Miners use this term for any unexpected geological feature that breaks the continuity of the target stratum, forcing a change in the mining plan. It can be a fault displacing the seam, a sudden thinning, or a washout filled with barren rock. Encountering one usually means driving through dead ground to relocate the pay zone, costing time and money.
We hit a bad trouble on the east face, the coal just pinched out against a sandstone wall.
When a coal miner says they hit trouble, they mean a geological fault, not an equipment breakdown.
Related terms
Fault
A planar fracture in a rock volume across which there has been significant displacement.
Nip-out
A geological anomaly where a coal seam thins rapidly or disappears completely.
Washout
A channel in a coal seam or orebody where the original deposit was eroded and replaced by barren sediment.
Dead ground
A barren section of a vein or geological structure that contains no valuable minerals.