
Here’s a collection of the biggest machines for digging in the world. A tunnel boring machine (TBM) also known as a “mole”, is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They can bore through anything from hard rock to sand. Tunnel diameters can range from a meter (done with micro-TBMs) to 19.25 m to date. Tunnels of less than a meter or so in diameter are typically done using trenchless...