Mosquito Missles. It will bust up any rock in one hit. Advantage when busting up Nvidium is the range you can do this at. This helps save fps, and thus less rocks cluster back up on you

When doing large clusters it is going to take multiple times of busting the roids up before they are all gone. So on the first visit, just break up all the rocks with mosquito missles ( or other looong range attack with no aoe ) untill all you have left are collectable rocks and the rocks that are one stage away from being collectible. ( plus possible clustering back up due to system performance ) This will fill up 10 mercuries with 400 plus ore each.
When those mercuries are done by either a full cargo or no more collectible rocks to pick up, go back in and use either apsg or a mobile mining laser. With all the rocks left being just one step away from being collectible you can safely bust them up with the psg, and its best to use mobile miner to bust up what ever rocks clustered back up again.
Doing it this way really seems to be the least time consuming/ least waste. Spent the last week doing nothing but mobile mining and started 5 new games ( experimenting.. I think I am gonna move on now before I start dreaming of asteroids

