This may have been asked and answered before, apologies if it has, I could find no reference.

Last night we were looking at (amongst other things) the old fall at the very end of Lake Level, two chambers further on than the drop into MQF4 (lost world).

It's not entirely impossible with the right tools and a not small amount of effort that a road through could be made.

Before committing to such folly I was hoping to see a survey that showed if there definitely is a level on the other side of the fall and if there was likely to be anything of any interest.

I note that it's not far from the old boundary so I would assume it doesn't go much further. I was hoping to find a chamber or roofing shaft up to 2. This was sometimes done at the end of a long run of chambers for ventilation and egress.

Trying to gauge whether it'll be worth the effort...

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Miles, if I was not a techno-nerd I'd put in a link to the plan on the Oakeley page by Graham Isherwood (Oakeley Back Vein S.W. 1904-10).

This seems to show that the chamber two along from the drop into the Lost World is the last one on Lake Level, but it looks as though it goes up to 3 with another chamber on that level to the east.

This one?

http://www.aditnow.co.uk/documents//Whole1-25pc.pdf 

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This one?

http://www.aditnow.co.uk/documents//Whole1-25pc.pdf 

That's the one.

I'll have to get you to teach me how to do it Simon :smartass:

It's easy - just copy and paste what shows in the address bar into your forum message - the linking is done automatically 🙂

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Thanks for that survey. Very interesting indeed. Shame there is detail missing in the Z4/Z5 BV area.

As you say LL does terminate in that chamber, it really is the last one so not much to be gained by driving though it!

Last night we (well, Pete) managed to climb up this chamber quite a long way, easily past where Floor 2 should have been. Probably buried, and unlikely to get to anything anyway as blind inbye and run in outbye. Unsure from survey if that end chamber reaches fl3 or not, but we couldn't find it last night.

Moving onto MQBV3...

Nice to see all this so clear, not seen it presented like this before.

Z3BV is the big fall then, and we know Z2BV is also fallen from Speedy and Llion's snake-down-a-hosepipe exploits 8 years ago. I tried hard to repeat this last night, but failed, possibly due to being somewhat fatter, but more likely because it's moved since.

Z4BV we know has a level in the back at the horizon of Floor 5, but there is no floor 5 on the map or any hint of the level so it'll just be guess-work if an attempt is to be made on that. I assume it will connect to what the survey shows as an end-of-drive in Z5 (dated 5/6/1899). It doesn't line up though, hmmm.

Gotta say then that Z5 North Vein (if that's what it is) is probably the one then.

I like that the caban is on there, if not labelled. I saw a date written in there last night, 1904. I suppose that's about right, the survey says it was cut in 1899.

It's probably a fair conclusion to say a major simultaneous assault on Z5 NV and BV falls is potential wasted effort, as suspected they rejoin anyway further inbye.

Even on this 1910 survey, wall Z3 is documented as under pressure. It's directly under the Llyn. Everything directly under the Llyn is in a bad way. for instance, Ch31 on DE floor (the one with the pump) is presently actively disintegrating, and has never been pretty. Interesting that it is precisely underneath.

I would venture to suggest the crack from the great fall is actually vertical.

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Miles, what do you mean by saying there is detail missing in the Z4/Z5 area? What is on my drawing is all there was on the original survey - so without interpolation it is all we have - unless I can find it on another survey in the archives of course. ;);)

Cheers

Grahami

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Hello Graham :)

Well, looking at Z4 in the back vein, the survey shows the chamber just topping blind but in reality there is a level up there about the height of floor 5. It's only short and run-in after a few yards, but it's certainly a level.

Attempted to dig through it is not an impossible proposition but there is no saying if it will connect to Floor 5 proper as that level is not on the survey.

One possibility that has just occurred to me is that the level at the top of Z4 might have been driven straight through the roof of Cwmorthin's easternmost chamber. The connection is not shown but looking at the survey, there cannot be much rock between them.

I say through the "roof" because Z4 is higher than Z6. I used my laser-measurer the other day... Z4's roof is 48m long angled up the bedding plane. Z6, which holes into Cwm 1, is 38m.

One bit of evidence that points to this fact that I've just remembered from when I climbed up Z4 about 8 years ago, is that the fall in the level looked a bit strange, because the fall went down and up. IE, the floor ended. I thought it was odd back then.

If Z4 was driven through the roof of that last Cwm chamber on the horizon of MQ5, it would explain why MQ5 doesn't exist there on the survey.

What do you think?

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Miles, I don't recollect seeing the caban. Is it in one of those stub tunnels? And/or do you have to scramble over a fall to get to it?
Secondly, we were very interested in the levels and smallish chambers in the rather isolated section beyond the cross-cut tunnel to the north of the main workings in the back vein. The rock looks different here, as I may have mentioned before, with deposits of little snow white crystals, and iron formations like curtains. The chambers here are rather undeveloped, and we were interested in the long level in this area which seems to lead roughly westwards and curves round back towards the region of Cwm floor A. I wonder what the miners where trying to do here? - an exploratory tunnel in the hope of hitting better rock perhaps? Maybe they came to a halt, when they realised they were too near the Cwm workings? Which brings me to the question of the level at the top of chamber Z4, which you think may hole through into the roof of the last Cwm chamber (as mentioned above). If this is correct, I wonder what exactly was going on? A mistake perhaps, because the exact position of the Cwm chambering at this point wasn’t on the plans that Oakeley had at the time? ( By the way did Oakeley actually hold plans of the Cwm workings then?) I remember you mentioning that the level at the top of Z4 appears to meet an odd inclined shaft of something similar. I wonder if there’s actually a hole in the roof of this last Cwm chamber, simply overlooked because no one’s thought to look for it so to speak, and such things can easily be missed!

Another point of interest, to me at least, are the very nice selection of slate blocks in chamber Z4. They appear to be beautifully dressed,and one is actually split, but I was under the impression this wasn’t usually done underground, but rather in the mills, so they are something of a mystery. Wonder why such apparently good blocks are still there? Perhaps a fall made it difficult to transport them out, so they were simply left. I haven't seen blocks quite like this is any other part of the workings that I have visited and would be interested to know if anyone has seen anything similar elsewhere.

I must admit to being amazed by the extent of the chambering and levels( shown on the above mentioned plan) cut off behind the falls on floor 3 This plan also clearly shows that the back vein chambering seems to be split into 2 sections – This may indicate the position of the drop fault, but I'm not quite sure.

Also I haven’t quite worked out what vein those small chambers not roofed though to anywhere else are in. Since they are found beyond the end of the northward heading cross-cut, and the rock looks different, they may actually be part of the true Oakeley north vein workings lying to the north of the back vein, or maybe they are just another part of the actual back vein but with different quality of rock, as the quality of the veins is certainly not uniform - Plenty of examples of this is documented in the Oakeley History.

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Miles, I don't recollect seeing the caban. Is it in one of those stub tunnels? And/or do you have to scramble over a fall to get to it?

Yeah bit of crawling and squeezing through dodgy ground to get to it, and it's only a small one.

Secondly, we were very interested in the levels and smallish chambers in the rather isolated section beyond the cross-cut tunnel to the north of the main workings in the back vein. The rock looks different here, as I may have mentioned before, with deposits of little snow while crystals, and iron formations like curtains. The chambers here are rather undeveloped

Yeah, I'm not sure which these are but in the bedding sense this slate is the highest, therefore the youngest, I know of in the mine. I suppose it must be North Vein perhaps? I know the Oakeley fellas were keen to try it on the Cwm side, as the separate North workings of the 1920's testify. I heard the vein was quite productive on the Oakeley side but on the Cwm side it didn't seem to impress them much.

we were interested in the long level in this area which seems to lead roughly westwards and curves round back towards the region of Cwm floor A. I wonder what the miners where trying to do here? - an exploratory tunnel in the hope of hitting better rock perhaps? Maybe they came to a halt, when they realised they were too near the Cwm workings?

GrahamI will know better than me. Seems to just be exploratory, but the last thing they'd have wanted to do is hole into Cwmorthin there as it was flooded then of course and the whole of A floor would have emptied into Oakeley. Looks from the survey they'd have driven into it if they'd have carried on much further.

Which brings me to the question of the level at the top of chamber Z4, which you think may hole through into the roof of the last Cwm chamber (as mentioned above). If this is correct, I wonder what exactly was going on? A mistake perhaps, because the exact position of the Cwm chambering at this point wasn’t on the plans that Oakeley had at the time?

Personally, and I stress this is just my opinion, not the result of research, I think they holed into Cwm's back vein here long before Old Vein C, in fact I best they did it almost straight away after the buy-out in 1900 as it would have been easy. The surveying would have been done from the Oakeley end, quite a long way off, and doing the join-up with no exact point of reference must have been tricky* so perhaps that hole-though in Z4 was first just to get an idea of where they were exactly in relation to Cwm, but it's in a daft place so the more practical Z6 one went in a bit later maybe. Its definitely a through-fare, given the nice ladder.

(*Although they were certainly capable of extremely accurate surveying over great distances at the time. Like in the very late 1800's when they were driving the Milwr Tunnel from sea-level in Bagilt, whilst a shaft was sunk some miles away, and from the shaft bottom a tunnel was driven towards the advancing Milwr Tunnel. Even with both headings making numerous bends, when the two driving teams finally met the tunnel centres were less than an inch out of each other. Impressive stuff given the technology of the day).

( By the way did Oakeley actually hold plans of the Cwm workings then?)

I'd have thought so. They had access in any case.

I remember you mentioning that the level at the top of Z4 appears to meet an odd inclined shaft of something similar. I wonder if there’s actually a hole in the roof of this last Cwm chamber, simply overlooked because no one’s thought to look for it so to speak, and such things can easily be missed!

I bet there is. My friend Pete had a look up that chamber last week, but wouldn't have been paying much attention to levels in the roof as you wouldn't expect to find one. Might have a look next time I'm in there.

Another point of interest, to me at least, are the very nice selection of slate blocks in chamber Z4. They appear to be beautifully dressed,and one is actually split, but I was under the impression this wasn’t usually done underground, but rather in the mills, so they are something of a mystery. Wonder why such apparently good blocks are still there? Perhaps a fall made it difficult to transport them out, so they were simply left. I haven't seen blocks quite like this is any other part of the workings that I have visited and would be interested to know if anyone has seen anything similar elsewhere.

Yeah, lovely blocks aren't they? Some of the best slate I've seen. Yes as you say one has been split with a big chisel, I don't know why either.

I must admit to being amazed by the extent of the chambering and levels( shown on the above mentioned plan) cut off behind the falls on floor 3

Yeah, there is quite a lot, and I'm sure in time we'll get to see some of it. The vast bulk of the workings in that mountain are inaccessible or no longer there, despite the best efforts of many to open up more ground. But - despite this, I am confident the old girl has many secrets yet, and as digging and driving skills improve, some of those old falls that have hindered our way for decades may give up there blockade.

This plan also clearly shows that the back vein chambering seems to be split into 2 sections – This may indicate the position of the drop fault, but I'm not quite sure.

Also I haven’t quite worked out what vein those small chambers not roofed though to anywhere else are in. Since they are found beyond the end of the northward heading cross-cut, and the rock looks different, they may actually be part of the true Oakeley north vein workings lying to the north of the back vein, or maybe they are just another part of the actual back vein but with different quality of rock, as the quality of the veins is certainly not uniform - Penty of examples of this is documented in the Oakeley History.

Yeah. I don't know enough of the geology to say, GI is the expert of course.

Personally I think the ones in line with lake level are Back-Vein-South-of-the-fault, the middle row of small chambers being Back-Vein-North-of-the-fault, and the separate few chambers being North Vein proper.

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Bear me, I can't say I can answer all of this at once, but I need to cross reference the two cross sections of the area to the plan and try and identify the location of the drop fault.

Please do note that the original of this plan is dated well after the Oakeley takeover of Cwmorthin in 1900, and therefore Oakeley would have access to Cwmorthin plans.

Miles, it may (or may not) indicate the final extent of work before the Upper quarry was closed - it is possible that work continued after the date of the plan but was not recorded on it. It may have been recorded on another plan, then again it may not....

More when I get a minute, the plan needs annotating on floor 3 at least so we are clear which Z4 or Z5 etc. we aretalking about!

Grahami

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Miles,many thanks for the interesting feedback

Graham, I would be very interested to see the actually position of the drop fault marked on the lost world plan. It would certainly clarify what's going on with those workings, I think

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It's probably a fair conclusion to say a major simultaneous assault on Z5 NV and BV falls is potential wasted effort, as suspected they rejoin anyway further inbye.

Miles, do you mean falls in the vicinity of chamber Z3?

Yes, looks as if at one time a round trip on floor 3 was possible,Unlikely now though 😞 but then again who knows :)

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Miles, it may (or may not) indicate the final extent of work before the Upper quarry was closed - it is possible that work continued after the date of the plan but was not recorded on it. It may have been recorded on another plan, then again it may not....

Thank you so much :thumbup:

The level in the top end of Z4 is pretty old, and there is a jwmpr in it with candles, so I'd suggest it wasn't work done after your survey, if the survey is well post 1900. Perhaps as you say, they just left out some of the detail. Wouldn't be the first time we've found levels that were not recorded on the surveys. Question is... Where does it go? Looks so close to Cwm (chamber 17?)... might have a peek on Thursday...

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Dwarrowdelf fyi, the caban; I will put some more photos up soon

[photo]104421[/photo]

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In haste - I'm getting glares from SWMBO as I type:

As a starting point, the drop fault created two clay slants in the old vein. Thus one needs a map with all three main veins on it (I'll explain why in a minute).

The cross section of chamber 32 suggests that the fault forms the north side of the floor F south level and crosses DE Floor (in solid rock) roughly half way between the north and south clay slant levels on that floor. Measuring the original tracing will help to position it.

The cross section of chamber 38 requires the original tracing measuring to try and position it.

My 1930-on New Vein plan marks the drop fault as crossing chamber 25NV and then wall 26 on floor F at the top of the roofing chaft from chamber 25NV on G. It also marks the drop fault as crossing chamber 27NV on G. The two lines are parallel. It is annoying that the equivalent Old vein plan does not mark the fault at all.

More when I can.

Grahami ::)::)::)

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So the caban is on the other side of a fall or area of broken ground, in what appears to be the other (north of fault?) BV section – in other words the “central area of workings” shown on the plan and accessed via the northerly heading cross-cut, BUT before you get to the section containing the smaller run of chambers and levels right beyond the very end of the cross-cut. (If this makes sense)

Yes, I think I remember seeing a fall in the eastward heading level at this point, but we were running out of time, so didn’t investigate it. Goes to show how features are easily missed. It therefore got missed off my trip report as well 😞 (will have a look next time)

Miles, I did however have a good look at the fall at chamber Z3 east of chamber Z4: - to avoid any confusion, the Z4 section containing those lovely slate blocks and the upper level passage in the back wall (the main point of confusion with the “lost world” area of workings is that the chambers are broken up into sections as shows clearly on the plan)
Anyway this fall looked as if it could be carefully clambered over, but we didn’t try it. Is this the one which was explored to find a further fall beyond which consequently defeated further exploration? or does your description refer to the parallel level containing the caban, which I assume has yet another fall beyond it?
Overall I think I remember seeing a total of 3 falls arranged in a very systematic manner, all in a similar position in the roughly parallel running levels, mirroring what is encountered in the Oakeley old vein on floors 1, DE F and G etc. much lower down. It almost doesn’t look as if it’s happened naturally, bringing to mind those tales I’ve heard about basting down the Cwm/Oakeley boundary in more recent years to discourage further exploration, although I don’t suppose this applies quite so much to the obscure and remote “lost world” Makes me wonder if the DE collapse is basically more or less a natural consequence of the great fall as well

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This was the centre of those 3 falls that you mention. You wouldn't have seen much if you had investigated as it was completely blocked until last month. While it is now possible to get through, it's not for the faint hearted. And if anything moves when you're in there, you're going to have a long wait.
It certainly looks like a natural fall as the rock is pretty badly shattered.

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As Willy says really, its over a fall that's only partially cleared and involves squeezing through a very tight hole with tons of loose rubble wanting to slip down. Really not recommended to try it, and all it gains is about 20 foot of tunnel and that caban, which, cute as it is, has nothing of interest in it.

The level beyond is blocked quite comprehensively from a collapsed chamber, a bit like Z3 is, and the Cwmorthin floors you mentioned that are all in a vertical line.

I'd say to anyone wanting to go poke around those falls, please don't, you won't get through without specialist skills and equipment and will be at great personal risk just trying.

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This might explain why I did'nt really notice anything here except a blocked level. I was down in October 2015.

Thanks for clarifying this, as I thought I'd overlooked a bit. Also explains why no one else with me found it either. And no, we won't do any poking so to speak. A bit wary of slate falls to be honest. They have a nasty habit of moving ;(

Just out of interest, what's beyond the other fall east of Z4 with the blocks? Much the same I believe. Can you actually see up into any part of Z3 beyond this fall by any chance?

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