All right, for now he'll stick to the plan of getting spellsilver on-planet instead of trying to figure out whether this solar system has an asteroid belt.
Keltham will ask a few more incredibly strange questions, then have them go through every single step of the process with ingredient costs and labor costs and success reliability and lost mass attached to those, then ask about every other process that has ever worked for refining spellsilver out of any ore no matter how expensive that was, then spend any remaining time until dinner listening to summaries of bright ideas that definitely don't work.