this can be accomplished by just having your workers clear all the crystal, trees, etc until you find all the hidden artifacts. i got this just before heading off to the desert world, so it may require you to find some things unlocked by story progression. i do not remember specifically whether or not i found anything in the snow world, but there are a good number of things (gears, eyeballs, and so on) in the forest world. actually i found a few more gears after this achievement, so they may or may not count toward it.
UPDATE: according to other users in the comments you DO need to get all the gears and there is also nothing to get in the desert world.