It's almost irrelevant how much silver is underground or in other forms like jewellery and silverware. What matters is available silver to meet market demand. When entire economies are dependant on a metal in short supply, someone has to go without. It will become an issue of national security when militaries cannot access silver.
What we'll probably see is a campaign from governments to sell our jewellery, silverware and Bullion first. This will be accompanied with a sharp increase in price and the halting or restriction of production from government Mints. There will be signs before a buy back/confiscation takes place.
The US mint has been caught out intentionally limiting their production already (claiming it's a planchet shortage). They are in violation of the US code Chapter 31, Section 5112 (e) that requires them to produce coins in quantities sufficient to meet public demand... So we're already seeing this on small scale today.
As for below ground deposits: Remember that it doesn't matter how big the deposit is. What's important is the production capacity of the mine. A very large open pit mine will still have a production capacity of about 40-50 Mozs per year. Additionally, silver being mined as a by-product doesn't help at all. A gold, copper, zinc or lead mine isn't going to try to increase production to target silver. Also, we're expected to reach peak copper, lead and zinc mine production by 2028-2032, which will result in less silver mined as a by-product.
There's a lot to unpack when looking at the supply side of silver. The facts are that we're seeing 200+ Moz deficits. These deficits are being negated by aboveground stockpiles, and that's the only reason the price suppression is possible. There stockpiles will eventually run out, and when they do, we'll have major corporations and militaries around the world competing for scraps. We then have to ask: who will take priority? Mints will be the first to go (because making coins and bars will not take priority over making bombs etc), and a campaign for scrap metal refining will be enacted to come after jewellery and silverware.
^^^ with all of this said, that's exactly why China is encouraging it's citizens to buy gold and silver. It's so they can come in and take it from them when the timing is favourable. Silver is the second most useful commodity on the planet. Our modern world relies so heavily on silver that it only comes second to oil. Making private ownership of Bullion illegal is an easy course of action to take for such a necessary commodity. Much easier to target the very few with silver, than locking down the entire world and getting them to take an experimental shot
