Mapping Mountains – Hill Reclassifications – Y Pedwarau

Twyn y Waun (SO 085 065) – Pedwar addition

There has been an addition to the listing of Y Pedwarau due to a survey with the Trimble GeoXH 6000 that was instigated by an on-site visit by Rob Woodall and an article written by Aled Williams in 2015 entitled ‘Artificial Pedwar Hills.’  The Y Pedwarau is the title for the list of 400m hills of Wales and takes in all Welsh hills at and above 400m and below 500m in height that have a minimum 30m of drop, the list is a joint compilation between Myrddyn Phillips and Aled Williams and it commenced publication on Mapping Mountains on the 30.01.17.

The name of the hill is Twyn y Waun and prior to the Trimble GeoXH 6000 survey this hill was not listed as it is a relatively recent man-made construction and is the result of waste spoil that is now considered solid and stable from the Ffos-y-fran opencast mine, therefore it does not possess separate ring contours on either the Ordnance Survey 1:50,000 Landranger or the 1:25,000 Explorer map.

Twyn y Waun is situated in the Y Cymoedd – dwyreiniol range of hills and is placed in the Region of South Wales (Region C, Sub-Region C2).  The hill is positioned between the towns of Merthyr Tudful (Merthyr Tydfil) to its west and Rhymni (Rhymney) to its east and has the A 465 Heads of the Valleys Road to its north-west.

As the summit of this hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so a minor road to the north north-east of the hill gives access to a public footpath and a track that heads toward the critical bwlch of this hill.

The survey with the Trimble GeoXH 6000 resulted in a summit height of 460.5m (converted to OSGM15) and a bwlch height of 419.5m (converted to OSGM15), with these values giving this hill 41.0m of drop, and as this artificial hill is considered to be solid and stable in character these values are sufficient for it to be classified as a Pedwar.

The full details for the hill are:

Cardinal Hill:  Twyn y Waun 

Summit Height:  460.5m

Name:  Twyn y Waun

OS 1:50,000 map:  160

Summit Grid Reference:  SO 08549 06591

Drop:  41.0m

For the additions, deletions and reclassifications to the Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Twyn y Waun (SO 085 065) is now included as a Pedwar

For details on the survey of Twyn y Waun

Myrddyn Phillips and Aled Williams (January 2018)