Final answer:
The silver mines at Potosí were among the most productive in the world. However, the discovery of silver at Potosí had significant long-term consequences on the Spanish economy.
Step-by-step explanation:
The statements that accurately describe the silver mines at Potosí are:
b) The silver mines at Potosí were among the most productive in the world.
d) The discovery of silver at Potosí had no significant impact on the global economy.
The silver mines at Potosí, located in present-day Bolivia, were indeed among the most productive in the world. They provided a vast amount of silver that fueled the Spanish economy and contributed to the global commercial boom. However, the discovery of silver at Potosí had significant long-term consequences on the Spanish economy, leading to the country's decline.