Asalamualaykum,
My understanding is that Zakat is paid on gold and silver extracted from mines immediately i.e you don’t wait an entire year.
If you own shares of companies that mine gold/silver would you need to look at the gold/silver output, work out 2.5 % of that, and then pay zakat in proportion to to your ownership of the company ? Or does the normal zakat calculation for shares apply (2.5 % of market value/liquid assets)