Ambulances caled to Utah mine after reports of new collapse

[Johnny_Blaze_47]

It's on CNN, FOX, MSNBC.

[Sonia_TX]

This is horrible. I have been watching CNN every day and praying that they find the guys alive. Now there might be more injured/dead/missing... sad. :(

[ashbeeigh]

It sounds like it's rescue workers, independent work which caused more geological movement.




Rescue workers injured at Utah mine
Four ambulances, two helicopters dispatched to scene

Updated: 9:51 a.m. CT Aug 16, 2007
At least two people working to find six trapped miners were injured Thursday night on the 11th day of the rescue effort. At least four ambulances and two medical helicopters rushed to the mine after 9 p.m. EDT. One person taken to Castleview Hospital in Price was seen being resuscitated. There was a "mountain bump" inside the mine, according to a hospital official who spoke on condition of anonymity because he was not allowed to release information. A bump commonly refers to pressure inside the mine that shoots coal from the walls with great force. This breaking news story will be updated

http://www.msnbc.msn.com/id/20283387/

[Sonia_TX]

9 said to be injured. A few in critical condition...

[Sonia_TX]

1 has died... this is just so sad.

[spurschick]

How many mine collapses do we need to have before someone figures out a better way?

[1369]

How many mine collapses do we need to have before someone figures out a better way?

We do, it's called strip mining, but folks seem to not like having a big hole in the ground. But, sometimes it's just more practical to mine by tunnelling.

[boutons_]

Background on this type of mine.

=============
August 16, 2007

Facing the Multiple Risks of Newer, Deeper Mines

By KIRK JOHNSON, NY Times

As hope dims for the six miners trapped by a coal mine collapse in central Utah, engineers and seismologists are grappling with the broader implications of the Crandall Canyon Mine accident and the interplay of risks they say are mounting in the newer, deeper generation of coal mines, especially in the West.

The extreme depth of the mine, the history of mining-induced seismic activity in Utah’s coal-mining region, and the method of coal recovery called retreat mining that had been done in the past by the mine’s co-owner, the Murray Energy Corporation, all compounded the difficulties and dangers the miners faced, the experts said.

Whether and how any of those factors combined to set off the huge structural failure inside the mine on the morning of Aug. 6, a movement of earth so intense that it measured 3.9 in magnitude and was first thought to be an earthquake, is unknown. Officials at the federal Mine Safety and Health Administration said they would not formally begin their investigation until the rescue or recovery efforts were completed.

But there is little doubt, mine experts said, that retreat mining at extreme depth in Utah, where mine-produced tremors are common, creates a tapestry of forces that adds to mining’s inherent hazards.

First, the six men were working at a depth of more than 1,800 feet, which engineers say is where coal approaches its structural load-bearing maximum.

Second, the coal itself, carved into large pillars within the mine, was essentially what held up the weight of the mountain above Crandall Canyon, near Huntington.

Third, retreat mining involves removing or reducing the size of those pillars to extract as much coal as possible. Seismic jolts called bumps or bounces in the language of miners are often caused by compression of coal pillars and are most common in the deepest mines, like Crandall, where the pillars hold the most weight.

( So Murray, jumping on the "seismic" joit (aka, Act of God, not my fault, not my liability ) as the cause was lying by telling a half-truth. The other half is that his technique of mining CAUSES seismic jolts. )

“Typically, where you have problems with bounces is where cover depth exceeds 1,800 feet,” said Kim McCarter, a professor of mining engineering at the University of Utah who has studied mine jolts.

Over the last two decades, mines in Utah and in some other coal-producing areas have pushed past depths of 1,500 feet, which had been considered an impassable barrier with older technologies. (Appalachian coal mines are typically much shallower than those in the West.)

Seven of Utah’s 10 operating mines, including Crandall Canyon, take miners to depths of 1,600 to 2,000 feet below the surface, said James Kohler, chief of the solid minerals branch of the federal Bureau of Land Management in Utah, which monitors mines on its lands. An eighth Utah mine is scheduled to push through 1,800 feet in the next few years.

The days of easy, shallow coal are gone, Mr. Kohler said: “By necessity, we’re going deeper.”

( fact the coalcos and buildders/owners of coal-fired, polluting electrical generators don't put in their PR for coal )

The chief executive of Murray Energy, Robert E. Murray, has said that no retreat mining was being done at the time of the Crandall Canyon collapse. But engineers and seismologists say that mountains honeycombed by mine tunnels do not always react predictably to mining. Some seismic jolts in mine country have been associated with increased mining activity, while other bumps come much later, even in different parts of the mine, as the geology of the mountain settles out.

One mine safety expert said that increasing pillar size to bolster safety could come at a price. Larger pillars mean smaller passageways, said Stephen Dmytriw, a civil engineer in the safety and health program at the Colorado School of Mines. And narrower tunnels mean less air circulation.

Mr. Dmytriw said that some mines in Utah’s coal district, about 130 miles southeast of Salt Lake City, create methane, requiring extensive venting, but that Crandall Canyon was not one of them.

( methane = green house gas, like farts )

Mr. Murray had initially expressed optimism that pockets of breathable air remained inside the mine. But testing devices lowered through small shafts bored vertically from the mountain above have provided conflicting signals. One test found very limited breathable air; a second found enough to support life.

Richard E. Stickler, the director of the federal Mine Safety and Health Administration, said yesterday at a news conference at the mine that another seismic bump, on Tuesday night, had damaged a “continuous mining” machine, hampering efforts to tunnel a path to the miners. But Mr. Stickler said the machine had since been fixed and the tunneling continued. As of yesterday afternoon, 780 feet of debris had been cleared inside the mine, little more than a third of the distance to where the miners were believed to be.

Relu Burlacu, a seismologist at the University of Utah, said the overall relationship of mining activity to underground jolts in central Utah was quite simple, but more complicated on a mine-by-mine basis.

“If you increase production, and have more active mines,” Mr. Burlacu said, “you have a higher rate of seismicity.”

Beyond increased production, he added, many factors can intervene. What is clear, he said, is that the deeper a mine, the more pressure on whatever is supporting it.

“With depth, the overburden increases,” Mr. Burlacu said. “And when the overburden is bigger, the stress is bigger.”

Over the last 10 years, Utah has produced 25 million to 26 million tons of coal a year, about doubling production since the 1980s, according to state figures. The number of mine-related seismic jolts of magnitude 2.0 or greater has also increased, according to the University of Utah, from an average of about 50 a year through much of the 1980s, to 150 on average in the 1990s, followed by a decline beginning in 2003 to last year, when there were 52 mining-related jolts of significant size.

Dan Frosch contributed reporting from Huntington, Utah.


NYtimes.com