This achievement is easy and can be done within the first few hours of gameplay.
It can be done on any "Tier 2" dirt, I prefer Icehelm as the horizontal mining makes getting to it faster and water piping more simple.
Tier 2 dirt is approx. 14 depth, the best way to find the height is to use a Tier 1 pick (Green wrapped handle) and dig, when you hit sparks, that's the start of Tier 2 dirt, one more block down and plant a Tier 2 Harvester setup. Then wait.
The first time you get Corestone, the achievement will pop.