Reservoir Hole Digging Prospects

[The Old Ruminator]

Well thats if ever we see cavers return there. Also, of course , if digging is allowed though most sites were already in progress.

1 Potter's Heaven and Jill's Slither.

Both are relatively recent in terms of cave age. Potter's eventually entered a chamber beyond which little work was done. The appoach to this was a horrid sludge dig which may have silted up again. Equally horrid was Jill's Slither though good progress was being made to a small sumped chamber. Interestingly when sloshing the pool there glooping noises could be heard further away suggesting more airspace. Both lie at the current water table for the cave but this may be artificial. Cox's Mill took water from the risings but through waterfalls backing up the discharge from the risings. Such is the case today.

 

[The Old Ruminator]

The Potter's Heaven Dig 2011.

 

[The Old Ruminator]

Nigel Cox at Potter's Heaven in 2011.

 

[Badlad]

I can see why your Quarter way up Hole is quite attractive now

 

[mrodoc]

I have a great video clip of Johnathan Williams (Tangent) talking to camera after he had just entered the currently final chamber at the end of Potter's Heaven. And, yes, pots have been made from the clay/mud here. The passage leading to it is surprisingly mature and the inundation is clearly a relatively recent feature as is evidenced by the stal formations in the passage. Whether that links to a huge flood or a collapse is not known but certainly the whole area was flooded for some time relatively recently (speaking geologically).

 

[The Old Ruminator]

Possible sequential drainage routes down dip along the shear faults. Topless Aven is a phreatic up loop. TFD is fault controlled through Skyfall and along High Country. Note MSD.

 

[The Old Ruminator]

Hypothetical drainage routes for the Cheddar Catchment.

 

[The Old Ruminator]

The Goughs streamway and Reservoir Hole. Its likely that the Goughs active conduit will continue in the same direction crossing the TFD primary faults indicated by the white line.

 

[The Old Ruminator]

Sectional view showing the hypothetical Golgotha phreatic down loop.

 

[The Old Ruminator]

Stanton's survey showing heights OD. The water table at 150m plus at the top of the Golgotha up loop.

 

[The Old Ruminator]

Reservoir Hole entrance is at 128m ( MCR ) with a depth including the sump at 131m. Main Rising is at 27m though that could be artificially maintained by the lake and waterfall at the old Cox's Mill site. At a guess that by 3 metres. This artificial level probably accounts for the silt accumulation in Potter's and Jill's .

 

[The Old Ruminator]

Mud banks and phreatic pendants Potter's Heaven.

 

[The Old Ruminator]

Jill's Slither terminal sump chamber see boot for scale.

 

[The Old Ruminator]

So to wrap up the first sites at Potter's Heaven and Jill's Slither it seems that progress could still be made if the places are not silted back up again. Jill's does carry an active stream which emerges from Chain Chamber where it runs under boulders. The wash tub is here. At both sites we either washed off or wore paper oversuits which were carried out bagged up. Neither site could be dug without a wash or change of oversuit. As to further progress it looked like Jill's was the better prospect but only by banging the roof above the sump. As stated is does seem that there is airspace very close beyond the sump. Potters will remain horrible. I never got to see the final chamber which never got named. Perhaps Mr O'Doc can sort something out.
Next time we look at Magic Smoke Dig.

 

[The Old Ruminator]

Somehow the MCR stats sound a bit odd.

128m ( MCR ) with a depth including the sump at 131m. That would mean that the sump is below sea level. Maybe I am seeing it wrong

 

[The Old Ruminator]

Andrew Atkinson digging in Jill's Slither.

 

[The Old Ruminator]

Magic Smoke name came from the canister of stage smoke we used to trace draughts. We went all over TFD looking for elusive draughts. At one point at the east side it felt a bit draughty but in such a huge space it was difficult to pin down. Big scallops in the wall coincided with a cold area so we started our dig there. Not a difficult dig with one solid wall few boulders and compact sediments. A good depth was quickly attained resulting in the need for a ladder. I guess the long trip in got the better of the aged diggers and eventually we abandoned the site. The sediment at the bottom was getting harder to break up though removing it was easy with a pulley system. The chamber wall was just starting ro bell out towards the hypothetical line of any streamway passing under TFD floor. Being upstream of that made the site interesting. Really the dig was a passage through time burrowing down through the phreatic sediments in the chamber. TFD appears to have been a nexus for the various stage levels of development going back 4,000 years or more. All things passed this way from the 150m horizon down to the current rising level. Sadly I cant now remember how far the bottom of the dig was above rising level. 15m comes to mind but that might be wrong. Andrew Atkinson did survey it but too late to go on the published survey. It awaits a younger team should digging access be obtained.

 

[The Old Ruminator]

Reservoir Hole with High Country, Skyfall and the sump ommitted also the early stage development in the roof Ceiling Around. Probably pre dating TFD itself. Makes more sense on the usual northerly axis but easier to present as a plan and section this way. Solid lines fault pattern. Dashed line hypothetical modern stream route. Dotted line sump inlet route.

 

[mrodoc]

Yes all frustrating for digging as there is clearly more cave under the Frozen Deep and for such a large space the draughts are surprisingly noticeable. Magic Smoke had a lot to offer being against a solid wall and was easy digging. If we had started capping boulders there things would have gone a lot quicker too. Regarding the end of Potter's Heaven only a handful of people have been there. Some digging along a pendant roofed bedding was started but on my last trip with Alison Moody Alison pointed the sump level was rising (weather had turned damp) and as it would have flooded our exit we departed swiftly. Lee Knight visited with Eszter Domina a year or so after in a dry spell to do some biological sampling there. Eszter later asked me why we weren't digging there in view of the noticeable draught coming from our aborted dig (and that draught could not be coming from anywhere else but cave beyond Potter's Heaven). It was easy digging and spoil could be dumped in the terminal chamber (for quite a while at least) and once you are in the chamber it is a whole lot nicer than the Jill's Slither dig. Worth noting that I buried a hose from the stream inlet at the top of Grand Gallery and the gradient proved a powerful cleaning jet by the time the water reached Jill's Slither. The problem was that debris blocked the pipe but by some simple engineering at the top end it should be able to trap debris before it can get down the pipe. It is one thing worth reinstating when the cave is reopened as it also allows stal to be cleaned.

 

[The Old Ruminator]

Magic Smoke Dig. Now in hard sediments with the chamber wall undercutting towards the hypothetical line of the sump inlet.