West-dipping Lower Jurassic Hazelton Group volcanics consisting mainly of lapilli tuff and volcanic breccia have been intruded by a Late Cretaceous to Eocene composite quartz porphyry/aplite/felsite sill or dike. The two main mineralized fracture structures occur at the east and west contact zones of this intrusion. These zones have been referred to as the Santa Maria or footwall vein and the S.H. or hanging wall vein. The vein system strikes 330 degrees and dips moderately to steeply southwest. The Santa Maria vein has a strike length of over 518 metres. The vein systems have a surface width of 76 to 91 metres. The mineralization consists of chalcopyrite, chalcocite, bornite, tetrahedrite, malachite, azurite and pyrite. Other veins or mineralized fracture zones are also present. On a local scale the mineralization occurs within quartz veins and variably silicified, composite fracture-breccia zones. Strong propylitic alteration and minor silicification occur adjacent to the fracture zones. Alteration products consist of epidote, calcite, sericite, zoisite and prehnite.

In 1967, Norcan Mines Limited outlined an inferred reserve of 750,000 tonnes grading 34.3 grams per tonne silver and 1.50 per cent copper to a depth of 75 metres on the Santa Maria zone (Property File Cyprus Anvil C.J. Coveney, 1968).