Miasmos/Porpoise/Orca can drop a MTU and the barges can jetcan their ore when the hold is close to full. That’s the way I used to do it.
Mining drones are slow - you want to keep them close to your ship. I don’t like the idea of letting a Miasmos pilot assign targets for my drones and have those drones benefit from my skills and drone mining augmentor rigs - too much like an “easy button”. To be consistent, I don’t think you should be able to do that with combat drones either! One of the drawbacks of having 2 weapon systems should be the workload of managing them both.