Shaft swallows car park in St. Ives, Cornwall

Late on Saturday 28th April, a 40ft deep and 3ft wide hole opened in a car park in Garth-An-Creet, St. Ives, Cornwall. Local emergency services were called to assess the scene and undertake work to prevent the hole from widening and affecting nearby properties. Subsequent investigation by Terrafirma concludes the hole was created by the collapse of a disused mine shaft.

Merthyr Tydfil Sinkhole Opens Up on New Build Development

A sinkhole reported on 02/04/18 has appeared in Merthyr Tydfil within a new build site, Cwrt Aneurin Bevan. The sinkhole which is reportedly 20 ft (6m) deep has resulted in local residents losing access to their new homes.

Sinkhole Appears in Rugby Pitch in Swansea

A sinkhole which is said to have collapsed on the 14th February 2018 appeared in the corner of one of the Morriston RFC rugby pitches in Heol Gwernen, Cwmrhydyceirw.

February: A Month of Winter Sinkholes

In the past few weeks, Britain has been hit by an earthquake, the beast from the east and sinkholes. We at Terrafirma focus on the latter.  From collapsed mine workings to naturally unstable geological conditions, sinkholes are a very real and re-occurring risk to life and property.

Between the 14th-16th of February two sinkholes opened up in the City of Norwich, the second of which spanning over two front gardens in Meadowbrook Close. Although described by the water board as a ‘’red herring’’, a burst water pipe in the vicinity of the depressions remains a possible  cause for the collapses. This said, mining cannot be discounted here, with the area known for its historic underground chalk extraction, which is also thought to have caused another sinkhole 250 metres northeast of the Close in 2015.  

Further to this, on the 14th of February, on the pitches of Morriston RFC, Swansea, another sinkhole opened. Reported to the Coal Authority on the 19th, social media blamed the 4.4 magnitude earthquake that rocked the west of the country on the 17th. Further investigations by Terrafirma came to a different conclusion, the playing fields, already the Site of 2 past mine entry collapses, are underlain by deep mine workings and a coal seam along which multiple known mine entries and historical collapses are recorded. The sinkhole itself follows this same trend, and therefore, is most likely the result of an unrecorded mine entry or more ancient 'bell pit' mine collapse.

Not all sinkholes can be linked to mining however, as natural ground movement is another key geological avenue when it comes to subsidence and collapse. Ripon, a small town in North Yorkshire is geologically famed for natural subsidence issues, resulting from the natural dissolution of gypsum beneath its town footprint. On Saturday the 24th of February, another sinkhole open up in near the towns leisure centre, which was subsequently closed whilst remedial work was undertaken. This sinkhole is the 5th in only 6 months recorded by Terrafirma and our partners.

Analysis of the Harrington Sinkhole, Cumbria

On the 4th January 2018, a 1.2m deep, 0.6m wide ‘’sinkhole’’ opened next to the Whitehaven – Workington railway line, near the coastal village of Harrington in Cumbria. For fears of the hole expanding and damaging the rail line, services were delayed in order to complete emergency repairs and infill the void. Initial observations have led rail engineers to speculate that a collapsed drain or coastal erosion accelerated by Storm Eleanor are the cause of the collapse. However, the correlation with known mine entries and collapses along the railway line have prompted Terrafirma to research further to see if past coal extraction may in fact be the cause.