Ah, this one was intended 😅
Should have been in the description, but yeah, at 35 meters it's deemed "too far away". I entend to create a "research center" where you can unlock features as you progress into the game. Drilling deeper, better understanding of the ore body, gears or vehicles that don't break/get consumed as easily, etc.
In the future, I also intend to add inclined drifts allowing you to add up to +- 10 meters on your level, as well as secondary down ramps.