Author Topic: Warning - Devonshire Mine entrance subsidance (Read 2122 times)

DCA · « **on:** October 04, 2019, 07:18:56 pm »

Over the last day or 2 a small gap has opened up beneath the door at Devonshire Mine. Overnight this has grown to a much larger gap and there is evidence that the area has become unstable and is at risk of collapse. The deads that sit under the door have become dislodged and the whole area is settling. Please use the Upper Entrance (old show mine) to access the mine until further notice.
Safety warnings have been posted inside the mine and out and the landowner down the lane is aware.
DCA will try to establish a course of action as soon as possible once the movement has ceased. Please remember that this entrance is on a filled in shaft, so it would be wise to stay clear for now in case the shaft is attempting to un-fill itself!
Thanks to PICA member Tom Monck for the initial notification.
Pete Knight
DCA Projects

Gritstone · « **Reply #1 on:** October 04, 2019, 10:41:49 pm »

Just to clarify, is permission required to use the top entrance? I thought it was out of bounds in someone's garden. The last time I was in there was a new metal gate fitted. It was possible to get around the side of this but looked like a infill was due to be added.

paul · « **Reply #2 on:** October 05, 2019, 08:58:06 am »

See https://peakdistrictcaving.info/home/the-caves/derwent-south/devonshire-cavern

Pete K · « **Reply #3 on:** October 05, 2019, 10:22:15 am »

Quote from: Gritstone on October 04, 2019, 10:41:49 pm

Just to clarify, is permission required to use the top entrance? I thought it was out of bounds in someone's garden. The last time I was in there was a new metal gate fitted. It was possible to get around the side of this but looked like a infill was due to be added.

Things have moved on a lot since those days. See DCA website for current access info. Although a combination lock was initially fitted to the Upper Entrance, this has been removed and will stay off for the time being.

Pete K · « **Reply #4 on:** October 05, 2019, 11:27:47 am »

Sorry, just seen that the Devonshire listing on the DCA site does not seems to have been up updated when we added the other entrances to the access agreement. I've just submitted the following text to correct that:
"Devonshire Upper Entrance is not mentioned on the listing. This does not require permission to use. A combination lock may be present, if so the code will be ****. There are plans to convert this Upper gate to a Derbyshire Key in future. The shaft from surface above the main chamber and just inside from the Upper Entrance is also approved for access."

LarryFatcat · « **Reply #5 on:** October 05, 2019, 12:15:32 pm »

Quote from: Pete K on October 05, 2019, 11:27:47 am

Sorry, just seen that the Devonshire listing on the DCA site does not seems to have been up updated when we added the other entrances to the access agreement. I've just submitted the following text to correct that:
"Devonshire Upper Entrance is not mentioned on the listing. This does not require permission to use. A combination lock may be present, if so the code will be ****. There are plans to convert this Upper gate to a Derbyshire Key in future. The shaft from surface above the main chamber and just inside from the Upper Entrance is also approved for access."

Maybe the entry could also include a description of where the "Upper Entrance" is, inc a grid reference?

AR · « **Reply #6 on:** October 05, 2019, 01:07:37 pm »

slightly further up the hill, next to the path.....

royfellows · « **Reply #7 on:** October 05, 2019, 03:14:10 pm »

Thanks for all this. I often use the place for testing new lamps.
Please keep the thread updated on latest on the new 'sinking', I am enthralled!

Roger W · « **Reply #8 on:** October 05, 2019, 05:13:44 pm »

You've not been melting the rock somewhere with your latest bit of kit, have you?

Graigwen · « **Reply #9 on:** October 05, 2019, 06:38:24 pm »

Quote from: Roger W on October 05, 2019, 05:13:44 pm

You've not been melting the rock somewhere with your latest bit of kit, have you?

I used to call Roy's lamps "mobile suns".

.

aardgoose · « **Reply #10 on:** October 05, 2019, 07:15:45 pm »

Thanks AR, your description now included in the registry.

AR · « **Reply #11 on:** October 05, 2019, 09:14:52 pm »

If you want to be completely accurate, it's about 100m further up the hill, where the path divides in two, take the right-hand branch then head into the deep cutting.

AR · « **Reply #12 on:** October 07, 2019, 12:44:12 pm »

Would anyone be able to go into Devonshire in the near future and visit the chamber with the fill cone from the shaft and get some pics? It's most likely that it's on the move, hence the subsidence above at the door, but I'm out of action with a knackered ankle and Pete K is busy with work right now so someone giving us a better idea what's going on at the bottom of the fill would be a great help in coming up with a stabilisation plan.

phizz4 · « **Reply #13 on:** October 07, 2019, 05:40:48 pm »

As we use the cave a lot with our scout groups i owe we owe it to the community to try to help. i can get there on Thursday or Friday evening if that is soon enough?

AR · « **Reply #14 on:** October 07, 2019, 08:55:53 pm »

Any time soon is good, help is much appreciated while I'm laid up.

phizz4 · « **Reply #15 on:** October 11, 2019, 11:38:10 pm »

I went down Devonshire this evening (Friday) to have a look at the damage and take some pictures. What's the best way of communicating the pictures and my findings to those that need to know?

ttxela2 · « **Reply #16 on:** October 12, 2019, 09:58:27 am »

I have a vague recollection of accessing a small chamber directly underneath the entrance through a smallish tube like crawl, I'm guessing it's the roof of this that is collapsing?

phizz4 · « **Reply #17 on:** October 12, 2019, 10:50:49 am »

A quick report. I can send a more detailed report and pictures but I tried to do that earlier on this topic and it hasn't posted, don't know why. The pack below the door at the lower entrance seems to have moved forward and down. I'm guessing surface run-off from the slope leading to the entrance. There seems to my non-engineering eye, to be no downward slumping. Some material is going down the muddy slope to the left of the entrance (looking out) that leads to the lower series but that seemed unchanged (although it looks like some hanging death in the ceiling but I think that has always been there). Went to the base of the infilled entrance shaft, I believe (behind the large rectangular block) where there are two upward chokes. The left one is jammed blocks which don't look to have moved. No sign of new debris on the floor. Slightly right is a much looser looking infill. Again, no sign of collapse but quite muddy and water has obviously been trickling down. Recent shoulder surgery (rotator cuff tear) prevented me from investigating small holes. There is still a padlock on the upper entrance gate but a hole to the left of the gate was easily big enough to allow me in.

Pete K · « **Reply #18 on:** October 12, 2019, 10:51:26 am »

Drop me an email with some pics if you can please!
projects@thedca.org.uk
Cheers!

Additionally, I need to go take a look at Devonshire gate myself really, to start planning a fix. Anyone free later today or on the 15th or 16th to keep me company?

Pete K · « **Reply #19 on:** October 12, 2019, 10:54:13 am »

Quote from: phizz4 on October 12, 2019, 10:50:49 am

A quick report. I can send a more detailed report and pictures but I tried to do that earlier on this topic and it hasn't posted, don't know why. The pack below the door at the lower entrance seems to have moved forward and down. I'm guessing surface run-off from the slope leading to the entrance. There seems to my non-engineering eye, to be no downward slumping. Some material is going down the muddy slope to the left of the entrance (looking out) that leads to the lower series but that seemed unchanged (although it looks like some hanging death in the ceiling but I think that has always been there). Went to the base of the infilled entrance shaft, I believe (behind the large rectangular block) where there are two upward chokes. The left one is jammed blocks which don't look to have moved. No sign of new debris on the floor. Slightly right is a much looser looking infill. Again, no sign of collapse but quite muddy and water has obviously been trickling down. Recent shoulder surgery (rotator cuff tear) prevented me from investigating small holes. There is still a padlock on the upper entrance gate but a hole to the left of the gate was easily big enough to allow me in.

Ah, well someone unknown has put a new lock on then!
Sound's like the shaft is not running in then, good news. Probably just needs a team with some rebar and load of mortar to build a new wall up where the orange ladder currently sits. Anyone local fancy heading this job up?

owd git · « **Reply #20 on:** October 13, 2019, 08:48:58 am »

hi Pete, been too busy to commit till now; it will be done soon will report back! Ric'.

AR · « **Reply #21 on:** October 13, 2019, 10:10:41 am »

From the photos that Pete and I have seen, it does look like there's just minor instability in the area under the door so if that's the case then a bit of excavation and rebuilding with reinforcement should fettle it. However, I'd value a second opinion from you Ric (twisted ankle is preventing me from going and seeing for myself!), so if you could head up there in the near future and let us know what you think, that'd be great.

Pete K · « **Reply #22 on:** October 13, 2019, 06:32:02 pm »

Quote from: owd git on October 13, 2019, 08:48:58 am

hi Pete, been too busy to commit till now; it will be done soon will report back! Ric'.

Thanks Ric. As Adam says, your opinion would be very valuable as I'm struggling to find the time for a look at the moment with other jobs that keep popping up!

LarryFatcat · « **Reply #23 on:** October 26, 2019, 12:07:13 am »

Quote from: owd git on October 13, 2019, 08:48:58 am

hi Pete, been too busy to commit till now; it will be done soon will report back! Ric'.

There is a combination lock on the gate, the code works, and you can probably squeeze around it.

Pete K · « **Reply #24 on:** October 26, 2019, 09:01:31 am »

One of the locals will have replaced it then. Code available via the DCA website.
https://peakdistrictcaving.info/home/the-caves/derwent-south/devonshire-cavern