Penygawsi Primary School

The Rhondda Valley in Glamorgan in Wales was once one of the world’s most important coal mining regions. Between 1860 and 1939, the region boasted 79 collieries and levels, mining multiple coal seams across the area. This legacy poses a risk to contemporary development as some of the historic workings are unmapped and were abandoned in an unstable condition. 

Aarsleff Ground Engineering were contracted by Morgan Sindall Construction in order to undertake a strict specification of drilling and grouting on a 3m grid across the site. The works included injection of grout into the boreholes to sufficiently fill all cavities, breaks, and fissures in and above the historic workings. This would minimise the risk of measurable subsidence, formation of surface crown holes, and potential damage to structures in the vicinity of the mine workings.

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