Subsidence regularly occurs across NSW Hunter due to old underground coal mines

A subsidence exclusion zone was set up in Wallsend last week. (ABC Newcastle: Carly Cook)

From the surface, you might never know much of Newcastle in New South Wales has been built on top of mines — some more than 100 years old.

But for residents across the Hunter region, gaping holes in the backyard, depressions in roads and paths, and other subsidence issues are a consistent reminder.