Extensive research by eastern European scholars has reshaped our understanding of early copper ore mining techniques that were used during the Late Neolithic and Early Copper Age in the Balkans. Since the late 1960s, archaeological investigations at two copper mines—Rudna Glava and Ai Bunar— have revealed the complexity of early copper metallurgical techniques and revised our understanding of early copper exploitation strategies and their relationship to other socioeconomic processes.
One of the most well-known prehistoric copper mines is the site of Rudna Glava in eastern Serbia. The site, located 140 kilometers east of Belgrade on the Romanian border, was a magnetite mine until the late 1960s. Archaeological excavations by Boris-lav Jovanovic in the 1970s revealed over twenty prehistoric mine shafts that followed veins of copper ore throughout the limestone massif.
The mine was excavated in antiquity using techniques that had been employed for thousands of years to exploit lithic resources, such as chert. Armed with stone mauls and antler picks, the prehistoric miners followed the vertical veins of copper ore into the hillside. They employed a method of heating and cooling to break up the ore and facilitate quarrying. First they would light fires along the wall face. Then they would throw water onto the hot rock, causing it to crack and thus making it easier to chip apart. Some of the veins were followed 15 to 20 meters into the center of the hill, with small horizontal access platforms extending off the main shaft. In those cases where the shaft appeared to be in danger of collapsing the miners built stone supporting walls out of the debris they excavated.
The mine at Rudna Glava is well dated to the Late Neolithic and Early Copper Age, a period also known as the Chalcolithic, which took place during the second half of the fifth and the first half of the fourth millennium b.c. This dating is based on pottery from the Vinca culture that was found in the mine shafts. Jovanovic recorded three different accumulations of pottery in the shafts. The oldest, which was found on an access platform in the mine along with a damaged antler tool and a large stone maul, dates to the transitional phase, known as the Gradac phase, between Early and Late Vinca, during the fifth millennium b.c. The two other pottery concentrations are characteristic of Late Vinca culture and date to the early fourth millennium b.c.
Another early copper mine was excavated at the site of Ai Bunar in northern Bulgaria in the Sredna Gora Mountains of central Bulgaria. The mine at Ai Bunar is roughly contemporary with the mine at Rudna Glava, and the miners used similar techniques. They excavated narrow open trenches to follow the veins of copper carbonates into the hills. As at Rudna Glava, archaeologists found antler picks and stone mauls in the mine shafts, in addition to two shaft-hole copper tools and the remains of three human individuals.
The ceramics found at Ai Bunar are characteristic of the ceramics found in the sixth layer at the Ka-ranovo tell (Karanovo VI) and date to the late fifth millennium b.c. While this discovery demonstrates that the mines at Ai Bunar were in use during the later fifth millennium b.c., other evidence suggests the mines probably were in use somewhat earlier, possibly as early as the end of the sixth millennium b.c. Copper objects and ore that have been demonstrated chemically to have derived from the sources at Ai Bunar were found at several sites in south-central Bulgaria that are contemporary with Ka-ranovo V, a phase that dates to the beginning of the fifth millennium b.c.
Chemical analyses, primarily lead isotope analyses, carried out by E. N. Chernykh, Noel H. Gale, and several Bulgarian specialists have demonstrated that Ai Bunar and Rudna Glava were not the only sources for copper ore in prehistory. The analysis of copper artifacts from several sites in south-central Bulgaria suggests that at least four other copper sources were exploited, though they remain unidentified.
A handful of other copper mines have been located in northern Thrace, one of which contained Karanovo V and VI pottery, and another prehistoric mine also is known to have existed at Mali Sturac, a site in the Rudnik mountain range in central Serbia. Unfortunately, none of these sites has been extensively explored, and little has been published about them.
Zooarchaeologists distinguish between primary animal products, such as meat, bone, and marrow, and secondary products, such as milk, wool, and traction (animal labor). Primary products, also known as slaughter products, require the death of the animal and thus can be harvested only once. Secondary products are extracted from the living animal. This is a crucial distinction because secondary products permit a higher yield from the same number of animals. While people can acquire primary products from either wild or domestic animals, secondary products normally are available only from domestic herds. Some researchers have suggested that secondary products may have been the motivation for animal domestication, but the evidence does not support their use to any significant extent until considerably later than the time when animals were domesticated.
It is difficult to study the use of secondary products in prehistory because they typically are not preserved in the archaeological record. Most primary products leave relatively direct evidence in the form of animal bones. Bones are by-products of meat consumption, and bone breakage patterns can indicate their use for marrow. For the most part, secondary product use must be approached indirectly. Sometimes artistic representations portray these products or their use, but it is quite possible for societies to use them without leaving a pictorial record. Indeed, with the exception of the use of animal traction to draw wheeled vehicles, the first artistic depictions of secondary products generally are much later than their earliest use. Thus, the most widely employed method to detect the use of secondary products is the demographic study of the animal bone assemblage.
Such a study focuses on the differing herding strategies that are necessary to achieve significant production of secondary products. If meat is the main concern and secondary product use is absent or insignificant, most males typically are slaughtered at a juvenile or subadult stage, when growth slows and more feed produces little additional weight gain. If herders want milk, they need lactating females, and they must limit competition from the infant animals through slaughter or early weaning. Thus, most males likely will be slaughtered as infants, and the herd will consist mainly of adult females. Both males and females produce wool, so when wool is the desired secondary product, the herd will consist of both sexes, and most animals will live into adulthood. Traction (pulling plows or vehicles) also requires adults, and males or castrates may be better suited to the task. Each strategy creates a distinctive kill-off pattern, or mortality profile. Age and sex information can be derived from the study of the animal bone remains to reconstruct these strategies.
MILK
All mammals produce milk, so it is certainly possible that ancient herders used dairy products from the beginning of animal domestication. There are real advantages to dairy products. Animal milk is a good substitute for human milk when a mother dies or cannot produce adequate milk. Dairy products provide a sustainable source of protein and fat that substantially enhances the productivity of the herd. For example, Paul Halstead has calculated that a Greek Neolithic (early farming) village of 40 to 240 inhabitants could meet its caloric needs with 2,40014,400 sheep if the villagers ate only the meat, but they would need only 1,000-6,000 sheep if they used the milk as well. Dairying thus could be used to reduce herd size and devote more land to agriculture or, alternatively, to keep more animals alive for their wealth value while still deriving protein and calories from the herd. Moreover, processed milk products, such as cheese, can be stored, unlike fresh meat or milk.
