Posted on 08/18/2007 12:28:58 AM PDT by yorkie
A national mine safety expert believes the two collapses at the Crandall Canyon Mine [snip] were caused by "bumps" that resulted from the way operations were being conducted at the Huntington mine. Mining bumps are pressure-shifting seismic events than can cause the walls, pillars, ceiling and even the floor of a mine to literally explode and disintegrate. They can cause deaths and injuries, and can result in cave-ins. [snip] And while an investigation ultimately will determine the cause, Ferriter told the Deseret Morning News on Friday he feels certain the bumps were caused by mining activity.
"In my opinion, based on the evidence and the way it's described, I think it definitely was a mining-induced bump," he said of the initial Aug. 6 collapse.
[snip]"Earthquakes happen naturally. Bumps are a coal-mining phenomenon," Ferriter said, adding that bumps are more severe in Utah mining because thick (as much as 300 feet), heavy beds of sandstone often exist above mining operations, placing a great deal of stress on the man-made caves beneath them.
[snip]Ferriter said it is his understanding that around the time of the Aug. 6 collapse, miners had been extracting coal from the pillars themselves.
"Often, it's when you try and take too much of the pillar" that bumps occur, he said. "I understand they were retreating out of that section and taking some of that pillar out on the way out, maybe shaving it or splitting the pillar to get the coal. The more you take, the greater the load on the rest of the pillar."
And that is what may have led to the Aug. 6 bump, which registered 3.9 on the Richter scale.
"That's my opinion. (Miners were) taking too much" of the pillar, Ferriter said.
(Excerpt) Read more at deseretnews.com ...
No question about it. The land we mined and reclaimed produced a better crop, had better drainage, was terraced with ponds at the low corners (not last cut impoundments which are awful) and was worth more per acre. The land owner received a royalty on his coal and got his land back in superior condition. The federal surface mine law overreached in many areas but was generally beneficial.
You are very correct.
The big thing here is permafrost. Buildable land without permafrost is scarce. A subdivision down the road with typical ranch style houses is looking kind of uninhabitable here and there while subdivisions in Fox (totally mined out and mostly gravel now) will be permanent. Simply excavating forty feet down and backfilling as they did on the 1994 road project clearly doesn’t get the job done. Got to mine it down to bedrock.
Is Joe Usibelli still mining coal in Alaska ? Its been a while since I worked in coal, moving to petroleum products in 87...
Yes, cranky as ever.
He went to Stanford. Very sharp. Could have been one of Ayn Rand’s characters. But, like many in the mining industry in Alaska, driven to frustration by the legal environment.
Thanks for an understandable and comprehensive explanation.
I just read this tidbit on the ‘MIA’ whereabouts of Murray...
” Since Thursday night’s fatal cave-in, Murray has reportedly not left the Crandall Canyon Mine.”
One of the hallmarks of leftie reasoning is to ignore information that contradicts one's view, rather than changing the viewpoint. Unfortunately, it seems that many FReepers have adopted that same mentality on many topics, and science is one of them.
How do you mine away a pillar if the roof is going to simultaneously collapse in the same location?
How do you mine away a pillar if the roof is going to simultaneously collapse in the same location?
When the pillars are extracted, temporary roof supports are installed to keep the roof in the immediate area above the miners and equipment from falling. The miners and equipment are also positioned to keep the caving roof more ore less in front of them, with supported top over them and behind them. Keep in mind they are retreating, or backing out of the section as the pillars are extracted.
The temporary roof supports are withdrawn as the miners retreat, allowing the roof in front of them to cave.
This is a simplified explanation. The entire process is methodical and accepted practice, but it is the most risky part of the mining process. A miner operator must have nerves of steel when pulling pillars; the folks behind him (helper, haulage operators, etc) have to have big ones as well. As the pillars are removed and before the roof caves, you can hear the weight of the overburden trying to compress the remaining part of the pillar, and the adjoining pillars. The roof makes loud popping and thumping noises, and the coal pillars start to pop and snap. You can see coal popping off of the pillars due to the pressure. It is quite unnerving until you get used to it. When the roof falls, it creates this huge burst of wind and noise. More than one newbie has had to go outside and change his clothes after experiencing pillar extraction for the first time.
Interesting thread, lots of Freeper input of the same schooling you gave me on longwalling.
Only to the extent that the average American reader wants something more than news nuggets. In other words, no.
The point is, generalizations don't work. For example, hatred of the MSM shouldn't blind FReepers to the fact that it's not just liberal bias that's killing newspapers--it's the fact that Americans are reading less and wanting less in-depth information. Conservative newspapers are failing, too, unless they focus on Paris Hilton's latest histrionic display. Focus on supposed stupidity of journalists is distracting from the real issues of why people pursue that field and how journalism schools are teaching it).
Besides, is it stupidity, irresponsibility, ignorance, or something else that makes journalists from this week's TIME magazine caption a photo of a HMMWV as a "tank" (I don't subscribe, but saw it in doctor's office)?
Liberal bias is closing liberal newspapers quicker and in greater numbers than conservative papers. It is also costing liberal networks in viewer ship while center and conservative stations are flourishing. And yes the quality of all journalism has plummeted. At least partially be cause some journalist refuse to acquire knowledge about something they loathe. i.e. the military or firearms. The attitude of the journalist to the Utah mine owner was a good example, the first questions out of the box was why he was still mining for coal when it ways so dangerous, never mind that 50% of our electricity is coal generated.
You are free to believe that, but to convince me, I'm going to have to request a citation on that. Let's see... Cincy had conservative and liberal papers...now it's just the liberal one. Has The Bulletin in Philadelphia taken off? If it's such a gold mine opportunity, are you investing in starting up conservative papers?
The attitude of the journalist to the Utah mine owner was a good example, the first questions out of the box was why he was still mining for coal when it ways so dangerous, never mind that 50% of our electricity is coal generated.
Every question is an opportunity for an answer. Was a good answer given? Do you prefer the journalist not to ask questions?
At least partially be cause some journalist refuse to acquire knowledge about something they loathe. i.e. the military or firearms.
Every one of my editorial board members was a shooter, and some carried concealed. Lovely generalizations you make...would you like a job in journalism? ;-)
In general, my experience has shown that conservatives love to talk a big game about how they'd buy an unbiased paper, but when it comes down to it, they want to watch Paris Hilton, Natalee Holloway, etc., instead, just as much as libs do.
And your accusing me of generalising. Conservatives are sure watching what they perceive to be unbiased newscasts and are listening to conservative radio in droves. As to the loss of conservative newspapers, here in Dallas the Dallas Morning news was the conservative paper and The Dallas Times Herald was the liberal. The Dallas Morning News bought out the Times Herald and within three years went liberal and now is losing readers left and right. Even with that I still have a subscription.
At least I clarified both “In general” and “my experience”... so you knew my source of info.
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