I thought I had better share a thank god I've got the meter experience I had last week in Blackett level.
We went down Studdon Dene shaft with a view to having a look inbye as far as we could get and then heading out to the level entrance.
Oxygen level at shaft bottom was pretty much the same as at surface, ~20.9%. Heading inbye, walking in flowing water and in a large clear level, after about 200m the alarm went off at an Oxygen level of 16.5%, a further 50m or so further along, at the start of the arching, the level had dropped to 14%. Because it was easy walking no-one was showing signs of heavy breathing and it was only when walking out that we noticed that the air smelt different.

Assuming the rate of Oxygen depletion carried on at the same rate, without a meter we could have been in very serious trouble before we knew about it.

Be warned...

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What meter did you settle on - could you post a review in a new thread?

Whats the strata like down there? Also is there not lots of rotting wood Nick - I seem to remember that from someone. Eats O2 up if that is the case, shale also tends to oxidise and deplete O2. But then again might not be these things.

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Did you allow time to re calibrate the meter as that sort of descent readings would read very different at surface.

Mike

Meter is a BW Technologies Gas Alert Extreme. BW are part of Honeywell.

Meter had plenty of time to stabilise and going down, the reading would tend to go up (if the percentage is the same)as you descend until the meter stabilises. The shaft is only 30m or so deep anyway.
Reading went back to 20.9% when we returned to the shaft bottom and stayed there all the way to the entrance.

IIRC the strata was limestone at that point, plenty of rotting timber at shaft bottom but not a great deal inbye. Apparently the level is blocked not far inbye from where we got to, no doubt with shale and timber present.
My thought is that the turbulence from the air flow down the shaft turning into the level doesn't get very far along the level inbye so it the Oxygen isn't being replenished.

My significant point is that just because there isn't an obvious obstruction and you aren't out of breath doesn't necessarily mean that the air is good.

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On the note of bad air, the first time I went down the Brewery Shaft, 3 of us headed upstream to the final fall. I was 1st and thought the air was OK, the other 2 a little bit behind had been complaining for a bit saying it was iffy. I was thinking nancey boys, shut up. At the fall a lighter failed to light, matches smoldered....

Why did I not feel it? Less sensitive? Did I get the best of the air by being 1st breathing it - would that have made such a difference?

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was that you Friday then was talking to some people out for a walk at the leadmill site and they were saying the could here voices and see lights down the level :lol: when they were walking past

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"Bad air" is something that we all need an understanding of. I wonder if NAMHO would consider running a seminar /workshop on the subject?

I was 1st and thought the air was OK, the other 2 a little bit behind had been complaining for a bit saying it was iffy.

Too many variables, were you fitter, taller, shorter and did any of you smoke?

Why did I not feel it? Less sensitive? Did I get the best of the air by being 1st breathing it - would that have made such a difference?

In still conditions CO2 can form a layer at floor level.
By walking through this layer you disturbed it causing the following people to feel the effect.

Why did I not feel it? Less sensitive? Did I get the best of the air by being 1st breathing it - would that have made such a difference?

In still conditions CO2 can form a layer at floor level.
By walking through this layer you disturbed it causing the following people to feel the effect.

Ahhhh

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was that you Friday then was talking to some people out for a walk at the leadmill site and they were saying the could here voices and see lights down the level :lol: when they were walking past

That was indeed us - we saw them as well, unfortunately they had disappeared when we could have done with someone to take the group photo.

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A bizarre fetish?

Well no, and on a more serious note as Prince says, we are all different.

I have a tendency to get out of breath sometimes in my 'other hobby', freestyle fighting or 'serious' kata in particular, and have been giving the matter a lot of thought.

I think that when we need more oxygen and breath faster, this often results in taking shallower breaths, so about half of the air we take in isn't doing anything. A bit like a poorly adjusted SRT setup, up 12 inches and fall back 6.

I force myself to take deeper breaths, and the 'reprogramming' is starting to stick.

We are indeed all different.
This is what makes us interesting to each other and gives us things to talk about.

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A bizarre fetish?

I force myself to take deeper breaths, and the 'reprogramming' is starting to stick.

Ahhh Daniel Son, breathe in, breathe out. Karimaska.

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The medical data regarding lung function vs age explains another angle, well worth a Google.

Just a suggestion, you could try using a pulse oximeter (about £30 from Boots etc) on your finger to see how your blood oxygen level or "SATs" is doing. Should be about 98% for healthy people. 100% is saturation. I average about 95% because my health is not good.

If it goes below about 88% you need to take urgent and immediate action, deep breathing to get as much oxygen as is available into the bloodstream, and/or some oxygen gas from somewhere. At somewhere not far below 85% you are in very serious trouble indeed.

I have a suggestion for a portable oxygen supply too. Some airliners, notably those designed by cowboys, such as the DC-10, don't carry around a bank of oxygen cylinders, like the 777 that had one rupture in flight a while back. Instead they use a canister containing sodium chlorate, and a heat source, something combustible, which is triggered when you pull the mask out of its storage. Now you would not want to drag an oxygen cylinder around old mines, but a small chemical oxygen generator may be feasible. But be warned, they get very hot in use and at least one plane crashed because a crate of them went off in the cargo bay. Might be better to use an electrical heating element and a reliable battery to make the thing go. It need not be able to contain significant pressure, so can be quite lightweight. Someone will probably be along to tell me that you can get such things already...

But all of this is for use in the immediate aftermath of feeling a lack of oxygen. You really should avoid getting into that situation, by testing the air frequently. I am told that a good old fashioned miner's safety lamp, properly set up and used, is adequate. It has three functions in one, provides some useful amount of light, warns of low oxygen level, and warns of inflammable gas. Self-monitoring too, if the flame is burning, it is working, not like some electronic thing that may silently die unless very carefully designed by experts.

Further to that suggestion, it would be quite reasonable for every home to have a pulse oximeter and a blood pressure tester, as well as a thermometer, and use them regularly. They don't hurt at all or cost much to run, and they can provide health warnings that may save lives.

I am told that a good old fashioned miner's safety lamp, properly set up and used, is adequate. It has three functions in one, provides some useful amount of light, warns of low oxygen level, and warns of inflammable gas. Self-monitoring too, if the flame is burning, it is working, not like some electronic thing that may silently die unless very carefully designed by experts.

I've used flame lamps for years, ok but several major drawbacks.
Progress can be slow as you have to constantly monitor the flame and retreat to the last 'good air' position to re-light.
They are very susceptible to any knocks when adjusted to a gas test flame.
They are a pain when one lowers it down a shaft and retrieve to find it's out, high gas/low O2????

On the plus side they are cheap at around £30 for an unused Protector Type 6.

I am told that a good old fashioned miner's safety lamp, properly set up and used, is adequate. It has three functions in one, provides some useful amount of light, warns of low oxygen level, and warns of inflammable gas. Self-monitoring too, if the flame is burning, it is working, not like some electronic thing that may silently die unless very carefully designed by experts.

I've used flame lamps for years, ok but several major drawbacks.
Progress can be slow as you have to constantly monitor the flame and retreat to the last 'good air' position to re-light.
They are very susceptible to any knocks when adjusted to a gas test flame.
They are a pain when one lowers it down a shaft and retrieve to find it's out, high gas/low O2????

On the plus side they are cheap at around £30 for an unused Protector Type 6.

I think I paid about £30 for my ex BT Wolf FS. I bought this specifically to use, however all it has done so far is to sit on my mantelpiece gathering dust.

First lamp i bought was through a NCB mate, stamped 1976 for something like £16, the last one was stamped 1985 and had never been lit, took about a week to get it open due to Brasso and lacquer ingress.;D