Regional Geology

The Krumovgrad License area is part of the Rhodope Metallogenic Zone, a volcanic arc of Tertiary age that extends approximately 800 kilometres from Serbia through southern Bulgaria and northern Greece to Turkey. Volcanism was related to collision of the Rhodope massif with a fragment of the African platform. At the end of the Eocene era and during the Oligocene era, the collision was followed by extension, formation of grabens and an intense volcanism was induced.

Basement rocks of the area consist of Precambrian gneisses and metasediments together with lesser Paleozoic-Mezozoic metasediments. Tertiary (Paleocene-Eocene) conglomerates, sandstones, siltstones and limestones unconformably overlie the basement metamorphics. The basal portion of the sedimentary package is the primary host to mineralization within the Krumovgrad License area.

Acid to Intermediate volcanism began in the Upper Eocene and progressed episodically until the Upper Oligocene. Several lead-zinc (gold-silver) epithermal vein deposits are related to volcanoes formed during this period, including Zvezdel and Madjarovo, which are situated 15 kilometres west and 25 kilometres north-east of Krumovgrad, respectively. More recent Neogene-Quaternary sedimentary cover occurs throughout the region.

Regional Geology of the Krumovgrad Area

Prospects in the Krumovgrad License area are hosted within a Lower Tertiary (Paleocene) terrestrial graben. They are predominantly hosted within the basal breccioconglomerate unit (Krumovgrad Group) which is composed of coarse basement blocks (up to metre-scale) within a variously clay-rich to sand-rich matrix. They were deposited during the fault-bounded basin development and associated rapid erosion. The sediment package through time progressed from breccioconglomerates, coarse sandstones, through to the siltstones and limestones. The limestone towards the top of the sequence has been dated as Upper Eocene (Priabonian) and represents the end of sedimentation and the initiation of volcanism.

Krumovgrad Project Geology

Mineralization

The Ada Tepe deposit is a high level epithermal gold-silver deposit, formed during the Neogene within the Southern Rhodope tectonic zone. Hydrothermal breccias, open-space fill textures and also the presence of sinter material, suggests proximity to the paleosurface and a low-sulphidation nature of mineralization.

The gold and silver mineralization at Ada Tepe has been subdivided into two types, based on the mineralized zone geometry and style, as follows:

• “Wall” mineralization: A shallow dipping (15 degrees north), tabular (nine metres average thickness) zone developed directly above the basement-sediment contact; and
• “Upper” mineralization: A series of east-west trending steeply dipping vein sets with ancillary vein sets in other orientations, occurring as complimentary structures.

Texturally the high grades are related to open-space filling textures, which is common in bonanza-type epithermal gold deposits.