Alliance Pipeline announced Thursday that it had restarted its mainline system from northern British Columbia and Alberta to Chicago, six days after it halted operations to clean poisonous contamination out of the system (see related story).

The company lifted its force majeure and said flaring operations in southeast Saskatchewan — at a block valve near Arcola and its Alameda compressor station — have concluded. Alliance said it began receiving operational lineback from shippers on Wednesday, allowing it to begin a controlled restart of the mainline system.

“Alliance is pleased to be safely resuming operational service for our customers,” said Daniel Sutherland, Alliance’s vice president for commercial operations. “We appreciate the cooperation and patience of local residents, officials and communities and our customers as we safely reduced the amount of hydrogen sulphide (H2S) in the pipeline to a safe level through our flaring operations.”

Last Friday, Keyera Corp. disclosed that a “brief operational upset” at its Simonette processing plant in northwestern Alberta had put sour gas into the Alliance system. The pipeline declared a force majeure and began cleanup operations the next day. It was the first traffic-stopping incident on Alliance since deliveries began 15 years ago (see Daily GPI, Aug. 12; Aug 11; Aug. 7).

Alliance carries about 1.6 Bcf/d of liquids-rich gas. High-value byproducts are extracted at Aux Sable near Chicago.