The Mine Shafts Project. Hydrology.

The Old Ruminator

Well-known member
New Years Eve. Last Digs of 2023.

Left home at 7.45 am and arrived at Mikes at 8-15. A quick coffee then off to our far destination getting back at 11-15am. Gear up to the shaft then down to the 16m platform. All went very well there so lots of clearing to be done.The water level has dropped back to 1.40m down 300mm from last time. ( see graph ). Then to Aisholt for a repeat performance. Again successful. Filled three bags and took them back to the entrance, The corner marked in brown should be gone now, Cold incoming draught. Carefully checked with smoke. Went down the hole marked as a circle. No doubt about that. Home by 5.30pm after a very useful day. ( special dispensation from SWMBO ).

The Old Ruminator

Well-known member
Last two images from video as its easier to get remote views that way. To complete the record here are the local rainfall figures.

July 91mm
Aug 62mm
Sept 101mm
Oct 102 mm
Nov 115mm
Dec 125mm

Hard to correlate them with the water level in the shaft but a few drier days does see a a drop even if the monthly figures are high. A good omen for Summer next year if we are still here after the licence expiry date in April.

The Old Ruminator

Well-known member

The Hole In The Wall Dig.

We parked at the hall and walked up the zig zag path to the fallen tree. So much easier. Quickly down to the 16m platform where I drilled three holes. Mr Goldie drilled the fourth whilst I measured the water and retrieved the bags and drill case left in the tunnel. We did three 600mm holes in a line then one 500mm hole below. The water was at the highest level yet recorded at 460mm up a metre from Dec 31st. The rain in that time frame being 48mm. The far end of the traverse pole was under water. Now that means a higher hydrostatic head so maybe it will help the outflow. The holes came quite easily using one and a half batteries.

The Old Ruminator

Well-known member
I was not going to bother recording the shaft water levels over winter and spring this year but I shall while we are digging "The Hole In The Wall". That was " prepped " for a big clearance session next week if I get support. The water below us in the shaft had dropped 1.5m in three weeks during a dry spell. Certainly the mine water levels respond quickly to rain and dry . Mosty the input seems to be water coming down the other shaft some distance away. Anyway the dig is continuing to follow the low space a metre wide. As stated out licence expires in April maybe they will give us an extension.

So at the mine Friday night. Aisholt later today then hopefully the mine again on Tuesday then perhaps Friday.

Basically only two of us available though Feb though we can cope with that.

On the graph the green line shows the Alcove dig and drainage adit level. Purple 2022 -2023. Orange 2023 - 2024. The peak came higher and earlier this winter due to the higher rainfall from July. Perhaps the greater hydrostatic pressure from that has helped upped the outflow.

The Old Ruminator

Well-known member
Today. 6th Feb.
Shattered At The Hole In The Wall.

Yes. The rock and me both. Four digging trips in eight days.

Mr Goldie drove up and we parked at the hall. Lots of small stuff to move so I went to The Alcove to fetch a tub,shovel and hoe.Mr Goldie cleared and I hauled. This went on for a while. I went back down to The Alcove to get another tub. Water at 2.40 m down 300mm since Friday. Inspected The Dining Room and tunnel. All OK but sloppy. Water in the end dig. When clear we could get our head over the top of the lode rock. Its higher at the back but blocked with mud and rocks. I got back two big rocks from the very end. Took about an hour.The very end is now 4.2 m from the platform and still a metre wide. The lode rock needs removing. Its shattered but you cant get a swing at it.The lode in the floor needs reducing to make space. A chisel drill and generator would work well here. Another visit from Mike due I suppose as endless bashing is tiring. So looking a bit more hopeful as there is more space at the very end though blocked with mud and rocks. A mud blocked vugh goes off on the right cleared to about 500mm. Tuesdays likely to be out until March . Fridays clear for me and Mike at Aisholt or here .


The Old Ruminator

Well-known member
Eight digging trips in ten daysso not caught upwith stuff. This yesterday.

Another thread talks about dig reports. We have an interested group and Peter G. saves them to a blog that he will use to write another book sometime.

The Hole In The Wall.

Arrived at Mike's at 8.15 am then back at the mine around 11 am with two drills, supplies a pie and other odds and ends . After six hours hard labour all of the lode boulder was gone moving us forward a metre or more. Behind where the lode boulder was the development gets bigger and we stopped at a boulder and mud choke. The roof line goes onward over the rocks and mud. Another hole goes down to the right passing through the lode to mud etc beyond. A small hole goes left as well. We both thought there was an outward draught. From the platform to the farthest discernable point is now 5.5m. In reality the supplies were not needed but we used them up to lower the floor. Time at site 7 hours so both home later than planned. Water level up at 1.80m. Shaft and dig drippy wet.

I try with the videos which helps the group understand things. Suffers badly from the execution though. Maybe I need help from Caver Keith. I bet he has good models.


The Old Ruminator

Well-known member
A follow up group report from next day as I like to get them out the same day.

Yes there were " technical issues " at the end. Sheila Wise was so worried that she rang Liz. Trying to finish on time I went to the end to " tidy up " and take the photos for the armchair cavers here. One big lump of lode rock was still left which Mike was going to sort. In the tidy process it sort of came apart in my hands.Then exposing the choke behind. I got a big rock down as " cave fever " took over then realised that time was going on. Its still there. So in the session we have moved from 4.2m on the previous visit to 5.5m this time.( including onward probe c 1 m ). The dig face is about 1.3m forward.There are two lodes. The hard crystaline one in the centre forming a ridge in the roof. The bit in the video. On the right is another lode. Pink in colour and very friable. From the start of the dig the right hand lode has a thin mud filled bedding running through it. This gets bigger at the end going right through the lode to create a void going off down. The roof remains the same. A metre wide going onwards over the choke. The hard centre lode has raised the dig floor on the left. This can be chiseled out but we used a more speedy process. I will take a bearing next time to see how it lines up with our " caverns " below. Essentially the chiselling went well burning through two double sets of batteries but capable of reducing lode rock well. At the end the air flow got cold and steamed up the camera lens.Draughts can be imagined but we both thought there was an outward air flow. I rather think Mike's dinner was in the dog. Mine was in the cat. I am away until the weekend now to repair my domestic relationship.

The Old Ruminator

Well-known member
End choke with explainations.

1 The pink friable lode.

2 The rock I left having pulled it out.

3 The hard lode in the floor.

4 Loose mud and rocks choke going onwards.

5 The hard lode in the roof.

6 The hole going through the pink lode and downwards.

The Old Ruminator

Well-known member
I am almost getting excited. The Hole In The Wall Gets Promising.

Dig account first then survey details

Filmed the descent on head mounted camera. 2G file so it wont be Flickr.

The shaft drippy and a puddle in the dig. Mike dug and I hauled and tipped. Loads of mud and large rocks came out. The development is getting bigger. Going down in the floor. Straight on and vertically following the pink lode wall. Two more big boulders at the end. One we split in two and both bits wobble.The other in the roof should drop down .Next visit we will try capping and p and f. I did a survey of sorts . Furthest descernable point now 6m in at a bearing of 125 degrees. Steady outward cold draught blowing the haze out from the end. With the end boulders out we can go forward in a mud and boulder choke still with a wide flat roof. Next dig aiming for Tuesday night with Mike. ( I cant do Fri 1st March ). After hopefully some sort of full day team for Tuesdays. Last week was Mikes longest trip in the mine at seven hours.Water level up to 1.10 m


Mike in the dig showing the twin lodes. White centre. Pink right.

The mucky drag run. Mike digging down in the floor at the end.

Haze shot indicating a steady outward air flow.



The Old Ruminator

Well-known member

Numbers are spot heights below the gate. The bottom platform is at 20.3m ten metres above the main adit. The Hole In The Wall Platform is at 15m which puts it ten metres above The Dining Room floor. The end of The Hole In The Wall dig is about one metre lower than the platform and approaching The Dining Room but high up the lodes are differant. A hard white centre lode and a softer pink lode the latter perforated by mud filled vughs. The pink lode essentially forms the right hand wall and continues beyond the end of the current dig. Lengths and bearings and heights are pretty accurate but probably not all accurated when added together. Second is the water levels. The earlier dry spell showed a drop of 100 mm a day hopeful for summer if we are still there.
The current end is a mud and boulder choke .

1 The boulder in the roof to come out.

2 The spilt big wobbly boulder in the middle to come out.

3 The hard white lode

4 The soft pink lode.

X Muddy voids going forwards.

At the monent this rates as the best chance we have had so far though it could all change.


The Old Ruminator

Well-known member
Another Dig At The Hole In The Wall.

Mike got the afternoon off for an attack on the three big boulders at the end of The Hole In The Wall. Everything wet and rather horrible. Mike drained the puddle whilst I measured the water level in the shaft. A new record for us at 0m. Yes right up to the marker with the traverse pole under water. 130mm of rainfall( Taunton ) has raised the level 2.5m in three weeks since the two dry weeks at the beginning of the month when the level was going down 100mm a day.
It was six hours of attrition as we ( mostly Mike ) hammered and p and f ed the right hand boulder. I filled ,hauled and tipped the debris down the shaft. During this process a large lump of right hand lode " fell " out turning the dig face into a more commodious area of work. At last the final big bit of the boulder got hauled out with a sling and rolled back to the shaft.The left hand boulder is bigger and moved but more advantagious means are required to move it as it could be a metre long. After six and a half hours we were knackered and everything was covered in mud. We might have moved the big boulder but it only have jammed against the lode wall. The third big boulder remains at roof level. It could be left but if it was gone we would have a nice chamber at the end where one can sit up and two can work.
The measuring was done. 4m from the platform to the boulder in the roof. Another metre forward on the right where we got the boulder out. From the 4m mark the tape was pushed along the void for another three metres.So in extent the development is 7m plus long from the shaft. A joss stick showed a small outward air flow but this did not pick up until evening. Then it all got cold and steamy. Trudged back down the path in light rain to wash off a bit in the farm pond.

The Old Ruminator

Well-known member
Photos 2.

1 Onward void probed 3m.

2 Lode structure. White hard lode in the roof to the floor. Friable pink lode running back to the platform left. Mud filled vughs going off through it ( x ).

3 End dig. Onward voids marked with an arrow.

1 Boulder in the roof at 4m
2 Boulder and part white lode that moves but too big to get out.
3 The softer pink lode.

Last image. Somebody who wants to go home -----

On the bottom platform looking up to The Hole In The Wall platform hoping he wont thow any boulders down.

Text here copied from emails sent to the group.