That is the secret to a gold pegged currency, in a way. The value of gold and the currency both explode relative to other trade values. I don't know if anyone knows exactly what will happen, but it completely borks the asset class, who sit on massive sums of property while the banking class forces useless currency down the throats of working castes.
I "expect some turbulence on re-entry."
However… There is an order to things. A team with 40 years to plan, research, observe, etc… They may be able to pull off some magic where the economic timult is kept to a minimum while the swindlers suddenly find themselves holding the bag as the citizens of every nation have wealth restored to their currencies.
I don't know exactly what that magic would be, but there is a reason China only went to the gold standard after our tarrifs took effect. It appears like a trade war, but remember that China and the U.S. were mutual hostages as producers and consumers, respectively. With the tarriff in place, the Chinese will likely lose that requirement to devalue their currency due to the trade deficit, which means less buying of our treasury bonds.
It looks like a trade war, but it is really a procedural deconstruction of the current world financial system while installing both temporary and permanent supports so as to avoid collapse.
As for what if new deposits are found… There are a ton of deposits all over the world that are completely unexploited. Look up "Pea Ridge Mine" - Soros started fucking with Missouri really hard right after that survey came out.
The thing is, though, that mining requires work. Energy, labor, equipment, etc - miners won't sell for less than it costs to mine, and it sets a sort of baseline level for gold, silver, etc. Going full bore into new nuclear power sources and other such things will give us much wider access to all processed minerals. We have been rather stagnant and dormant for half a century or more. A full century if you exclude the fun and games to support World War 2. The Great Depression was an earlier version of the script before Hitler started running a bit too far outside of his.
When we were given reign over our economy, again, we snapped into overwhelming industrial output. Any nation can follow a similar course, and the world would be all the better for more nations flooding the world with innovation and intrigue.