Reserves & Resources

(All figures below are in United States dollars unless otherwise noted.)

1. All Mineral Reserves and Mineral Resources have been calculated in accordance with the CIM Standards and NI 43-101, or the AusIMM JORC equivalent.
2. Mineral Reserves and Mineral Resources are reported above in millions of metric tonnes (“Mt”), grams per metric tonne (“g/t”) and millions of ounces (“Moz”).
3. Individual qualified persons (“QPs”), as defined by the NI 43-101, for the Mineral Reserve and Mineral Resource estimates are as follows:
   • Peñasquito – Guillermo Pareja, Ph.D., P.Geo. (Manager, Mineral Resources), Peter Nahan, P.Eng. (Senior Evaluation Engineer), both employees of Goldcorp Inc.
   • San Dimas –Velasquez Spring, P.Eng. (Senior Geologist, Watts, Griffis and McOuat Limited)
   • Pascua-Lama – Dino Pilotto, P.Eng. (Principal Mining Consultant, SRK Consulting (Canada) Inc.); Bart A. Stryhas, Ph.D., CPG (Principal Resource Geologist, SRK Consulting (U.S.) Inc.)
   • Yauliyacu – Neil Burns, M.Sc., P.Geo. (Director of Geology, Silver Wheaton); Samuel Mah, M.A.Sc., P.Eng. (Director of Engineering, Silver Wheaton), both employees of the Company (the “Company’s QPs”)
   • Company’s QPs are responsible for overall corporate review and all other operations and development projects.
4. The Mineral Resources reported in the above tables are exclusive of Mineral Reserves. The Minto, Cozamin, Neves-Corvo, Zinkgruvan and Aljustrel mines report Mineral Resources inclusive of Mineral Reserves. The Company’s QPs have made the exclusive Mineral Resource estimates for these mines based on average mine recoveries and dilution.
5. Mineral Resources which are not Mineral Reserves do not have demonstrated economic viability.
6. Mineral Reserves and Mineral Resources are reported as of December 31, 2010, other than the following:  
   • Resources and Reserves for Yauliyacu are reported as of July 31, 2010.
   • Resources and Reserves for Neves-Corvo and Zinkgruvan are reported as of June 30, 2010.
   • Resources for Rosemont are reported as of October 22, 2008 and Reserves as of March 17, 2009.
   • Resources for Mineral Park are reported as of December 29, 2006.
   • Resources and Reserves for Aljustrel are reported as of December 31, 2007.
   • Resources for Campo Morado’s El Largo, El Rey, Naranjo and Reforma deposits are reported as of February 29, 2008, Reserves and Resources for the G-9 deposit as of December 31, 2009.
   • Resources and Reserves for Stratoni are reported as of August 10, 2010.
   • Resources and Reserves for Cozamin are reported as of December 31, 2009.
   • Resources for Keno Hill are reported as of November 9, 2009 and April 22, 2010 for the Elsa Tailings.
7. Process recoveries are the average percentage of silver in a saleable product (doré or concentrate) recovered from mined ore at the applicable site process plants as reported by the operators.
8. Mineral Reserves are estimated using appropriate process recovery rates and commodity prices of $15.00 per ounce of silver, unless otherwise noted below:
   • Pascua-Lama, Lagunas Norte, Veladero and Pierina – $16.00 per ounce.
   • Yauliyacu - $18.50 per ounce.
   • Neves-Corvo – 1.6% Cu cut-off for the copper Reserve and 4.3% Zn cut-off for the zinc Reserves above the 550 level and 6% Zn cut-off for zinc Reserves below the 550 level.
   • Rosemont –$10.00 per ounce.
   • Mineral Park – $7.50 per ounce.
   • Zinkgruvan – 3.1% Zn equivalent cut-off for the zinc Reserve and 2.0% Cu cut-off for the copper Reserve
   • Aljustrel – 1.5% Cu cut-off for all copper Reserves and zinc cut-offs of 4.5%, 4.0% and 4.0%, respectively, for the Feitais, Moinho and Estação zinc Reserves.
   • Campo Morado - 3.0% Zn cut-off for the Abajo, West Extension and South East zones and 5% Zn cut-off for the North zone.
   • Minto – $3.90 per ounce silver and $300 per ounce gold.
   • Cozamin – $4.00 per ounce.
9. Mineral Resources are estimated using appropriate recovery rates and commodity prices of $17.00 per ounce of silver, unless otherwise noted below:
   • Yauliyacu – $18.50 per ounce.
   • Neves-Corvo – 1.0% Cu cut-off for the copper Resource and 3.0% Zn cut-off for the zinc Resource.
   • Rosemont – 0.2% Cu cut-off.
   • Zinkgruvan – 3.1% Zn equivalent cut-off for the zinc Resource and 1.5% Cu cut-off for the copper Resource.
   • Mineral Park – $7.50 per ounce.
   • Aljustrel – 1.5% Cu cut-off for all copper Resources and zinc cut-offs of 4.5%, 4.0% and 4.0%, respectively, for the Feitais, Moinho and Estação zinc Resources.
   • Campo Morado – 3.0% Zn only cut-off grade for the G-9 zones and 5% Zn cut-off for the South West zone and El Largo, El Rey, Naranjo and Reforma deposits.
   • Loma de La Plata – $12.50 per ounce
   • Minto – $12.00 per ounce silver and $900 per ounce gold.
   • Cozamin – 1.15% Cu cut-off for San Roberto Area and 3.0% Zn cut-off for San Rafael Area.
   • Keno Hill – $15.25 per ounce for the Southwest and 99 Zones, $14.50 per ounce for the East Zone and $17.00 per ounce for the Elsa Tailings.
10. The San Dimas purchase agreement provides that from August 6, 2010 until August 5, 2014, Primero Mining Corp. (“Primero”) will deliver to the Company a per annum amount equal to the first 3.5 million ounces of payable silver produced at San Dimas and 50% of any excess, plus the Company will receive an additional 1.5 million ounces of silver per annum to be delivered by Goldcorp. Beginning August 6, 2014, Primero will deliver to the Company a per annum amount equal to the first 6.0 million ounces of payable silver produced at San Dimas and 50% of any excess, for the life of the mine.
11. The Company’s attributable tonnage at Lagunas Norte, Pierina and Veladero was estimated by assuming 2010 production levels for the remaining three years. This tonnage was pro-rated between Proven and Probable Mineral Reserves according to the ratio of the December 31, 2010 Proven and Probable Mineral Reserves as published by Barrick Gold Corporation (“Barrick”), applying average reserve grades.
12. The Company’s Yauliyacu purchase agreement (March 2006) with Glencore International AG provides for the delivery of up to 4.75 million ounces of silver per year for 20 years. In the event that silver produced at Yauliyacu in any year totals less than 4.75 million ounces, the maximum amount to be sold to the Company in subsequent years will be increased to make up the shortfall, so long as production allows. Depending upon mine production levels, it is possible that these attributable Resources and Reserves may not be completely mined before the agreement expires.
13. The Mineral Park and Rosemont Resources and Reserves do not include the SX/EW leach material since this process does not recover silver.
14. Los Filos Resources and Reserves now include the Bermejal deposit.
15. The Company has filed a technical report for each of its mineral projects considered to be material to the Company, being San Dimas, Yauliyacu, Peñasquito and Pascua-Lama, which are available on SEDAR at www.sedar.com.
16. Silver is produced as a by-product metal at all operations with the exception of the Keno Hill mine and Loma de La Plata project; therefore, the economic cut-off applied to the reporting of silver Resources and Reserves will be influenced by changes in the commodity prices of other metals at the time. 

Cautionary Language Regarding Reserves and Resources

Readers should refer to the Annual Information Form of Silver Wheaton for the year ended December 31, 2009 and other continuous disclosure documents filed by Silver Wheaton since January 1, 2010, available on SEDAR at www.sedar.com, for further information on Mineral Reserves and Resources, which is subject to the qualifications and notes set forth therein as well as for additional information relating to the Company more generally. Mineral Resources which are not Mineral Reserves, do not have demonstrated economic viability. Cautionary Note to United States Investors Concerning Estimates of Measured, Indicated and Inferred Resources: These tables use the terms “Measured”, “Indicated” and “Inferred” Resources. United States investors are advised that while such terms are recognized and required by Canadian regulations, the United States Securities and Exchange Commission does not recognize them and expressly prohibits U.S. registered companies from including such terms in their filings with the SEC. “Inferred Mineral 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 Mineral Resource will ever be upgraded to a higher category. Under Canadian rules, estimates of Inferred Mineral Resources may not form the basis of feasibility or other economic studies. United States investors are cautioned not to assume that all or any part of Measured or Indicated Mineral Resources will ever be converted into Mineral Reserves. United States investors are also cautioned not to assume that all or any part of an Inferred Mineral Resource exists, or is economically or legally mineable. United States investors are urged to consider closely the disclosure in Silver Wheaton’s Form 40-F, a copy of which may be obtained from Silver Wheaton or from http://www.sec.gov/edgar.shtml