(PORT HURON) -- Construction of the final 50 miles of an Enbridge oil pipeline replacement project in Michigan resumes in May. Enbridge spokesman Jason Manshum says exact timing of work will depend on weather conditions. Calgary, Alberta-based Enbridge last year pushed back completion of the project until this year. Work in Oakland, Macomb and St. Clair counties was supposed to wrap up in 2013, but Enbridge said delays in environmental approvals stalled work. The overall $1.3 billion project is replacing Line 6B, which runs between Sarnia, Ontario to Griffith, Indiana. Manshum says work is complete in Indiana and other parts of Michigan. A portion of Enbridge's existing pipeline ruptured in southwestern Michigan in 2010, dumping more than 800,000 gallons of oil into the Kalamazoo River system.