Just read C2 again.....it says. "gold" and silver"......it DOES NOT SAY ORE!!!!!!!
This is the entire point to the "processes" that weren't even available at the time!!!!!!
So given the amount of time, the region in question, the era in question, the number in the party, then "thousands of pounds of refined silver and gold" could not have come from a mine!!!!!1
This is proven science, established and supported by historical documentation. The rate of loss being as high as 70% prior to 1867. Jewels could not have been traded for without an extremely long process of essay "per-piece" in order to assess, "trade value." And your author clearly states "silver" and "gold" and not "ore."

Something that could not have been achieved due to all of the factors above. "PERIOD"
Now I understand your wanting to believe in such things, as we would all like to, but "it just wasn't possible until a much later date in time" for all of the reasons posted above.

And you can take that to the bank, pardon the pun.