Comment on Underworld: How the Sinaloa Drug Cartel Digs Its TunnelsparentComments−joshuapants11yGPS signals don't work underground do they?They probably wouldn't. But you also don't necessarily need GPS to do this. Have someone survey it topside, use that data and a compass underground.
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They probably wouldn't. But you also don't necessarily need GPS to do this. Have someone survey it topside, use that data and a compass underground.