From the local paper website, it appears some workers were overcome by a "gas leak" and required rescuing. Gas from a gas bottle or from the tunnel surrounds is not clear, but there has always been a good draft when I have explored in here

http://www.thisisstaffordshire.co.uk/news/Workers-rescued-gas-scare/article-264813-detail/article.html

Atypical interior shot showing some ochre formations...

Brains said:

From the local paper website, it appears some workers were overcome by a "gas leak" and required rescuing. Gas from a gas bottle or from the tunnel surrounds is not clear, but there has always been a good draft when I have explored in here

http://www.thisisstaffordshire.co.uk/news/Workers-rescued-gas-scare/article-264813-detail/article.html

Atypical interior shot showing some ochre formations...

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They chose a lousy day to go though, my barometer took a fast dive from 1000+ to below 980. My guess would be blackdamp from the associated old coalworkings and/or bubbling up from that lovely ochrey mud as they tramped through it.
No doubt they didn't believe their gas detector at first, as you can see both ends and there's usually a draft, as you say. I've found it bad in there myself on one occasion.

Apparently the HSE / Mines Insepectorate found low levels of black damp in the main tunnel, but lethal amounts in the low connected crawls leading off from the main tunnel where the ventilation is very poor. I havent noticed gas bubbling up through the ochre, but it certainly cant be ruled out ...

Dosn't supprise me, as I think I've said before, the western level has some of the best quality blackdamp I've ever encountered!!
Where did you see the HSE findings?

Can I just ask why the tabloid style topic headings in this one? It wouldn't hurt to mention the location etc. - I don't know the specific location myself but if folk are likely to descend, why not make it possible to find here via Google?

According to Brains' newspaper link:

the disused Harecastle railway tunnel in Kidsgrove

Reading the article, the guys were maintenance workers, so amybe this isn't an accesible spot to most of us- yet the fact that it happened won't hurt to be reiterated.

Shotlighter, are you 'Nigel, Kidsgrove'?

And, the possibility that 'they didn't believe their gas detectors'.... you'll have to forgive me again - do they give 'false positives'? if so how do you know when to believe them? Just before falling unconcious?

underground said:

Shotlighter, are you 'Nigel, Kidsgrove'?

And, the possibility that 'they didn't believe their gas detectors'.... you'll have to forgive me again - do they give 'false positives'? if so how do you know when to believe them? Just before falling unconcious?

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Indeed I am. I've known this site for nearly 50 yrs since when my grandad used to hold me up to watch trains emerging!
I've not been in for several years, but as I say the blackdamp from one level in particular is hideous & the sudden drop in pressure must of dragged it into the main tunnel. I really can't understand why a stopping wasn't put on it while the tunnel was still in use. The coal working (Bread & Herring or Ashwood?) must have stopped work in the early 1900s. It's a popular place for kids to go for an "adventure" but luckily the level is easily missed, as it's in the back of a manhole. Otherwise it could easily have been the site of a tragedy.
As for gas detectors, all sensors can give false +ves in the presence of other certain other gases/vapours (not usually a situation encountered in our application) but with age just stop working, so give no response at all. The exception to this is the O2 sensor (presumably the one that alarmed), which will become less sensitive to O2 as it ages & will therefore give a false -ve, which in this case is the alarm condition. This is why it is so vital to have gas detectors regularly calibrated.
Hope this makes sense, as it's late on Fri night!
I will make no comment on the training of the maintenance team, or the quality of any information that may have been given them prior to them entering the tunnel, as of course I was not privy to it.
Sorry, to answer your last point, you have to believe them - if the alarm goes goes off, you go out! If you stay it's at your own risk.

shotlighter said:

underground said:

Shotlighter, are you 'Nigel, Kidsgrove'?

And, the possibility that 'they didn't believe their gas detectors'.... you'll have to forgive me again - do they give 'false positives'? if so how do you know when to believe them? Just before falling unconscious?

Click to expand...

As for gas detectors, all sensors can give false +ves in the presence of other certain other gases/vapours (not usually a situation encountered in our application) but with age just stop working, so give no response at all. The exception to this is the O2 sensor (presumably the one that alarmed), which will become less sensitive to O2 as it ages & will therefore give a false -ve, which in this case is the alarm condition. This is why it is so vital to have gas detectors regularly calibrated.

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I'm with You on this one.
  A few years ago I was on a job that required a G.D., the one supplied by the site looked old and a bit battered, and like it hadn't been out of the cupboard in years. New batteries, and I switched it on. It instantly went potty, indicating imminent death, which was a worry, as We were out in the open, in a field, it was a "breezy" day, and the Manhole cover hadn't even been lifted, let alone entered.
Also, My Refrigerant leak sniffer had to have it's sensor head replaced once a year, as then tend to "die" after about 18 months of use.

underground said:

And, the possibility that 'they didn't believe their gas detectors'.... you'll have to forgive me again - do they give 'false positives'?

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Mine used to go bananas if I farted!

Apparently all work is now finished at this site till next time.
Went to have a quick look the other day and a new access road has been put into the southern end with new gates to allow vehicle access. Inside there is little evidence of work being done other than a few small patches of pointing and the drainage pits being dug out. The ochre banks on the floor have been driven through, but the ocherous stals and formations are otherwise undamaged. There was a more than good breeze blowing through the tunnel (flippin cold!), and no trace of bad air BUT the open coal drifts and the cleared pits were not entered.
We did find amongst the undisturbed balast a patch of "TunnelPearls!" These were a little sooty...

And of course some ochre


The only evidence of the place being unhealthy was a dead squirel that must have run up the tunnel when the portal was being worked on. A bit beyond CPR?

Brains said:

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I know its dead but still a little unfair to stick your finger up its arse!!! 

shotlighter said:

Sorry, to answer your last point, you have to believe them - if the alarm goes goes off, you go out! If you stay it's at your own risk.

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Damn right!!! It may be a false positive but why take the risk?

Hatstand said:

I know its dead but still a little unfair to stick your finger up its arse!!! 

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JD's hand is only there for scale, well mainly, he does have an aversion to tree rats, as does his dog since being bitten. His sense of humour is a little, different, shall we say?
Besides we couldnt flick its eye balls as the ultimate "field test" of being dead - they had gone - so we had to make sure it wasnt just resting after a long sqwark...

We investigated this side heading on 26/10/90 and arrived at a tunnel running at around 90 degrees to the other 3 tunnels at about the same level as the 2 canal tunnels. Driven out by very poor air. After some discussion with 'shotlighter' I'm fairly certain that we had investigated this tunnel.

From Wiki:
"There was coal mining on a small scale in the 1700s. James Brindley, builder of the Harecastle Tunnel in the 1770s, built a branch canal from the tunnel to an underground wharf of a colliery in Goldenhill in which he had a share;"