History
Nant-y-Mailor Reservoir, was one of four reservoirs which once provided drinking water to Pontypool, Abersychan, Talywain, Garndiffaith, Varteg, Griffithstown, Sebastopol and New Inn, is located in woodland to the east of Abersychan village. It had a capacity of 4,500,000 gallons and was topped up by water pumped from disused collieries.
The tunnel was built in 1888 to provide a clear path to the source of the spring in Nant-y-Mailor. Prior to it being built, water from the spring was contaimnated by mineral deposits, including coal and iron deposits, in the sub strata. The tunnel has had remedial maintenance work carried out over the years by Dwr Cymru / Welsh Water including the spraycreting of a large section. The tunnel leads downhill for 200m to a boulder choked passage and a sump. The sump was dived in 1972 - no way on and too loose - and in 2005, when a 2nd sump was tried. Approximately 100m into the tunnel on the left side, a passage leads to a large collapse chamber. The tunnel follows the line of a low bedding plane containing a stream, still visible in places.
The reservoir itself has been closed for nearly 40 years.
First visited on a cold, windy, rainy and in general, shitty winters South Wales Friday afternoon about 8 or 9 years ago. For some reason (which I can't recall), despite finding the tunnel, we didn't actually try and do it and put if off for another day. Whether that was because we had already visited a couple of other places earlier and wanted to go home or because access was not quite straight forward, I don't know. Fast forward to March 2018 and up pops a photo that brings back all the memories of that day so better late than never, the reservoir tunnel was back on the radar.
Visited solo.
Pics
1. Entrance slant
2. First sight of the pipe with added valve
3. Spraycretion
4. Follow the pipe...
5. ...and keep on following
6. Roof
7. Collapse
8. Choo choo
9. Old workings
10. Support
11. Closing in
12. Nant-y-Mailor Spring !
Thanks for looking.
Nant-y-Mailor Reservoir, was one of four reservoirs which once provided drinking water to Pontypool, Abersychan, Talywain, Garndiffaith, Varteg, Griffithstown, Sebastopol and New Inn, is located in woodland to the east of Abersychan village. It had a capacity of 4,500,000 gallons and was topped up by water pumped from disused collieries.
The tunnel was built in 1888 to provide a clear path to the source of the spring in Nant-y-Mailor. Prior to it being built, water from the spring was contaimnated by mineral deposits, including coal and iron deposits, in the sub strata. The tunnel has had remedial maintenance work carried out over the years by Dwr Cymru / Welsh Water including the spraycreting of a large section. The tunnel leads downhill for 200m to a boulder choked passage and a sump. The sump was dived in 1972 - no way on and too loose - and in 2005, when a 2nd sump was tried. Approximately 100m into the tunnel on the left side, a passage leads to a large collapse chamber. The tunnel follows the line of a low bedding plane containing a stream, still visible in places.
The reservoir itself has been closed for nearly 40 years.
First visited on a cold, windy, rainy and in general, shitty winters South Wales Friday afternoon about 8 or 9 years ago. For some reason (which I can't recall), despite finding the tunnel, we didn't actually try and do it and put if off for another day. Whether that was because we had already visited a couple of other places earlier and wanted to go home or because access was not quite straight forward, I don't know. Fast forward to March 2018 and up pops a photo that brings back all the memories of that day so better late than never, the reservoir tunnel was back on the radar.
Visited solo.
Pics
1. Entrance slant
2. First sight of the pipe with added valve
3. Spraycretion
4. Follow the pipe...
5. ...and keep on following
6. Roof
7. Collapse
8. Choo choo
9. Old workings
10. Support
11. Closing in
12. Nant-y-Mailor Spring !
Thanks for looking.
