• Moles also known as 'Tunneling machines' are now-a-days used for full face tunnel driving, which has a rotating cutter head fitted in the front.
  • Mechanical moles can be classified in many ways, namely: according to the type of material to be mined or cutting principle employed or cutter head movement but mainly fall under following two categories based on the action of their cutter-heads: 1. Rotary type 2. Oscillating type

Rotary type moles:

• It consists of a wheel fitted with either teeth of disc cutters or roller bits which revolves in either direction around the central shaft.
• These are primarily used in firm underground formations including hard rock applications.

Oscillating type of mechanical moles:

• These are generally used for soft or semistable formations.i.e. clays, sand, gravels.
• These machines are used in changeable ground conditions or where underground formations vary.
• Special openings in cutter arms and bulkhead can be controlled by the operator while using the machine in varying formations in order to facilitate varying amount of cuttings through the bulkhead.
• The cutting arms operate like wipers in the automotive vehicles and are mounted on seperate shafts close to the centre.