legendrider
Active member
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.
MARK
Also available on I-Player for rest of UK.
MARK
Gleision Mine Disaster
- Thread starter legendrider
- Start date
tomferry
Well-known member
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 .
sinker
New member
Tomferry said:
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.
sinker
New member
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Obviously it assumes some knowledge of the working method; small scale and outdated drill / blast / hand-loading / propping / back-filling etc but its a very interesting read.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.
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Obviously it assumes some knowledge of the working method; small scale and outdated drill / blast / hand-loading / propping / back-filling etc but its a very interesting read.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.
rhychydwr1
Active member
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.
tomferry
Well-known member
rhychydwr1 said:
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 .
Cantclimbtom
Well-known member
http://www.mineaccidents.com.au/uploads/gleison-colliery-inrush-report.pdf
The_Bogieman
New member
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.
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.
Graigwen
Active member
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.
.
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.
.
tomferry
Well-known member
The_Bogieman said:
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 !
tomferry
Well-known member
sinker said:Tomferry said:
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!
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
Cantclimbtom
Well-known member
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.
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.
Roger W
Well-known member
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.
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.
rjw
New member
Roger W said:
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
Roger W
Well-known member
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.
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.
