 Mercury became very valuable in the Americas in the mid 16th century due to the introduction of amalgamation, a process that uses mercury to extract the metals from gold and silver ore. Mercury was exported to the Americas, although there was also a source of mercury in Peru.As Spain was impacted by the loss of its South American colonies, and the increasing economic importance of coal, Almadén became less appropriate for the site of a national mining school.It was relocated to Madrid in the 1830s.