Cuckoo Cleeves Closed

[Aubrey]

A Wessex party visited Cuckoo Cleeves last night with Nick Williams gas tester to check the reports of bad air in the cave.
Our intention was to record the level of oxygen (and by deduction the level of carbon dioxide) at various points in the cave.
The tester showed an oxygen level of 20.9% at waist level near the entrance of the cave. Ominously the analyser started bleeping a warning at ground level near the entrance pipes.
We aborted the trip about 10m inside the entrance with an indicated oxygen level of 15.0%. Breathing was difficult.
These readings suggest there is a safety issue and we have therefore closed the cave pending discussions with the owner.

 

[graham]

Ouch!

I bet we have problems elsewhere in the next day or two.

 

[Hatstand]

Hatstand hopes the batteries for the gas tester run out very quickly and replacements are ludicrously difficult to source...  :spank:

 

[dpegg]

This may be opening a can of worms, but where does the bad air in cuckoo come from? Last time I went in there I didn't see any organic material lying around and the diffusion rate out of limestone must be very slow  .

 

[Clive G]

Hatstand hopes the batteries for the gas tester run out very quickly and replacements are ludicrously difficult to source...   :spank:

"Hand-held and fixed-point oxygen meters use electrochemical cells and are calibrated in terms of percentage of oxygen by volume."

However, if the meter has not been calibrated at the prescribed interval (at a cost of around ?100) then the results are not going to be reliable. If someone breathes into the sensor or the sensor is held too close to loose clothing or you have 2 or 3 people close together in a confined space, where there is no strong draught, then the alarm could sound prematurely without there necessarily being a dangerous deficiency in the oxygen level.

Approved instruments in a satisfactory form for reliable underground use measure methane, carbon monoxide, oxygen, products of combustion. temperature, pressure and air velocity. As far as I understand there are no approved transducers for carbon dioxide. "In fire situations, the readings from the current range of carbon monoxide transducers may not agree with laboratory analysis results because of a degree of cross-sensitivity to other fire gasses, such as hydrogen."

What you need to be very careful about is whether explosives have been used in this particular cave by persons known or unknown, because such a situation, in the case of poor ventillation, can prove fatal in certain instances - especially where there is a proximity of a large quantity of water (such as a lake or sump), which seems to magnify the toxicity of harmful gasses and carbon monoxide. (See 'Blasting fumes kill two cavers in Yorkshire accident', Descent No. 44, pp 4?5.) In dry passages, where there is some ventillation and only small quantities of explosives have been used then you may just experience headaches and nausea - but otherwise survive.

In the case of oxygen or rather oxygen deficiency - the gas we all need a regular supply of to keep our metabolism running - the standard concentration and effects for reduced levels are given as follows:

OXYGEN
20.93%  -  normal proportion in fresh air.
17-14%  -  safety lamp flame will go out at some point within this range
13%       -  work is difficult; breathing becomes rapid and lips blue;
                nausea and headache develop slowly and may become severe.
11-8%    -  exertion leads to unconsciousness.
<6%       -  rapid unconsciousness and death.

And for:

CARBON MONOXIDE
0.02%     -  headache after about seven hours if resting, or two hours if working.
0.04%     -  headache and discomfort with possibility of collapse
                 after two hours at rest, or 45 minutes exertion.
0.12%     -  palpitation after 30 minutes at rest, or 10 minutes exertion.
0.20%     -  unconsciousness after 30 minutes at rest, or 10 minutes exertion.

CARBON DIOXIDE
0.50%     -  lung ventillation slightly increased.
3%         -  breathing difficulty and slight headache.
10%       -  headache, visual disturbance, palpitation, breathing difficulty
                after one minute, followed by unconsciousness.
(constituent of 'Blackdamp')

I think if people start swapping practical awareness of the symptoms of depleted oxygen levels (usually as a result of increased carbon dioxide levels) in limestone caves, followed by consequent rapid evacuation to a better ventillated area, for running around with multi-gas detectors - then we'll probably end up seeing several caves being 'closed' for fear that they are 'unsafe'. This will lead to cavers assuming that caves which are not closed are therefore 'safe' and a consequent liability will be inherited by those responsible for carrying out and making pronouncements on multi-gas detector tests - which will, as a result, have to be carried out at regular intervals, everywhere - when we all know that caves are potentially dangerous places and they should be approached with the caution and care that they deserve.

Read the guidebooks, check the chat columns, call in at the most local caving shop or caving club and remain alert at all times. Don't leave fear behind, but if you end up finding it becomes your main companion, then go and try some other activity instead. Where you find others trying to instill fear into you look very carefully into the reasoning and motivation behind their actions and act accordingly. And don't confuse 'fear' with a reasoned sensible warning, based on practical experience.

 

[graham]

Clive, do you seriously think that, of all people, Mr Williams will have not done this properly?

 

[Goydenman]

Excellent information and advise Clive.
When I used to run confined spaces training courses we used to get the detectors going off in the classroom on many occasions. Numerous people in a room without a window open and hey presto dips below 19% beep-beep. Bit embarrassing  :-[

As Clive says risks of gases in caves can be handled by simple practical actions like 'rapid evacuation to well ventillated area' and guarding against entry when/after using explosives. Otherwise we could end up with again as Clive says 'gas detection carried out at regular inetrvals everywhere' and that would be a nightmare for the caving community.

Some types of mines though are different in my view since they can contain some very nasty gases and rapid evacuation would not be possible before being overcome.

 

[Clive G]

Excellent information and advise Clive.
When I used to run confined spaces training courses we used to get the detectors going off in the classroom on many occasions. Numerous people in a room without a window open and hey presto dips below 19% beep-beep. Bit embarrassing  :-[

As Clive says risks of gases in caves can be handled by simple practical actions like 'rapid evacuation to well ventillated area' and guarding against entry when/after using explosives. Otherwise we could end up with again as Clive says 'gas detection carried out at regular inetrvals everywhere' and that would be a nightmare for the caving community.

Some types of mines though are different in my view since they can contain some very nasty gases and rapid evacuation would not be possible before being overcome.

Many thanks for the response to my posting. I agree 100% with the observation that mines (as opposed to limestone caves, which I specifically indicated in my piece) are a completely different case and I should have emphasised that my remarks are not intended to cover mines as well as caves.  Elsewhere in another thread on UKCaving some people seem to view mines as potentially being a 'softer option' to caving for beginners - which, of course, they are anything but such!

 

[whitelackington]

Why does Cuckoo keep getting bad air.
I go there very rarely but have never known the air good.

 

[cap n chris]

Bueller, Bueller?...

I guess it is a possibility that no-one knows the answer but p'raps there's no harm asking nonetheless.

 

[MSD]

Oxygen meters are used all the time by technical divers (since they use gases with various percentage oxygen content, they need to be able to check that the contents of a cylinder are what it says on the label). Checking that the meter is working correctly is quite simple. Check that it reads 21 (rounding to the nearest whole number) for fresh air, 100 for a cylinder of pure oxygen and 0 for a cylinder of something containing no oxygen (like pure helium). That procedure does NOT cost 100 pounds. Of course if you want to be sure of the accuracy of your reading to three or more significant figures a more accurate calibration procedure is needed, but to get a reading accurate enough to give a general indication of a possible safety risk the simpler procedure is perfectly adequate.

I'm also quite sure that Nick knows what he is doing.

Mark

 

[nickwilliams]

1. The meter concerned is in calibration.

2. There are a variety of meters available for this type of analysis, from a range of manufacturers. The choice of which meter to use is a matter for the user and there is no requirement for independent approval of any kind. Even where the meter is sold as being suitable for use in a flammable atmosphere (which happens to be the case with the meter used for these tests) the requirement for independent approval extends only to the measures taken to prevent an accidental ignition of the atmosphere in which it is used, and not to the gas analysis function itself. I am confident that the meter is an appropriate piece of equipment for the job it was being used for and that the people who were using it knew enough about what they were doing for the readings to be valid.

3. The issue of closure if the cave and the possible impact on other caves locally is a matter for the CSCC and I do not intend to comment on it here.

Nick.

 

[Aubrey]

Clive wrote:
"What you need to be very careful about is whether explosives have been used in this particular cave by persons known or unknown"

From the vegetation in the depression it was obvious that no one had visited the cave for some time. Also, I am fairly sure I would have heard through the grapevine is someone was banging in Cuckoo.

Cuckoo is generally considered to be a suitable trip for beginners and our main concern is for parties who may not be very experienced and also are not aware of any potential bad air problem in the cave.

This bad air experience, and the other threads on this forum about draughts in caves highlights our lack of knowledge about air movements underground. To study these we need some way of detecting and monitoring very slow air movements. There are theories about how the CO2 will sink downwards in a cave, but these would suggest that the air would not be as bad at higher levels and that the further down you go the higher the concentration of the gas. We know this is not always the case.

In the late 1960's and 1970 we were digging and banging at the bottom of Cuckoo and did not experience any problems with the air. The bang fumes always cleared between trips which were frequently both mid week and at weekends. There were later reports that the Radon testers found high levels of that gas in some parts of the cave, which does suggest that there was limited air movement where they found the Radon. The only possible explanation I can suggest for these facts is that there is a localised air circulation at the bottom of the cave which is separate from the main passage.

We suspect that the lid on the cave entrance is restricting the airflow in the upper parts of the cave and contributing to the bad air problem. There is no obvious rotting vegetation in the cave to be generating the CO2.

 

[matty007d]

Hope the air doesn't take too long to clear. Lake Passage has been on my to-do list for a while. 
I'm guessing the air down the there would be worse than that recorded nearer the surface?

 

[whitelackington]

If Cuckoo Cleaves suffers bad air and that bad air is caused by bovine waste
collecting in the cave's entrance hollow and dripping down to be consumed by bacteria, there may be a way to thwart it.
Extend the entrance pipe up and fill in the entrance hollow, mounding earth up like a mini Glastonbury Tor,
bovine waste may not then accumulate at the cave entrance.

 

[Les W]

We suspect that the lid on the cave entrance is restricting the airflow in the upper parts of the cave and contributing to the bad air problem. There is no obvious rotting vegetation in the cave to be generating the CO2.

A closed cave lid will not account for the low O2 levels before you entered the cave though, so I suspect this is a more general problem with low lying areas. The fact that the O2 was depleted before you even got into the cave suggests that the problem is derived at ground level and the inferred increased CO2 has collected at the lower areas.

What was the condition of the field? Has the grass just been cut? Sileage or hay? The last few days have been a real mad dash in this area to get hay and crops in before the forecast bad weather. I believe cutting grass and crops promotes growth with increased production of CO2 as a by product of growth. I am not aware of any research in this area but there is defiantly circumstantial evidence for this seasonal event.

Yesterday was also very hot with still air, ideal weather for the settling of gasses in low areas. Will you go back now it has rained with the windy weather we now have? At the very least it would be good to get a result soon to compare.

On another note, who made the decision to close the cave? As CSCC's access officer I would have at least expected a courtesy call.  :-\

 

[Aubrey]

We suspect that the lid on the cave entrance is restricting the airflow in the upper parts of the cave and contributing to the bad air problem. There is no obvious rotting vegetation in the cave to be generating the CO2.

A closed cave lid will not account for the low O2 levels before you entered the cave though, so I suspect this is a more general problem with low lying areas. The fact that the O2 was depleted before you even got into the cave suggests that the problem is derived at ground level and the inferred increased CO2 has collected at the lower areas.

What was the condition of the field? Has the grass just been cut? Sileage or hay? The last few days have been a real mad dash in this area to get hay and crops in before the forecast bad weather. I believe cutting grass and crops promotes growth with increased production of CO2 as a by product of growth. I am not aware of any research in this area but there is defiantly circumstantial evidence for this seasonal event.

Yesterday was also very hot with still air, ideal weather for the settling of gasses in low areas. Will you go back now it has rained with the windy weather we now have? At the very least it would be good to get a result soon to compare.

On another note, who made the decision to close the cave? As CSCC's access officer I would have at least expected a courtesy call.  :-\

1. I think the poor air at the entrance may have been CO2 coming out of the cave after it was opened and laying below the level of the pipe. The analyser was within a few inches of the pipe when it bleeped.

2. The grass had not been cut - it was long enough for the dew dampened grass to clean the mud off our boots.

3. My theory about the coincidence of grass cutting and high CO2 is that the grass is usually cut in good weather and good weather is more common when the atmospheric pressure is high. High pressure may therefore be the relevent parameter.

4. The air was not still - it was quite windy yesterday. There was also low cloud which was shown by the lights of the Pen Hill Mast being visible or covered at frequent intervals as we walked across the fields.

5. Les, we came to look for you at the HE store (where we were told you should have been). I Emailed you this morning.

 

[Les W]

Thank you for those clarifications Aubrey

I acknowledge receipt of your email which was unfortunatly received in my inbox after I left for work. (I can't get my personal emails from work) 

What do you propose as a way forward now?

I don't think we should start generally measuring the air in caves, as that is a very large can of worms.
I also don't think we should be closing caves, if we start down that route we will end up closing half of Mendip's underground every summer! 
I have spoken with the land owner, who advises me that he has totally devolved all access control to CSCC and it is up to them what is done.
He did say that he was not in favour of closing the cave but that it was up to CSCC.
He suggested that a notice at the entrance would be a good thing, telling of the findings i.e. Low oxygen levels were measured recently in this cave, you are advised to take care, etc.

I will be speaking to the rest of the Officers of CSCC tonight, but am open to suggestions on peoples opinions. 

Do you still have Nicks Meter? It would defiantly be worth another measurement now after the weather change, can you get there this evening?

On another note, the land owner has asked that if you have the meter for any length of time, that you try a few measurements with the lid removed for a period of time (e.g. a day or two) to see if this makes any difference (as the depression is fully enclosed by a very fine fence, a couple of signs notifying the open shaft will be all that is needed to discharge any liabilities). This will help him make a decision on whether the lid should be modified.

Les Williams CSCC C&A Officer

 

[graham]

I don't think we should start generally measuring the air in caves, as that is a very large can of worms.
I also don't think we should be closing caves, if we start down that route we will end up closing half of Mendip's underground every summer!

Les, speaking as somebody who closed a cave a couple of summers back for this very reason, I think you need to think very carefully about this. If a cave is dangerous - especially in a way that is not immediately obvious to visitors then it is CSCC's duty to keep both landowners and cavers as well informed as we can. Had this been a cave with an entrance pitch that was normally abseiled then we might already have a death on our hands. Each and every rumour of this should be taken seriously, checked out and appropriate advice given.

That is, after all, is surely what CSCC is for.

 

[Les W]

I don't disagree with what you say Graham but we really should be aiming for a situation where we have an "informed" caving community with the decisions on entry being theirs.

I don't have the time to debate this further as I am just off out to measure the air in a local cave...

I will return to this debate later, suffice to say there is quite a lot going on behind the scenes at the moment and Cuckoo Cleeves will remain closed for the moment.