Factual research will reveal that there is no possible way that author would have known an estimated value of the treasure/weights unless he was talking about refined gold & silver, to which this research will reveal that there was no process for refining this gold and silver from the described area in the 1820's. Mining companies of this period suffered HUGE losses in material due to there being no efficient refining process, these losses in material sometimes being as high as 70% depending on the exact makeup of the matrix. This is all documented, it's all fact. This same research will also reveal that there is no possible way that 30 men (only 15 to 20 most of the time) could have mined that much material in the short time described, let alone process it without a process for doing so. So very-very clearly the author was completely oblivious to these facts when he penned his story many years later.

i.e., the author had no first hand knowledge of hard rock mining or the refining process, nor did he have any first hand knowledge about a few other things relating to the adventure as well. In short, his story is 100% made up.