The Kran Krum deposit is located about 3 km in southeast direction from the town of Krumovgrad, at the area known as Ada Тepe hill. The geological model comprises of two well-defined lithological units: a Pre-Paleogene Metamorphic Basement, and a Paleogene Sedimentary Complex.
The upper contact of the metamorphic sequence is marked by transgressional and discordant position of the Paleogene sediments, later cross-cut by oblique reverse and sub-horizontal detachment faults. The complicated morphology of the orebodies is caused by combination of structural and lithological factors. The gold mineralization is hosted predominantly by the sediments of Krumovgrad group and has textural and geochemical signature of typical low-sulfidation epithermal deposit. Two major zones of mineralization are defined – the Lower zone is represented by massive quartz-metasomatic body at the contact with basement rocks and Upper zone, represented by steeply dipping and East-West striking veins.
The area of the deposit has been explored by surface workings until 1997, but later on the team of BMM (now DPM) is conducting detailed trench and drill campaigns leading to the start of the first modern mine in Bulgaria in 2019, Ada tepe.