In my past timelines with American domesticates that butterfly European colonialism, I kind of took it for granted that gold and silver would flow with trade to the Spanish even without their conquest.
Looking back on it, however, I think that I must have been wrong but I wonder how wrong. There's mixed evidence of Native Americans using mercury to extract gold and silver before contact, they seemed to prefer less intensive methods that would generally produce less gold or silver. Even if they had mercury, their elites would be far less willing to poison both the commoners and the land with mercury. With European diseases, there would be less of a labor force to mine and smelt precious ores, and while the Native American civilization's traditional methods for gaining labor could be rough they did not practice anything as harsh as the encomienda system or chattel slavery, if only because the elites needed the commoners to grow food and not revolt.
So does anyone have any thoughts on how much gold and silver the Spanish would get through trade if they did NOT conquer any territory in the mainland Americas? I'm guessing "some, but not a lot" and was just curious as to what others would think.