was derived from
agricultural raw materials; the proportion of industrial materials in
manufacturing continued on its post-World War II upward trend in the
1960-70 period from a level of 24 percent in 1948 and 49 percent in
1960. This trend was sustained by the relatively rapid rise in the
production and imports of industrial materials compared to the slower
increase in agricultural output and imports. Because of the limitation
of domestic resources, further industrial expansion will necessitate
ever larger material imports.

Iron and Steel

The main deposits of iron ore are located at Kremikovtsi, northeast of
Sofia, and at Krumovo in the lower Tundzha valley. Other small deposits
of little or no commercial value are scattered in the Strandzha
mountains, in the western Stara Planina, and at several locations in the
Rodopi (or Rhodope Mountains). The ore in the Kremikovtsi deposit is of
low grade; it has a mineral content of about 33 percent and requires
beneficiation. Reserves at Krumovo were reported to be of better grade
but much smaller. Available evidence suggests that mining at this
deposit was discontinued after the mid-1960s. Its site is far removed
from the country's two iron and steel mills.

Reserves at Kremikovtsi were estimated a number of years ago to contain
from 200 million to 250 million tons of ore. An official
Russian-language survey of Bulgaria, published in 1969, cited a figure
of 317 million tons for total iron ore reserves but mentioned only the
Kremikovtsi deposit as one being mined. In a review of the country's
natural resources, published in a Bulgarian technical journal in
mid-1970, it was stated that known reserves of iron ore would last
another fifty years. At the average annual rate of iron ore output in
the years 1968 and 1969 the reported life span of the deposits indicates
a reserve of only 133 million tons as of 1970. Whatever the actual
reserves may be, domestic iron ore has had to be supplemented by imports
of about 1 million tons per year from the Soviet Union and Algeria to
meet the requirements of the metallurgical industry.

Reserves of steel-alloying minerals are reported to be available,
particularly manganese, chromium, and molybdenum. The quality of the
manganese ores, however, is low, and reserves of chromium are
insufficient for the needs of the economy. Output data are available
only for manganese ore. Production of this mineral declined by about 60
percent in the 1