Alberta’s Progressive Conservatives romped to a surprise landslide in elections on Monday, trouncing opposition parties that had threatened to put a brake on development of the Canadian province’s vast, bitumen-like oilsands deposits.

The Conservatives, who have held office for the past 37 years, won 72 out of 83 seats in the provincial legislature, up from 60 previously. The Liberals, the main opposition party, lost seven of their 16 seats.