How three inches enabled four storeys in south Wales3 April 2020CultureT Alwyn Lloyd's Ystrad Mynach FE College, build in an area of mining subsidenceT Alwyn Lloyd's Ystrad Mynach FE College, build in an area of mining subsidenceRegion: WalesMore: Ystrad MynachHylton WarnerFelix J SamuelyRhymney ValleyPhotographCurtain wallingStephanie JohnsonT Alwyn Lloyd