@750 meters, there is no light, and anything that grows down there ,does it very slowly but your right about anybody thinking this will not be a problem at smal

@750 meters, there is no light, and anything that grows down there ,does it very slowly but your right about anybody thinking this will not be a problem at smaller scales closer to the surface Similar technology is bieng used to pump air into abandoned mines and caverns, Also gravity batteries, where an electric train is run up hill and the used as a generator on the downhill run, also used in abandoned mine shafts. And somewhere there is a mine useing giant electric trucks that produce a surplus of electricity through regenerative braking, as the trucks are filled with rock, high on a mountain, and brake the whole way down, but climb back up empty, which uses less energy than what was generated, not significant, other than as highlight of what is possible.