Mapping Mountains – Hill Reclassifications – Humps

Twyn y Waun (SO 082 070) – Recommended Subhump addition

This is the thirty first in a series of Hill Reclassification posts that detail hills whose status has either been altered in the listing of the Humps (HUndred Metre Prominences) through map study and / or surveys that I have instigated, or it is the recommendation that their status is altered.

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

Many preceding posts detailing these alterations to the Humps are retrospective as these hill reclassifications were either initiated from studying the Ordnance Survey Interactive Coverage Map that is hosted on the Geograph website, or initiated from a survey with the Trimble GeoXH 6000, and for the recommended addition that affects the Humps the survey of this hill took place on the 01.12.17.

The listing of Humps was published in book format by Lulu in 2009 and entitled More Relative Hills of Britain, its author; Mark Jackson gives credit to a number of people who contributed toward the formation of this list, these include; Eric Yeaman, Alan Dawson, Clem Clements, Rob Woodall, Bernie Hughes, Pete Ridges and others.  When the list was published in book format there were 2987 Humps listed with their criteria being any British hill that has 100m or more of drop, accompanying the main list is a sub category entitled Subhumps, with the criteria being any British hill that has 90m or more and below 100m of drop.

More Relative Hills of Britain by Mark Jackson

The details for the recommended reclassification appear below:

There has been a recommended reclassification to the listing of the Humps (HUndred Metre Prominences) instigated by a survey with the Trimble GeoXH 6000 which took place on the 01.12.17.

This hill has an intact natural summit and an artificial summit that now overshadows it and Mark Jackson lists this hill with 63m of drop based on an estimated c 451m height for the natural summit which has an uppermost 450m contour on the Ordnance Survey 1:50,000 Landranger map and the Interactive Coverage Map hosted on the Geograph website, and an estimated bwlch height of 388m based on bwlch contouring at 10m intervals and between 380m – 390m on the 1:25,000 Explorer map.  However, OS Maps which is the recent replacement for OS Get-a-map gives bwlch contouring at 5m intervals and between 375m – 380m, with the latter height taking in the width of a road and indicating an estimated bwlch height of c 380m, which if the artificial summit was taken for that of the hill gives this hill c 96m of drop.

However, it was not until LIDAR became available that the bwlch details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

The natural summit of Twyn y Waun is now overshadowed by its artificial summit

Twyn y Waun is adjoined to the Y Cymoedd – dwyreiniol group of hills and is positioned between the town 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.

Therefore, if the artificial summit is taken as that for the hill it is recommended that its status is amended to that of Subhump.

The full details for the hill are:

Name:  Twn y Waun (as listed in the Tumps)

Summit Height:  451m (as listed in the Tumps) (476.0m [converted to OSGM15] artificial summit)

OS 1:50,000 map:  160

OS 1:25,000 map:  12, 166

Summit Grid Reference:  SO 08457 07348 (as listed in the Tumps) (artificial summit at SO 08209 07041)

Drop:  63m (as listed in the Tumps) (96.0m Trimble GeoXH 6000 summit and LIDAR bwlch, artificial summit)

Myrddyn Phillips (January 2018)

Mapping Mountains – Hill Reclassifications – Y Pedwarau - The 400m Hills of Wales

Twyn y Waun (artificial summit at SO 082 070 and natural summit at SO 084 073) – Pedwar reclassified to Dual Summit Pedwar

There has been a reclassification 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 and 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.

Accompanying the main Y Pedwarau list are five categories of sub hills, however this hill has not been reclassified from one of these categories to another, as a new classification of Dual Summit has been created to accommodate the details relating to this hill.

Dual Summit hills:

A hill classified as a Dual Summit is defined as one which has an extant natural summit coupled with that of a higher artificial summit, with the latter that can be described as stable in character.  In the main, these recent man-made constructions are the result of quarrying activities producing spoil tips.  These recent man-made constructions are treated differently to ancient man-made constructions such as hill forts and tumuli, as if the latter are deemed stable and of an earthen character their age dictates that they can be viewed as being permanent in nature and are now effectively a part of the hill.  For those bagging Dual Summit hills, a visit to either the natural high point or the elevated man-made high point is sufficient to claim an ascent of the hill.

The name of the hill is Twyn y Waun and prior to the Trimble GeoXH 6000 survey this hill was listed with an estimated c 451m summit height based on a 450m uppermost contour on the Ordnance Survey 1:50,000 map and the Interactive Coverage Map hosted on the Geograph website and a drop of c 63m which has now been re-evaluated.

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Twyn y Waun is situated in the Y Cymoedd – dwyreiniol range of hills and is listed as a Cardinal Hill, 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.

Twyn y Waun is now listed as a Dual Summit hill and its natural summit is a part of designated open access land and can be approached from the convenience of a minor road to its east, whilst as its man-made summit is a part of a working mine permission to visit should be sought, however the artificial summit is on the border of designated open access land shown on the Ordnance Survey 1:25,000 Explorer map, and for those wishing to visit an ascent of this artificial summit from the natural summit is  an easy extension of the short walk from the minor road to the east.

The full details for the hill are:

Cardinal Hill:  Twyn y Waun 

Summit Height:  476.0m (artificial Dual Summit) 450.6m (converted to OSGM15, Trimble GeoXH 6000, natural Dual Summit)

Name:  Twyn y Waun

OS 1:50,000 map:  160

Summit Grid Reference:  SO 08209 07041 (artificial Dual Summit) SO 08442 07378 (LIDAR, natural Dual Summit)

Drop:  96.0m (Trimble GeoXH 6000 summit and LIDAR bwlch, artificial Dual Summit) 70.7m (Trimble GeoXH 6000 summit and LIDAR bwlch, natural Dual Summit)

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:

The Dual Summit of Twyn y Waun with the pastoral natural summit in the foreground and the man-made summit in the background

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (January 2018)

Mapping Mountains – Significant Height Revisions – Y Pedwarau - The 400m Hills of Wales

Twyn y Waun (SO 082 070) 

There has been a Significant Height Revision to a summit of a hill that is now listed as a Dual Summit in the Y Pedwarau, and which was initiated by a survey with the Trimble GeoXH 6000, with the survey that confirmed this height revision being conducted on the 1^st December 2017.

The criteria for the list this height revision affects are:

Y Pedwarau – All Welsh hills at and above 400m and below 500m in height that have 30m minimum drop.  Whilst the criteria for 400m Sub-Pedwar status are all Welsh hills at and above 400m and below 500m in height that have 20m or more and below 30m of drop.

A hill classified as a Dual Summit is defined as one which has an extant natural summit coupled with that of an artificial summit, which can be described as being stable in character.  Twyn y Waun meets these criteria as it has an intact 450.6m natural summit at SO 08442 07378 and a 476.0m (converted to OSGM15) higher man-made summit at SO 08209 07041, and this article relates to the latter man-made summit.

The name of the hill is Twyn y Waun and it is situated in the Y Cymoedd – dwyreiniol range of hills which are in the central part of South Wales (Region C, Sub-Region C2), and the hill is positioned between the town of Merthyr Tudful (Merthyr Tydfil) to its west and Rhymni (Rhymney) to its east.

As this man-made hill is a part of a working mine permission to visit should be sought, however its summit is on the border of designated open access land shown on the Ordnance Survey 1:25,000 Explorer map, and for those wishing to visit a public footpath leaves the convenience of a near minor road to the east of the hill.

Prior to the survey with the Trimble GeoXH 6000 the man-made summit was not classified although it had been noted; most recently by Rob Woodall who reported its significant height difference when compared to the natural summit of Twyn y Waun.  The man-made summit possesses no ring contour on Ordnance Survey maps with conflicting highest ring contours for the natural Dual Summit of Twyn y Waun of 430m on the 1:25,000 Explorer map and 450m on the 1:50,000 Landranger map and the Interactive Coverage Map hosted on the Geograph website.  The resulting survey with the Trimble GeoXH 6000 produced a summit height of 476.0m (converted to OSGM15) which is a dramatic increase in height compared to map data and therefore comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term Significant Height Revisions applies to any listed hill whose Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these revisions.

Therefore, the new height for this man-made Dual Summit is 476.0m (converted to OSGM15), and as no contours exist for the upper part of this Dual Summit this is a dramatic 26m increase in height compared to the uppermost 450m contour on the Ordnance Survey 1:50,000 Landranger map and a 46m increase in height compared to the uppermost 430m contour on the Ordnance Survey 1:25,000 Explorer map.

The full details for the hill are:

Cardinal Hill:  Twyn y Waun

Summit Height (New Height):  476.0m (converted to OSGM15) for man-made Dual Summit

Name:  Twyn y Waun

OS 1:50,000 map:  160

Summit Grid Reference:  SO 08209 07041

Drop:  96.0m (Trimble GeoXH 6000 summit and LIDAR bwlch) for man-made Dual Summit

The Trimble GeoXH 6000 gathering data at the man-made Dual Summit of Twyn y Waun (SO 08209 07041) which resulted in this summit's significant height revision

For details on the survey that significantly revised the height of this Dual Summit

Myrddyn Phillips and Aled Williams (January 2018)

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

Y Pedwarau – Two new Pedwar hills and re-classification of an existing Pedwar to Dual Summit status

The Pedwar listing has been updated with the addition of two new Pedwar hills and the re-classification of an existing Pedwar to Dual Summit status, all of these hills are in close proximity of one another and situated to the east of Merthyr Tudful in south Wales.

Dual Summit:  Twyn y Waun    476.0m (artificial) at SO 08209 07041 / 450.6m (natural) at SO 08442 07378

Firstly, a note on the term ‘Dual Summit’.

A hill classified as a Dual Summit is defined as one which has an extant natural summit coupled with that of a higher artificial summit, which can be described as being stable in character.  In the main, these recent man-made constructions are the result of quarrying activities producing spoil tips and to put a spin on the term ‘Dual Summit’, the natural and artificial summits of such hills could be thought of as duelling with each other for the merit of summit status, which well describes the polarising affect that such instances can have on the hill bagger, with some baggers preferring to ignore the artificial summit in favour of the natural high point and vice versa.  For those bagging Dual Summit hills, a visit to either the natural high point or the elevated man-made high point is sufficient to claim an ascent of the hill.

These recent man-made constructions are treated differently to ancient man-made constructions such as hill forts and tumuli, as if the latter are deemed stable and of an earthen character their age dictates that they can be viewed as being permanent in nature and are now effectively a part of the hill.  The concept of a ‘dual summit’ is a new one, having been devised by the authors of the Y Pedwarau listing in response to the circumstances of the following Pedwar hill.

Twyn y Waun is now considered a Dual Summit hill with its remaining natural high point positioned at SO 08442 07378 and listed with a height of 450.6m derived from a Trimble GeoXH 6000 survey, whilst the man-made construction which dominates this hill has its summit positioned at SO 08209 07041 and has a height of 476.0m.  The remains of the natural summit of this hill still exists and consists of undistinguished grazing pasture, it is now overshadowed by a man-made construction consisting of waste spoil from the Ffos-y-fran opencast mine.  The man-made construction is considered stable and can be easily climbed and consists of grassed side slopes and in the main solid waste spoil on the summit area which is interspersed with patches of grass. 

The 450.6m natural summit of Twyn y Waun is now overshadowed by its 476.0m artificial Dual Summit

The elevated man-made construction is situated on the edge of the natural summit area of Twyn y Waun and is known by mine employees as the North Tip and Overburden 1 (OB1), as it is an overburden mound from the mine extraction.  This Dual Summit hill has a prominence of 96.0m (artificial) / 70.7m (natural) and therefore if the elevated man-made construction is taken, it is a prospective new Subhump.

The 476.0m artificial Dual Summit of Twyn y Waun

As detailed above, the artificial summit of Twyn y Waun was surveyed by Myrddyn Phillips using the Trimble GeoXH 6000, with the survey having been instigated by a recent Facebook and Tump Forum post by Rob Woodall. 

New Pedwar:  Twyn y Waun    460.5m artificial summit at SO 08549 06591

This hill is a new artificial Pedwar and consists of waste spoil from the Ffos-y-fran opencast mine.  The man-made hill is considered stable and can be easily climbed and consists of grassed side slopes and in the main a grassed summit area.  This hill was created on the southern slope of Twyn y Waun and is known by mine employees as the South Tip and Overburden 2 (OB2), as it is an overburden mound from the mine extraction.  It has an artificial prominence of 41.0m.

The 460.5m artificial summit of one of the two new Pedwar hills

The survey of this hill had been on our surveying radar for some time, having been detailed in a 2015 document entitled ‘Artificial Pedwar Hills’ by Aled Williams, and was finally prompted by a recent visit communicated to Myrddyn Phillips by Rob Woodall. 

New Pedwar:  Garth Fawr    410m artificial summit at SO 082 059

This artificial hill is positioned to the south of the Ffos-y-fran mine and to the knowledge of the authors, it currently has no recorded summit visit from anyone in the hill bagging community, therefore its inclusion as a Pedwar is reliant upon detail from OS Maps (the recent replacement for OS Get-a-map) and independent visual inspection, albeit from a distance, by Rob Woodall and Myrddyn Phillips. 

The 410m artificial summit of Garth Fawr; the second of the two new Pedwar hills.  Photo:  Rob Woodall

Garth Fawr had been on our surveying radar for some time, having been detailed in a 2015 document entitled ‘Artificial Pedwar Hills’ by Aled Williams.  In early 2017, Aled Williams analysed LIDAR data for this area and recorded a summit height of 388.0m at SO 08521 05968 and a bwlch height of 374.8m at SO 08618 06004, giving a drop of 13.2m.  In late 2017, Myrddyn Phillips was contacted by Rob Woodall who reported that an unrecorded artificial hill existed on the spur known as Garth Fawr.

Garth Fawr had little natural prominence and was a southerly spur of Twyn y Waun, but due to mining activity its height has increased with OS Maps giving it three separate uppermost ring contours of 410m and a bwlch height of c 376m based on contouring between 375m – 380m, whilst LIDAR analysis conducted by Aled Williams gives the height of the bwlch as 374.8m at SO 08618 06004.  It is apparent that the mine spoil was deposited post measurement of the LIDAR data.  The northern slopes of the hill are grassed and the summit area consists of waste spoil, which is undoubtedly of a stable character.  This man-made hill is known by mine employees as Overburden 3 (OB3), as it is an overburden mound from the mine extraction.  It has an artificial prominence of c 35m.

As the mining activity in the area is ongoing, these summits could undergo a levelling process in the future.  If this does occur, the Y Pedwarau - The 400m Hills of Wales listing will be updated accordingly.

Myrddyn Phillips and Aled Williams (December 2017)