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The Tunnel Challenge
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Soft Sand

Beneath City
The soil beneath this city is soft and sandy. Tunneling through soft sand is a tricky business! Choose a tool or technique below, and try to figure out the best way to dig a shallow subway tunnel through this loose, shifting ground!

Hint: The tunnel score will help you compare the different methods. A score of 100 is the best solution for this location.


fire-setting Hand Tools Gunpowder
Fire-Setting Hand Tools Explosives
Compressed Air Drill Tunnel Boring Machine Tunnel Shield
Compressed
Air Drill
Tunnel Boring Machine Tunnel
Shield

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