Author Topic: Saturday night under Mendip  (Read 2119 times)

Offline PeteHall

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Saturday night under Mendip
« on: May 09, 2021, 03:38:51 pm »
During maintenance work at a potable watet borehole in Shepton Mallet, a scaffolder dropped his impact driver into the water. There were concerns that the lithium ion battery could pollute the water supply and after unsuccessful attempts at magnet fishing, they got in touch with some local cavers they knew.

A message went out on a Mendip cavers Facebook group and the next day, Kev and I were looking down a 50m hole, ready for an unusual evening underground.

We'd brought SRT and diving kit, but they had managed to pump the well down to a depth of 1.6m, so it seemed diving kit would be redundant.

We sent a gas meter down first, then I  put on my long-john wetsuit (opting to leave the jacket off) and headed down on SRT, with a hood and mask in my bag, just in case.

On reaching the water surface it became clear that 1.6m was the depth above the pumps,  not the depth to the bottom... I plumbed it with a piece of lead on the end of my SRT rope and estimated a further 10m to the bottom, leaving me little choice but to return up the 50m back to surface and reorder my equipment for diving.

Meanwhile, Kev set about magnet fishing from just above the water, but only managed to retrieve a length of scaff tube...

Once I was kitted up, Kev returned half way up, to take a break in a side passage that had been dug unsuccessfully looking for water, while I descended alongside my diving cylinders that were cautiously lowered from the top. Once I was past him, Kev followed me down and helped me kit up in the water, observing that the magnet fishing had had a slightly detrimental effect on the previously crystal clear water.

After a bit of faff, I was off the rope, in the water. Redundant SRT items removed and slack rope tied out of the way above water. Diving kit on, tested and ready to descend.

Below the pumps, the viz immediately returned and the drill could be seen right next to the lead weight on bottom of my line, nestled in a cradle of rusty steel beams. No wonder the magnet hadn't managed to find it!

With the drill returned to a tackle bag above water, I made a second descent to have a look at two side Passages that I'd spotted, one at the base of the shaft and  one about 4m below the waterline. Both were about 5-6m long blasted tunnels, that had been dug looking for water. The lower tunnel had clearly succeeded, as by the time I'd returned to dive base, my tackled bags were hanging underwater and Kev, who'd been several metres above the water had just got a welly full!

We joked about getting the beers sent down and waiting for the water to carry us back out, but agreed Kev would get a  bit cold in a fury suit, so it was best to use the SRT rope instead.

With Kev part way up to steer it, the chaps at the top hauled out the bag of diving kit and we were soon back at the surface, de-rigging.

Mission accomplished.

We both had plenty of fun and the scaffolder was clearly very relieved and has pledged a donation to Mendip Cave Rescue in return for our efforts. A good result all around.  :thumbsup:

Offline cavemanmike

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Re: Saturday night under Mendip
« Reply #1 on: May 09, 2021, 04:35:57 pm »
Thought the scaffolder would have had his impact driver on a lanyard but that would have spoilt all your fun  :clap2: :clap2:

Offline PeteHall

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Re: Saturday night under Mendip
« Reply #2 on: May 09, 2021, 05:03:46 pm »
Thought the scaffolder would have had his impact driver on a lanyard but that would have spoilt all your fun  :clap2: :clap2:

The thought had crossed my mind!  :lol:

Offline Pitlamp

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Re: Saturday night under Mendip
« Reply #3 on: May 09, 2021, 05:14:09 pm »
A damn fine effort.

I'm hoping to read a log in the next CDG Newsletter as "well".

Offline Mark Wright

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Re: Saturday night under Mendip
« Reply #4 on: May 09, 2021, 06:32:07 pm »
Thought the scaffolder would have had his impact driver on a lanyard but that would have spoilt all your fun  :clap2: :clap2:

It's quite rare to see 'scaffolder' and 'lanyard' in the same sentence.

Mark

Offline cavemanmike

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Re: Saturday night under Mendip
« Reply #5 on: May 09, 2021, 06:37:02 pm »
 :lol: :lol: :lol:

Offline PeteHall

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Re: Saturday night under Mendip
« Reply #6 on: May 09, 2021, 10:11:36 pm »
Not the highest quality footage or editing, but gives an idea of what we were up to:


Offline Pitlamp

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Re: Saturday night under Mendip
« Reply #7 on: May 10, 2021, 07:45:17 am »
Nice one - and great PR for the caving community.

Out of interest it looked like there was quite a flow; was that just water movement from ascending bubbles or it it actually flowing up at surface? It seemed to clear quickly.

Offline PeteHall

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Re: Saturday night under Mendip
« Reply #8 on: May 10, 2021, 08:47:32 am »
It was a bit murky when I was kitting up, from the earlier magnet fishing, but was crystal clear by the time I got a few metres down, as it was clearing/ filling from the bottom.

They switched the pumps off once I was ready to dive and from that time to when I was de-kitting again (15 minutes tops) the water had risen about 2m, so in round numbers, at 2m diameter at the bottom, that would be about 25 cubes per hour refill rate.

Offline PeteHall

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Re: Saturday night under Mendip
« Reply #9 on: May 10, 2021, 10:32:30 am »
so in round numbers, at 2m diameter at the bottom, that would be about 25 cubes per hour refill rate.

Not far off. BGS records show a yield of 5,000 gallons per hour when it was dug, which would be about 23 cubes.
« Last Edit: May 10, 2021, 01:17:34 pm by PeteHall, Reason: sensitive details removed »

Offline Duncan Price

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Re: Saturday night under Mendip
« Reply #10 on: May 10, 2021, 11:31:41 am »
This is the second dive at this site:

December 2004
Diver: J Beal

The diver had been asked to dive in a well... ...where a gas monitor and a large torch had been dropped into the water and needed recovering. Diver and support abseiled 55 m down the 2 m diameter shaft between two water pipes to access the adit at the water level. Diver then kitted up to enter the water with pony cylinders and no fins to squeeze between the pumps to a depth of only 6m to recover the items. Initial visibility was excellent allowing another adit to be seen. This was half-full with silt but was followed for 10 m to a 90 degree bend where a blasted face was found. A slow prussik out introduced the diver to the joys of double ropes and shunts.
« Last Edit: May 10, 2021, 01:25:25 pm by PeteHall, Reason: sensitive details removed »

Offline Mark Wright

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Re: Saturday night under Mendip
« Reply #11 on: May 10, 2021, 12:30:22 pm »
Back in the early 80’s the TSG did a similar exercise for a mining company in Derbyshire. I can’t remember the name of it but it was on the right between Calver and Bakewell at the Calver end of the road.

Chris Rhodes and I descended a similar sized shaft to recover a load of wriggly tin that had been thrown down the water pumping shaft and damaged the pumping hoses.

In return the mining company gave us access to explore another more interesting shaft on their land.

It was a great day out and everybody was happy with the outcome.

That, however, was in the 80’s when Health and Safety legislation was not what it is today.

The number of Health and Safety laws that have been broken on this occasion by the company who put out the call on Facebook are considerable and if the HSE got wind of it, heads would certainly roll. The fines could likely run into the 10’s if not 100’s of thousands of £‘s!!!

Whilst, as Pitlamp says, it might be good PR for the caving community I’d be more inclined to accept the donation and pull this thread from the forum before it is spotted by the powers that be.

Mark



Offline Pitlamp

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Re: Saturday night under Mendip
« Reply #12 on: May 10, 2021, 01:04:14 pm »
Mark - was that ever recorded anywhere? I ask because there's a Peak District sump index in the pipeline and it'd be useful to have at least a note of it in there. Could you send a PM rather than posting here, in case your advice immediately above is taken?

Offline PeteHall

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Re: Saturday night under Mendip
« Reply #13 on: May 10, 2021, 01:29:51 pm »
The number of Health and Safety laws that have been broken on this occasion by the company who put out the call on Facebook are considerable and if the HSE got wind of it, heads would certainly roll. The fines could likely run into the 10’s if not 100’s of thousands of £‘s!!!

Whilst, as Pitlamp says, it might be good PR for the caving community I’d be more inclined to accept the donation and pull this thread from the forum before it is spotted by the powers that be.

Mark

For the record, the company did not put a call on Facebook. An employee contacted friends who were cavers, those cavers put a call on a private cavers Facebook group.

I have removed details above that could identify the location of the site.

Offline mikem

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Re: Saturday night under Mendip
« Reply #14 on: May 10, 2021, 01:41:28 pm »
The company will still be fairly easy to identify if it sparks an investigation, so I'd follow Mark's advice.

Offline mrodoc

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Re: Saturday night under Mendip
« Reply #15 on: May 10, 2021, 06:53:11 pm »
You are safe anyway as you didn't take any money. Otherwise it would have been a commercial dive. Estelle (BEC) and I have received payment in kind in the past but indirectly (freeing a prop once and what turned out to be a rather nefarious activity in Portland Harbour with Mrs Mrodoc).

Offline Cantclimbtom

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Re: Saturday night under Mendip
« Reply #16 on: May 10, 2021, 07:33:34 pm »
At about 50 secs in the vid I see 2 knots on that dark rope and a big gap to something maybe a shunt just above water surface, at 1:30 in vid there is much less rope below the 2nd knit and shunt or whatever it was is submerged, at 3:00 or so water is now near the second knot. That water is rising up that bore very quickly!
Expert in incompetent tomfoolery

Offline PeteHall

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Re: Saturday night under Mendip
« Reply #17 on: May 10, 2021, 07:40:11 pm »
Yes, they switched the pumps off before I dived. By the time I was back in my SRT kit afterwards, it had come up a couple metres.

The video isn't continuous, so it's not as quick as it looks though...

Offline PeteHall

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Re: Saturday night under Mendip
« Reply #18 on: May 23, 2021, 08:26:14 pm »
We returned with Chunky and his camera, plus a GoPro from one of the chaps on site.

Since Frampton's have put the underwater GoPro footage on YouTube, I see no reason not to share it here.



Note the air-bell in the side passage, where the water enters the well. This is perched at a reasonable depth below the water surface in the well (over 8m while we were there,  but obviously varies depending on pumping).

My theory is that as the water enters the well, the pressure drops from circa 30m depth (un-pumped water level) to circa 8m depth.  The sudden drop in pressure causes dissolved air to come out of solution, forming a perched air-bell. Any scientists out there care to verify of quash this theory?

Video credit to Chunky, with support from: J Burkey, L Phelps, D Price, T Williams and me.

Offline Judi Durber

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Re: Saturday night under Mendip
« Reply #19 on: May 24, 2021, 08:21:50 pm »
Managed to recover some scaff poles, spanner & rubbish.



We must be willing to get rid of the life we've planned, so as to have the life waiting for us.

Offline PeteHall

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Re: Saturday night under Mendip
« Reply #20 on: May 24, 2021, 10:32:59 pm »
Thanks for sharing Judi.

So that's the final chapter in the story, which saw Judi, Andy and I back down the well until late on Friday night, collecting water samples directly from the water source.

We also pulled out several bags of junk from the bottom of the well while we were down there (pictured above).

I think Andy kept the spanner as a souvenir, and we're hoping nobody cleared up the rest of it by chucking it back down the well over the weekend!  :lol:

Offline darkdescender

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Re: Saturday night under Mendip
« Reply #21 on: May 27, 2021, 02:41:46 pm »

On a similar topic. Back in the 60's a construction firm had quoted for a job to reline a metal pipe that ran horizontally right through a local reservoir dam. On trying to push through a replacement pipe they came across an obstruction. A club member was asked if he could help and two members crawled through and found iron reinforcing hoops every so often.
The lads said they could grind them out, so they asked me to take some photographs.
  Funnily enough the firm never mentioned anything about H & S !!

   Any other cavers been asked to do non caving jobs?


Offline darkdescender

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Re: Saturday night under Mendip
« Reply #22 on: May 27, 2021, 02:44:12 pm »


Edit  Photos did not attach. Will try again
« Last Edit: May 27, 2021, 02:57:29 pm by darkdescender »

Offline Fishes

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Re: Saturday night under Mendip
« Reply #23 on: May 27, 2021, 06:04:25 pm »
   Any other cavers been asked to do non caving jobs?

Inspecting/clearing blockages in Kiln and furnace flues. Removing undersize grinding media from inside a ball mill. Clearing culverts. Fixing a wiring problem inside a confined ceiling space.

I'm sure there have been more but that's what comes to mind at the moment.

Offline Laurie

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Re: Saturday night under Mendip
« Reply #24 on: May 28, 2021, 08:02:27 am »
I've been diving in a foot of water to remove a well rusted input grill on a ram pump.
MNRC

Offline AR

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Re: Saturday night under Mendip
« Reply #25 on: May 28, 2021, 09:17:50 am »
Back in the early 80’s the TSG did a similar exercise for a mining company in Derbyshire. I can’t remember the name of it but it was on the right between Calver and Bakewell at the Calver end of the road.

Chris Rhodes and I descended a similar sized shaft to recover a load of wriggly tin that had been thrown down the water pumping shaft and damaged the pumping hoses.

In return the mining company gave us access to explore another more interesting shaft on their land.

Missed this when it was first posted...
That would be the Red Rake pumping shaft, inside the now-collapsed wriggly tin shed close to the Newburgh Level, I'm guessing? It was owned by the Bleaklow Mining Company (IIRC) in the early 1970s, when they gifted the old pump to PDMHS and it was taken away to Crich though I don't know who owned the site a decade later. The shaft drops onto a branch level of Brightside Sough, which runs from Brightside Mine to a tail near Calver Village Hall.
Dirty old mines need love too....

Offline pwhole

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Re: Saturday night under Mendip
« Reply #26 on: May 28, 2021, 06:58:11 pm »
I've got photos of George Fletcher with the pump, but it's diverting a bit from the originl topic - i can dig them out later if anyone wants to see them? I thin they're from 1977.

 

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