OREANDA-NEWS. December 12, 2016.  Tallgrass Energy's Rockies Express pipeline (Rex) zone 3 east-to-west capacity expansion project will be partially in-service next week.

Rex will commence the phased in-service of the zone 3 capacity enhancement project on 13 December, beginning with about 200mn cf/d (6mn m?/d) of capacity, Tallgrass said.

The partial in-service was expected on 7 December but was delayed because of maintenance.

An inline inspection device came to an unexpected halt inside segment 390 of the pipeline between the Clarington hub the Chandlersville compressor station in eastern Ohio on 1 December. Such inspection devices, known as "smart pigs," are a major component in pipeline safety and accident prevention.

The final phase of the Rex zone 3 capacity expansion project was scheduled to be in service before the end of the year, adding 800mn cf/d capacity. That would bring east-to-west capacity on Rex zone 3 to 2.6 Bcf/d.

The pipeline is still working on an in-service date for the total capacity enhancement before the end of year, Tallgrass spokeswoman Phyllis Hammond said earlier this week.

Rex is a 1,698-mile (2,733 km), 1.8 Bcf/d pipeline that stretches from northwestern Colorado and Wyoming to eastern Ohio. The pipeline initially moved gas production from the Rockies to markets in the midcontinent and the northeast. It later established bidirectional service on zone 3 to move low-cost gas from the Marcellus and Utica shales to high-demand markets in Illinois, Indiana and Ohio.