Alexco Resource Corp. Silver Purchase Agreement

October 3, 2008

Cautionary Statements

Cautionary Note Regarding Forward Looking Statements

This news release contains “forward-looking statements” within the meaning of the United States Private Securities Litigation Reform Act of 1995 and applicable Canadianiti l i l ti F d l ki t t t i l d b t t li it d t t t t ith t t th t d f t il l b Sil Wh t d f tsecurities legislation. Forward-looking statements include, but are not limited to, statements with respect to the expected future silver sales by Silver Wheaton and future

production from the Bellekeno deposit. Generally, these forward-looking statements can be identified by the use of forward-looking terminology such as “plans”, “expects”or “does not expect”, “is expected”, “budget”, “scheduled”, “estimates”, “forecasts”, “intends”, “anticipates” or “does not anticipate”, or “believes”, or variations of suchwords and phrases or state that certain actions, events or results “may”, “could”, “would”, “might” or “will be taken”, “occur” or “be achieved”. Forward-looking statementsare subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of SilverWheaton to be materially different from those expressed or implied by such forward-looking statements, including but not limited to: risks related to the integration ofacquisitions, the absence of control over mining operations from which Silver Wheaton purchases silver, such as the Bellekeno project, and risks related to these miningoperations, including risks related to international operations, actual results of current exploration activities, actual results of current reclamation activities, conclusions ofeconomic evaluations, changes in project parameters as plans continue to be refined, as well as those factors discussed in the section entitled “Risk Factors” in SilverWheaton’s Annual Information Form dated March 28, 2008. Although Silver Wheaton has attempted to identify important factors that could cause actual results to differmaterially from those contained in forward-looking statements, there may be other factors that cause results not to be as anticipated, estimated or intended. There can beno assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements.p , y pAccordingly, readers should not place undue reliance on forward-looking statements. Silver Wheaton does not undertake to update any forward-looking statements thatare incorporated by reference herein, except in accordance with applicable securities laws.

CAUTIONARY NOTE TO U.S. INVESTORS CONCERNING ESTIMATES OF MEASURED AND INDICATED RESOURCES

This news release may use the terms “Measured” and “Indicated” Resources. U.S. investors are advised that while such terms are recognized and required by Canadianregulations the Securities and Exchange Commission does not recognize them U S investors are cautioned not to assume that all or any part of Measured or Indicatedregulations, the Securities and Exchange Commission does not recognize them. U.S. investors are cautioned not to assume that all or any part of Measured or IndicatedResources will ever be converted into reserves.

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Alexco Resource – Transaction Terms

25% life of mine silver production over entire 240km2 Keno Hill property

Upfront cash payment of US$50 million in two tranches:

• US$15 million payment to fund ongoing underground development

• US$35 million payment once permits received and mine and mill construction underway

P h i i th l f US$3 90/ t il iPurchase price is the lower of US$3.90/oz or spot silver price

Silver Wheaton has no ongoing capital expenditures or exploration costs

Completion guarantee

Silver Wheaton forecast to receive 800,000 ounces of silver annually ywith very significant upside potential

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Alexco Resource – Transaction Rationale

Silver Wheaton to receive 25% of all silver produced from one of the highest-grade historic silver producing districts in the world – Keno Hillhighest-grade historic silver producing districts in the world – Keno Hill

Resumption of high grade silver-lead-zinc production scheduled for 2010 from Bellekeno projectfrom Bellekeno project

Immense exploration potential and future production upside planned• Onek, Lucky Queen, Husky SW, Silver King and other near term production targets being , y Q , y , g p g g

advanced

100% debt financed – non dilutive

Alexco is financially strong• No debt, strong balance sheet, generating cash flow

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Keno Hill - Rich Mining History

One of the world’s highest-grade silver districts

• Located in Canada with over 30 historic mines

75 years of historic silver production (1913-1988):• 217 million ounces of silver produced

• Average grade in excess of 40 ounces per ton silver

• Silver grade in top 3% of global silver producersg g

Substantive byproduct credits with average grades in excess of 5% lead and 3% zinc

Historic resource (not NI 43-101 compliant):• 1.0 million tons @ 31.5 opt silver (with 3.0% Pb and 2.2% Zn)

• 70% of historic resource in three deposits

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Keno Hill – Historic Silver Production

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Grade = Profit – Keno Hill District Potential

50 0

Global Silver Deposits - Grade Comparison

40.0

45.0

50.0

on)

Martha

25.0

30.0

35.0

(oun

ces

per t Keno Hill Historic Resource

Juanicipio Platosa‐Saltillera

Ying

Bellekeno

Goltsovoye

10.0

15.0

20.0

Silv

er G

rade

SilvertipGreens  CreekCannington

San JoseTopia

Lucky Friday

UchucchacuaPrognoz

Dukat

Fresnillo

PallancataLa ColoradaGuanacevi

Yauliyacu

-

5.0

- 5.0 10.0 15.0 20.0 25.0

AresCaylloma

Hacket River

Morococha

San Cristobal

Palmarejo

Rock Creek

PitarillaFuwan

Piriquitas

Corani

San Bartolome

Yauliyacu

Base Metal + Gold in Silver Equivalent Ounces per Ton*

*Calculated using $12/oz Ag, $650/oz Au, $0.75/lb Zn, $0.45/lb Pb, $2.50/lb Cu (100% metallurgical recoveries)

Bellekeno Project – Near Term High Grade Silver Production

Production targeted for 2010 • Average annual mine production of 3 3

MASSIVE GALENA WITH HIGH GRADE SILVER

• Average annual mine production of 3.3 million ounces of silver, 30 million pounds of lead and 25 million pounds of zinc over initial 5 year mine lifey

Underground development underway to access deeper portion of deposit and expand resource base

Anticipated low cost producerAnticipated low cost producer

Cut and fill mining with conventional flotation

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Improved mining methods – fibrecrete and bolting

Bellekeno Schematic Long Section

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Bellekeno Project – East Development

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Bellekeno Project – Preliminary Economic Assessment 1

Year 1 Year 2 Year 3 Year 4 Year 5 TotalProduction (tonnes ore) 91,000 91,000 145,750 145,750 139,700 613,200

Recovered Silver (million ozs) 3.4 3.4 3.7 3.7 2.2 16.5

35.00

40.00

4,000,000

4,500,000

Silver Head Grades (oz/t) 36 36 25 25 16 26

20 00

25.00

30.00

2,500,000

3,000,000

3,500,000

rade

(oz/

t)

ilver

(oun

ces)

10.00

15.00

20.00

1,000,000

1,500,000

2,000,000

Silv

er G

r

Rec

over

ed S

0.00

5.00

0

500,000

Year 1 Year 2 Year 3 Year 4 Year 5

R d Sil ( ) Sil H d G d ( /t)Recovered Silver (ounces) Silver Head Grades (oz/t)

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1 – Silver Wheaton to receive 25% of LOM silver productionSource: Technical report prepared by SRK Consulting (Canada) Inc. with Wardrop Engineering, disclosed in Alexco Resources press release of July 9, 2008

Keno Hill – Several Additional Near Term Production Opportunities

Onek Mine:

• 1.5km from Bellekeno

• Potential phased production

• Significant historic production

• Updated 43-101 resource due in Q4 2008Q4 2008

Several near term production targets being aggressively explored:

• Past producing Lucky Queen Silver King Husky NW targets• Past producing Lucky Queen, Silver King, Husky NW targets

• Other high grade silver-lead-zinc Bellekeno type deposits

240 square kilometer land package

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240 square kilometer land package

Onek Mine Long Section

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Alexco Resource – Financially Strong

Strong balance sheet with no debt

Generates cash flow through profitable and growing environmental services business

Well positioned for future production growth

Primary objective to resume high grade silver production in Keno Hill y j g g pdistrict

With near term high grade silver production from Bellekeno and significant additional production upside in the Keno Hill district, Silver Wheaton expects

a long and prosperous partnership with Alexco Resource Corp.

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