Southland Holdings said it's the largest TBM ever constructed in Texas, it is part of the Southland Mole Joint Venture (SMJV). The Robbins TBM is on site and will excavate an alignment at depths of 120-170ft (35-50m). The tunnel's design requires two different diameters, according to design engineer Halff. It is planned that after the the first two miles of the drive the TBM will be converted from it's larger size to a smaller 32.6m diameter for the remaining three.
The project started in March 2018 and is scheduled to be completed in 2023. Black & Veatch is the construction manager.
