Miners still research a bit of everything. I do, at least. Engines are important to upgrade every now and then, although I doubt Sloth needs new engines any time soon. (*cough* a billion duet *cough*) Weapons, armour, and shield techs are still important, as is having a good bit of defense to protect your nightly earnings. Fleetsaving is still very important.

But the big difference is pouring resources into mines instead of fleet.

I need at least three levels higher in Impulse; but my main focus is always Nanites.

More like Combustion for me.

Other than mines, I build mostly fusion reactors atm as a prerequisite to the next round of mine upgrades on the planet.