Return To Reservoir Hole

With Vurley still having + %5 Co2 we have decided to return to a previously dug site in Reservoir Hole. With Chris Milne returning home as the motorway was closed that just left Peter Glanvill and myself for the first trip. The dig is at Jill's Slither beyond the end of Grand Gallery. It appears to be an abandoned drain heading parallel to The Frozen Deep and with a huge amount of luck it could be heading for the main stream conduit. The survey shows the dig in black as a separate passage but in fact it is a lower part of Jill's Slither so was once a fairly large passage. It definitely has the appearance of a stream cut tube and was once a continuation of The Grand Gallery conduit which formed at a lower phreatic base level than other parts of the cave. Peter took a few pics on the way in as did I with the TG 2.

Several folk have had a go here including Alison Moody, Martin Grass, Tony Boycott, Andrew Atkinson and recently Mike Kushy with Mike Moxon. The dig is some 8m long ending at a mud bank and continuing beyond. On the way in we collected some kit left at The Silo.

Digging gear from The Silo in Chain Chamber. Pete taking photos.



Me ready for some work.





Peter by the entrance to Potter's Heaven.

Manganese stal in Jill's Slither.





Phreatic pendants in Jill's Slither.

Peter in the dig lowering the floor up to the mud bank.



The rocks come flying out ---









Muggins on the skip haul.



Well it was a good day with the floor lower now. A bit more to do then attack the mud bank. The good old TG 2 behaved well.

If I get no hassle from anyone I hope to keep this updated. we are planning another trip next week.

This part of the Reservoir Survey released under creative commons. ( ( need to add the acknowledgment. )

The older parts of Reservoir Hole are fault controlled but the lowest area draining the Grand Gallery conduit revert to strike shown here as a black line. If this drainage continues along strike it will intercept the Golgotha fault at a lower level. A lot of work was put into Potter's Heaven a while back and we succeeded in passing the mud filled tube to enter a chamber. The tube refilled with water over winter and the strike aligned chamber was never surveyed or photographed.( marked X on the plan.) Currently the
Jill's dig is much cleaner ( relatively ) and at a higher level than the Potter's dig so should not be flood prone.

The Old Ruminator said:

If I get no hassle from anyone I hope to keep this updated.

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Please do! There's looks to be a good level of squalor from some of those photos.

It's been a while OR. Please don't stop now. 

Looking very interesting, OR.

How does that bit of Reservoir look on the vertical plane?  Where does Jill's Slither lie vertically in relation to Golgotha?

I have missed your posts about digging. Welcome back, OR.

This section of the survey shows the Grand Gallery conduit in profile.



The lines are at 25m intervals. The end of Potters is close to sump level though the unsurveyed chamber at the end rises above it.
Jills finishes up slightly higher and would pass under the Golgotha fault at a considerable distance below known cave if it gets that far.  Both Potters and Jills have the potential to go beyond The Frozen Deep. Although not as messy as the Potters dig where it was horrible sticky mud Jill's is mucky wet gravelly stuff. Clearly that cannot be transported out through the entrance series so we shall use the paper decorator's oversuits we used during the Potter's dig. The washing area in lower Chain Chamber, now ineffective ,will be restored and used as well.
Originally phreatic water flowed through Grand Gallery to rise up Topless Aven and into the digs through to The Frozen Deep. As the phreatic levels lowered to the point where they are today at 26m Grand Gallery water drained down through Potters Heaven and Jills Slither to arrive at the main stream wherever it is today. There is still a stream in Grand Gallery on occasion though we do not know where it originates. A separate trickle joint this from The Silo. A small stream also runs under boulders in lower Chain Chamber to enter the Jill's area. In wet conditions water flows down from the Golgotha area and through part of Topless Aven to sink in the floor at the bottom of Grand Gallery. In flood conditions water backs up from the sump at Dingley Dell and makes the Potters dig impassable. There is evidence that in the past water backed up into lower Chain Chamber though I dont know if anyone has ever seen that. Both Potter's and Jill's digs have evidence of dryer spells with stalagmite false floor forming above the sediments.

I still have a new white coverall left over from the Potter's dig. This one is a Tyvek Pro.Tech made by Dupont and sold by Screwfix at ?9.99. Screwfix also sell cheaper Alpha and Delta models as low as ?2.99 but the Alpha Solway at ?5.99 looks the better bet. It means dreadful photos in future but might be the single trip answer to digging in mucky places. Has anyone tried them ?

oh brill the adventure continues....I shall follow with interest

The Old Ruminator said:

I still have a new white coverall left over from the Potter's dig. This one is a Tyvek Pro.Tech made by Dupont and sold by Screwfix at ?9.99. Screwfix also sell cheaper Alpha and Delta models as low as ?2.99 but the Alpha Solway at ?5.99 looks the better bet. It means dreadful photos in future but might be the single trip answer to digging in mucky places. Has anyone tried them ?

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We use these for confined space cleaning in some pretty horrid places, not sure you'd get much more than single use out of them, they tear pretty easily, probably better off with boiler suits than the disposables.

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Thanks Chunky. I will give it a try then if no good resort to the proper boiler suit I have.

The Old Ruminator said:

Thanks Chunky. I will give it a try then if no good resort to the proper boiler suit I have.

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I'm in mendips this weekend and have some odd size disposables (xxl) they're even big on me!

If of use I could drop half a dozen off somewhere?

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Thanks for the vertical section, OR. 

If your dig keeps heading down at that sort of angle, it looks as if it's a diver's suit you could be needing rather than a Tyvek one. 

chunky said:

The Old Ruminator said:

Thanks Chunky. I will give it a try then if no good resort to the proper boiler suit I have.

Click to expand...

I'm in mendips this weekend and have some odd size disposables (xxl) they're even big on me!

If of use I could drop half a dozen off somewhere?

Sent from my SM-G935F using Tapatalk

Click to expand...

Many thanks. PM sent.

Roger W said:

Thanks for the vertical section, OR. 

If your dig keeps heading down at that sort of angle, it looks as if it's a diver's suit you could be needing rather than a Tyvek one.

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The section does imply that Roger however the Potters/Jills conduit departs the High Country Fault at their point of origin and are no longer dip controlled. They run along strike to level out just above sump level where the two digs commence. This could be the bottom of that particular phreatic loop. This is shown as such by Farrant et al in UBSS Procs Vol 27 No 1 ( 2016 ) where Reservoir Hole is discussed in detail. All four major phreatic development levels are shown as looping upwards steeply within the known cave.
( Golgotha, Topless Aven etc ). The terminal chamber beyond the Potters dig is trending back up and only some 10m short of the Golgotha Fault. Unfortunately the Potters dig is the most awful place I have experienced and prone to flood to the roof. I would not want to go back there and possibly more slimy silt has backed up there. Arguably Potters/Jills represent the same conduit and both were active under phreatic flow conditions. Both remained open and " dry " for a considerable time as stal formation shows. The Jill's dig represents formation along the conduit at the farthest point of dip. Currently it appears to stay at a level above flood. We might try the same remote camera we used at Potters which showed the dig opening slightly beyond the blockages. No doubt if this conduit ever reaches the Golgotha Fault " something "will happen but we dont know what.

Structural controls at Reservoir Hole.



Strike is shown as the solid line and the arrow shows dip. The Golgotha fault determines the North side of The Frozen Deep, Golgotha and Topless Aven dig, Hard Times etc. This is shown as a hatched line. The dotted line at the bottom shows the High Country Fault which determines the South side of TFD, High Country, Grand Gallery and Skyfall. The blob at the end of Potters represents the un surveyed chamber 10m short of the Golgotha Fault. X represents the hypothetical point that can be reached if the conduit passes through the Golgotha Fault.Y is the current Jills dig.

Farrant's model for phreatic phases 3 ( dots ) and 3a ( hatched line ).

Stal in lower Potters indicating a lengthy dry phase.



Difficult conditions in the 2011 Potters Heaven dig. ( Willie had an odd sense of humour ).



Phreatic pendants and stal in Potters 2011.



The " Ferret " remote camera that made us decide that the Potters dig was worth pursuing.