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 Post subject: Mine on Mythbusters Last Night
PostPosted: Wed Nov 09, 2005 11:10 am 
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Joined: Fri Jul 15, 2005 2:34 pm
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Location: Within 60 Miles of the Northern Anthracite Field
Hey anyone catch mythbusters on dicovery last night, miner greg i was gonna call you last night but it was like 1030. they went in an old gold mine to do this test with a drum and sound waves carring through rock. it was called the priest mine, dont know where it was though. they had a map. ok see ya

chirs

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PostPosted: Wed Nov 09, 2005 12:06 pm 
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Location: Above the Sterling Hill Mine
Sounds pretty intrestesting. Would have been cool to see that. I did a search on the internet and found more information on this...

The Priest Mine located in Placerville California. It was opened in 1849 and is near the Gold Bug Mine which is a self guided tour mine. I believe if you are visiting the Gold Bug Mine you can just go up and check this one out while you are there. I have a feeling it is probably a small mine, but still it might have been cool.

Any cool shots on TV of this mine? Here is what I found about the Myth Busting in that mine...

-------------------------------

Chinese Invasion Alaram

Myth: You can detect the tunnelling/mining of a beseiging army using pottery jars stationed below the ground.

The first started with an incorrect translation of the myth, which was that with a 80 liter pottery jars lowered into holes around the town, you can detect approaching armies. This is similar to the Hollywood portrayal of putting your ear to the ground to track your enemy. After getting the fact-checking sheets from the textbook publisher that included the myth, they were able to track it down to an ancient Chinese text by Mao Tzu written in 4th century BC.

Mao Tzu's text described a detection system for protecting walled cities for approaching tunnelling invaders. They system used 200 liter jars with 3 feet of water and covered with fresh goat skins. These drums were lowered into shafts 15 feet below the base of the city wall. The shafts were 5 paces apart and listeners would be stationed at each shaft. The intensity could be compared from different locations to determine where an approaching tunnelling army was.

During WWI, soldiers would listen in trenches and tunnels for the digging of opposing armies. When the enemy was detected they would blow up galleries full of explosive beneath the enemy position.

Grant and Kari prepared the drums. It turns out that Kari has some goat-shaving connections and got some proper advice on preparing the goat skin. Akbar the goat shaver recommended first using clippers to shave the skin, soaking it in water for half an hour, then stretching it. Finally, a disposable razor should be used to shave the remaining stubble.
Setup

They went to the Priest Mine, one of the oldest hard-rock mine in California (all hand-dug). They chose three locations in the mine: the first 50 ft away, the second below their shaft, and the third 50 ft deep and 100 ft away. Jamie and Tory were sent into the mine to do the pick-axing while Kari and Adam did the listening at the shaft. Grant manned a geophone and an audio frequency mic.

They tested their setup by picking away at the mine while Grant tried to detect the digging with the geophone and Kari listened at the drum-less hole. Grant was able to picked up the sounds of Jamie's digging but Kari couldn't hear anything.
The three tests

They lowered the drum in to start the tests. Kari listened with a traffic cone to focus the sounds and "Deaf as a post" Adam listened in as well.

At the first pick-axing location, Kari had no trouble picking up each strike with the pick-axe. She described it as a faint beating of the drum everytime the pick-axe hit and she believed that the shaft helped focus the sound. Grant also picked up faint signals with the geophone while "Deaf as a post" Adam heard nothing.

The simple drum in a hole seemed to equal or even outdo the performance of some of the more expensive that Grant had setup, including the audio frequency mic, which picked up nothing.

They moved to the second location beneath the hole, where Kari and Adam heard nothing. The earth was softer beneath the hole and it may also be possible that the detection system has a blind/deaf spot. Grant got faint signals on the geophone.

They moved to the final location 50 ft deep and 100 ft away. Kari was able to count off the strikes perfectly.

plausible: they were able to detect digging 50 ft deep and 100 ft away with the drum. They couldn't find any physical evidence of this ever being used, but the alarm worked so well and Mao Tzu's account was so detailed that it looks plausible.


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PostPosted: Wed Nov 09, 2005 1:18 pm 
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Location: Within 60 Miles of the Northern Anthracite Field
yea thats it, it was a cool show. the mine part was about a half hour, good shots.

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PostPosted: Wed Nov 09, 2005 1:46 pm 
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Location: Above the Sterling Hill Mine
Yeah, it would have been cool to see shots and stopes inside a gold mine if they showed that kind of stuff during the TV showI'lv. We went to a Gold Mine once in AZ, but it was a mine tour and we were only able to navigate the upper tunnels. They "weren't allowed" to take us down the mancage to the lower levels of the mine. Would have been intresting to check out the workings. I'm sure it wouldn't be much different than what we are use to in the Iron Mines.

I will have to check my channel guide on satellite and see if it is on again this week. Some of these shows are...


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PostPosted: Wed Nov 09, 2005 3:37 pm 
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Location: Hamburg, NJ
Yea I saw this one, it had an adit and was a pretty small mine. they only showed split second shots of the adit and most shots were of the drum outside.

one of the guys was swinging a pick at the rock, inside. they had so much studio lights in there it looked almost like a basement. He was swingin it so wimpy too.


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