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Mining Drill in Ancient China (II-III century AD)
Salt was one of the most vital resources in ancient times, as it was used to preserve food long before the invention of freezers. About 2000 years ago, people in China learned how to get salt directly out of the ground using advanced drilling technology. They used a bamboo drill with a heavy drum that beat rhythmically into the soil and could eventually reach a depth of 600 meters. Occasionally, during drilling, they would hit methane pockets, and, in the end, the engineers learned to mine and use it as well.
