Saturday, 29 July 2017

Mapping Mountains – Trimble Surveys – Fforest Fawr


13.06.17  Mynydd y Drum (SN 807 097), Teisen Priodas (SN 820 108) and MRF Tip (SN 828 114, not Trimbled)

Teisen Priodas (SN 820 108)

To my knowledge it was Kevin McGovern who first analysed the ridge known as Mynydd y Drum via LIDAR data, the result being that although the south-western point still exists and is deemed natural, the north-eastern part of the ridge has been dramatically altered due to the workings of the Nant Helen Opencast Mine, with the mining activities having produced two new P30s, one of which is landscaped and higher than the remaining south-westerly natural high point, whilst the second new P30 is further north-west.  Aled Williams then used LIDAR data to analyse these hills and furthermore George Gradwell then did so, their results matched those obtained by Kevin McGovern.  The timeframe for these analyses spanned six months and it seemed no one from the hill bagging community had ventured to these hills for an on-site inspection, and although each had been documented as Hill Reclassifications in the Twmpau with one P30 becoming a sub and two P30 additions, I thought it time to visit these hills, and with the forecast for Wales predicting better weather in the south of the country this instilled enthusiasm for me to visit.

Parking on the outskirts of Y Coelbren next to the A 4221 road I turned the Trimble on and headed toward the coordinates for the ten figure grid reference obtained via LIDAR data for the bwlch position of the highest point and still relatively new P30.  I found this beside a hedge, or to be precise it was in or under a thick and untidy hedge consisting of all manner of exotic plants, including hawthorn, my only option was to set the Trimble up beside the hedge and gather the customary five minutes of data.

Gathering data at the critical bwlch of Teisen Priodas

Once the equipment was packed away I drove the short distance to the start of my walk and followed a paved road toward the first hill, this road continues to the buildings of the Nant Helen Opencast Mine.  I left the paved road to follow a track designated a public footpath that led toward the south-westerly hill listed as Mynydd y Drum and which is the remaining highest natural summit on the ridge.

It felt good to be out with an objective for the day, on ground that I had not been on before with views farther south to hills that one day I hoped to visit.  Nearing the summit of Mynydd y Drum I quietly passed a herd of grazing cows and then came across a number of friendly horses and although a great number of each remained close to the summit of the hill whilst I Trimbled it, the survey took place without disturbance.

Approaching the summit of Mynydd y Drum

Gathering data at the summit of Mynydd y Drum


Gathering to inspect the Trimble

My next objective was the connecting bwlch between the hill listed as Mynydd y Drum and the highest and still relatively new and landscaped P30, without the aid of the ten figure grid reference produced by LIDAR data I would probably have been a good few metres from the critical point in the Trimble set-up position, even with the ten figure grid reference I still spent a number of minutes wandering round in a bog slowly zeroing in to the correct placement.  After the allotted five minutes of data were gathered I switched the equipment off, packed it away and headed toward the steepening ground consisting of three landscaped tiers of what is now the high point of the Mynydd y Drum ridge.

Gathering data at the critical bwlch of Mynydd y Drum

This new high point is large in area and is now landscaped, I passed an open drainage duct that resembled a water shoot on my way up and proceeded to the relatively flat summit area, I again used the Trimble as a hand help GPS to zero in to the summit coordinates, five minutes of data were duly collected and before leaving I took compass readings toward where the next connecting bwlch lay and the summit of the last P30.

The drainage duct on the south-west slope of Teisen Priodas


Mynydd y Drum from Teisen Priodas

As I crested the lip of the summit plateau I realised that reaching the last P30 may prove problematic as there were a number of vehicles parked outside a large building and machinery chugged away close to it, the mine was still operational, which was a surprise as I’d found a BBC report the previous evening that mentioned that the mine was to be mothballed with the loss of a number of jobs.  Realising that I should not be where I was, I decided to at least walk toward the workings and see if I could ask permission to visit the next P30 hill.

The whole summit plateau of Teisen Priodas is vegetated with foxgloves adding colour to the scene


Gathering data at the summit of Teisen Priodas


MRF Tip from the eastern slopes of Teisen Priodas

Descending steeply down the eastern grassed slopes I crossed a drainage stream coloured a murky looking orangey yellow and clambered up to a dirt track leading to where coal was pouring out of large stationary machinery, I spotted a mine vehicle and headed toward it but gave up as the only way to reach it was past the heavy machinery, the next bwlch I hoped to survey was somewhere near this point and deciding against further progress in this direction I opted for a safer route and back-tracked a few metres and walked up a grassed and landscaped slope and down steeply to another drainage channel and up the other side to a track leading to the main mine building.

Approaching the mine workings
Heading toward the main mine building
Teisen Priodas from the Nant Helen Opencast Mine

I walked round the building looking for someone to ask permission for onward progress, no one was there so I hesitantly carried on and walked up the mine track leading to the top of the last P30, I stopped when a vehicle headed up the same way, I waved and walked a few metres down to it. 

Beside the mine building


Just below the summit of MRF Tip

The person driving the vehicle was friendly and I apologised for being where I was, a few minutes later and another vehicle pulled up, we chatted for twenty minutes or so about the mines history, the loss of jobs, the remaining skeletal staff of six, and the Trimble and place-name research.  They both knew the higher landscaped hill as Teisen Priodas, which translated into English means the wedding cake, an apt name as the hill has three tiers and is relatively flat on top, with the hill I was on my way up being known as MRF Tip.  However much cajoling I did I could not get permission to visit the summit and Trimble it, this was understandable as I should not have been where I was, however one of them kindly offered to drive me over the summit and back down to my car, passing over the summit I looked out on small piles of waste spoil dotted about resembling a lunar landscape, on the way down I was advised to contact Celtic Energy to seek permission to visit the mine with the potential of surveying the last P30; MRF Tip.



Survey Result:


Mynydd y Drum

Summit Height:  296.2m (converted to OSGM15)  

Summit Grid Reference:  SN 80718 09753

Bwlch Height:  271.4m (converted to OSGM15)

Bwlch Grid Reference:  SN 81526 10519


Dominance:  8.38%





Summit Height:  337.9m (converted to OSGM15) (significant height revision) 
 
Summit Grid Reference:  SN 82013 10833

Bwlch Height:  244.6m (converted to OSGM15)

Bwlch Grid Reference:  SN 84569 11383

Drop:  93.3m (Trichant addition confirmed) (Subhump addition confirmed)

Dominance:  27.61%






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