15 July 2019

Godre’r Graig: risks to a school from a spoil tip landslide

Posted by Dave Petley

Godre’r Graig: risks to a school from a spoil tip landslide

At the end of last week, Godre’r Graig Primary School, near Pontardawe in South Wales, was temporarily closed due to the risks of a spoil tip landslide.  The decision was taken after a survey by Earth Science Partnership,  commissioned by Neath Port Talbot Council, determined that there a medium level risk from a quarry spoil tip near the school. The decision to close the school temporarily is understandable in light of the terrible history of spoil tip landslides in South Wales, including of course the appalling Aberfan disaster in 1966.

This Google Earth image, from 2006, shows the site of the school and the hillslope above it:-

Godre'r Graig landslide

Google Earth image of the Godre’r Graig Primary School, showing the potentially unstable slope above

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The heavily modified topography, the legacy of mining and quarrying, is clear.  According to news reports, “the risk identified is linked to springs and ground water near the school. Officials said that if a stream was blocked during bad weather, rising water levels and pressures in the tip could cause material to flow downhill.”

This is the Ordnance Survey six inch map of the site, from 1948 (accessed via the National Library of Scotland archive).  The school is marked Sch., with the buildings outlined in black:-

Godre'r Graig landslide

Ordnance Survey six inch map of Godre’r Graig, showing the location of the school and the mining sites on the hillslopes above. Map accessed via the National Library of Scotland.

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Note on this sheet the multiple sites marked “Coal Level”, the quarries (including the Old Quarry directly above the school) and the “rises”, which are springs.  There are also indication of made ground (i.e. fill) to the west of the school, below another quarry.

Perhaps most interestingly, there is a Jacobs report online from December 2013 that provides some detail about landslides at Godre’r Graig.  However, this large landslide complex appears to be just to the east of the site that is now causing concern.

The summer school holidays were due to start this week.  The local authority will have until early September before the school is due to reopen.