the mineral industries of bulgaria and romania 2000 6 1 by walter g steblez northeastern region balkan peninsula comprising borders black sea to east ukraine moldova north greece turkey south southeast macedonia serbia montenegro west hungary northwest danube river forms a natural boundary between in is encompassed within mediterranean alpine folded zone which comprises carpatho branch dinaric hellenic bogdanov 1982 also constitutes primary incorporating eastern southern carpathian mountains as well apuseni arc transylvanian plateau ianovici borco? mining metalworking this has long history that was documented roman times when respectively known thrace dacia were important sources base precious metals gold nonferrous mined remain attractive investment opportunities foreign investors