Emerald Isle Property: Geology

GEOLOGICAL SETTING AND MINERALIZATION

Typical turquoise-green and black copper oxides in Tertiary age conglomerate.  Copper oxides are dominantly chrysocolla, black chrysocolla, tenorite, neotocite and minor melaconite (rock pick is ±14” long).

The Emerald Isle Property is underlain by the Late Tertiary Gila Conglomerate and Cretaceous granitic rocks similar to those present at the nearby Mineral Park Mine. To the south, the area is covered by Quaternary alluvium.

There are three types of copper mineralization at Emerald Isle. The first type is primary fissure vein mineralization containing copper sulphides. This was the type of mineralization which was mined in 1917 and 1918, but which is no longer the target at the present time. The second (and the main) type is primary copper mineralization within the dark conglomerate reported to consist primarily of tenorite (CuO). The third type is secondary copper mineralization, in the form of copper staining, such as malachite (CuCO3.Cu(OH)2) and chrysocolla (CuO.SiO2.H2O), which are commonly observed on fracture planes as well as within the matrix of the dark conglomerate.

North wall, Emerald Isle open pit.  Conspicuous dark copper-bearing horizons are above and in front of the vehicle.  Looking northerly.

Copper mineralization at Emerald Isle is hosted by the Gila Conglomerate. The copper zone is in the form of a mineralized lens contained within a paleochannel some 2,500 ft long, 500 ft. to 750 ft. wide. The thickness ranges from 20 ft. to 300 ft., averaging about 100 ft. In places, the conglomerate is absent and in other places it is very thick, due to faulting.

The source of the copper at Emerald Isle is interpreted to be the low grade porphyry-type copper mineralization at Alum Wash, about 3.5 mi northeast of the Emerald Isle deposit, and mineralization is characterized by dark blue to black rock.

In this respect, the style of mineralization appears to be somewhat similar to the Exotica deposit, a satellite of the giant Chuquicamata copper deposit in Chile.