Wednesday, November 24, 2010

Pikes River Mine Disaster

Ok, it is time to stop pissing in other peoples’ pockets and make my position very clear on the Pikes River Mine disaster.

No, I am not going to pull my punches. It is, and has been from day one, a disaster. It is NOT a disaster because of anyone’s incompetence, however much other people might like to make it so. There are aspects of the handling by police, mine company, et al that I question, but I think that I can see a rationale for the approach taken. It has as much to do with empathy for the families involved than it does the perceptions of the wider public. It has as much to do with the probable situation and conditions in the mine as it does the safety of any rescue team (or individual for that matter.
I wrote the following comment in response to one particularly vociferous gent by the name of Bammbamm whose qualification to speak includes “years of service in mining” and also (implied) several science degrees.
Like so many others, including Wishart, you forget about the few hundreds of a second when the explosion occurs.
So, seeing you have such vast knowledge of the situation - you have said yourself, you have many years mining experience - and of the science involved you could perhaps give us all a brief exposition on what happens, and the effects on the human body.
Information like the air temperature, the time for that atmosphere to cool, the effects of compression and decompression, the likelihood of injury resulting from both debris and bodily impact would all be greatly appreciated.
My uneducated guesses -
Temperature reached - in excess of 1000C for perhaps 0.5 sec.
Time to cool - depends upon decompression rate. Boyles Law and all that. Could be as long as 2 secs.
Effects of compression - broken eardrums, burst eyeballs, extensive internal bleeding, ruptured liver, ruptured spleen... extent dependant upon intensity of compression.
Effects of decompression - eyeballs lost, eardrums, collapsed lungs, gas oedemas... extent dependant upon intensity
Likelihood of injury from debris and bodily impact -
High.
Effects - could very probably be fatal.
Then you can start considering CO and CO2 effects if you want...
That was the basis of my early assessment of the miners' chances.

It is well-meaning idiots like this Bammbamm character who boil my blood. Most significant perhaps is his choice of handle – a stone-age baby cartoon character whose response to external stimuli was to either cry or destroy with a stone axe. Appropriate and well said.

The real questions in my mind are –

First, should the mining company et al have been more honest about the chances of the 29 still in the mine? The converse to that is that the ol’ probligo is again being far too pessimistic; that glass is bloody near empty!

My feeling and analysis is based solely upon seeing open air videos of BLEVEs. There are plenty of them on the ‘net. The application of what you might see there to the mine disaster depends upon; the quantity of methane involved in the mine explosion; how quickly it came out of the rock face; how far down the mine that cloud had travelled before ignition; how long the discharge of methane continued after ignition; whether the explosion also blew the coal face off; and how much of the explosion was caused by dust ignition.

Second, the talk of “survivability” is not a crock, but the chances are extremely remote to even worse. The debate centres on the presence of features such as breathing gear, safety adits, oxygen bottles (actually forbidden) and other well-meant mis-information. The crux here is that the most likely cause of ignition is human activity. Someone drops something, trips and dislodges a rock, or even a drill being blown out of a hole by escaping gas and the whole lot goes. But the real point is that the gas has to be there, in quantity, considerable quantity, to make a blast of this magnitude. Given that the mine company knows that OSHA and Police have their microscopes at the ready it is quite unlikely that their reports that the mine was clear of methane at the end of the previous shift (less than 45 minutes before the explosion?) were false. To me, that points to the likely explosive ejection of a large quantity of methane from a drill hole or cut. Does that happen? Don’t know for sure but I think we will find out.
This might help answer that question -
For the purpose of discussion in this chapter, gas emissions associated with geologic features are divided into two categories. The first includes subtle emission events that are often associated with various geologic features or anomalies. These emissions are often not easily detected without instrumentation, but may lead to hazardous accumulations of methane if not remedied. The second category includes large-scale, easily recognizable emission events such as blowers or outbursts that potentially have immediate and often catastrophic consequences. Documented methods to recognize and remedy both types of hazards have been established worldwide and are discussed here.

Although not generally considered to be hazards in domestic mines at present, both outbursts and blowers historically have occurred in certain U.S. mining districts [Darton 1915; Campoli et al. 1985]. The two features are mainly distinguished by their duration of occurrence. Outbursts are sudden, often violent expulsions of large quantities of gas, usually methane, and are generally associated with the ejection of great quantities of coal or other rock material. Blowers, on the other hand, historically have been viewed as the release of large quantities of gas, but over an extended time period of months or even years. Also, blowers are not associated with the expulsion of coal or rock material. A subset of blowers is methane bleeders, which also continually emit gas, but at lower rates and generally for shorter timeframes.

Based on past observations, outbursts and blowers are often associated with tectonically disturbed and faulted strata where gassy coals are mined at considerable depth. Thus, mine planners who are aware of such conditions should give some thought to the possibility that they will be extracting coal under conditions that have produced outbursts and blowers in other mining districts.


Hmm, there perhaps is a lesson missed by Pike River. I would need to check if Strongman was a methane explosion; it may well have been in which case there might perhaps have been a need for better planning at Pike River.

UPDATE –

Yes, I watched the 5:30 news report on TV1 last night. NOW I think that the company is being more honest. The chances have (as I outlined above) been pretty damned bleak since 5 minutes after the explosion.

To wind this up, here is the rest of what I started writing yesterday morning –

Look at it this way. It would take me (very unfit and middle-aged as I am) at least 20 minutes to walk the 2 km to the “face”. After seeing the plan of the mine for the first time last night I consider that an “area” rather than specific position. Uneven ground, and all of the other barriers of the mine being taken into account.

A man can die from CO gas in three minutes.

It took two hours (?) to get the first rescue crews to the mine. They jump off the trucks and run straight into the mine. On the assumption that there is no residual fire, no methane, no CO (they can NOT carry oxygen – it would be one of the most dangerous substances in a mine) they gallop up the tunnel to find -

An explosion of the magnitude of this one is going to remove all, I repeat ALL of the oxygen from the immediate vicinity. That is one of the primary causes of CO generation – partial combustion due to low oxygen levels. So, a guy who was 100m “upstream” from the explosion would find a portion of the fireball travelling in his direction; low oxygen levels as a result, increasing CO levels as the air cools and sucks back from the explosion centre. He has “oxygen” from a regenerator that lasts perhaps 2 hours. That is how I read the earlier reports.

- all of the miners died in the explosion, or the following two hours from asphyxiation

3 comments:

Monkfish said...

In this disaster, as in many (maybe all) others, there are plenty of 'knowledgeable' people ready to offer solutions. Couch experts are aplenty - they don't realise that the real world of mining (or whatever) is not the same as a Dan Brown novel with its slick solutions.

The horrifying thing is that they, with all their fine reasoning capabilities, represent a sizeable voter base. ("I'll vote for him - look at how quickly he made the decision to send in the rescue team/bomb the bastards to hell/cut off the funding for...")

In the Pike River incident, thankfully, true experts, science and very measured responses won the day. Gary Knowles and Peter Whittle no doubt knew from the outset that the 29 were beyond all help - but naturally, they would be most reluctant to have said that in the early days. Lives were undoubtedly saved by not rushing in.

Once the dust has settled (no pun intended) the politicians will almost certainly be fighting tooth and claw to gain mileage from the incident. Let's hope that something useful comes out of the inquiry, rather than simply finding someone to blame.

The probligo said...

Monkfish,

The thing that really grinds my teeth are those who make contributions to a discussion like this with patently obvious political motives.

In the instance of the Pike River Disaster (as it will inevitably be remembered in history) that group includes those who argue "cover-up", "incompetent police", and the rest of those scurvy crews.

Will there be political infighting? There may, but I suspect that both N and L will allow the process to proceed without comment or interference. Government is not involved - so far as I can tell - so no Ministerial culpability by present or past can really be created.

Ann said...

Thanks for visiting. I shall like to exchange comments with you.

I am passionate about Pike River Mine. What ever it is, 29 mums lost their sons.

They became bereaved mums just like me, I know as a mum who lost a son, how heavy the empty arms can be.

This Christmas will be a bleak and heart wrenching one. To all the bereaved wives, all the kids, and one BOOM, and their life will never be the same again.