Regional Geology

The Kapan mine is situated in the eastern part of Zangezour mining region, and with respect to its geological structure and metallogeny, is one of the most geologically complicated areas within the bounds of Small Caucasus. The mine area covers an area of Jurassic-age intermediate volcanics that have the potential to host significant bodies of epithermal-porphyry mineralization similar to those currently defined within mine area. These mainly Middle Jurassic volcanogenic and sedimentary formations have a stratigraphic thickness of approximately 1,000 metres.

The Upper Jurassic and Lower Cretaceous volcanic and sedimentary formations are localized on the north-eastern and northern limbs of the Kapan Anticline and have a total thickness of 2,500 metres. Middle Jurassic and Upper Jurassic-Lower Cretaceous formations are cross-cut by Palaeogene age extrusive and sub volcanic dikes of diabase, andesite and dacite composition. In addition, quaternary basalts occur locally within the bounds of the mine area.

Generalized geology of Armenia

Mineralization

Typically for Kapan, mineralization is hosted in veins which often present as closely spaced anastamosing vein structures, displaying a broadly east-west strike and steep (70-85°) dip to the north or south. The strike length of the mineralized bodies varies from several tens to several hundreds of metres, and average vein width is 0.7 – 1.5 metres. The down dip extent of the veining varies from 100 to 200 metres, and rarely extends beyond 300 metres down dip.

The mineralization at Shahumyan occurs in altered dacite, andesite and basaltic host rocks. The main ore minerals are chalcopyrite, sphalerite and minor galena, along with gold and silver. Mineralization styles include massive sulphide veining, stock work and network veining and disseminated styles.

The mineralogy of the Kapan mining area is distinguished by its constant pyrite-chalcopyrite association. In some areas chalcosine, bornite, spalerite, galena, tenatite, telluride and others are present. The mineralogy of the pyrite-polymetallic mineralization also shows constant associations of pyrite + chalcopyrite + sphalerite. Galena, telluride and native gold are also present.

In the western area of the mining area, proximal to the Dzorastan River, molybdenum mineralization is found in hydrothermally altered volcanic rocks. Copper-pyrite and pyrite-polymetallic mineralization is hosted by Mid-Jurassic volcanics. The host rocks have been subjected to intense tectonic deformation and metasomatic alteration. Mineralization is generally proximal to large structures, especially at the intersections of large scale faults. The Mets-Magarin, Khalaj, Khotanan, Bashkend, Central and Western-Shahumyan fractures have all been identified as fluid pathways for mineralization.