[Ruy Dias de Bivar]

***Figuring out that the galena came from Spain led to the question, why bring ore? The documents report that the expedition also brought lead. ***

Possibly Colombus "salted" the area to keep the Spanish crown interested in the area.

[nmh]

I think you maybe right!

[Sawdring]

By contacting an expert in medieval chemistry, the scientists learned that a common practice of the time was mixing galena with powdered ores suspected of having gold or silver. The process provided an assay of the gold or silver in the newly discovered hunk of ore by comparing it with galena containing a known, small quantity of silver.

Either your theory or the theory at the end of the article.