Damiana & Quebrada M are large exotic secondary copper deposits developed to the west and north respectively of the Cerro Indio Muerto, where the El Salvador porphyry copper deposit is located.
Damiana forms a gently west inclined layer covering a surface area of some 3.4x2.2 km. It has an average thickness of 23 m and overburden of 20 m. It is primarily hosted by andesitic volcaniclastics of the early Cretaceous Llanta Formation, with lesser mineralisation in the overlying rhyolitic ash flow tuffs of the Palaeocene to Eocene Indio Muerto Dome and gravel cutting the Miocene pediplain.
The predominant copper minerals are chrysocolla and lesser copper wad, while close to El Salvador thin chalcocite films coats pyrite and turquoise is associated with kaolinitic lenses.
Damiana is reported to contain between 1.2 and 3.5 Mt of contained Cu
(Source: Porter GeoConsultancy, www.portergeo.com.au, 2001)