Measured and Indicated Resources

As at December 31, 2015 (100% basis – only the last column shows our share)

(tonnes in thousands; pounds in millions; totals may not add up due to rounding)

  Measured Indicated Total Measured and Indicated
Tonnes Grade
(lbs U3O8)
Tonnes Grade
(lbs U3O8)
(lbs U3O8)
Cameco’s Share
(lbs U3O8)
McArthur River 62.0 3.83 5.2 4.8 3.02 0.3 5.6 3.9
Cigar Lake  2.7 6.06 0.4 17.5 7.59 2.9 3.3 1.6
Rabbit Lake        1,402.7 0.86 26.7 26.7 26.7
Millennium        1,442.6 2.39 75.9 75.9 53.0
Wheeler River       166.4 19.13 70.2 70.2 21.1
Tamarack        183.8 4.42 17.9 17.9 10.3
Kintyre        3,897.7 0.62 53.5 53.5 37.5
Yeelirrie 24,013.5 0.17 92.4 12,626.5 0.13 34.9 127.3 127.3
Inkai        31,366.1 0.08 52.6 52.6 30.3
Smith Ranch-Highland 1,241.9 0.11 2.9 14,338.1 0.05 16.9 19.8 19.8
North Butte-Brown Ranch 232.6 0.08 0.4 5,530.3 0.07 8.4 8.8 8.8
Gas Hills- Peach 687.2 0.11 1.7 3,626.1 0.15 11.6 13.3 13.3
Crow Butte 1,418.2 0.21 6.6 1,354.9 0.29 8.6 15.2 15.2
Ruby Ranch       2,215.3 0.08 4.1 4.1 4.1
Shirley Basin 89.2 0.16 0.3 1,638.2 0.11 4.1 4.4 4.4
Total 27,747.4 - 109.9 79,811.2 - 388.7 498.5 377.2

UG - underground
OP - open pit
ISR - in situ recovery

Estimates in the above table:

  • use constant dollar average uranium prices of $57 to $59 (US)/lb U3O8
  • are based on an average exchange rate of $1.00 US=$1.15-$1.25 Cdn

Mineral Reserves and Resources

Our mineral reserves and resources are the foundation of our company and fundamental to our success.

We have interests in a number of uranium properties. The tables in this section show our estimates of the proven and probable reserves, and measured, indicated, and inferred resources at those properties. However, only three of the properties listed in those tables are material uranium properties for us: McArthur River/Key Lake, Cigar Lake and Inkai.

We estimate and disclose mineral reserves and resources in five categories, using the definitions adopted by the Canadian Institute of Mining, Metallurgy and Petroleum, and in accordance with Canadian National Instrument 43-101 – Standards of Disclosure for Mineral Projects (NI 43-101), developed by the Canadian Securities Administrators. You can find out more about these categories at

About mineral resources

Mineral resources do not have demonstrated economic viability, but have reasonable prospects for eventual economic extraction. They fall into three categories: measured, indicated and inferred. Our reported mineral resources are exclusive of mineral reserves.

  • Measured and indicated mineral resources can be estimated with sufficient confidence to allow the appropriate application of technical, economic, marketing, legal, environmental, social and governmental factors to support evaluation of the economic viability of the deposit.
  • measured resources: we can confirm both geological and grade continuity to support detailed mine planning.
  • indicated resources: we can reasonably assume geological and grade continuity to support mine planning.
  • Inferred mineral resources are estimated using limited information. We do not have enough confidence to evaluate their economic viability in a meaningful way. You should not assume that all or any part of an inferred mineral resource will be upgraded to an indicated or measured mineral resource but it is reasonably expected that the majority of inferred mineral resources could be upgraded to indicated mineral resources with continued exploration.

Our share of uranium in the mineral resource tables is based on our respective ownership interests, except for Inkai which is based on our interest in potential production (57.5%), which differs from our ownership interest (60%). Mineral resources that are not mineral reserves have no demonstrated economic viability.

About mineral reserves

Mineral reserves are the economically mineable part of measured and/or indicated mineral resources demonstrated by at least a preliminary feasibility study. The reference point at which mineral reserves are defined is the point where the ore is delivered to the processing plant. Mineral reserves fall into two categories:

  • proven reserves: the economically mineable part of a measured resource for which at least a preliminary feasibility study demonstrates that economic extraction is justified
  • probable reserves: the economically mineable part of a measured and/or indicated resource for which at least a preliminary feasibility study demonstrates that economic extraction is justified

We use current geological models, constant dollar average uranium prices of $57 to $59 (US) per pound U3O8, and current or projected operating costs and mine plans to estimate our mineral reserves, allowing for dilution and mining losses. We apply our standard data verification process for every estimate.

Our share of uranium in the mineral reserves table is based on our respective ownership interests, except for Inkai which is based on our interest in planned production (57.5%) assuming an annual production rate of 5.2 million pounds, which differs from our ownership interest (60%).

Changes this year

Our share of proven and probable mineral reserves decreased from 429 million pounds U3O8 at the end of 2014, to 410 million pounds at the end of 2015. The change was primarily the result of production, which removed 30 million pounds from our mineral inventory. However, the decrease was partially offset due to the replacement of raiseboring with blasthole stoping in some areas of McArthur River, as well as additional information from drilling surface freeze holes at Cigar Lake, which both resulted in higher reserves when the related probable reserves were converted to proven reserves.

Measured and indicated mineral resources decreased from 379 million pounds U3O8 at the end of 2014, to 377 million pounds at the end of 2015. Our share of inferred mineral resources is 380 million pounds U3O8 , an increase of 68 million pounds from the end of 2014. The variance in mineral resources was mainly the result of:

  • the addition of 4.5 million pounds U3O8 to indicated resources and 8 million pounds to inferred resources at Rabbit Lake from additional drilling, and from a revision to the equivalent grade formula

  • first time reporting for the Fox Lake deposit, on the Read Lake property near McArthur River, adding 53 million pounds U3O8 to inferred resources

  • the addition of 13 million pounds U3O8 of inferred resources from the Gryphon deposit on the Wheeler River property

  • a revised pit shell defining the mineral resources at Kintyre

Qualified persons

The technical and scientific information discussed in this MD&A for our material properties (McArthur River/Key Lake, Inkai and Cigar Lake) was approved by the following individuals who are qualified persons for the purposes of NI 43-101:

McArthur River/Key Lake

  • Alain G. Mainville, director, mineral resources management, Cameco
  • David Bronkhorst, vice-president, mining and technology, Cameco
  • Baoyao Tang, technical superintendent, McArthur River, Cameco

Cigar Lake

  • Alain G. Mainville, director, mineral resources management, Cameco
  • ​Les Yesnik, general manager, Cigar Lake, Cameco
  • Scott Bishop, manager, technical services, Cameco


  • Alain G. Mainville, director, mineral resources management, Cameco
  • Darryl Clark, general manager, JV Inkai
  • Lawrence Reimann, manager, technical services, Cameco Resources
  • Bryan Soliz, principal geologist, mineral resources management, Cameco

Important information about mineral reserve and resource estimates

Although we have carefully prepared and verified the mineral reserve and resource figures in this document, the figures are estimates, based in part on forward-looking information.

Estimates are based on our knowledge, mining experience, analysis of drilling results, the quality of available data and management’s best judgment. They are, however, imprecise by nature, may change over time, and include many variables and assumptions, including:

  • geological interpretation
  • extraction plans
  • commodity prices and currency exchange rates
  • recovery rates
  • operating and capital costs

There is no assurance that the indicated levels of uranium will be produced, and we may have to re-estimate our mineral reserves based on actual production experience. Changes in the price of uranium, production costs or recovery rates could make it unprofitable for us to operate or develop a particular site or sites for a period of time. See here for information about forward-looking information.

Please see our mineral reserves and resources section of our annual information form for the specific assumptions, parameters and methods used for McArthur River, Inkai and Cigar Lake mineral reserve and resource estimates.

Important information for US investors

While the terms measured, indicated and inferred mineral resources are recognized and required by Canadian securities regulatory authorities, the US Securities and Exchange Commission (SEC) does not recognize them. Under US standards, mineralization may not be classified as a ‘reserve’ unless it has been determined at the time of reporting that the mineralization could be economically and legally produced or extracted. US investors should not assume that:

  • any or all of a measured or indicated mineral resource will ever be converted into proven or probable mineral reserves
  • any or all of an inferred mineral resource exists or is economically or legally mineable, or will ever be upgraded to a higher category. Under Canadian securities regulations, estimates of inferred resources may not form the basis of feasibility or pre-feasibility studies. Inferred resources have a great amount of uncertainty as to their existence and economic and legal feasibility.

The requirements of Canadian securities regulators for identification of ‘reserves’ are also not the same as those of the SEC, and mineral reserves reported by us in accordance with Canadian requirements may not qualify as reserves under SEC standards.

Other information concerning descriptions of mineralization, mineral reserves and resources may not be comparable to information made public by companies that comply with the SEC’s reporting and disclosure requirements for US domestic mining companies, including Industry Guide 7.