Production of pig iron and steel increased about sevenfold in the 1960-70 period, reaching levels of 1.25 million tons and 1.8 million tons, respectively. The same was true of rolled steel products, the volume of which rose to 1.42 million tons. Nevertheless, Bulgaria remained a net importer of iron and steel throughout the entire period. In 1970 the import surplus amounted to 272,000 tons of pig iron and 96,000 tons of steel. Nonferrous Metals Reserves of nonferrous metals are reported to be more plentiful than reserves of iron ore. Unofficial claims have been made that copper reserves will meet requirements during the next fifty years despite the planned rapid growth in output. Similarly, known reserves of lead and zinc ores were said to be sufficient to supply the needs of available smelters until 1990. A foreign observer, however, noted that plans for large-scale expansion of nonferrous mining and smelting may be frustrated by the deteriorating quality of the ores being mined and that metal output may not rise much beyond the level attained in the late 1960s. In fact, mine output of lead and zinc in 1970 was not higher than it had been in 1960, although the mine output of copper increased at an annual rate of 7.1 percent from 1967 to 1971. In this context it is noteworthy that data on nonferrous metals were omitted from the official statistical yearbook published in 1972. In 1972 the minister of heavy industry pointed out that the relatively small planned increase in the output of the nonferrous metals industry in the 1971-75 period--22.8 percent--was dictated by inadequate supplies of raw materials. He stated that prospecting for new deposits would be intensified and stressed the urgent need to increase the degree of metal recovery from ores and the need to utilize fully all ore components. Nevertheless, the minister assured his audience that the requirements of the economy for copper, lead, and zinc in the 1971-75 period would be met from domestic production, except for 3 to 10 percent of certain types of rolled metal. He called for the construction of plants to extract the metal from the industry's tailings as a means for partially eliminating the troublesome shortage. Copper is mined south of Burgas; in the Sredna Gora mountains near the town of Panagyurishte; and in the western Stara Planina mountains, south of Vratsa. A deposit is also being developed at Chelopets, near Sofia. The ore is concentrated locally and is smelted and refined in plants at Eliseyna, Pirdop, and the Medet complex near Panagyurishte. Production of refined copper from ores and reused scrap increased from 14,000 tons in 1960 to 24,000 tons in 1965 and 41,000 tons in 1971. More than half the copper output is processed into copper profiles, sheet, and wire at the Dimiter Ganev plant in Sofia--the only plant for manufacturing rolled products. Bulgaria has both imported and exported copper and copper products.