Narcea Gold Belt is a 45 kilometres long, 4 kilometres wide northeast- trending zone located in Northern Spain. Gold deposits lie within the 15 kilometres long central part of the belt and the Carlés and El Valle deposits were mined by modern methods during the first part of this century.

The gold mineralization in the central part of the belt is principally hosted by a series of Lower Cambrian to Devonian sedimentary rocks. This stratigraphic package was intruded by felsic magmas and thrusted and folded into a N20°E-trending, overturned anticline during the Hercynian Orogeny. Later extensional events resulted in the formation of three main sets of normal faults: NNE-SSW; NNW-SSE and E-W, which were the conduits for gold-rich hydrothermal systems.

The gold-copper mineralization at El Valle is characterized by mesothermal magnesium- and calcic-rich skarn deposits at the contacts of late Paleozoic intrusives as well as younger epithermal vein mineralization related to subvertical faults and quartz-feldspar porphyry dykes. Chalcopyrite, bornite, pyrite, magnetite, and pyrhhotite comprise the mineral assemblage. Where the epithermal systems crosscut the skarns, hematitic jasperoids formed. Leaching and enrichment is common in the structural zones where chalcocite, cuprite, native copper, and native gold are encountered.

Gold-copper calcic skarns characterize the Carlés deposit. The mineralized skarns are better developed along the northern contact of a granodiorite.  Key minerals are chalcopyrite and bornite. Gold prospects include La Brueva, Godán, and Ortosa. Drilling has yet to define a significant resource at any of these prospects. At Godán, drilling has encountered up to 0.45% Molybdenum.