Coal Mine Accident GPS Question

[FJH1]

When one of the miners was interviewed yesterday he said that immediately after the water started coming into the tunnel the head guy in the crew used his GPS to locate the closest area of high ground. How do their GPS units work 240 feet under ground? My GPS has a tough time finding a signal in my car :-). Just wondering.

Best Regards,

FJH

[TT troller]

Got me,...generally a bit of tree canopy knocks em out. Are you sure you heard him right?

[Western Walleye Editor]

I think it was a rescuer that said they looked on a map for the highest point near the accident site and then used the GPS to locate that spot above the ground. That was how the decided where to drill the air hole and subsequently the rescue shaft. I may be mistaken, but that was my understanding.

Honsie

[Erie Drifter]

I think you may have misunderstood his statement, they have maps of the new tunnels they were working in and know all the elevations, once the accident happened they used GPS on the surface to locate the elevated area in the mine near the last known location of the miners to drill the reccue shaft

The miners would have already known these areas and common sense says head for the nearest high ground, that's what the rescuers were depending on. Just my humble opinion.

Bill W. (War-N-Peace-ch 68)

[Erie Drifter]

Ya beat me to it Honsie, I should have typed a little faster.

Bill W. (War-N-Peace-ch 68)

[FJH1]

When I listened to the interview with rescued miner Mayhugh he mentioned a couple of times that the mine chief that was with them used his GPS to locate the closest area of high ground and that's how they located the relatively "dry" 20' x 50' area that they stayed in. He used the word "GPS" a couple of times. That's my story and I'm stickin' to it :-).

Best Regards,

FJH

[Chad]

I would think that they have some sort of special GPS set up for underground. How do you think they are able to map out where the mine boundries are.

[Survey Guy]

Mines are mapped out using lasers and theodolites. GPS does not work underground but the coordinates of the shops and safe areas are known. If the mine is modern there would be automation and certain set points would be known to the party chief who would carry a receiver that would tell him his location. It is configured to satellites but would get its signal from the "beacons" set underground. These guys plan for emergencies like this and this training and modern equipment as well as a dedicated group of coworkers got them out. God bless them all.

[JohnF]

Hey Survey Guy, never being one to pass up a learning experience I have to ask you; what's a theodolite?

John

[Tom]

i agree with survey guy GOD BLESSED THEM, being from not that far away from the accident scene i didn,t think it would get the media attention that it did, i,m sure glad they all got out and would like to say thanks to all of you who watched and prayed for those fellows, this time it turned out for the better.





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[FJH1]

Thanks Survey Guy! Ok, I have to ask also, what's a theodolite?

Best Regards,

FJH

[Erie Drifter]

Just did a search on the Theodolite, It's the Surveyors telescope you see them using on a tripod to check road grades and angles.

http://www.usd.edu/honors/HWB/2001/2001c/sub%20pages/theodolite.htm

Ya learn something new every day.

Bill W. (War-N-Peace-ch 68)

[TTtroller]

Interesting,...I'm still not totally understanding how that works but the original news report that FJ heard, might have been inaccurate. Ever give an interview?,..they sometimes get it very wrong. I have been impressed that in the past, tunnels could be done accuratly. We have a tunnel near here that is 6 miles long through a Mt. They dug from both ends and it was less than 1 inch off when they broke through. I think this was around year 1910.

[Boatnut]

theodolite is sorta the modern day version of the old "transit". It's used to measure horizontal and vertical angles, usually displayed electronically or digitally. vs. having to use a magnifying glass to read the degrees/mins/seconds on the old style transits.