Suncor, the biggest Alberta oil sands producer, plans to restart work on a huge mothballed project as part of a near-doubling in capital spending next year.

But the Calgary-based company cautioned on Friday that it would take a more disciplined approach to expansion than during the last oil-price boom. “I don’t want to go back to a world where we made C$10bn project commitments upfront”, said Rick George, chief executive.