The hammer drill, called in jargon “gun”, is the tool used to pierce the rock creating holes about 3 centimeters in diameter to be loaded with sticks of explosive connected to each other. The drill works with compressed air produced by an external compressor and transported inside the mine through steel pipelines with flexible rubber terminal hoses. Normally the arrangement consists of close central holes and side holes along the perimeter of the gallery. The drilling varies between 1.5 meters and 4 meters in depth depending on the quality of the rock. After the explosion the subsequent activities are the detachment by hand of rock fragments only partially removed and the clearance of the material produced by the explosion.
The hammer drill
The hammer drill, referred to as "gun," drills through the rock to insert explosives, creating the blast. After the explosion, the removal of the crushed material follows.
