New data on the largest ancient mining of copper ores in Central Kazakhstan

Human has used the ore minerals of the northern Betpakdala (Central Kazakhstan) since ancient times: on copper manifestations, centuries-old abandonment is not uncommon here. Archaeological studies of the area testify to the mass production of copper and bronze items during the Bronze Age. A long-term study of the Atasu settlement, a metallurgical center of the Bronze Age, established the local nature of the ore raw materials: the tin source could have been the area of ​​tin ore occurrences in the neighboring mountains, and the Dzhezkazgan deposit, located 330–350 km west of the settlement, served as the copper ore base. The materials of modern geological works in northern Betpakdala indicate that the region of the Kenkazgan polymetallic deposit, which is located 80 km southwest of the Atasu settlement, was also a large ancient mining center. There is an abandoned quarry 500 m long and up to 100 m wide with a wall height of 5–10 m above the modern bottom. The thickness of modern proluvial loams covering the bottom of the quarry exceeds 2.5 m—tools of ancient miners and fragments of pottery from the Bronze Age. The working base of the quarry (face) is covered with ancient dump masses, the thickness of which in some places reaches 17.5 m; consequently, the working depth of the quarry here was 30 m. The total volume of the mined rock mass was about 600 thousand cubic meters. m, ore in it - 300 thousand cubic meters. m (800 thousand tons). The high rationalism and skill of ancient miners are seen in the combination of dumps with the worked out space of the quarry. This fact marks an important stage in the development of ancient mining industries: such a mining system could only appear in conditions of a significant increase in the scale of ore mining. In small industries, in small quarries, it was simply inappropriate.

Spectral analysis of oxidized copper ores from the Kenkazgan quarry and its environs and ores, slags, and pellets of smelted metal from the furnaces of the Atasu settlement revealed a qualitative unity of the chemical spectrum of the analyzed samples. In light of this, the Kenkazgan-Atasu mining and metallurgical complex of the Bronze Age looks quite natural. When calculating the amount of copper smelted from the ores of the ancient Kenkazgan quarry, the amount of ore (800 thousand tons) and the average copper content in enriched ore (20%) are taken into account. With a 20-30% extraction of copper from ores in the ancient metallurgical process, Kenkazgan produced 30-50 thousand tons of copper, which is certain testifies to the existence of a powerful metallurgical production in northern Betpakdala in the Bronze Age.