Disclaimer....I have little to no knowledge of mining....so this is more of a question.

The idea is to develop a small device to be carried by miners. When it is placed against the rock face, it generates a vibration (or sound) at the optimal frequency to be carried by rock. This way, if a miner is trapped, he could communicate with the surface via morse code. This device should also be able to receive and amplify said vibrations (or sound) It seems that tapping is the best way to search for trapped miners, so it would seem a logical step to automate/improve on this tapping.
-- senatorjam, Apr 02 2010

Teenager Invents “Cave Texting” Underground Low Frequency Radio http://www.inquisit...ow-frequency-radio/
[Spacecoyote, Apr 05 2010]

" I'll just signal my location by creating an earthquake - they can trace me by the fallen debris " ;-)
-- normzone, Apr 02 2010


Normzone...I am thinking more along the lines of tapping on a rock, not earthqauke starting strength
-- senatorjam, Apr 02 2010


+
-- Mustardface, Apr 03 2010


Sorry, bad signal-to-noise ratio likely. With the reverberations a long-wall mine excavator makes, I don't think the tapping is going to be heard.
-- RayfordSteele, Apr 05 2010


The various veins and impurities would have different resonant frequencies and therefore make it very difficult to communicate an intelligible signal through them.
-- Postscript, Apr 05 2010



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