The neighboring mountain of Kosmaj was also rich in ores which were excavated by the Romans. In July 2000, during the excavations for the new sports complex in the village of Babe, a spring was discovered in the valley of the Pruten Creek. In the process, a hidden entry into the vast complex of Roman mines was discovered, too, being obscured for centuries. There is evidence of the extraction of silver, iron and lead. In the 3rd century AD, the Kosmaj mines were one of the most important in the Roman Empire, and were administered by the Roman procurator Babenius, whose name is preserved in the name of the Babe village. In the 1970s and 1980s, experts from the National Museum in Belgrade explored the area and discovered many mining necropolis, centered around the villages of Babe, Stojnik and Guberevac. It is estimated that there are some 100 ancient mining shafts on Kosmaj, which go below the ground and are wide. After the Roman period, mining activities ceased, only being revived in the Medieval Serbia.