Dunns Creek Crossing - Jacksonville, Florida

The 24-inch diameter steel casing was a replacement for a failed HDPE reclaimed water main installed previously by a local HDD contractor. Drilling was through sand, clay and limestone. Previous HDD installations by other contractors of a fiber optic cable, a potable water main, a sanitary force main sewer and the failed reclaimed water main have as-built drawings showing severe horizontal alignment changes all at similar locations. Mears staff concluded that the alignment changes were caused by an existing fiber optic handhole which acts like a beacon by interfering with the Trutracker guidance system. Therefore, when Mears drilled, no corrective steering was performed through this zone enabling a true alignment for the new pipeline. Once the pilot bore exited the ground, reaming operations commenced until the bore achieved sufficient gauge for pipe pullback. Pullback operations for the steel casing were completed during one drilling shift. Upon casing installation, the HDPE carrier pipe was inserted into the steel casing by using the drilling rig.