Mapping Mountains – Trimble Surveys – Cefn yr Ystrad

01.12.17  Twyn y Waun (SO 082 070) and Twyn y Waun (SO 085 065)

The man-made and now classified as the Dual Summit of Twyn y Waun (SO 082 070)

Twyn y Waun now stands testament to an industrial age where earth has been dug and waste spoil gathered.  The hill is situated to the north-east of Merthyr Tudful in south Wales and its slopes have long been desecrated by excavation to the point that its natural summit is now overshadowed by a large mound of waste spoil that is significantly higher.  The bi-product of this waste spoil has also created a separate hill which is positioned to the south-east.  The present height of these two man-made summits is the result of the Ffos-y-fran Land Reclamation Scheme which consists of an opencast mine with the waste spoil deposited and latterly forming three hills, two of which are detailed in this post.

The survey of the Twyn y Waun hills was instigated by a Facebook post by Rob Woodall who recently visited them and reported that the listed Pedwar was now overshadowed by its adjacent man-made hill due to further waste spoil deposit, these hills and other man-made Pedwarau had long been on the radar for a Trimble survey as Aled had produced a Word Document in 2015 detailing these and other such hills.

By 8.30am I was shivering beside my car trying my utmost to get my walking boots on and also at the same time gloves, ear warmer, balaclava and over-trousers as a fiercely chilled northern wind blew in across south Wales.

It was only a short walk from my parking spot to the base of the higher of the two man-made Twyn y Waun hills; during which I passed over the listed Pedwar.  Although decidedly cold a blue sky glimmered in to life and a pack of horses inquisitively trotted my way as I headed toward the hill.

The pastured natural summit and now classified as a Dual Summit of Twyn y Waun (SO 084 073) with its adjacent man-made Dual Summit (SO 082 070) rising on the right and the other man-made Twyn y Waun hill (SO 085 065) in the background on the left

Steep and solid grassed slopes led up to a desolate landscape where black waste spoil pre-dominated with intermittent glimpses of grasses trying their darnest for a foothold on an otherwise barren land.

The waste spoiled summit stretched away flat in nature with occasional undulations, I spent about twenty minutes assessing the lay of land and gathering two data sets, during which I looked out from the lipped edge of the summit area to a large black hole still being worked by heavy machinery, I took a few photos and quickly retraced my steps to the Trimble which quietly beeped away gathering its data.

Part of the Ffos-y-fran opencast mine

Once two data sets were gathered I headed steeply down to the connecting bwlch with the second Twyn y Waun hill.  The bwlch was positioned at the base of the hill’s northern ridge which was inviting and pleasant in nature as it was grassed and looked natural.

Twyn y Waun (SO 085 065)

Gathering data at the bwlch between the two man-made Twyn y Waun hills

The ridge led up to what was a relatively easily identified summit, in utter contrast to its predecessor.  I took two data sets from the summit area and whilst the Trimble beeped away gathering its 300 allotted data points I peered down to the Ffos-y-fran mine which spanned out across the land to the south.  I had considered continuing my walk and dropping down to this mine to enquire about locally known names for these spoil tips, but decided otherwise and reversed my inward route back to the connecting bwlch and back up to the summit of the first hill having decided to get a third data set from the area where Rob had noted a ten figure grid reference for the summit. 

Gathering data at one of two points surveyed for the summit position of Twyn y Waun (SO 085 065)

The Ffos-y-fran mine

Large pylons march between these two hills and I was later told that if not for these the two hills would have been constructed as one.  Crossing the bwlch I found a narrow path which I’d missed on my inward route, I was soon back on top and the Trimble led me to the area where Rob noted his preferred summit position.  As the Trimble gathered its final data set for the day I spent time beside two pools, both iced over, each added much needed variety to this summit and its harsh blackened exterior.

Descending back toward the bwlch between the two man-made hills

The summit area of Twyn y Waun (SO 082 070)

Packing the Trimble away I retraced my inward route back to the car and drove the short distance to the mine workings where I was directed to the site office.  I hoped that my visit may unearth names that have become established in the mining community for these two man-made hills.  Having chatted with one mine worker and the security guard at the site office I left with a telephone number and a contact for further enquiries.

The Dual Summits of Twyn y Waun with the natural summit (SO 084 073) in the foreground and the man-made summit (SO 082 070) in the background

The two man-made Twyn y Waun hills

I drove the two hours home and arrived just in time to unpack my car and walk back up the road to spend a half hour admiring the intricacies of a beautiful sunset whose colour sped across the sky. 

Sunset

It had been a good day on the hill and the afterglow of the sunset stayed with me as I wandered back home in the chill air of an early winter’s late afternoon.

Survey Result:

Twyn y Waun (reclassified to Dual Summit status)

Summit Height:  476.0m (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SO 08209 07041 (Dual Summit confirmed)

Bwlch Height:  380.0m (LIDAR)

Bwlch Grid Reference:  SO 08277 08338 (LIDAR)

Drop:  96.0m (Trimble GeoXH 6000 summit and LIDAR bwlch) (prospective Subhump addition)

Dominance:  20.16% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Twyn y Waun

Summit Height:  460.5m (converted to OSGM15) (Pedwar addition confirmed on height and drop) (significant height revision)

Summit Grid Reference:  SO 08549 06591

Bwlch Height:  419.5m (converted to OSGM15)

Bwlch Grid Reference:  SO 08580 06962

Drop:  41.0m (Pedwar addition confirmed on drop and height)

Dominance:  8.89%

For details on the 2^nd visit to Twyn y Waun

For further details please consult the Trimble Survey Spreadsheet