BHP Billiton will face a key hurdle this week in its attempt to acquire Canada's PotashCorp. The Canadian government is expected to give its decision on whether the deal will provide a net benefit to the country on Wednesday.

BHP Billiton needs regulatory approval for the deal, and the province of Saskatchewan has already rejected the deal as "grossly inadequate" for a company that controls at least one-fifth of the world's potash reserves. 

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