Ignoring hidden voids in former coal mining areas is the most expensive mistake a developer in Stoke-on-Trent can make. The city sits on the North Staffordshire Coalfield, where unrecorded shafts, bell pits, and backfilled marl workings riddle the shallow subsurface. A standard borehole gives you a single point. It can miss a 2-metre void sitting two metres to the left. Vertical electrical sounding maps resistivity contrasts across a wider profile and picks up the air-filled or water-filled cavities that traditional drilling skips. We run VES arrays across brownfield sites in Hanley, Longton, and Burslem before the first excavator arrives, often pairing the survey with test pits to calibrate resistivity anomalies against exposed strata. The result is a ground model that accounts for the mining legacy, not just the soil type.
A VES line across a Stoke-on-Trent brownfield can reveal a bell pit that no historical map recorded—and save the piling contractor a very expensive surprise.
