Trenching is a form of primary breaking in which a narrow trench is excavated especially for laying pipes, cables or for installing drainage
Scaling is removal of loose material from the tunnel roof and walls to prevent accidents by falling rocks.
Hammer fitted to an excavator working directly in a bench to breaks away rock which can then be removed by truck. This is most commonly used where blasting is not allowed.
There's no margin for error in tunneling. It demands high quality in every aspect – from drilling to organization, health and safety, and environment.