Abandoned copper ore field on the Medni Rid ridge near Atia village, with mining history extending from prehistory to final closure around 2001.
The Rosen ore field, centred on the Medni Rid ridge in Sozopol Municipality, Burgas Province, is an abandoned copper mining district adjacent to the Black Sea coast village of Atia. Copper has been extracted from this area since the second millennium BC, making it one of the oldest continuously exploited metal-mining districts in Bulgaria. The ridge takes its name, Medni Rid meaning Copper Ridge, from its long association with copper ore.
Modern industrial extraction began in 1954 under state ownership; mine by-products were deposited in shallow coastal waters between 1954 and 1977, contaminating the beach at Atia with mercury and radioactive elements. Following the end of state-era mining, the last copper mine in the district, the Rosen mine, closed by 1995, with other operations in the vicinity ceasing by around 2001. Decontamination works were initiated in 1997 after radiation levels in the area were found to be approximately twice the normal limit.
The ore field is now described as exhausted.
The Medni Rid ridge, whose name translates as Copper Ridge and which was known as Bakarlak until 1942, forms the north-eastern extreme of the Bosna Ridge in the Strandzha Mountains, extending from the Gulf of Burgas to the valley of the Ropotamo river. Its highest point, Mount Bakarlaka, rises to 376 metres in the northern section. Copper, along with some quantities of silver, has been mined from the ridge since the second millennium BC; the ore field is among the oldest known metal-mining districts on the Bulgarian Black Sea coast, with evidence for prehistoric copper smelting in the Medni Rid area.
Archaeological finds in the wider coastal zone document copper processing as early as the fifth millennium BC, with research suggesting exploitation of the Rosen ore field before the Early Iron Age. Thracian fortresses are known from the principal high points of the ridge. The geological character of the Rosen ore field is vein-type, with more than forty east- to northeast-striking veins along the western contact of the syenite-dominated Rosen pluton.
The most important veins were formerly mined to depths as great as 1,000 metres. Mineralisation contains magnetite, chlorite, carbonates, quartz, chalcopyrite, pyrite, and numerous other metallic minerals with an unusual geochemical signature combining iron, copper, gold, molybdenum, cobalt, nickel, uranium, light rare earth elements, tungsten, bismuth, zinc, and lead; the deposit has been classified as an iron oxide-copper-gold type. Modern industrial extraction began in 1954 under the Bulgarian state.
Between 1954 and 1977 mine by-products and waste were deposited in the shallow waters near the Black Sea coast adjacent to Atia village, resulting in contamination of the beach with mercury and radioactive elements that give the sand a distinctive dark colour. Following transition from state-owned operations, the Rosen mine — the last copper mine in the district — was closed in 1995. Other copper mines in the vicinity of Atia continued briefly, with the final closure occurring around 2001.
Decontamination work was initiated in 1997 after monitoring determined that background radiation in the Atia area was approximately twice the normal limit. The National Earth and Man Museum in Sofia holds samples of ore from the Malko Tarnovo/Burgas coastal copper mining district, described as already exhausted in its collection documentation. No current mining activity is reported in the ore field.