Author Topic: Gleision Mine Disaster  (Read 1556 times)

Offline legendrider

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Gleision Mine Disaster
« on: September 15, 2021, 01:35:25 pm »
BBC are showing a documentary about this tragic event at 8pm tonight 15/9/21 on BBC1 Wales

Also available on I-Player for rest of UK.

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Offline mikem

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Re: Gleision Mine Disaster
« Reply #1 on: September 15, 2021, 08:23:27 pm »
On now (8 to 9pm)

Online Tomferry

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Re: Gleision Mine Disaster
« Reply #2 on: September 16, 2021, 07:42:25 am »
I watched it very interesting, I personally cannot believe they have escaped without going to prison ,with so many people claiming to of seen illegal workings it shocks me that they did not clear up some of the mess inside to re survey the mine and then continue the trial .

Offline sinker

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Re: Gleision Mine Disaster
« Reply #3 on: September 16, 2021, 10:01:07 am »
I watched it very interesting, I personally cannot believe they have escaped without going to prison ,with so many people claiming to of seen illegal workings it shocks me that they did not clear up some of the mess inside to re survey the mine and then continue the trial .

Like most things in life, it's never as straightforward as it first appears.
There were failings all round but a lot of what happened leading up to the final event was done with the best of intentions.

A tragedy happened but it would be difficult to nail anyone to a tree for it and what good would it serve. Lives had been lost, lives had been destroyed, the owners had been through hell, nothing would ever be the same for any of them.

Worst mining disaster in Wales in a generation and all because a few people wanted to earn a living and keep a tradition alive.

Truth is the place should never have been operating in the first place, at least not in the manner it was.

Ah, well, now, you see...erm...

Offline sinker

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Re: Gleision Mine Disaster
« Reply #4 on: September 16, 2021, 10:22:12 am »

Link to the HSE report.

http://www.mineaccidents.com.au/uploads/gleison-colliery-inrush-report.pdf

The HSE investigated thoroughly but sympathetically; its definitely one of the better reports I've read.
Obviously it assumes some knowledge of the working method; small scale and outdated drill / blast / hand-loading / propping / back-filling etc but its a very interesting read.
Read that report....and then imagine you are the Owner, Mine Manager or Surveyor looking after that lot.
The complexity along with the million and one things you have to think about was the ultimate cause of the accident.

Ah, well, now, you see...erm...

Offline rhychydwr1

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Re: Gleision Mine Disaster
« Reply #5 on: September 16, 2021, 11:07:50 am »
Just watched it.   Easy to be wise after the event.  I would have left the mine BEFORE setting off the charge.  The whole mine looked shaky.


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Re: Gleision Mine Disaster
« Reply #6 on: September 17, 2021, 07:55:43 am »
Just watched it.   Easy to be wise after the event.  I would have left the mine BEFORE setting off the charge.  The whole mine looked shaky.

I agree to have that much supports installed in such a tight span they only looked 2ft-4ft gaps in the roof support system, I don’t no the local geology but makes me wonder was they driving the heading through clay or mudstone ? The real photos that was shown in the end look very bad what got washed in lots of silt from them old workings makes me thing the geology was also against them .

Offline Cantclimbtom

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Re: Gleision Mine Disaster
« Reply #8 on: September 17, 2021, 09:17:59 am »
Thanks Tom shall have a read when got time  :thumbsup:

Offline The_Bogieman

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Re: Gleision Mine Disaster
« Reply #9 on: September 17, 2021, 11:10:53 am »
I watched it then read the HSE report. TBH, looking at the pictures from both the TV report and the HSE report, being a mine explorer, I would have looked in that entrance adit and run away! Being mainly into slate mines, I view chambers where pillar robbing has taken place with great suspicion before deciding whether to go in - you won't find me in certain chambers in Cwmorthin for instance 8E OV for one!)
However, they were supposed experienced miners so dug it to scratch a living. It seems the mine plan was reasonably accurate - except it didn't show the illegal workings but these were stated by HSE to not have caused the tragedy. It seems that where the mine plan failed was that the old workings were shown to have been 7m nearer where they were digging that stall and that they hadn't used the long test drill searching for old workings / water before that last blast. They had previously used the long test drill as it was found in the debris but no sign of it being used for that last pattern... And they paid the price, 2500 - 3000 Te of water rushed in through the hole...
The survivors, including the manager, will have to live with what happened for the rest of their lives.

Offline Graigwen

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Re: Gleision Mine Disaster
« Reply #10 on: September 17, 2021, 11:59:39 am »
I have not seen the programme but have read the report. I think the report gives a comprehensive and convincing analysis of what happened, apart of course for the few minutes before the inrush for which no direct evidence is available. (What is missing is the mine managers account.)

The strategic aim of driving up dip to connect with old workings in order to form a circuit to improve ventilation was justified, as evidenced by airflow after the accident. The tactical failure to appreciate how proximate the danger from standing water in old workings was is unexplained. The investigation noted (para 74) that old workings extended down dip 7m further than indicated on the plan available to the miners, but concluded that this "had no bearing on the incident" (para 163). This conclusion was reached because there was some evidence that advance drilling had been used in an attempt to detect the old flooded workings.

The question then becomes, why did the advanced drilling fail to detect just how close work was getting to the flooded workings? The report does not answer this question because the evidence was not there. We are left with a range of possible alternatives and no basis fror knowing which were relevantL

Was the advance drilling insufficient or badly conducted?
Were the results of advanced drilling misinterpreted?
Did the advance drilling, purely by chance, go into solid rock when flooded voids were alongside the drill hole closer to the new work?
Were the last couple of metres of rock between the old and new work abnormally and unpredictably mechanically weak?

A statement at para 113 "Also, a statement from a worker who had been in the stall the day before the accident described water running into the stall through an advance borehole ‘...like a tap half turned on’. " This suggests an awareness of the presence of water nearby and a prudent approach.

The destruction of the section of face that failed prevents the final two possibilitiies listed being discovered by forensic analysis after the event. This is why the Lessons Learned section of the report is so weak. You can't learn lessons if you don't know exactly why the event occured in the way it did.


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Re: Gleision Mine Disaster
« Reply #11 on: September 17, 2021, 12:27:45 pm »
I watched it then read the HSE report. TBH, looking at the pictures from both the TV report and the HSE report, being a mine explorer, I would have looked in that entrance adit and run away! Being mainly into slate mines, I view chambers where pillar robbing has taken place with great suspicion before deciding whether to go in - you won't find me in certain chambers in Cwmorthin for instance 8E OV for one!)
However, they were supposed experienced miners so dug it to scratch a living. It seems the mine plan was reasonably accurate - except it didn't show the illegal workings but these were stated by HSE to not have caused the tragedy. It seems that where the mine plan failed was that the old workings were shown to have been 7m nearer where they were digging that stall and that they hadn't used the long test drill searching for old workings / water before that last blast. They had previously used the long test drill as it was found in the debris but no sign of it being used for that last pattern... And they paid the price, 2500 - 3000 Te of water rushed in through the hole...
The survivors, including the manager, will have to live with what happened for the rest of their lives.

Pillar robbing is not the end of the world if the cogs have been installed properly ie notched and Infilled, this  obviously varies greatly with what strata your driving through  if the ribs are also left in this is a major benefit it’s much better all being left in , I have read up about pillars exploding under pressure that sounds scary ! And floors erupting upwards just as bad !

Offline sinker

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Re: Gleision Mine Disaster
« Reply #12 on: September 17, 2021, 02:00:49 pm »

And floors erupting upwards....


At Point of Ayr colliery you could walk out to the face at the start of your shift and *just* reach up and touch the roof.
End of the shift walking back your head could be bumping the same roof!  :o


Ah, well, now, you see...erm...

Online Tomferry

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Re: Gleision Mine Disaster
« Reply #13 on: September 17, 2021, 02:17:37 pm »

And floors erupting upwards....


At Point of Ayr colliery you could walk out to the face at the start of your shift and *just* reach up and touch the roof.
End of the shift walking back your head could be bumping the same roof!  :o

That does not sound good ! I got a large collection of ncb books I won of of eBay the amount of detail inside of them covers everything it’s truly mind blowing,  I estimate probably 70 books! The Tesco’s food boxes your delivery come in 3 of them full to read   :o

Offline Cantclimbtom

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Re: Gleision Mine Disaster
« Reply #14 on: September 17, 2021, 02:46:25 pm »
Maybe as a non mining engineer and not familiar with every fact that I am seeing it simplistically.

A previous mine surveyor quit because he felt he was obstructed in being able to survey the mine accurately
There were illegal workings including close to old working
The place was in a shocking condition for access and safe egress
There was an account before the fatal blast that one hole was spouting water (as Graigwen earlier quoted para 113)
The mine manager supervised the charging and blasting of the coal anyway

That has to be bad judgment in an environment full of shortcuts. I just can't see it as a freak/unlucky accident.
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Offline Roger W

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Re: Gleision Mine Disaster
« Reply #15 on: September 17, 2021, 03:15:49 pm »
Am I right in understanding that they were pushing their tunnel uphill towards old workings in a "wet" area that could have contained - and in fact did contain - a considerable quantity of water that would undoubtedly flow into their tunnel when they broke through? 

They may well have been expecting this to happen, but thought they had a margin of safety that they didn't have with the  - was it 7 metres? - error between where they thought the old workings were and where they actually were.

I can't help feeling they should have been a bit more prepared for what happened.  Mind you, hindsight is a wonderful thing.
"That, of course, is the dangerous part about caves:  you don't know how far they go back, sometimes... or what is waiting for you inside."   JRR Tolkein: "The Hobbit"

Offline rjw

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Re: Gleision Mine Disaster
« Reply #16 on: September 18, 2021, 04:33:51 pm »
Am I right in understanding that they were pushing their tunnel uphill towards old workings in a "wet" area that could have contained - and in fact did contain - a considerable quantity of water that would undoubtedly flow into their tunnel when they broke through?

They were working up to the 1984 workings to improve ventilation to the H1 heading. The 1984 workings were accessible and the mine manager says he inspected them on the day prior to the inrush and they were dry. Or at least only had water "ponding" against the coal. His description was held to be consistent with the amount of water that came out of the advance drilling. "Like a tap turned half on".

If this was the case, then the 1984 workings must have flooded overnight before the blasting and inrush the next day. Mechanisms by which this could have happened existed in the mine eg pillar collapses displacing large amounts of water, debris dams giving way etc.

His account was held to be credible i.e. it could have happened.

Lots of detailed info here:

https://static1.squarespace.com/static/54199a46e4b05afa19b4e68c/t/589073e0d2b8574821aa8635/1485862009266/Cobb+176-193.pdf
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Offline Roger W

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Re: Gleision Mine Disaster
« Reply #17 on: September 18, 2021, 05:40:34 pm »
That's a very interesting link. Thanks.

It does raise the question, though - if mine workings like that can flood overnight, should more care/precautions have been taken as they dug towards the old workings?

The jury evidently thought that the precautions taken were all that could have reasonably been expected.
"That, of course, is the dangerous part about caves:  you don't know how far they go back, sometimes... or what is waiting for you inside."   JRR Tolkein: "The Hobbit"

Online Tomferry

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Re: Gleision Mine Disaster
« Reply #18 on: September 18, 2021, 06:32:13 pm »
Now that changes things  taking that into account surly the weather history record’s would show some serious rain on that day like flash flood weather, to fill x cubic meters of previous air space?

Offline mikem

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Re: Gleision Mine Disaster
« Reply #19 on: September 18, 2021, 08:45:02 pm »
Not if something had collapsed overnight, moving water from one place to another, or the blast disturbed other unrecorded workings nearby.

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Re: Gleision Mine Disaster
« Reply #20 on: September 19, 2021, 05:22:46 am »
Not if something had collapsed overnight, moving water from one place to another, or the blast disturbed other unrecorded workings nearby.

I don’t think it could have Mike due to this being a drift mine I suspect  all the mines here where on a set gradient for example 1-7 they would all follow the same seam or deeper ones .


Offline Graigwen

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Re: Gleision Mine Disaster
« Reply #21 on: September 19, 2021, 08:37:34 am »
When discussing this furher we need to remember that Cobb was an expert witness for the defence at the trial of the mine manager and mine company. Most of what he wrote was high quality factual detail.

It was part of his job to float possible explanations that the 1984 workings might, just by incredible chance, have filled with water a few hours before the blast that caused the breach. Put yourself in the place of the jury. Would you be able to say beyond reasonable doubt that such an event did not occur? I don't think so - although personally I don't find his arguments for this sudden flooding very convincing, but they are not completely implausible. He is just putting the case for what might have occurred, introducing doubt is part of his job

For what it is worth I thought about what the jury would have done if the mine manager's evidence had instead been along the lines of "I looked at the flooded 1984 workings and found no more water than usual ponded there. I thought it safe to proceed with cautious advance drilling". I don't think he would have been convicted without further evidence.

Incidentally, the "Like a tap turned half on" of water coming out of an earlier advance drill hole should not be interpreted as evidence that the 1984 workings were not flooded at that time. There is no suggestion that the hole reached the 1984 workings. If you are drilling a few metres in front of you, holing through into a void will be immediately noticeable. That hole terminated in coal/rock and was just a warning that some water was around.

In answer to Tom Ferry's point about the weather before the accident, Cobb did consider this. He said "The rainfall the day before the incident was only 0.4mm.  It is highly unlikely that the inflow from rainfall would have been high enough to cause the flood.".

Sometimes we have to accept that full evidence will never be available.

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Re: Gleision Mine Disaster
« Reply #22 on: September 19, 2021, 06:31:58 pm »
Agreed it is very hard to say without more first hand accounts which is the critical information that is missing . I can see why family members further down the line are pressing on another investigation , my personal opinion is though I don’t believe a true answer is their now, I think the manager knows exactly what happened if he is wrong he will never say and to finally seal the fate the only other evidence is with miners who are the fatalities. I do believe ilegal workings may be found and it be proven old surveys are wrong for the old workings but leave the mine in peace now .

Offline mikem

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Re: Gleision Mine Disaster
« Reply #23 on: September 19, 2021, 08:10:14 pm »
I doubt even the manager knows where the water came from. He is lucky to be alive.

Offline Cantclimbtom

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Re: Gleision Mine Disaster
« Reply #24 on: September 20, 2021, 09:35:51 am »
... Cobb was an expert witness for the defence ... introducing doubt is part of his job...
Maybe again I'm being deeply naïve, but suggesting and driving possible explanations to the jury, to undermine the beyond-reasonable-doubt status of the prosecution's argument, is the job of the defence team's lead barrister. And the job of an expert witness is to state a professionally competent honest opinion, not spin stories and supposals. (I warned you I might be naïve)

I doubt even the manager knows where the water came from. He is lucky to be alive.
I'm sure he doesn't, otherwise he wouldn't have overseen firing the face
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