Long-term mercury mining activities in the soil-plant system in Almaden (Spain)

摘要

Almaden is the worlds largest mercury mining district and is located in Central Spain within the Province of Ciudad Real, extending over an area of about 100 square kilometres. Production from Almaden represents more than 30% (285000t) of the total known mercury produced throughout the world. Exploitation of the mercury deposits can be traced back to the Celtic and Roman times and the long-term mining activities ceased in May 2002. However, significant quantities of ore were stockpiled prior to that time and retorting of the ore was discontinued at Almaden in February 2004. Hg ore at Almaden is dominantly cinnabar (HgS), but elemental Hg (Hg<'0>) is also present and in some deposits it is locally abundant. The three most important mines included: Almaden, El Entredicho (an open pit) and Las Cuevas. Even after many years of inactivity, areas of Hg mining contain elevated Hg concentrations primarily as a result of inefficient mining procedures and incomplete extraction of Hg, and Hg contamination can be significant over 100km from the source