PUF 3

[soiledup]

Can anyone point me in the direction of reference material for the use of PUF in abandoned mine workings. Can it used to stabilise shallow surface mining features? Does it have any structural strength? Is it just a void filling mechanism?
Thereason i ask is that I have shallow surface mining features that require stabilisation, the common (and crude) method is excavation and fill. PUF in principal sounds like it could be more effective?
Any help appreciated

Soiledup (UK)

 

[Kivi]

what is PUF?

 

[BigH]

Polyeurethane Foam (PUF)

See:

http://www.blm.gov/aml/amldocs/puf analysis paper.htm

http://mining.state.co.us//pdfFiles/bmp.pdf

http://www.ose.state.ok.us/documents/TarCk/MineShaftFinalReport.pdf

 

[jacare]

In response to your questions regarding PUF (polyurethane foam). The former US Bureau of mines has written articles about PUF and the Colorado School of Mines actually applied tests to demonstrate its use in mining. I have used PUF-Seal (brand name) for a number of years now to close abandoned mine shafts, adits and other hazardous openings, such as an abandoned well. 2 years ago, I demonstrated the use of PUF to mine engineering students by closing one of the school's dangeous mine shafts with PUF-Seal. While it can be used to stablize shallow mining features, it is not always cost-effective to do so, if the feature is located where heavy equipment has access. Most of my use has been associated with abanonded mine features that are isolated with or limited no vehicular access. In the case where there is access, a pump can be used to apply the PUF in bulk (cheaper). I have also used PUF-Seal to preserve cultural resources such as a prehistoric indigenous pit house. Worked very well! PUF-Seal is a void filler mostly, but has a limited amount of strength. It acts like a wine cork. The more down pressure you apply, the tighter it clings to the rock walls. You can find more technical information from the mfg & supplier: MineSeal, LLC at

http://www.mine-seal.com

To give you an idea of its strength, many times 30 minures after I close a mine shaft, I take pictures of our work crew & equipment parked on the mine shaft to demonstrate its remarkable versatility!

jacare (US)

 

[BigH]

jacare - (snaps) to you! Good response.

 

[Kivi]

Is this the same stuff that I can buy at Home Depot in a can to spray in behind door and window frames?

 

[kenvlach]

Kivi, basically yes, although industrial product can have tailored properties.

As a result of the W. Virginia mining disaster, I foresee some future restrictions on PU seals for coal mines & anywhere else explosive/flammable gases may accumulate:

Reported in the Los Angeles Times, 13-Jan 2006:

Foam Seals Could Be a Factor in Mine Disaster
Concrete barriers might have blocked off last week's fatal explosion in W. Virginia, experts say.

By Daniel Wagner and John Riley, Newsday

BUCKHANNON, W.Va. — Last week's fatal coal mine explosion might never have reached the operational part of the mine if operators had sealed off unused areas with traditional concrete barriers instead of a weaker industrial foam product, experts say.

In a media briefing Wednesday [Jan. 11], officials from the federal Mine Safety and Health Administration acknowledged that large abandoned sections of the Sago Mine were sealed off with barriers constructed from Omega block, which weighs and costs less than standard concrete designs.

They said preliminary investigations indicate that the explosion began in the unused portion of the mine and blew the seal outward, releasing the smoke and dangerous gases, eventually killing 12 men.

A similar explosion in sealed-off parts of a Pineville, W.Va., mine in 1995 shook the unused area but was stopped by seals made of concrete. "When we went in, the seals weren't damaged or anything," said Gary Trout, a United Mine Workers representative.

Trout said it appeared that lightning had struck a nearby gas pipe that ran into the Pineville mine, igniting the gases collected there. In the abandoned area, temporary ventilation barriers called stoppings had been destroyed, suggesting the blast had considerable force.

Officials investigating the Sago disaster have advanced the theory that lightning striking a gas well ignited that explosion also. But at Sago, the shattered seals allowed the blast to reach and destroy stoppings in the working mine, disrupting the ventilation system and preventing workers from finding a clean-air escape route.

The mine agency requires that seals withstand 20 pounds per square inch of explosive pressure, but two recent studies by the National Institute for Occupational Safety and Health suggest concrete barriers survive much stronger blasts, while foam structures similar to those at Sago withstand about 20 psi.

"Foam is easier to handle, and it probably costs less," said Steve Webber, former head of West Virginia's mine safety agency. He said some explosions could be stopped by concrete seals, but not by the foam material.

Mine administration officials said Wednesday that they had obtained documents relating to the seal, and that it would be one focus of their investigation.

 

[jacare]

Did you ever find the info you were looking for concerning PUF?

 

[soiledup]

jacare - Yes and No, I work in a part of the UK with a bad historical mining legacy. I was wondering if PUF could be applied to some fo the problems we have with site remmediation. This line of throught is still on-going!!!!

Soiledup