The Omarska deposit was originally comprised out of three ore bodies: Jezero, Buvac and a small ore body known as Mamuze. Ore reserves from Jezero and Mamuze have already been fully excavated. Since 2011, only the Buvac pit is in operation. It is formed within a carboniferous clastic and carbonate sediments. The genesis of this deposit is attributed to hydrothermal replacement and syn-sedimentary processes. The ore body is mainly composed of limonite-goethite mineralization, which was formed during weathering and oxidization of the primary siderite bodies.

Omarska mine is located in the north-eastern part of the Ljubija metalogenetic area in the north- western part of Bosnia and Herzegovina. Since the foundation of ArcelorMittal Prijedor until today, approximately 29 million tons of ore have been excavated at the site of Omarska mine, around 115 million tons of waste has been removed, and more than 21.5 million tons of iron ore concentrate has been produced and dispatched. The annual production stands at the level of 1.5 to 2.1 million tons. Originally, "Mamuze" and "Jezero" open-pit mines were used for exploitation, whereas the production continuity was achieved in 2009, when the "Buvac" open-pit was launched. It remains in operation today, within the scope of mining operations performed in the Omarska mine.

From a historical perspective, industrial iron ore mining in the area of the mine was first established by an Austrian mining company in 1916. The mines were nationalized in the 1950s and were then owned by the Iron Ore Mines Ljubija until 2004.

The ore is excavated at the open pit Buvac of the Omarska mine and processed in the processing plant.

The processing plant involves crushing, screening, gravity separation, magnetic separation and filtration. The plant is close to the mine site and crude ore is transported to the plant through a conveyor. Power is supplied from the national grid through a local power distribution company. The mine is in close proximity to public roads and a state railway, which is used for transporting the final product to the customer. Additionally, ArcelorMittal Prijedor operates a limestone quarry, from which the output is used for filling of the roads in the mine, as well as product for external customers.

The technology applied in the ore preparation is based on the gravitational and magnetic separation of limonite iron ore, featuring an average quality of 49.50% Fe, 12.50% SiO 2 and 12% H2O. Further on, through crushing and multiple screening processes, followed by classifying on spiral classifiers and hydro-cyclones, and the treatment of fine fractions on high-intensity elec ........