Under harbour obstructions have delayed the last phase of the $99m Southern Pipeline project, and contractor Brian Perry Civil is now expected to continue into the New Year.

'The contractor is working hard to complete the last drilling phase before Christmas but it is likely some work will need to continue in January,” says Tauranga City Council Project Manager for the Southern Pipeline, Steve Wiggill,

'We've faced challenges since August when the 40 inch reamer encountered an obstruction under the harbour. It was later identified as a piece of Totara wood, around 51,000 years old. It took the contractor three weeks to overcome this issue. The reamer itself was damaged while being dislodged, and it's possible that debris from the reamer has compromised subsequent drill runs.

'Since then it has also become apparent that the material we're reaming through is generally more challenging than the contractor initially thought. To address these issues, we've recruited international experts and brought in additional specialist machinery.”

The contractor is in the final stages of widening the hole under the harbour with a 54 inch reamer. Drill rods have broken on two separate occasions during the reaming. Both instances resulted in two-week repair periods and damage to one of the reaming tools.

The contractor is working on reinstating the drill rods to complete the last phase of reaming work. Their expert team has also introduced a number of measures to mitigate the risk of the drill rods breaking again, says Steve.

Once the 54-inch reaming work is completed, a period of between three-to-seven-days of 24-hour work will be required to pull steel pipes through from Memorial Park to Matapihi. This and the thrusting of the plastic pipe through the steel pipe will be the last phase of harbour crossing construction aside from pipe connections at Matapihi and Memorial Park. On completion of construction, the temporary reclamation at Matapihi will be removed and Jordan Field at Memorial Park will be returned to public use.

'This has been an incredibly challenging project. We've been successful in overcoming each of challenges as they have arisen, but the cumulative effect is pushing out the completion of the project,” says Steve.

There is currently no work planned for the Christmas and New Year period.