This type of machine operates with a closed system at the tunnel face and can be used in hard to moderate ground conditions. 

TBM will full face cutting wheel, a cylindrical tapered steel structure, is supported by means of hydraulic cylinders between the cutting wheel and casing pipe. The cutting wheel is fitted with hard rock disks, which roll across the tunnel face, cutting notches in it.

These notches dislodge largish chips of rock. Muck bucket lips, which are positioned at some distance behind the disks, carry the extracted rock behind the cutting wheel. The excavated materials is brought to the muck skip by conveyors.