PetroChina is making its largest oil sands investment to date - a $1.7 billion investment in the Athabasca Oil Sands' MacKay River and Dover projects. PetroChina is a state-owned enterprise. Given the significant size of the investment, Canadian officials haven't so far announced whether it will be approved by government authorities who still must review the transaction in light of the Investment Canada Act which covers all large foreign investments in Canada.