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

9.9K views · 130 reactions | We’re performing drilling and blasting for this project in Idaho to add six miles of highway to US-95. This four-lane segment will be wider, flatter, and straighter, improving safety for all users of this busy interstate. | McCallum Rock Drilling | Facebook