Double Shield TBM (SBU-DS) Technical Description The Double Shield TBM (SBU-DS) is ideal for long tun- nels (over 3,300 ft) without intermediate access. The SBU-DS is a manned-entry, hard rock tunnel boring machine. The machine is used in conjunction with a single-track back-up system for auxiliary functions. In unstable ground, the SBU-DS can erect liner within the tail skin, while in stable ground the machine can be used without lining. Muck is removed using muck trains with conveyor-loading muck skips. Tunneling with No Limitations Not just for utility crossings, the SBU-DS can bore entire tunnels in much harder rock than other SBU Division products. A ring bearing and bull gear drive allow for larger diameter 17 inch disc cutters to be used, with greater thrust and higher torque. The machine is capable of boring in rock of 44,000 psi UCS or higher over long distances. Guided Boring The SBU-DS can be steered throughout the drive using hydraulic stabilizer pads and articulation cylinders. Line and grade accuracy is continuously monitored with a laser targeting system. SBU-DS APPLICATIONS • Long tunnels with no intermediate access • Line- and grade-critical tunneling • Bore lengths from 1,600 to over 20,000 ft AVAILABLE FOR PURCHASE OR LEASE

Side View Hydraulic Stabilizer Auxiliary Thrust Gripper Shield Cylinder High Capacity Chd Drive Torque Cylinder Main Bearing Motor Tail Shield Ring Beam Expander Front View MACHINE DIAMETERS ROCK STRENGTHS GROUND CONDITIONS 78 to 118 in (larger sizes available) Medium to very hard rock, or mixed ground Both hard rock and mixed ground cutterheads are available All machines can be equipped with 14 inch or 17 inch discs Bore Diameter Boring Stroke Main Bearing Machine Thrust Cutterhead Drive Drive Motors Tapered Roller Bore Diameter Boring Stroke Main Bearing Machine Thrust Cutterhead Drive Drive...