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By Robert Rapier on Apr 8, 2010 with 31 responses

The Mining Disaster in West Virginia

The following guest post is by Dave Summers. Dave is known on The Oil Drum as Heading Out, and he is friend of mine and a recently retired professor from the Rock Mechanics and Explosives Research Center at Missouri University of Science and Technology. Dave maintains a very informative blog called Bit Tooth Energy that seeks to educate people on technical issues around the extractive industries.

I have intended to write something about the mining disaster, as it is a stark reminder of the dangers involved in the mining industry. Some of you may remember that I recently reviewed Big Coal, and in that book author Jeff Goodell was highly critical of Massey CEO Don Blankenship’s track record on safety. In fact, Goodell pulled no punches in a New York Times article following this disaster. While acknowledging that underground mining has inherent risks and that the safety record has improved, Goodell argues that Blankenship has used political influence to water down safety reforms:

“The second reason mine safety reforms have failed is the political power of the coal industry. After every coal mining tragedy, there are passionate calls for new safety rules and regulations. After those reforms are proposed, they are fought over in Congress and state Legislatures, where politically connected coal operators make the case that the reforms are too onerous, too expensive, too difficult to implement. And so they are watered down, loopholes are inserted, timelines extended.

This is particularly true in West Virginia, where Don Blankenship, the head of Massey Energy, the coal company that owns the Upper Big Branch mine, holds sway over state politics there like one of the old coal barons of yore. In West Virginia, you mess with Don at your peril. If you want to know why a mine with a sorry safety record like Upper Big Branch wasn’t shut down long ago, that’s your answer.”

My thoughts are with the friends and families of the miners who perished.

With that introduction, here is Dave’s excellent and very comprehensive essay weighing in on the matter.

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The news of the death of at least 25 coal miners at the Upper Big Branch Mine in West Virginia is a reminder of the human costs that are incurred in the provision of fossil fuels. Although American mines have grown considerably safer over the years, the nature of the work can mean that when there is an explosion in a mine, that there are multiple fatalities because of the layout which is most effective for getting the coal out. It also underlines the higher costs that must be met when mining coal from underground operations, rather than the more visible, and criticized surface mining operations.

In the United States this is the largest mining disaster in more than 25 years at a mine that produced 1.2 million tons of metallurgical coal last year. Because of the pressures on surface mining operations Massey Energy were moving an increasing percentage of their production to the underground. The mine uses longwall techniques as the main means for producing coal and so I thought that it might be helpful if I reposted some of the information on that technique.

Part of the problem in controlling the ignition of gas in such an operation is that the mining machine breaks out the coal in relatively small fragments, by rotating a drum laced with picks against the coal face.

Surface test of a shearer used in longwall (Bureau of Mines Bruceton)

The fine crushing of the coal can lead to the release of methane gas (natural gas) that is found and formed with the coal. Levels of the gas are measured, and controlled by sending enough air down the face to dilute the level of the gas below that at which it is at risk of ignition or explosion. However within the space that the drum is carving out it is not always possible to get that air flow into the area to ensure that dilution is immediate.

At the same time if there are layers of rock within the coal, then the pick can rub against these and generate sparks, and heat up the rock to the point that it becomes hot enough to ignite any methane pockets that have been released. Once that ignition starts the very fine coal dust that is also a part of mining (as the above picture shows) means that this can also ignite, intensifying the resulting explosion. That becomes particularly deadly, given the geometry of the longwall.

And to explain that let me repost something I had written about before.

Back in the mid-1800′s underground mining was usually carried out by crews of men and boys, where the coal was first removed by undercutting the coal seam manually with a pick, to a depth of about 3 ft. The bulk of the coal was then broken down to this slot and the fragments (ideally about 4-inches in size) were shoveled and hand-loaded into pit tubs, to be hauled away. A good day’s work was about 20 tubs.

As the miners drove the tunnels (also called entries, headings, drifts, drives etc) into the coal they left pillars between the tunnels to hold the roof up. However in about 1870, and possibly in the Lancashire coalfield in the UK, they discovered that if they put these entries together, they could develop a way of getting all the coal out from that section (or panel). How could they get away with this?

Well there are two things that make it possible. Firstly, when you make a hole in the ground, the rock pressure that was applied to the rock (about the same pressure as the depth of the hole) has to move somewhere. And it moves just a little so that the weight of the ground over the hole is carried by the rock on either side. However, what happens if this additional load is too high for the rock and it fails?

Well if the rock were just a thin column it would collapse, but if it were thicker, then the weight would just move further into the coal. Now if we came along and moved the coal that had failed, then the hole would just continue to get bigger. But if we leave the coal in place, then the broken coal acts to confine the coal further into the solid. And this confinement gets higher, as the failing pressure continues to move into the wall. And what happens is that this confinement builds up the strength of the coal, so that at some distance into the wall (or face) the coal strength reaches a point that it can carry the weight of the ground above the working area.(For a simple analogy think of a deck of cards, which individually cannot bear weight, but when held together by a rubber band, or a carton, can support quite a bit of weight).

The second thing to know is that when a layer of rock breaks the rock lumps when piled together occupy more space than the solid rock. As a rule-of-thumb the bulking is about 60%. So that if we let the roof over the working area break and collapse, after we have taken the coal out, then by the time about twice the seam height of rock has collapsed, it has filled the hole where the coal used to be, and reaches up to the solid layers of rock above, to hold them in place. The confinement of the rock around each piece allows it to regain some strength, and so collectively the broken rock behind the working face (called the goaf or waste) will carry the weight of the ground from about twice the seam height, all the way to the surface, and with the other end of the “bridge” as it were resting on the confined coal ahead of the working face.(While the width of this bridge varies with depth, coal and rock strength etc, for an initial estimate you can imagine it as being around 500 ft).

What this means is that the miner, working at the face, needs to support only the rock that is up about twice the seam height above his head (in those days women did not do the actual mining). And this could be done with relatively small tree limbs, called props. However, because the rock could break into pieces, the prop support would be distributed, by having a plank, or half split timber, as a bar on top of the prop. Putting one prop at each end thus gave a sort of “goal post” support. Thus, along the face, there would be, at about 4-5 ft intervals, these prop supports holding the roof up.(The coal is made slightly blue in the pictures to give a better contrast – sorry!)

Now, to get the coal out it was possible to put in mechanical assistance. The first step was to use a machine, rather like a large chain saw, that was pulled along the face, undercutting the coal, to give that first free surface. At the same time holes were drilled along the face, about 6 ft apart, with a stick of dynamite in each one. After the face was cut the coal was blasted down between shifts (7.5 hours) then the collier shift would come in and each man would have about 10 yards of face to load the coal from, and to re-support. To get the coal from the face, a rubber conveyor belt was run along the back end of the supports that were in place before the blast, and the coal would normally not break that far from the face. As the miner shoveled he would also put in a new set of timbers, overlapping the old, and supporting the new working area. Typically this would take another seven hours, with an ideal seam height being about 4.5 ft. Above that the coal volume to move was much greater, and below that it got a bit awkward. For example, below 2 ft thick you lie on your back, with a prop under your shoulder and shovel over your head – how would I know? Yes, there was a reason to go to college).

In the third shift, the men would come in and break down and move over the conveyor belt, and then remove the last row of wooden supports, bringing the roof down, beyond the new line of supports.(Smart folk would use a come-along and a chain to pull down the props, young idiots (guess who) would go in with an axe to chop them first).
The process needed mechanization and this required three different components to work. And these all came together in a period around 1960 – 65. Firstly there was a better way of removing the coal. The machine that was developed initially took the coal cutter power pack, and turned it on its side. By then putting a drum with picks on it, over the shaft to replace the cutter bar, the Anderton shearer was invented (named after its inventor). The drum rotated, and a shaped cover behind it moved the broken coal over onto the second part of the process.

This is a rigid framed conveyor, made up of segments that can move against one-another, and with rigid metal walls. The shearer can ride either on top of, or along side this conveyor, and load the coal onto it. The conveyor then carries the coal to the end of the face, and onto a second conveyor, that carries the coal out of the panel.

It is the third part of the concept that makes the whole system viable, because we now add the powered roof support. These are sets of hydraulic rams that ride on one plate of steel, pressing a second up against the roof. They are connected to the conveyor by a horizontal ram.

The mining process is thus that first the shearer moves down the coal face, grinding off the coal to a depth of around 2 ft. After it passes, the rams on the roof supports, in turn, are released, so that they drop away from roof contact. The horizontal ram is retracted and the support moves forward until it contacts the conveyor. It is then raised, and re-supports the roof. Each support moves forward it turn, so that the miners (which now include women) are always under a roof of steel. After the supports are re-established, the horizontal ram extends, pushing the conveyor over into the open space where the coal has just been mined. The exposed roof rock then collapses into the open space behind the back of the supports.

If one were to look at the operation from above, and with the roof removed, it might look a little like this:

I have taken away some of the canopies of the shields so that you can see the conveyor snake after the shields move forward. The view closer in shows the conveyor and supports better.

Because of the way the roof rock weight distributes, it is usual to drive entries out to the edge of the panel first, and then mine back to the main drive tunnels, rather than mining away from the mains. In part this is to keep the excess weight from acting on the tunnels the miners travel through. Because of the collapse of the roof as the coal is removed the panels usually start at the back of the section (known as a panel) and mine toward the main transport tunnel, with coal and people travelling in roadways on either side of the panel.

Initial stages of a longwall panel development, showing how the access tunnels from the main haulage are located.

Over time the ground movement works to the surface, and the surface of the ground will drop, by some significant percent of the height of the coal removed, since the rock in the waste will crush and consolidate. This is called subsidence, and if the mining is carried out badly, then it can cause significant damage to surface buildings. However, if done properly, it should not.

I will cite two examples of the latter. Firstly in the height of mining and before North Sea Oil and Gas, Britain mined coal at a high rate of production, from where it was found. This included under the city of Coventry, which was at the time home to large manufacturing plants, with precision lathes. By back-filling behind the face props with the blown-in waste from the colliery treatment plant (called stowing the goaf), the waste was filled, and the ground movement minimized to the point that I only heard of one factory being closed for less than a week to realign their lathes.

The second example was in Duisburg in Germany, and a different problem. The town is a port on the Rhine, and over the centuries the river had eaten into the bed, so that the quays were becoming too high above the water for easy loading of the barges, and the town was losing business. They went to the local coal company and asked them to mine out seams under the harbor, and thus to lower the quays to bring them back in reach of the water. The miners complied, and lowered the area by over 11 ft. The area that was mined included highway overpasses, and a Shell oil storage facility in the middle of the river. The story goes that the tank farm manager went to the miners and asked them to tell him when they were going to start, so that he could drain the tanks as a precaution. They pointed out that the farm had actually already been lowered about 3 ft, as I recall the story.

As usual this has been rather a superficial description of a process, but hopefully it gives you more of a sense as to what goes on in a longwall mining operation.

Additional comment : It is possible to mine coal without using picks in a longwall, though it is a technology that has found much greater application in other industries, beyond mining.

Our thoughts and prayers go out to those in West Virginia at this time.

(RR comment: Dave has also written a follow-up post to this: More explanations of coal mine gas and coal dust explosions)

  1. By Benny BND Cole on April 9, 2010 at 12:37 am

    Excellent post. I call for no regulation, except one: Mine executives have their offices in the tunnels.

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  2. By Kit P on April 9, 2010 at 10:02 am

    And refineries should put their
    executives in trailers next to relief valves. Pickens should be put
    on an off shore drilling rig.

     

    And Benny you should have your office
    at the epicenter of gang shootings or are you already there?

     

    The coal mining industry has a very
    good safety record. You may want to wait for the root cause before
    suggesting executives are the blame. The CEO of Massey Coal gave an
    interview on the condition that it not be edited.

     

    A tragedy has occurred. Children lost
    their parents.

     

    Unless you have some inside
    information, why is a California guy gossiping?

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  3. By Wendell Mercantile on April 9, 2010 at 11:18 am

    In 1901 Wilbur Wright told the Western Society of Engineers about aviation safety: If you are looking for perfect safety, you will do well to sit on a fence and watch the birds.

    No one wants people to die in coal mines, but we also have to be pragmatic enough to realize that in any big operation there will inevitably also be some losses. The only way to ensure perfect safety in coal mines would be — as Wilbur Wright said about flying — not to mine coal.

    There needs to be high safety standards for all industries, but we must also realize that no standard can ever be perfect unless we want to bring an industry to its knees and have them stop production completely. Safety standards have to be balance of benefit and return.

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  4. By rrapier on April 9, 2010 at 1:30 pm

    “The coal mining industry has a very good safety record.”

    And that particular mine had a long history of safety infractions. The irony is that Jeff Goodell was raising red flags around Massey in his book, and Kit said “He doesn’t know what he is talking about.”

    I agree with Wendell that accidents are going to happen. It is unavoidable. We lost people every year in the petroleum industry. But you don’t flaunt safety regulations, and if you are constantly getting cited, there is a systematic problem that you need to address.

    RR

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  5. By RC in Houston on April 9, 2010 at 1:42 pm

    While there is certainly something to the idea that mining is an inherently dangerous occupation, there is a past history here of safety “ambivalence” that cannot be ignored. 

    Massey plead guilty in 2008 to criminal charges associated with the Aracoma mine disaster that killed two, and paid 4.2 millions in criminal and civil fines.  And yet in the last year, this particular mine has received over 50 closure notices to either all or specific areas of the operation. 

    http://www.wvgazette.com/News/…..0812230591

    Mine explosions occur because of an explosive atmosphere of either dust or methane, and without the atmosphere, then no explosion.  There are procedures prescribed to mitigate that risk, and here we have a company with many, many violations for not following those procedures……and then we have a disaster.  It doesn’t matter whether the explosion was caused by a cigarette or a faulty piece of equipment…..if this mine took safety ventilation as seriously as it should, and others do, it’s very likely we would not be having this discussion.  Safety culture is from the top down. 

     

    Another way of looking at it….BP got hit hard with initial fines, follow up fines, and lawsuits after their Texas City explosion a few years ago.  I’ll be amazed if the repercussions that follow this incident come anywhere near that level of enforcement. 

     

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  6. By rufus on April 9, 2010 at 4:09 pm

    Coal Mining Should, and Could be completely automated. Period.

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  7. By Wendell Mercantile on April 9, 2010 at 4:27 pm

    Rufus,

    Should? Perhaps. Could? Exactly how do you think that “could” be done?

    Since coal mine owners don’t like the UMWA very much, don’t you think that if they could automate everything and eliminate all those union miners*, they would have already done that?
    ________________
    * I do realize the Upper Big Branch mine was non-union. but you get the point.

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  8. By paul-n on April 9, 2010 at 6:35 pm

    Kit P wrote;

    Unless you have some inside
    information, why is a California guy gossiping?

    Perhaps he is just following your lead. This is what you wrote the day after the gas explosion at the Connecticut power plant;

    “I thought it was a little odd that so many was working on Sunday. What is more disturbing is that a lesson was not learned from other fatal evens.

    “The CSB issued a safety bulletin on gas purging in October 2009, because of the occurrence of multiple serious accidents during purging operations. Key safety lessons described in the bulletin included purging gases to a safe location outdoors away from ignition sources, evacuating non-essential workers during purging, using combustible gas monitors to detect any hazardous gas accumulations, and effective training for personnel involved in purging,”

    and the next day, you added

    There are a lot of very smart stupid people. It is called arrogance. Young males of our species think they are invincible and find near death experiences funny rather than a learning experience.Maintaining a strong safety culture is contrary to the human nature of power plant engineers who like to demonstrate how good they are at getting the job done. It takes much less time to prevent accidents than it does to attend a funeral. This is obvious in hindsight but not so obvious when you are trying to meet some arbitrary schedule. It has been a long time since I have read the results of a fatal industrial accident that was not avoidable or some new previously unidentified hazard. The hazards of producing energy are well known.

    Sounds like speculating on the causes to me.

    An “unidentified hazard” in this case would likely be some geological anomaly. They may or may not ever find out what really happened, but as long as we need coal, there will be people down coal mines, and there is always a risk, however small, of things going wrong.

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  9. By rrapier on April 9, 2010 at 7:26 pm

    Sounds like speculating on the causes to me.

    You have to realize that consistency in reasoning is not one of Kit’s strong points. That’s what makes arguing with him so frustrating.

    RR

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  10. By petes on April 9, 2010 at 8:50 pm

    Delighted to hear that “Heading Out” has his own blog. Finding and reading his excellent technical articles was the only reason I checked The Oil Drum regularly. Now there’s no reason to go there at all any more… I’ve just bookmarked “Bit Tooth Energy”.

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  11. By rbm on April 9, 2010 at 9:00 pm

    Robert Rapier said:

    Sounds like speculating on the causes to me.

    You have to realize that consistency in reasoning is not one of Kit’s strong points. That’s what makes arguing with him so frustrating.

    RR


     

    My take of Kit’s style on RR’s blog,

     

    Kit is an ‘emotion argueer’ first and foremost. Consistency is a element of logic, among other things. bit not ANY part of the emotional argument. Logic is at the other end of the continum of possible elements to consider when carrying on a dialog.

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  12. By rufus on April 9, 2010 at 10:24 pm

    I saw an article about a month ago about a fully automated mine. It can be done, and, eventually, it will be done.

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  13. By paul-n on April 10, 2010 at 12:30 am
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  14. By Kit P on April 10, 2010 at 2:29 pm

    “Kit is an ‘emotion argueer’ first
    and foremost.”

     

    I am passionate about safety. This is
    because I have worked the majority of my career in a hazardous
    environment. I did link the applicable safety authority for those
    who wanted to be better informed. I did share personal experience
    about a time in my industry had fatal accidents.

     

    “Sounds like speculating on the
    causes to me.”

     

    No but you may want to read it again
    PaulN. This old guy shared some wisdom with you.

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  15. By russ on April 11, 2010 at 1:05 am

    Wisdom? That explosion was nothing more than a lousy safety department/officer who did not control the job.

     

    Above that safety officer there was poor management that set up the circumstance to allow the incident to happen. 

     

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  16. By Wendell Mercantile on April 11, 2010 at 12:43 pm

    Dave Summers wrote a very good piece about in-situ coal gasification a few weeks ago….

    “In-situ” gasification would be one way to use coal w/o taking it out of the ground. It would be much like hydro-fraccing shale, or taking advantage of the byproducts of incomplete combustion from the underground coal mine fires that in some places have burned for decades.

    But gasification wouldn’t have worked for the Big Bend disaster. They were mining a special kind of anthracite that is of special use in making steel. What they were mining wasn’t even being burned for electricity and physically needs to be at the steel mill. (Apparently Chinese mills in this case.)

    Much of the coal we are burning for electricity is already being excavated by huge automated machines without even needing to go underground.

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  17. By Kit P on April 11, 2010 at 12:48 pm

    “Wisdom?”

     

    Sure Russ, what do you do when you are
    surrounded by morons? Let your butt get blown to bits!

     

    I have had three near death experiences
    in the work place before joining the navy which was before OSHA.
    Once the guys in the foundry heard me fall and pulled my out of the
    room where chemicals has spilled. The second time my foreman saw it
    coming and pushed me the opposite direction that my instincts were
    sending me. The third time, I was just lucky. Each time somebody
    made a mistake without thinking it could kill somebody. These were
    caring people too. At one job I worked along side the owners son.
    When mom was dying in the hospital they were there. They took action
    to save her life.

    For my near death experiences, there
    were no root cause investigations. No lesson learned. If fact we had
    no safety training at all. At the time most people did not wear seat
    belts.

    So Russ, you might want to think about
    having a plan to work someplace with a ‘lousy safety
    department/officer’. Russ keeps writing stuff that makes me think
    that he is already at that place and just lucky.

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  18. By rbm on April 11, 2010 at 6:19 pm

    “I have had three near death experiences”

     

    Clarification please, I’m guessing  you don’t mean the kind that Google returns, right or wrong ?

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  19. By Kit P on April 11, 2010 at 9:02 pm

    “you don’t mean the kind that Google returns”

     

    Oh that is funny!  No, think close call. near miss.

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  20. By russ on April 12, 2010 at 12:13 am

    @Kit P – Never any facts – just tidbits here and there. Seems you make it up as you go. Makes it very difficult to be consistent. 

    On  one of the nuke sites you claimed to be a safety officer not long back İ believe. You were busy trying to lecture Rod Adams on some point.

    İ have no idea what your comparing safety programs/requirements of 40 years back has to do with today.

    Your ‘real life’ experiences – what do they have to do with anything though İ should think that you may have learned something from them.

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  21. By Kit P on April 12, 2010 at 8:35 pm

    “just tidbits”

     

    I can write more if you are interested
    Russ.

     

    “İ have no idea what your comparing
    safety programs/requirements of 40 years back has to do with today.”

     

    Russ it does not matter what safety
    programs are today if you are someplace that has not learned the
    lessons of the past.

     

    Just for the record, I do not have a
    problem lecturing my juniors like Rod Adams. I was in an all day
    meeting with about 20 people. One of the interesting things was the
    diversity of the group. At the end of the meeting, a couple of us
    were where we were from because the young engineer sitting next to me
    has worked at tow of the same nuke plants as a coop student. Another
    old guy was from a nearby university. Oh me too. Then my boss came.
    That made three. All of us were navy nukes.

     

    The work place culture is interesting.
    If you were a navy nuke, you have a framed picture displayed. If you
    got your navy nuke training in the shipyard, you have a picture of
    the nuke ships you built. If you have an SRO, you have a picture of
    the nuke plant where you earned it. One of the old guys in the
    meeting was an SRO at TMI. He does not have a degree but a valuable
    resource. One of the management customs is to have a monthly
    breakfast for new comers. When I arrived back east, the largest alma
    mater of new comers was Moscow University. It takes all kinds to
    make a team and the best I can tell everyone is proud of their
    background.

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  22. By Kit P on April 15, 2010 at 8:38 pm

    It seems that ‘clean’ energy has safety
    issues too with solar panel fires because of smoke and flame emitting
    diodes.

     

    “A small house fire caused by a solar
    panel in San Diego last week exposed a potentially dangerous flaw in
    the building codes of many cities across California, which is pushing
    for tens of thousands of homeowners to install the generating systems
    on their rooftops.”

     

    http://www.nctimes.com/busines…..28c7e.html

     

    “Snyder, who has investigated
    electrical fires for 25 years, said he’s seen 50 solar-fed fires like
    this one, and on five occasions there was major damage.”

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  23. By russ on April 16, 2010 at 9:02 am

    Not built to code – which means it was an outlaw installation. İf the installation was inspected then shame on the inspector. At any rate it would seem the loss would most likely not be covered by insurance should the company check up on it. 

    NEC requires the cutoff switch to be there and the location is clearly spelled out. 

    Homeowners insurance generally requires UL approved equipment and codes to be followed in order to make a successful claim. 

    Or so they say on solar sites that İ watch!

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  24. By Kit P on April 16, 2010 at 5:55 pm

    “solar sites that İ watch!”

     

    Did you read the article Russ? According to
    the article, installation was to local codes. Thatt is what the
    experts were complaining about, inadequate local codes in California.
    I am sure that PV systems components are built to national codes and
    UL but what about 30 years of operation.

     

    Nuke power plants are required to to
    follow national codes by federal law, 10CF50.

     

    At nuke plants we spend huge amount of
    money to ensure the risk of hurting ‘Pavis and her two children’ is
    less than 0.00000000000001. Assuming proper installation and
    maintenance PV system must meet a standard of 0.0000001 but Pavis
    assumes this risk to show how ‘green’ she is.

     

    Unless there are 50 million PV systems,
    the solar industry is not meeting standards if there have been fifty
    fires.

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  25. By russ on April 17, 2010 at 12:28 am

    ‘Experts say that in most cities, installers are not required to place a switch on the roof to cut power from panels in an emergency’

    The quote is from the article and is plain BS. Either the writer is trying to make a point at the expense of truth or does not know. Not at all untypical in advocacy reporting whether from the pro or con viewpoint. NEC requires the switch!

    İ just sent a message to a friend in CA who is an EE, presently is building his own system and does know his stuff about this – İ expect to hear from him in a day or two.

    Forget your nuke power plant risk numbers – outside the site fence they mean nothing. The same electrician installs a PV panel as installs regular household wiring.

     

     

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  26. By russ on April 17, 2010 at 9:56 am

    İ misunderstood – they are talking about a switch in the DC side between the panels and the inverter.

    It seems that ‘clean’ energy has safety issues too with solar panel fires because of smoke and flame emitting
    diodes
    . The inverter failed – not a solar panel fire – where the ‘flame emitting diodes’ come in İ am not certain. 

    The writer and inspector are arguing for a cut off switch on the roof which would accomplish nothing except to de-energize the wires from the panels to the inverter. The individual panels would still be producing power. İt is argued that having such a switch on the roof would be more dangerous as the fireman or worker would have to climb up there to disengage it.

    A cutoff switch at the inlet to the inverter should do the job nicely – there is no reason to have to go on the roof. İf the wires are isolated at that point the panels would still be energized (if there is sun) but no connection between them.

    Apparently the lady could not call the installer for some reason – maybe a DİY job (though not bad looking). İn general DİY with solar should be discouraged unless the person is qualified for the task. As with any power system there are dangers and the rules (code) needs to be followed. 

    Maybe the inspector, Snyder, is a bit of an opinionated fellow – not like anyone we know (you or me for example).

    The lady apparently is not too bright if this went on for hours before she finally called an electrician!

    Still waiting to hear from Mike.

     

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  27. By Kit P on April 17, 2010 at 10:04 am

    “NEC requires the switch!”

     

    NEC is a national code not local. So
    far Russ I do not think you know BS from apple pie. You keep getting
    them confused.

     

    “outside the site fence they mean
    nothing”

     

    What does that mean? BTW the numbers I
    provided were outside the site fence. Russ seems to be unclear about
    exposing children to hazards when it can be avoided.

     

    “The same electrician installs a PV
    panel as installs regular household wiring.”

     

    When I built my house in California, I
    did all the wiring from the breaker panel out with the help of my
    dad, son and one of his cousins. Also designed and installed the
    radiant hot water heating system and solar hot water system. Did all
    the plumbing from the pump house out. Did all the windows on this
    log house by beveling into the 12” logs. All the structural design
    and installation was done buy other. When you are working 80 hours a
    week at a nuke plant you can not do everything.

     

    It is possible your friend EE friend in
    California know more about making electricity and power plant
    electrical systems than me. If he was navy nuke trained and worked
    in power plant.

     

    Lots of folks engage in dangerous
    hobbies. Hang gliding, ski diving, make biodiesel on the kitchen
    stove, making their own electricity. I also learned the lesson of
    not being able to turn off the sun. My solar hot water system would
    lift the relief valve on hot summer days. We learned run wash the
    dishwasher and washing machine before leaving the house in the
    morning. It was only few days a year but you see the risk on relying
    on a relief valve.

     

    I am in favor of passive solar pool
    covers and windows for winter heating. Very cost effective.
    However, all PV and hot water systems aimed at individual homeowners
    are a scam. If you are in that business you are either a scam artist
    or stupid. Maybe no worse than going to a used car lot or stereo
    shop but still a rip off.

     

    I am open to being schooled in the
    latest and greatest but in 30 years the consumer aimed solar industry
    has not changed.

     

    It comes down to economy of scale. It
    takes a larger system to cover the cost of doing the engineering to
    make it safe. Utility scale system are not surrounded by children
    when they catch fire.

    [link]      
  28. By russ on April 18, 2010 at 6:25 am

    @ Kit P – Every time İ read your posts İ see plenty of BS so İ do recognize it.

    İ keep telling myself not to read anything you post and just reminded myself one more time.

    İ doubt anything you claim to know or have done actually.

     

    [link]      
  29. By Kit P on April 18, 2010 at 11:38 am

    “İ doubt anything you claim to know
    or have done actually.”

     

    Then Russ do not read my posts or
    comment on them.

     

    Is it true you have not training or
    experience in fighting electrical fires? If so maybe you should
    refrain from commenting on safety issues like these.

     

    For the other readers, when it comes to
    making electricity, solar PV is mickey mouse. However, the hazards
    are not. If you insist on doing it, make sure you are doing it
    right.

     

    The electricity generating has a very
    good safety record. Let the people who are trained and paid to take
    the risk, take the risk.

    [link]      
  30. By Kit P on April 30, 2010 at 8:44 am

    Current events suggest that drilling
    for oil and gas may not be better than mining coal.

     

    In any case the risk associated with
    producing energy is insignificant compared to the benefit.
    Furthermore, compared with the past and the record in other countries
    the US energy workers do an overall excellent job of protecting the
    public, workers, and the environment.

     

     

    http://en.wikipedia.org/wiki/L…..ite_note-6

     

    [link]      
  31. By Kit P on May 19, 2011 at 11:07 pm

    A comprehensive report was published:

    http://nttc.edu/programs&p…..Report.pdf

     

    This sums it up.

     

    “Three layers of protection designed to safeguard the lives of miners failed at Upper Big Branch. First, the company’s pre-shift/on-shift examination system broke down so that safety hazards either were not recorded, or, if recorded, were not corrected. Second, the U.S. Mine Safety and Health Administration (MSHA) failed to use all the tools at its disposal to ensure that the company was compliant with federal laws. Third, the West Virginia Office of Miners’ Health Safety”

     

    Evidence of black lung is indication that good industrial safety was not being practiced.

     

    “The fact that 71 percent of them show evidence of CWP is an alarming finding given the ages and work history of these men.”

     

    How a minor accident became a disaster:

     

    “strongly suggests otherwise: the witnesses who testified that the mine was not well dusted; the series of citations issued by state and federal officials in the year leading up to the disaster; the preshift examination records of the conveyor belts, which indicate that only 11.6 percent of the rock dustings requested were completed; the absence of a systematic rock dust procedure; the frequent changes in rock dust personnel; the fact that rock dust crews were given other assignments; the physical distance the explosion traveled; and the findings from the rock dust samples taken after the explosion. Had coal dust not been a factor in the explosion, the damage at Upper Big Branch might well have been contained to the longwall area. The victims on Headgate 22 were located about 0.75 miles from the longwall.”

     

    There are other examples but defense in depth does not work when there is a pattern of multiple failures. Clearly Massey had a terrible safety culture.

     

    Not that there is not enough blame to go around.

     

    “MSHA spokesperson said it is a matter being examined by MSHA’s “internal review” team.11 Despite MSHA’s considerable authority and resources, its collective knowledge and experience, the disaster at the Upper Big Branch mine is proof positive that the agency failed its duty as the watchdog for coal miners.

     

    Equally disturbing is the fact that high-ranking MSHA officials apparently were aware that the agency was falling short in its responsibilities.”

     

    Senior worker also failed to protect less experienced workers.

     

    “preceding the disaster, investigators found that one UBB foreman’s hand-held methane detector had not been turned on, even though he filled in examiner’s books as if he had taken gas readings. This foreman was responsible for assessing gas and water levels in the critical entries adjacent to the longwall panel and reporting conditions leading to the Bandytown fan. Data downloaded from methane detectors indicated that devices used by other foreman also had not been turned…”

     

    On the positive side, the accident was preventable and the report list many recommendations to make mining safer.

     

    [link]      
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