The mine is located in Diaccialetto, along the ditch Siele in the municipalities of Castell’Azzara and Piancastagnaio and it was the largest field cinabrifero the Amiata.
They had levels of cinnabar up to 38% in mercury and the field was cultivated to a depth of 200 m.
It is one of the most famous mercury mines in the area and seems to have been cultivated already in proto-historic and Etruscan (the Etruscans used cinnabar to paint pottery and frescoes grave, digging deep for up to 40 m) and certainly also in the Middle Ages.
It was probably part of the quarries of “quicksilver” Selvena exploited by Aldobrandeschi already in the thirteenth century.
The mine was reopened in 1847 only to be abandoned in 1939, together with the nearby mine of Solforate Schwarzenberg. The resumption of work in 800 emerged that most of the richest veins had already been cultivated in ancient armor and found in fir and stone wedges.
Mining activity was revived in the contemporary pit No. 1 since 1974 by companies SMMA and Samim group ENI, until final disposal in 1981.
The Siele was a complex structure consists of both mining (tunnels and wells) from both plants for ore processing. In the early ‘900, around the field was born a real village, with houses, schools and church.
Of this mine and ‘was completed the environmental cleanup of the metallurgical plant with the recovery of some facilities for reuse in the Mining Park of Monte Amiata, and you can visit the factory and the houses of the miners.