Drifting & Tunnelling

Drifting, tunneling, and bolting are all different methods and approaches utilized in underground drilling and mining to both drill and blast the rock and support the rock.

Tunneling, on the other hand, is the general reference to any sort of horizontal excavation of landmass, the goal of which is to produce a tunnel, rather than to dig for minerals. Tunneling can utilize drifting, but also other methods such as forepoling, and is often used for construction purposes.

And finally, there is bolting, which does not aim to extracting rock materials. This is a security technique that is made use of in mining and tunneling. Bolting involves drilling holes on the roof of the tunnel and driving steel rods, or bolts, into the holes. This distributes the weight off the face of the rock or landmass deeper into the ground, thus stabilizing it and helping prevent collapses.

What all the above concepts share is the act of horizontal drilling, also known as drifting due to the way the drill travels on its rails. As opposed to drilling down, horizontal drilling does not support the use of rotary drilling equipment but leans heavily into percussive drilling, such as down-the-hole or top hammer. In drifting and bolting, the diameter of drill bits used is typically 33-60 mm as the holes required are smaller than in many other types of drilling.