The "unknown" author mentions the gold, silver, and jewels, but leaves it to the readers imagination as to condition- raw ore, crude field sand cast bars, and for the jewels, quantity, quality, type, it is questionable what was available on 1820's St Louis where furs were accepted as collateral for a bank loan.
There is no description of all the supplies they purchased in Santa Fe that filled their needs, or a description of their mining activities.
All this is based upon the alleged letters (Beale Papers) to Morriss by TJB, which only the "unknown" claimed to have seen.
The agent for copyright and publisher, James Beverly Ward never claimed to have seen these letters, the iron box- he only had the authors submitted handwritten manuscript, that is IF there ever was an "unknown" author.