Your mod gave me an idea for a different mod: an open-pit mine :D

There would be an entity/bot which digs the sand from one area and stockpiles digged material on another pile, effectively reducing the depth from a bunch of tiles and increasing the height elsewhere. It could then also uncover hidden underground resources. You could then fill the dug out area with water. The levels you dug out or dump on would also spawn cliffs indicating the pits and mountains.

Could be a fun way to dig the reources and overhaul ore patches -> you would then need to uncover them first and do something with the collected sand :D

Sounds cool. I would dump the sand somewhere to make a hill.

Yeah, that sounds really exciting :) The ground in Factorio will get a 3rd dimension — height. The main question is how to visualize it

Yeah, visualization could be pretty hard. I had an idea to spawn cliffs each X feet to visualize "countour line", similar to how it's done on vulcanus/fulgora.