Fornás Mine, Aríns, Santiago de Compostela, A Coruña (La Coruña), Galicia, Spain
|Latitude & Longitude (WGS84):||42° 51' 9'' North , 8° 29' 18'' West|
|Latitude & Longitude (decimal):||42.85250,-8.48833|
|Name(s) in local language(s):||Mina de Fornás, Aríns, Santiago de Compostela, A Coruña (La Coruña), Galicia, España|
|Other regions containing this locality:||Iberian Peninsula|
Fornás Mine is located approximately 100 m south of the town of the same name, crossing a small stream. It was an iron mine mainly, operated by Rio Tinto S.A., and closed in the 1970s. This mine was important and famous as the main reservoir of pyrrhotite in Spain, at least until early 1980s (Galán and Mirete). Depression of the mine was completed during the decades of 1990 and 2000 with rubble and waste generated in the municipality. Today, the upper stays (gossan) of the open pit and the dumps, partly buried by rubble generated recently by civil works (AVE) and vegetation.
It is a massive sulfide deposit, hosted in basic amphibolites (metabasites). The predominant minerals are pyrrhotite and pyrite.
There is a local legend about the origin of the mine´s exploitation, since Roman times for its wealth in gold and / or silver (not verified), whose origin is maybe a publication of Juan Lopez Cancelada (1831) "Mines of Spain "(page 23), which allocated to silver, and by its proximity to the quartz vein of the Pico Sacro, (supposedly) exploited by the Romans to extract gold, but there are no archaeological or metallogenic studies.
24 valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
298.9 - 358.9 Ma
Age: Carboniferous (298.9 - 358.9 Ma)
Comments: allochtonous units of the Hesperian
Reference: Mapa Geológico de la Península Ibérica, Baleares y Canarias a escala 1:1.000.000. Instituto Geológico y Minero de España. 
Pascual, E; Estévez, A. (1981) Estudio geológico del yacimiento de Fornás (Santiago). Cuaderno do Laboratorio Xeolóxico de Laxe 2 (vol II):191-211.
Urrutia, M., Graña, J., García-Rodeja, R., Macías, F. (1987). Pyrite oxidation processes in surface systems: acidifying potential and its interest in minesoils reclamation. Cuaderno do Laboratorio Xeolóxico de Laxe 11:131-145.
ATLANTI, C., & BISCAY, B. (1983). The mineralogy and metamorphism of some gahnite-bearing silicate inclusions in massive sulphides from Fornas, north-west Spain. Mineralogical Magazine, 47, 233-235.
IGME. Mapa Metalogenético 1:100.000, La Coruña.