Oil beats coal in an underground naval base

What fuel problems would coal- and oil-fired ships create in a cold underground naval base?

Oil is the better choice because it stores efficiently and avoids coal dust choking the cave, while a habitable interior should keep it warm enough to pump.

Coal handling would spread dust throughout an enclosed cave system and create a serious ventilation and cleanliness burden. Oil can be stored more compactly and moved through pipes, making it far better suited to the base. Cold can require preheating before pumping, but a cave maintained at a temperature suitable for personnel should also keep the fuel workable. Fuel choice therefore shapes base infrastructure as well as ship propulsion.