After its assembly and sliding through the launching addit, the TBM commenced its around-the-clock boring in July 2015. As of July 31, 2016, the TBM driven by the tunneling contractor SELI Overseas S.p.A. completed 6,442 m. In the last three months, the machine has registered sustained advances of 806, 824 and 1,004 m. This is believed to be a record for Southeast Asia for a shielded machine of its diameter (5.74 m) evacuating muck by rolling stock.
The TBM has been boring through different formations, mainly mudstone, sandstone and siltstone with an average Uniaxial Compression Strength (UCS) of 80 MPa and peaks up to 200 MPa. The TBM has gone through fractured zones as well and crossed three faults successfully on its way. The smooth and close cooperation between SELI Overseas and TERRATEC in design, technical solutions and execution has been key to achieve this.
The remaining 5 km of boring are expected to be completed by early 2017, at which point SELI Overseas will hand the tunnel over to SK Engineering and Construction, the main contractor, to complete the project.