Canadian pipeline operator Enbridge Inc. notified oil shippers on Sept. 1 that it would offer capacity for 620,000 bbl/d on its Line 3 oil pipeline starting in October, signaling confidence in completing the long-delayed project.

The aging pipeline, which Enbridge is replacing, carries oil from Alberta to U.S. Midwest refiners. The replacement will eventually allow Enbridge to double capacity to 760,000 bbl/d.

Enbridge said in its notice to shippers, seen by Reuters, that its planned capacity is subject to finishing construction activities to replace the aging line in Minnesota.

The initial capacity breaks down to 350,000 bbl/d for light oil and 270,000 bbl/d for heavy crude.

Two sources said line fill is expected to start as early as Sept. 15, and Canadian crude traders said price differentials were tightening in anticipation of the extra capacity on Line 3.

Enbridge spokesman Jesse Semko declined to comment on the shipper notice.

“Line 3 is expected to be fully operational at 760,000 barrels per day in the fourth quarter. We are not getting more specific at this time,” he said in an email.