Summary:
The Salave gold deposit is located within the West Asturian-Leonese Zone (WALZ) of the northwestern portion of the Iberian Massif. The Salave concessions are situated at the eastern border of the Mondoñedo nappe within the WALZ, which is separated from a less deformed area to the east by the basal thrust of the nappe the Mondoñedo thrust.
West of the Mondoñedo thrust, and within the Salave property, the area is underlain by quartzite, sandstone, argillite, shale, and greywacke of the Cambro-Ordovician Los Cabos Series that have been metamorphosed to slate, arenite, quartzite, and graphitic slates. The Mondoñedo t hrust places the Upper Cambrian Los Cabos Series over the Upper Ordovician Agüeira Formation.
The Salave deposit is underlain by granodiorite, which is a small part of the Porcia Intrusive Complex that extends approximately 4km, from Rio Porcia to Represas Playa just east of Tapia. The granodiorite crops out in the western part of the complex. To the south, the Complex is covered by thin Quaternary alluvium. Igneous rocks in the Salave area are directly related to the mineralisation and comprise several stocks and dykes whose ages range from 330Ma to 287Ma (Carboniferous). Oxidation is not intensive and extends for a few metres below the surface except along larger faults and structural zones where it can locally exceed 200m vertically.
The deposit is hosted mainly by the strongly altered Salave granodiorite at its western boundary, close to the contact with the Los Cabos sedimentary sequence.
Gold mineralisation occurs in a series of stacked, north to northwest trending, shallowly southwest dipping irregular lenses related to faults and fracture zones that are parallel to the contact of the intrusive and metasedimentary rocks. The faults and fracture zones appear to be related to one or more vertical structures some of which contain high-grade gold mineralisation.
These structures may play an important role as conduits and opening shallow dipping structures with subsequent deposition of hydrothermal solutions, particularly at the contact with the metasediments.
Most of the gold mineralisation has been delineated within an area of approximately 500 m wide, 780 m long, and tested to 420 m deep. Gold mineralisation occurs in a series of stacked, north-to-northwest trending, shallowly southwest dipping irregular lenses related to faults and fracture zones that are parallel to the contact of the intrusive and metasedimentary rocks. The faults and fracture zones appear to be related to one or more vertical structures some of which contain high-grade gold mineralisation. These structures may play an important role as conduits and opening shallow dipping structures with subsequent deposition of hydrothermal solutions.
Gold mineralisation at Salave is related to hydrothermal alteration of the host granodiorite. The highest gold grades are associated with intense albitesericite alteration with fine-grained arsenopyrite, commonly disseminated as fine needles, pyrite and stibnite. Destruction of the original texture is a major feature of the most intensively altered and mineralised granodiorite. Quartz veins, and quartz¬carbonate molybdenite-bearing veins present in the deposit do not contain gold and represent a separate mineralising event.