A blasting in tunnel. Drill and blast method is one of the most flexible tunnelling methods in hard rock. This method can be performed in wide variety of geological condition, in any tunnel shape and dimension. Design of the drill and blast pattern is an important part of this method. Ground borne vibration, air blast and fly rock are important factors that should be considered in the design along with more common parameters such as advance rate, powder factor, drill factor, maximum instantaneou