A small-diameter tunnel or bore driven ahead of the main excavation profile. Miners and engineers use it to explore ground conditions, establish ventilation, or provide a void to blast into when expanding to the full tunnel diameter. It reduces the risk of unexpected ground failures in the main heading by exposing faults and water inflows early.
Heard on the job
We'll drive a pilot through the fault zone first to bleed off any trapped water before widening to full face.
Also heard as
- pilot hole
- pilot tunnel