[Noble713]

The appropiate menu would be the orders menu, I guess. If you build a converter, go to the planet where you put it and the aforementioned "coal cart" button will be visible next to the activate AI minister button.

I too love converters. In my current game, I've had a minerals deficit of -40,000 per turn for the past 5 years or so. Fortunately, I have an organics/radioactives surplus of about 80,000 each. Whenever my minerals supply dips below half a million I convert a bunch of the other stuff to it. Without that one converter, there is no way I'd be able to maintain my fleet.