And you'd have to move and process that one cubic kilometer of water as well, which sounds easy on paper (just use a pump bro) but that's err. 1.000.000.000.000

And you'd have to move and process that one cubic kilometer of water as well, which sounds easy on paper (just use a pump bro) but that's err. 1.000.000.000.000 liters of water. Heating that up by 1 degree takes 4 kW per liter, or 4 petawatt for the whole lot. Ridiculous scales, in any case. If I were to think creatively, I'd create a compound or a filter creature that accumulates gold particles naturally and concentrates it. I have no clue what that involves.