Watching an early game Let's Play from a beginner, it occurred to me that the principle of self-refueling could be extended to the burner drills without much downside.
It would remove the self-refueling puzzle from mining coal, but burner drills on any other resource would have the same level of challenge.
A box (or looped drill setup) would still be needed to store large amounts, but for the beginner player it could be that one extra bit of "Aha! Smart machines!" before wondering "But how will I refuel the drills on everything else?" ...
![Smile :)](./images/smilies/icon_e_smile.gif)