassified 108.2 million pounds from proven to probable reserves in upper zone #4 at McArthur River (Cameco’s share is 75 million pounds). Cameco does not expect this change to significantly impact its long-term production plans. Production from this zone is scheduled to begin in 2012.

In addition, the revisions to the proposed mining plan for the upper zone #4 and re-interpretation of a small portion of zone #2 have resulted in a decrease in proven reserves at McArthur River of 12.9 million pounds (Cameco’s share is 9 million pounds).

Reconciliation of Cameco's Share of Uranium Reserves
(in thousands of pounds U3O8)
    2005 2005  
  December 31, 2004 Throughput1 Addition (Deletion) December 31, 2005
Reserves – Proven        
Cigar Lake 113,222 –  –    113,222
Crow Butte 7,794 (979) –    6,815
Highland 1,162 (894) 1,539  2 1,807
Inkai 21,211 –  –    21,211
Key Lake 590 –  –    590
McArthur River 233,087 (12,620) (84,144) 2 136,323
Rabbit Lake 8,096 (5,337) 368  2 3,127
Smith Ranch 896 (763) 2,712  2 2,845
Total Proven Reserves 386,058 (20,593) (79,525)   285,940
           
Reserves – Probable          
Cigar Lake 2,625 –  –    2,625
Crow Butte 1,013 –  –    1,013
Gas Hills – Peach 22,056 –  (2,372) 2 19,684
Highland 2,855 –  (192) 2 2,663
Inkai 47,412 –  –    47,412
McArthur River 59,722 –  75,536  2 135,258
North Butte/Brown Ranch 7,939 –  585  2 8,524
Rabbit Lake 6,132 (740) 2,471  2 7,863
Ruby Ranch 5,082 –  380  2 5,462
Ruth 3 1,470 –  219  2 1,689
Smith Ranch 11,057 –  (2,740) 2 8,317
Total Probable Reserves 167,363 (740) 73,887    240,510
Total Reserves 553,421 (21,333) (5,638)   526,450
Notes:
1 Corresponds to mill feed. The discrepancy between the 2005 mill feed and Cameco's share of 2005 pounds U3O8 produced is due to mill recovery, mill inventory and the processing of low-grade material.
2 Changes in reserves or resources, as applicable, include reassessment of geological data, results of information provided by mining and milling, change in mining plan and subsequent reestimation and reclassification of reserves or resources, as applicable.
3 For United States reporting purposes, Industry Guide 7 under the Securities and Exchange Act of 1934, as interpreted by the staff of the US Securities and Exchange Commission, applies different standards to classify mineralization as a reserve. Accordingly, for US reporting purposes, the mineralization at the Ruth in situ leach project in Wyoming is classified as mineralized material.


Uranium Resources Reconciliation

The following reconciliation of Cameco’s share of uranium resources reflects the changes in resources during 2005. The 2005 additions and deletions result from additional information provided by mining and milling, analysis of drilling results, property acquisitions, change in mining plans, re-estimation and reclassification.

There were only modest changes in resources in 2005 as outlined in the table below. The more noteworthy of these changes are:

  • at Rabbit Lake, indicated resources increased by 3.5 million pounds and inferred resources increased by 3.7 million pounds due to drilling and reclassification.
  • at McArthur River, inferred resources decreased by 7.5 million pounds due to drilling.
  • at Millennium, indicated resources increased by 4.7 million pounds and inferred resources decreased by 1.9 million pounds due to additional surface drilling during 2005.
  • at Crow Butte, indicated resources increased by 1.3 million pounds and inferred resources increased by 3.1 million pounds due to re-estimation and re-acquisition of the Marsland property.
  • at Inkai, indicated resources increased by 6.8 million pounds due to re-estimation.
RECONCILIATION OF CAMECOS SHARE OF URANIUM RESOURCES
(in thousands of pounds U3O8)
    2005  
  December 31, 2004 Addition (Deletion)1 December 31, 2005
Resources – Measured      
Gas Hills – Peach 4,662   (1,316)   3,346   
Highland 1,663   -   1,663  
McArthur River 6,879   (452)   6,427  
North Butte/Brown Ranch -   1,857   1,857  
Reynolds Ranch 2,654   1,839   4,493  
Ruby Ranch 862   (277)   585  
Ruth -   216   216  
Shirley Basin 304   -   304  
Smith Ranch 138   -   138  
Total Measured Resources 17,162   1,867   19,029  
             
ResourcesIndicated            
Crow Butte 6,849   1,251   8,100  
Dawn Lake 7,436   -   7,436  
Gas HillsPeach 3,845   (1,535)   2,310  
Highland 92   -   92  
Inkai 1,740   6,781   8,521  
McArthur River 5,136   -   5,136  
Millennium 14,520   4,700   19,220  
North Butte/Brown Ranch 6,788   (485)   6,303  
Northwest Unit 2,361   (20)   2,341  
Rabbit Lake 4,009   3,477   7,486  
Reynolds Ranch 7,791   (831)   6,960  
Ruby Ranch 581   (438)   143  
Ruth 609   (417)   192  
Shirley Basin 4,085   -   4,085  
Smith Ranch 4,951   33   4,984  
Total Indicated Resources 70,793   12,516   83,309  
             
Total Measured & Indicated 87,955   14,383   102,338  
             
ResourcesInferred            
Cigar Lake 59,105   -   59,105  
Crow Butte 6,979   3,104   10,083  
Gas HillsPeach -   845   845  
Highland 1,977   -   1,977  
Inkai 160,793   -   160,793  
McArthur River 73,675   (7,524)   66,151  
Millennium 6,630   (1,930)   4,700  
North Butte/Brown Ranch 734   232   966  
Northwest Unit 1,093   (585)   508  
Rabbit Lake -   3,701   3,701  
Reynolds Ranch 7,099   (2,187)   4,912  
Ruby Ranch -   184   184  
Ruth -   365   365  
Shirley Basin 1,132   -   1,132  
Smith Ranch 1,010   (114)   896  
Total Inferred Resources 320,227   (3,909)   316,318  
Notes:            
1 Changes in reserves or resources, as applicable, include reassessment of geological data, results of information provided by mining and milling, change in mining plan, and subsequent re-estimation and reclassification of reserves or resources, as applicable.

Gold Reserves and Resources

Reserve and resource estimates, the scientific and technical information, and description of the geology relating to Centerra’s gold properties, as presented in this Annual Information Form, were reviewed by Alain Gaston Mainville, Geologist and Professional Geoscientist, who is Manager, Mining Resources and Methods at Cameco, and were prepared by or under the supervision of the following qualified person:

Qualified Person Properties
Rob Chapman, geologist and professional geoscientist, director, mergers and acquisitions, Centerra. Kumtor
Boroo
REN
Gatsuurt

To the knowledge of Cameco, the qualified person, beneficially owns, directly or indirectly, less than 1% of the issued and outstanding common shares of Cameco.

Cameco’s gold reserves and resources are located in the Kyrgyz Republic, Mongolia and the United States of America.

The following table shows the estimated gold reserves and resources as at December 31, 2005 on a property basis and Cameco’s share. Cameco’s share amounts to 52.7% of Centerra’s share of the reserves and resources of the properties. The amount of reported resources does not include those amounts identified as reserves.

Cautionary note to investors concerning estimates of measured and indicated resources:

This section uses the terms “measured resources” and “indicated resources”. US investors are advised that while those terms are recognized and required by Canadian securities regulatory authorities, the US Securities and Exchange Commission does not recognize them. Investors are cautioned not to assume that any part or all of the mineral deposit in these categories will ever be converted into proven and probable reserves.

Cautionary note to investors concerning estimates of inferred resources:

This section uses the term “inferred resources”. US investors are advised that while this term is recognized and required by Canadian securities regulatory authorities, the US Securities and Exchange Commission does not recognize it. “Inferred resources” have a great amount of uncertainty as to their existence and as to their economic and legal feasibility. It cannot be assumed that all or any part of an inferred resource will ever be upgraded to a higher category. Under Canadian securities regulations, estimates of inferred resources may not form the basis of feasibility or prefeasibility studies. Investors are cautioned not to assume that part or all of an inferred resource exists or is economically or legally mineable.

RESERVES1,3 PROVEN
(100% basis)
PROBABLE
(100% basis)
             
PROPERTY* Tonnes (thousands) Grade g/t Au Content 1000 oz Au Tonnes (thousands) Grade g/t Au Content 1000 oz Au
Boroo 8,810 2.8 774 4,580 3.0 444
Kumtor 17,600 3.7 2,099 22,562 3.9 2,854
Total 26,410 3.4 2,873 27,142 3.8 3,298

RESERVES1,3 - CONTINUED TOTAL RESERVES
(100% basis)
 
             
PROPERTY* Tonnes (thousands) Grade g/t Au Content 1000 oz Au Cameco’s Share 1000 oz Au Estimated Metallurgical Recovery % Mining Method 2
Boroo 13,390 2.8 1,218 609 89% OP
Kumtor 40,162 3.8 4,953 2,609 83% OP
Total 53,552 3.6 6,171 3,218
*tonnes and ounces in thousands

 

RESOURCES1 MEASURED
(100% basis)
INDICATED
(100% basis)
             
PROPERTY* Tonnes (thousands) Grade g/t Au Content 1000 oz Au Tonnes (thousands) Grade g/t Au Content 1000 oz Au
Boroo 4, 5 1,870 2.4 147 782 2.2 54
Gatsuurt 6 18,597 3.1 1,854
Kumtor 4,7 13,406 3.8 1,634 10,601 4.1 1,387
REN 2,753 13.6 1,201
Total 15,276 3.6 1,781 32,733 4.3 4,496
RESOURCES1 - CONTINUED MEASURED AND INDICATED RESOURCES
(100% basis)
 
           
PROPERTY* Tonnes (thousands) Grade g/t Au Content 1000 oz Au Cameco’s Share 1000 oz Au Mining Method 2
Boroo 4, 5 2,652 2.4 201 101 OP
Gatsuurt 6 18,597 3.1 1,854 977 OP
Kumtor 4,7 24,007 3.9 3,021 1,591 OP/UG
REN 2,753 13.6 1,201 393 UG
Total 48,009 4.1 6,277 3,062
*tonnes and ounces in thousands
  INFERRED RESOURCES1  
  (100% basis)  
PROPERTY* Tonnes (thousands) Grade g/t Au Content 1000 oz Au Cameco’s Share 1000 oz Au Mining Method 2
Boroo 4, 5 2,563 2.0 167 84 OP
Gatsuurt 6 3,980 3.0 378 199 OP
Kumtor 4, 7 5,475 4.6 803 423 OP/UG
REN 8 301 13.2 128 42 UG
Total 12,319 3.7 1,476 748
*tonnes and ounces in thousands
Notes:
1 Cameco reports reserves and resources separately. The amount of reported resources does not include those amounts identified as reserves.
2 Mining Method: OP – Open Pit; UG – Underground.
3 For the purpose of estimating reserves in accordance with National Instrument 43-101 of the Canadian securities regulatory authorities and in accordance with US Securities and Exchange Commission's Industry Guide 7 for US reporting purposes, reserves were estimated with cut-off grades based on a gold price of $400 (US) per ounce.
4 Open pit resources occur beneath the current ultimate pit designs using a gold price of $400 per ounce.
5 The resources at Boroo are estimated based on a variable cut-off grade depending on the type of material and the associated mill recovery. The cut-off grades vary from 0.9 grams per tonne to 1.1 grams per tonne.
6 The resources at Gatsuurt are estimated based on a cut-off grade of 1.6 grams per tonne.
7 The open pit resources at the Kumtor mine are estimated based on a cut-off grade 1.3 grams per tonne. Underground resources occur below the main Kumtor pit shell and are estimated based on a cut-off grade of 5.0 grams per tonne.
8 The resources at REN are estimated based on a cut-off grade of 8.0 grams per tonne.

Gold Reserves and Resources Reconciliation

The following reconciliation of Cameco’s share of gold reserves and resources reflects the changes in gold reserves and resources during 2005. Part of the 2005 additions and deletions at Kumtor and Boroo results from mining and milling, additional information provided by mining experience, drilling results analysis, reclassifications and a change in gold price.

RECONCILIATION OF CAMECO'S SHARE OF GOLD RESERVES AND RESOURCES1
(in troy ounces)
  December 31, 2004 2005
Throughput 2
2005
Addition (Deletion)3
December 31, 2005
Reserves – Proven        
Boroo 34,000 (152,000) 505,000 387,000
Kumtor 4 1,106,000 (323,000) 323,000 1,106,000
Total Proven Reserves 1,140,000 (475,000) 828,000 1,493,000
         
Reserves – Probable        
Boroo 552,000 (330,000) 222,000
Kumtor 4 06,000 897,000 1,503,000
Total Probable Reserves 1,158,000 567,000 1,725,000
Total Reserves 2,298,000 (475,000) 1,395,000 3,218,000
         
Resources – Measured        
Boroo 74,000 74,000
Kumtor 5 525,000 336,000 861,000
Total Measured Resources 525,000 410,000 935,000
         
Resources – Indicated        
Boroo 97,000 (70,000) 27,000
Gatsuurt 6 469,000 508,000 977,000
Kumtor 5 483,000 247,000 730,000
REN 259,000 134,000 393,000
Total Indicated Resources 1,308,000 819,000 2,127,000
Total Measured and Indicated Resources 1,833,000 1,229,000 3,062,000
         
Resources – Inferred        
Boroo 97,000 (13,000) 84,000
Gatsuurt 6 80,000 119,000 199,000
Kumtor Gold 5 763,000 (340,000) 423,000
REN 169,000 (127,000) 42,000
Total Inferred Resources 1,109,000 (361,000) 748,000
Notes:
1 Cameco reports reserves and resources separately. The amount of reported resources does not include those amounts identified as reserves.
2 Corresponds to mill feed. The discrepancy between the 2005 mill feed and Cameco's share of 2005 ounces produced is due to mill recovery.
3 Changes in reserves or resources, as applicable, are attributed to information provided by drilling and subsequent reclassification of reserves or resources, an increase in the gold price, changes in pit designs, reconciliation between the mill and the resource model, and changes to operating costs.
4 Kumtor reserves include the main pit and the Southwest Zone satellite deposit.
5 Kumtor resources include the main pit, the Southwest Zone and Sarytor satellite deposits.
6 Gatsuurt resources include the Central Zone and Main Zone deposits.