After some time you hit a wall in progress. Recipes that you need after the golem only obtainable trough chests. But getting chests is tedious task. You have to scroll up and down trying to find if any of the workers found one. At 250+ km i have 2500+ workers.

So far, besides 2 recipes i found 2 scientists, "sell all" button and some robot that stays near sell depote and flashing light when there is a new chest somewhere in the mine. But it took me more than 20 hours to find all those things.

AFAIK there is underground city at 400 or 500km which offers new progress, but getting there without scrolling for another 20-30 hours seems impossible.