Teresita mine (Aramo Mine), Riosa, Asturias, Spain

Epigenetic carbonate-hosted Cu/Co/Ni deposit.
Host-rocks : Black fetid Namurian bituminous limestones (700 meters thick).
Complex mineralization with three successive primary stages and an important later supergene stage:

1) Pyrite-marcasite-bravoite: Co/Ni sulfarsenides and arsenides in dolomite; associated with acanthite. Cobaltite, Safflorite, gersdorffite.
2) Intermediate stage: Tennantite and sphalerite in quartz/dolomite.
Renierite. Chalcopyrite (with briartite inclusions) and talnakite replacing early assemblage. Tennantite and sphalerite replace cobaltite and safflorite.
3) Cu/Fe sulphides: Chalcopyrite, talnakite and bornite. Chalcocite, djurleite, digenite, covellite.
4) Oxidation sequence: Cementation copper sulfides, native elements and oxidation minerals.

Production and reserves: 200,000 tons extracted.
400,000 tons ore reserves @ 1-3% Ni and 1-3% Co, 1-20% Cu.

Ref.:
Paniagua, A. et al (1988) Bull. Minéral: 111: 383-391.