Tuesday, 28 March 2017

Mapping Mountains – Hill Reclassifications – Y Trichant

MRF Tip (SN 828 114) - Trichant addition

There has been an addition to the listing of the Y Trichant, these are the hills within the 300m height band of the Twmpau (thirty welsh metre prominences and upward) due to analysis of LIDAR data by Kevin McGovern and also independently by Aled Williams.  The Y Trichant takes in all hills in Wales at or above 300m and below 400m in height that have a minimum drop of 30m.

Prior to analysis of LIDAR data the ridge known as Mynydd y Drum was listed with one summit, but due to opencast mining a further two summits have been created which are artificial and comprise the remains of waste spoil, the summit which this Hill Reclassifications post details is the lower of these two artificial hills, this has resulted in new bylchau heights and positions and also drop values for these three hills, all of these will be detailed in this and the previous and next Hill Reclassifications posts, with the name MRF Tip being found from local enquiry and the other two hills being Mynydd y Drum (SN 807 097) and Teisen Priodas (SN 820 108).

The hill is adjoined to the Fforest Fawr group with its Cardinal Hill being Fan Gyhirych (SN 880 191) and is placed in the Region of South Wales (Region C, Sub-Region C2), and it is positioned between the small communities of Abercraf (Abercrave) to the north-west and Y Coelbren towards the east.

The summit of the hill is situated within the Nant Helen Opencast Mine so permission to visit the high point should be sought, however it has open access land to its east and a little farther away to its south, and two public footpaths are marked on Ordnance Survey maps that head extremely close to the summit of this hill.

The name of the hill is MRF Tip and its reclassification to a Trichant is due to the analysis of LIDAR data by Kevin McGovern and also independently by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Kevin’s analysis of LIDAR data gives the hill the following details:


Summit Height:  311.8m (converted to OSGM15)

Summit Grid Reference:  SN 82850 11432

Bwlch Height:  277.6m (converted to OSGM15)

Bwlch Grid Reference:  SN 82186 11128

Drop:  34.2m

Therefore, the 311.8m LIDAR data produced for the summit position at SN 82850 11432 and the 277.6m LIDAR data produced for the bwlch position at SN 82186 11128 is sufficient for this hill to be classified as a Trichant with 34.2m of drop.

This now revises the total in the Y Trichant and the Twmpau and the lists will be updated accordingly.

The full details for the hill are:

Cardinal Hill:  Fan Gyhirych

Summit Height:  311.8m (LIDAR data, converted to OSGM15)

Name:  MRF Tip

OS 1:50,000 map:  160

Summit Grid Reference:  SN 82850 11432
Drop:  34.2m (LIDAR data, converted to OSGM15)

MRF Tip (SN 828 114) now listed as a Trichant

My thanks to Mark Jackson for bringing the details of this hill to my attention and to Kevin McGovern and Aled Williams for their analysis of LIDAR data.

Myrddyn Phillips (March 2017)

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