Legend has it that the enchanted millers used this magical pond to wash their gold.
In the case of this legend it can be said that there is some truth in it, in fact the water of the lagoon was used in the process of extraction of alluvial gold by the Romans around the first century A.D. The form of extraction consists of pouring water from some height over the land in order to separate the gold from the inert materials. At the end of this process there is a set of round stones that are removed from the mining site to form the conheiras.
In the case of this cache you only need to look around to see the piles of round stones. Most of the conheiras are placed near streams, but in this case the extraction center is in a lagoon.
On the Roman installations was built in the twentieth century a structure for the extraction of aggregates for use in construction, which has since been deactivated.
The conheiras are currently in the process of recognition by the European Union, and legislation is expected soon that will lead to their protection throughout Europe. While this is not happening, and also due to ignorance about these kinds of places, the conheiras continue to be desecrated, as many locals take the stones for use in outdoor flooring.