Gold During the Classical Period
"The metals obtained by, mining, such as silver, gold, and so on, come from water."
Science in the Classical period was confined mostly to speculation. The pre-Aristotelians explained the origin of the universe and natural phenomena in the light of four basic elements - earth, water, air, and fire. This theory probably originated in the ancient Indus Valley civilization, was taken up by the early Babylonian natural scientists, and passed on to the early Greek philosophers, among whom Empedocles (c. 490-430 B.C.) is usually credited with refining the concepts of the theory. Aristotle embraced the four element theory and added another concept, that of the ether.
During, pre-Hellenistic and Hellenistic times gold and silver were mined extensively throughout the Mediterranean, in Asia Minor, and elsewhere in western and northern Europe and in Africa and Asia. A large literature exists on ancient mining in these areas, all admirably summarized and synthesized by Rickard (1932), Davies (1935), and Healy (1978).
Initially it would seem from the evidence presented by many of the deposits and dumps in Egypt, the Aeizean, Turkey (Anatolia), Iran, India, and contiguous regions that most of the gold came from eluvial and alluvial placers; only later as these placers approached exhaustion were the oxidized zones of gold quartz and sulphide deposits exploited, first by open-cut methods and then by underground workings. Fire-setting seems to have been widely employed by the Greeks and the Romans in underground mining. Pliny, in his Historia naturalis, claimed that vinegar was better than water in quenching and disintegrating the hot rock. Because of water and ventilation problems, the depth of exploitation of bedrock deposits was limited, probably to 200 m or less in most auriferous regions. Slaves and convicts did all mining. Prospecting knowledge was crude and was based principally on visual signs of the presence of gold in quartz float, in exposures in quartz outcrops, in gossans, nearby soils and weathered residuum, and in the sediments of streams and rivers. Much gophering was employed in prospecting, evidenced by an abundance of pits and shallow shafts in most of the ancient mining areas of the Aegean, Turkey, Egypt, India (Kolar), and elsewhere. The gold pan appears to have been employed for testing gossans, soils, and alluvium and for winning the metal since the earliest times. Likewise, the rocker and sluice with riffles, animal fleeces, or mats for trapping the gold seem to have been in use almost from the beginning of placer gold mining. The animal (sheep or goat) fleeces were dried and the gold was then shaken out of them into pans for further concentration. When ulex (a prickly plant of the furze or gorse family) was used, it was burned and the gold washed out of the ashes.
Some placer operations employed the boulder-riffle method of concentrating the gold; in this method boulders were arranged in such a way that as the water rushed along carrying the gold, it swirled around the boulders, depositing the nuggets and dust in the slack-water zones around and between the boulders. After an appropriate interval, the sluicing water was turned off or diverted to allow the cleanup. Stretches of streams with natural riffles, such as slate and schist beds and folia oriented at right angles to the stream direction, also appear to have been employed in some placer areas. In large placer operations, especially where high-level (terrace) gravels were exploited by the Romans, as along the Sil in Northwestern Spain and the Vrbas in Yugoslavia, hushing (booming) was employed. This method frequently required aqueducts and canals several kilometers in length for transport of the water to the crude monitors. Where bedrock quartz deposits were exploited, the separation of the native gold from the dross, mainly quartz, was accomplished by hand picking, followed by crushing and grinding in stone mortars, querns, and crude "hour glass" and other types of mills, and finally by washing on sloping boards or flat rocks. These "washeries" can be seen in pictorial form on walls and tablets in Egyptian tombs and in a dilapidated condition in a number of ancient mining regions in Greece, Egypt, and the Middle East.
GOLD DEPOSITS AND THEORIES OF THEIR ORIGIN
In early Classical times ancient gold placers and mines were known on many of the Aegean Islands, particularly Siphnos, in mainland Greece, along the southern shores of Pontus Euxinus (Black Sea), and near the western coast of Asia Minor; most were small and soon worked out by the fifth century B.C. Prospecting farther away, particularly in the region of Mt. Tmolus (the modern Boz Dag), revealed the rich electrum placers of the rivers Pactolus and Hermus (the modern Gediz). Legend has it that the Pactolus is the river in which Midas, the mythical founder of the Phrygian kingdom, on the advice of Bacchus bathed in its waters to rid himself of the fatal faculty of turning everything he touched into gold. From the Pactolus came large stores of placer gold won mainly by the Lydian kings, of whom Ardys (c. 650 B.C.) minted at Sardis the earliest gold coins existent. In the course of time the Lydian monarchs became the richest princes of their age, especially Croesus who followed Alyattes (605-560 B.C.) on the throne and whose name we associate today with enormous wealth. Another source of gold described in early Classical and later Classical times was located in Thrace and Macedonia, where the mines at Dysoron and on Mt. Pangaeus provided great wealth for Thracians, Athenians, and Philip 11 of Macedonia, founder of Philippi near Mt. Pangaeus. It appears that much gold also reached the Aegean area in early Classical times from Egypt, Armenia (Turkey), Dacia (Romania, Hungary) and from as far as Spain, Siberia, and India.
During Hellenistic times, many of the gold mines of Macedonia and Thrace were exploited intensively as were also some of those in various auriferous regions of Asia Minor. The Ptolemies, the dynasty of Macedonian Kings that ruled Egypt (323-30 B.C.), prospected extensively in Egypt, Nubia (Sudan), and probably also in Arabia, winning considerable gold from these ancient mining regions. Many of the early Greek authors mention gold and silver, but without any particular geological reference. The Iliad and Odyssey of Homer (c. 1000 B.C.), the traditional epic poet of Greece, refer to gold and silver in numerous contexts and locations, the latter probably authentic in many cases. We have also the Greek myth of Jason and the Golden Fleece. According to this myth, the Golden Fleece was taken from the ram on which Phrixus and Helle escaped from being sacrificed. It was hung up in the grove of Ares in Colchis and recovered from King Aeetes by the Argonautic expedition under Jason, with the help of the sorceress Medea, the king's daughter. In actual fact the Argonauts were early prospectors who sought the source of the ancient placers on the Black Sea. At that time (1200 B.C.) the workers of auriferous placers recovered the gold by trapping the metallic particles on sheep's fleeces placed in crude sluices. The fleeces were then hung up to dry in nearby trees and were later shaken to collect the gold.
Rafal Swiecki, geological engineer email contact
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