Late 15th and early 16th century mining techniques, De re metallica It is estimated that the total gold production in Karnataka to date is 1000 tons. The metal continued to be mined by the eleventh century kings of South India, the Vijayanagara Empire from 1336 to 1560, and later by Tipu Sultan, the king of Mysore state and the British. During the Chola period in the 9th and 10th century AD, the scale of the operation grew. ) The Champion reef at the Kolar gold fields was mined to a depth of 50 metres (160 ft) during the Gupta period in the fifth century AD. (Golden objects found in Harappa and Mohenjo-daro have been traced to Kolar through the analysis of impurities - the impurities include 11% silver concentration, found only in KGF ore. In the area of the Kolar Gold Fields in Bangarpet Taluk, Kolar District of Karnataka state, India, gold was first mined prior to the 2nd and 3rd century AD by digging small pits. Under the Eastern Roman Empire Emperor Justinian's rule, gold was mined in the Balkans, Anatolia, Armenia, Egypt, and Nubia. The legions were led by the emperor Trajan, and their exploits are shown on Trajan's Column in Rome and the several reproductions of the column elsewhere (such as the Victoria and Albert Museum in London). Gold was a prime motivation for the campaign in Dacia when the Romans invaded Transylvania in what is now modern Romania in the second century AD. The gold served as the primary medium of exchange within the empire, and was an important motive in the Roman invasion of Britain by Claudius in the first century AD, although there is only one known Roman gold mine at Dolaucothi in west Wales. Mining was under the control of the state but the mines may have been leased to civilian contractors some time later. Romans used hydraulic mining methods, such as hushing and ground sluicing on a large scale to extract gold from extensive alluvial (loose sediment) deposits, such as those at Las Medulas. īronze Age gold objects are plentiful, especially in Ireland and Spain, and there are several well known possible sources. A group of German and Georgian archaeologists claims the Sakdrisi site in southern Georgia, dating to the 3rd or 4th millennium BC, may be the world's oldest known gold mine. The graves of the necropolis were built between 47 BC, indicating that gold mining could be at least 7000 years old. The exact date that humans first began to mine gold is unknown, but some of the oldest known gold artifacts were found in the Varna Necropolis in Bulgaria. Landscape of Las Médulas, Spain, the result of hydraulic mining on a vast scale by the Ancient Romans