How does one mines a glacier tile?

Question

It seems that it is possible only later in game. I'd suppose that this is conditional to the discovery of a certain technology, but I cannot seem to find a reference to that effect.

Does anyone knows ?

Answer 1

You can transform glaciers into tundra. Transforming terrain is only possible with engineers, which replace workers once you have the Explosives tech.

This image sums up all the possible terrain alterations (classic ruleset):

And here's the extensive wiki page: https://freeciv.fandom.com/wiki/Terrain.