Moving Mountain

A WELSH LANDSLIDE.

TWO VILLAGES IN PERIL.

Villagers in the Rhymney Valley, on the Glamorgan and Monmouthshire border, are again alarmed over & threatened renewal of the landslide, which did considerable mischief in the New Tredegar district some months ago. On that occasion some colliery surface buildings were swept away, several isolated cottages demolished, and a main road broken up. Several years ago, the Rhymney Railway Company had to alter the course of their main Line in order to protect their property. The origin of these recurring disturbances is a quicksand in the underlying strata. In the bed of the valley on the Monmouthshire side of the river two large fields have sunk, and small lakes have formed in the depressions. There is a gaping fissure in the mountain above the hamlet of Troedrhiwfuwch, and this is the secret of the immediate danger.

The new schools at this hamlet, built about three years ago, hare some ugly cracks in the walls, and wide apertures are forming in the boundary wall. Most serious of all however, is the news that the bridge at the village of Sebastopol under which the Rhymney railway passes and which is practically a new structure, is becoming seriously affected. The buttresses are either sinking down or the line is being gradually forced up, for the headroom is becoming less. For the past month it has been noticed that trains slacken speed when approaching this spot and the explanation is now given that a man is kept on duty day and night to measure the headroom and signal “All’s Well” to the engine drivers. From this it will be gathered that the railway authorities are apprehensive as to a sudden disturbance. A blocking or breaking of the line there would not only break off communication with the upper end of the valley but would paralyse the mining and other industries. Other telegrams received last night state that the inhabitants of the village of Sebastopol and Troedrhiwfuwch, which is situated higher up the mountainside, are in dread of their homes being removed bodily down the mountain. During the past few days there have been indications on the Rhymney Railway that the permanent way is being forced out of position.

Sometime ago the Railway Company spent a considerable amount of money in building retaining walls on the mountain side of the line, but these have now been forced to within a few inches of the passing trains. Both villages are upon an extremely steep gradient, and almost overhanging Troedrhiwfuwch there are a number of huge rocks. A small reservoir of water has developed such serious leakages that the supply of water to the village has failed. The local council's main sewer, which runs along the hillside, has also suffered damage.

Birmingham Mail - Friday 16 February 1906

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"Water And Gas Supplies Again Affected" a landslide in 1906 again affected the water supply. It was decided by Gelligaer Council on the 5th August 1906 that the people of Sebastopol & Troedrhiwfuwch would be relieved of water payments in consequence of shortage of water.

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Reported in November 1925, "Welsh Water Main Again Broken". The mountain is on the move again and causing considerable interference with public services, especially the water supply. There's another big breakage to the main water pipes causing the top of the valley to be without. Over 100,000 people were left without water. This had happened several times before by similar fractures. The road had cracked in several places and started sinking. Men worked through the night to restore the water supply. The Water Board are powerless to provide against occurrences of this kind. The fissures created by the moving mountain cannot be cured by engineers. Watchmen are employed 24 hours a day to keep an eye on the road and also the railway line down in the valley. Several sections of a new sewage scheme which cost nearly £750,000 (£37,673,015.47 in 2023 according to bankofengland.co.uk) were seriously damaged by being pushed 20 - 30 feet out of position.  

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Fresh cracks appeared again in 1926 this time extending to New Tredegar. Mr E Watkin Edwards, the engineer stated that Troedrhiwfuwch, Pontlottyn & Deri were in trouble. The mountain between Troedrhiwfuwch and Deri was so badly damaged it was barely walkable. The cracks on top of the mountain grew so big, a horse fell into one of the huge cracks. The horse was eventually rescued after a great deal of difficulty. Concerns grew as the Gilliwen reservoir started to crack. The reservoir held a capacity of 250,000 gallons and measures were taken to keep it as low as possible.

 

In February 1927 the water supply was cut off to 120,000 people in the Upper Rhymney Valley due to the dislocation and damage to the main water pipes cause by a land disturbance at Troedrhiwfuwch. Although the road was damaged at several points it was reported that the traffic continued fairly normally.

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For a time in 1929 The Rising Sun Inn was closed due to damage from the moving mountain.

 

In 1935, the new road was closed due to safety concerns. 1936 it is again reported on the moving mountain. Rumbles have been heard from minor landslides. It is impossible to get transport from New Tredegar to Abertysswg . The only way was to walk, picking out what remains of the old road as you go.