Economopoulos - Mining Activities in Ancient from the 7'h to the 1" Centuries BC 109

Mining Activities in Ancient Greece from the 7th to the 1st.Centuries BC

John N. Economopoulos* the sources of the metals still remain vague. It is interesting to note that gold is in fact a very com­ Greece, considering its relatively small size, monly mentioned metal in the Iliad and the Odyssey. contains an extraordinary variety of mineral wealth At the beginning of the 8th century BC, several mining with exceptional commercial value. The tectonic centers emerged and developed (Rodopi, Paggaion, structure of Greece is rather complex characterized by Thassos, Lavrion, Kythnos, Serifos, Sifnos, etc.) and six main geotectonic zones which contain a wide some of them became famous. In Cyprus, copper and variety of igneous, sedimentary, and metamorphic was also produced. rocks. The country possesses world class deposits of There is no doubt that among the famous mining several industrial minerals, notably magnesite, benton­ and metallurgical centers of Greek antiquity, Lavrion ite, perlite, pumice, asbestos and marbles as well as remains at the top not only because of the importance globally important metallic ores, especially bauxite. and duration of its activities, but also because of the Significant deposits of Ni, Pb-Zn-Cu-Fe (mixed value and significance of the spectacular archeological sulfides) Cr and Mn also exist and have been ex­ findings. Many ancient authors, poets, historians, and ploited. Quartz, feldspars, kaolin, emery, and other geographers mentioned the Lavrion area in their minerals have also been mined on a secondary scale. works. That is why the focus and central concentra­ On the other hand, due to the unlimited deposits of tion of this paper is on the mining and metallurgical limestone, the days; the schists and the slates, the activities of the Lavrion area during ancient times. cement industry is currently flourishing along with the Before going into detail on the subject, it must be construction industry which depends on these miner­ stated that the main metals known to the Greeks, with als. Finally, coal mining is very extensive and Greece the exception of gold, were rarely found in a free, ranks seventh in world production of lignite-brown native state, but as compounds (ores). Early on, coal. miners exploited placers and veins which outcropped Nevertheless, mining and metallurgical activity in on the surface. When these sources became ex­ Greece is nothing new. Exploitation of the mineral hausted, the Greeks turned to underground mining. wealth of the country started during the ancient Generally speaking, mining involved prospecting for period. If we consider the archaic period from and collection of the minerals, followed by a specific 2500 BC to 1125 BC, we must admit that our find­ processing technique designed to enrich the precious ings and information are very limited, if not poor. By material. The subsequent refining was achieved in the the end of the period, it was known that gold existed metallurgical process. Plato, Aristotle, Theophratus, mainly in northern Greece (Macedonia, Thrace, Island Diodorus, Siculus, Strabo, Herodotus, Plutarch, of Thassos) in the native state as well as in placer Xenophon, and Pliny are among the sources and all deposits. Some gold objects were found in the central described these processes. Specifically, these authors Peloponnese not far from a small placer deposit. The recorded the principal locations of the minerals and precise source of the Minoan and the Mycenaean gold processing techniques of their times, while also occa­ are not known. Probably some local sources had been sionally including the commentaries of earlier authori­ used but soon they were exhausted. ties. During the period 1125 BC to 800 BC, Unfortunately, their chronological evidence is often metallotechnical activity expanded considerably but vague and confusing and different mining and process­ ing techniques are elaborated on in their descriptions. The first attempts to exploit mineral deposits were " john N. Economopoulos is a Professor of Mining at limited to easily won ores (outcrops) which could National Technical University of , Greece. · readily be collected and treated in primitive furnaces. When vein mining began, however, in each succeeding 110 1996 Mining History Journal period, with the development of improved techniques, BC and there are indications that production of silver miners penetrated progressively deeper underground. took place during the 7th century BC. In the 6th As all mining engineers know, it is in the nature of century BC, the production of silver was gradually mining that each phase of exploitation tends to increased and reached its peak during the 5th centu.ry destroy evidence of previous workings so that ancient BC when Athens was under the leadership of an mines are fundamentally poor sites for archeological amazing statesman, Pericles, who initiated the well stratification. An attempt to establish a precise known Golden Age of the glorious classical period of chronological sequence is at best a complicated matter Ancient Greece. During the year 483 BC, a rich new and often virtually impossible to re-create. Neverthe­ deposit was discovered--the Maronia deposit. Its less, in spite of this difficulty, mines can provide a exploitation tremendously advanced the mining wealth of enlightening archeological material to activities in Greece which has continued ever since and discern the various techniques employed. As we will taken the form of an industry. see, in our case at Lavrion, pits, open-cast workings, The production of silver was considerable during the adits, shafts, galleries, washers, furnaces, and cisterns 4th century BC, only to decline in the 3rd century BC. are still intact and may be examined. Likewise, some There was a revival during the middle of the 2nd tools and mine working devices, even in a fragmentary century BC that eventually went bust. The time of the condition, can be found and contribute to the overall Roman domination was close at hand. Indeed, during picture. Piles of rejected material can yield valuable the first part of the 1st century BC (probably 87 BC) information not only about the scale of the operations, mining and metallurgical activities, which resulted in but, following analysis of their contents, show evi­ a total production of about 3500 tons of silver, dence of the degree of the success and recovery probably came to an end. For the next 2000 years, achieved in processing and refining. , statues, Lavrion was erased from the annals of mining history, and other metal objects can give us important infor­ passing into oblivion beneath centuries of pine-tree mation on the metallurgical side when subjected to debris. chemical and X-ray fluorescence analysis, electron probe microanalysis, spectrometry, and other examina­ GEOLOGY tion techniques. The composition of metals and alloys and their In order to cover the subject in a spherical way let physical characteristics in turn reveal their method of us first give some general information concerning the manufacture and the mechanical work to which they geological and mineralogical picture of the Lavrion have been subjected. Now, let us go back to our area. There are five main geological strata composed Lavrion case. Lavrion lies at the southern edge of of alternate layers of calciferous rock (limestone and Peninsula, about seventy-five kilometers south­ marble) and of micaschists. These layers have differ­ east of Athens. When mining and metallurgical ent degrees of porosity and offer different resistance to activities acrually started in this area during the the upward thrust of hot, mineral-rich liquids from the ancient period is not clear. By the middle of the 4th earth's depths. century BC, the great Athenian historian Xenophon, In a typical cross section we notice--from the top referring to the period when mining in Lavrion down--the upper schist (Cretaceous), the upper marble started, wrote: "Everybody knows that the Lavrion and the lower schist Qurassic), and the lower marble mines are very old, but nobody even dares to say (Precambrian). In this way, three contacts are formed about the time they have started." Therefore, the where the ore exists. The first and third contacts question is still pending: How old are they? proved to be the richest ore-bearing levels. As already There are some indicators. The lead that occurs in suggested, the metalogenesis is of hydrothermal nature. Minoan artifacts found on the island of Thera, when Hot liquids with the dissolved metals came from veins examined by isotopic analytical methods, proved to be appear generally where the ore is. identical to the Lavrion lead ore. Near Thorikos, very Ancient miners, although they had a very limited close to Lavrion, a runnel was discovered containing knowledge of geology, knew this rule very well. They ceramic which could be dated to the early Bronze Age. were looking for guides--e.g., the granitic veinlets--so Consequently, work probably started circa 3000 BC, they followed the contact in order to meet the min­ and blossomed later. It is today accepted that ore was eral, and even when the veinlets disappeared they still actually won in Mycenaean times, that is, between followed the contact. The ores were mixed sulfides 2000 and 1200 BC. It seems that organized mining called BPG (from Blende, Pyrite, Galena) as well as probably began during the middle of the 8th century oxidized minerals, mainly smithsonite (ZnC03) and Economopoulos- Mining Activities in Ancient Greece from the 70. to the 1" Centuries BC 111

cerussite (PbC03) . The ancient miners were only stoping" technique. As the length of the galleries searching for galena and cerussite because these increased ventilation problems inevitably appeared, minerals were argentiferous. Rich galena of the third forcing them to sink vertical shafts. Later, the shafts contact could contain 1.2 to 1.4 kilograms of silver were sunk not only for ventilation purposes, but they per ton of ore. They naturally exploited the first served for exploration (reaching the contact), develop­ contact and, when the mineral was gradually ex­ ment, and transportation (hoisting) of the extracted hausted, they were obliged to dig deeper to meet the material. The ore was loaded into baskets and carried second and third contacts. Their effort to reach and by workers (on their shoulders) who climbed the to exploit the rich third contact is obvious, but the ladders installed in the shaft. The rate of advance of shafts never exceeded a depth of 120 meters and no the galleries and the shafts was, of course, very low, exploitation took place whenever there was water, i.e., probably a few centimeters per day. The miners used below sea level. a limited range of hand tools: hammers with iron heads, chisels or needles of iron for use with hammers, MINING and shovels, mostly wooden. To carry the ore, they used leather sacks or baskets of woven grass. For The earliest mining technique was to cut horizon­ lighting they had torches and oil lamps especially tally from the surface at the contact level, forming in designed to last a whole work shift. Elementary mine such a way open-cast pits and workings of consider­ maps were drawn on day plates and stones to depict able volume. Penetrating deeper they started driving topography. galleries of very small cross sections, usually 0.6 m2 (0.7 m x 0.85m). Only young boys could walk along PROCESSING THE ORE these openings. When the galleries intersected the metalliferous area, they were enlarged in order to win After a preliminary sorting of the lumps of ore the ore, forming considerable chambers or rooms (see underground, a secondary sorting was done outside Fig. 1). Where these rooms were quite large a column near the shaft head or the gallery mouth to remove or pillar of natural rock or ore was left to support the sterile, rock pieces. If the mineral collected in such a roof. Obviously they applied the "room and pillar• way was already rich enough, it went directly to mining method so widely used today in coal and metal smelting. As the exploitation became more intensive, mmmg. Sometimes they tried to recover the rich especially during the 5th century BC, they were mineral pillar by replacing it with a pile consisting of obliged to extract ore having a lower silver content waste rock. In thicker veins they utilized the "breast which required certain processing. The first stage was to break the large lumps of ore into small pieces by hammering it with iron mallets, fairly flat­ topped boulders, or blocks of

1 " limestone or marble. The v second stage was to grind the ' I already broken ore pieces into a fine, sandy, granulated form. This was done in hard stone mills of various kinds. The flat type (hopper queen) mills were mostly used which consisted of trachyte. They measured 40 centimeters by 60 centimeters and were 15 centimeters high. Some conical mills were also found but they were probably used only for grind­ ing wheat. Nevertheless, this Fig. 1 Enlarged gallery in [he ancien[ Lavrion mines. type of mill was "invented" 112 1996 Mining History Journal

Fig. 2 Rectangular washery some 2500 years later in the U.S. by Simon, who containing some ore and the lighter sterile grains, first developed the well-known Simon's cone. In the went into a transverse channel and then to consecutive meantime, it was widely used to grind corn in Pompeii channels and sedimentation basins. Lastly, the water up to 79 AD. was freed from all the ore and sterile rocks and, once The next stage of ore processing was to wash the clarified, was redirected into the water tank to refill it. fine-milled ore in a flow of water in order to separate The contents of the troughs were emptied and allowed the heavier grains of ore from the lighter grains of to dry, whereas the contents of the channels and sterile rock. This way, a classification by gravity basins were emptied and disposed of, forming various occurred and the ore was cleaned and concentrated, piles. making it ready for smelting. For this purpose two Repetition of the process might be necessary to main types of washeries were used: The level, rectan­ obtain maximum recovery of the argentiferous ore. gular one (see Fig. 2) which was the most common There was a big problem with the water supply and the helicoidal (spiral) one which was developed because the Lavrion region was and is one of the later, probably by the end of the 4th century BC (see driest areas of the country. That is why the sparse Fig. 3). There are many rectangular washeries scat­ seasonal rainwater had to be collected and conserved tered around the Lavrion area, but only a few have in large round or rectangular cisterns to be used all been uncovered, cleaned, and maintained. The year. In the helicoidal washeries water and ground method of operation was as follows: Water was ore was introduced at one end and, due to the form allowed to flow through the funnel holes out of the and inclination of the helix, the water carried the main water tank and into wooden troughs (sluices) set material from trap to trap depositing first rich ore, in front of the tank on the washcry's floor which was then poorer ore and finally sterile rock, reaching a slightly inclined. The trough's bottom contained cup­ lower tank in a clarified state to be used again. The like depressions (traps) where the heavier grains of the trough was cut into the upper surface of a series of ore (finely ground ones were shoveled in the upper large stone blocks set side by side. end of the trough) was concentrated. The water, still It was an ingenious and amazing achievement. Its Economopoulos - Mining Activities in Ancient Greece from the 7'h to the 1•• Centuries BC 113

SMELTING, CUPELLATION, AND RESMELTING OF THE LITHARGE

The enriched, concentrated ore was next taken to the furnace for smelting in order to recover the argentiferous lead in a metallic state. The ore was subjected to smelting under reducing conditions in vertical furnaces using charcoal as the reducing agent. The furnace had an inside diameter of about one meter and its height probably did not exceed four meters. Its structure consisted of micaschist, and the internal walls were lined with fire day. The operation was continuous. The furnace was fed from the top with a mixture of ore (mainly oxidized ores and eventually small amounts not exceeding l5o/o galena) and charcoal. The necessary air was pumped in with the aid of hand blowers and a temperature of from 1000° to 1200° C was reached. The produced metal as well as the slag emerged from a taphole near the floor. The molten metal produced in these furnaces was a mixture of lead and silver. In order to separate these two metals, they used cupellation furnaces. Air was pumped in vigorously with the aid of blowers and, in the heat produced by burning wood, the lead was oxidized to lead-oxide (PbO) or litharge, leaving the silver in a molten state of its own. The process required special cupels consisting of suitable refractory materials. Fig. 3 Helicoidal (spiral) washery Cupellation was done at a temperature of from 900° to 930° C and when the silver appeared the principle was "invented" again 2300 years later by temperature was then increased to at least 960° C. Humphrey with his well-known "spiral concentrator." The whole process was very delicate. The quantities It is worth writing a few words concerning another of the metal to undergo cupellation were very large remarkable achievement: the various mortars were and the silver content relatively low. This process was used for the lining of surfaces coming in contact with absolutely necessary to attain excellent recovery of water to make them impermeable to avoid leakage. silver since litharge was later resmelted to produce As was proven, these mortars contained considerable metallic lead and, therefore, any amount of silver

amounts of PbO, Fe20 3, ZnO, and MnO and were contained in it was a definite loss. Further heating of applied in three consecutive layers. Even today they the litharge in a furnace similar to one used for are remarkably well preserved and present a complete smelting the ore could reduce--with the aid of example of impermeability. charcoal-the lead oxide and produce lead metal again Recendy, two additional helicoidal washeries, which for commercial use. do not contain traps (riffles), were discovered in Lavrion. They were probably used for the treatment MINING RIGHTS of poorer ores. It must be noted that every helicoidal AND TilE LABOR FORCE washery was located very dose to a rectangular one. Furthermore, there was another startling discovery. The mines of ancient Lavrion belonged to the state. Pieces of stones and sluices were found in Macedonia Any free man could obtain a concession by paying the that probably date from the 4th century BC. If in the proper fees to lease a certain mine, or even a certain final analysis they are remnants of helicoidal washeries gallery, for three, seven, or ten years, depending on then a transfer of technology took place from Lavrion the conditions that prevailed in the works. It seems to other Greek mines in the ancient world. that there were many operators as suggested by the 114 1996 Mining History Journal

plates found on the site. These operators could also ples and mosaics of Pella in Macedonia, and the have been owners of washeries and smelting furnaces. erection of glorious monuments such as the Athenian According to estimates, there were about 11,000 Acropolis, all of which made a lasting "imprint on workers employed during the 5th century BC in the Greek society and culture as well as the rest of the major Lavrion area, producing 20 tons of silver per Hellenized world. year. Some of the workers, especially the supervisors, Apart from its other claims to fame, Classical lived near the mines in rooms having baths and Greece can attribute much of its glory to individual showers and other facilities. There were also slaves achievement, assuring the nation a place among the working at the mines. Their standard of living was Great Ages of humankind. The miners of Lavrion tolerable. If they proved very capable they could be during the ancient period had almost nothing. They promoted to higher positions. had no doctors to cure them, and no drugs to fight their illnesses. They had no power to help reform INFLUENCE OF MINING AND their work, and they had no recreation aside from a METALLURGICAL ACTIVITIES ON di:ama play in an open air theater. They had only CULTURE their brawn and their brains. AND CMLIZATION In the eternal darkness of the underground workings they had a flickering light to help them extract the Much of the silver of the Lavrion mines was taken valuable minerals. To overcome these unfavorable to Athens to be minted into coins by the state, while odds, they had a power and a will that shadowed a good portion was exported. The lead--1.4 million them and led them to their destiny: the light of tons was produced--was also used for domestic and progress. commercial purposes. Copper was also a valuable product of the district, whereas iron was used for ' REFERENCES making necessary tools. During the archaic and Ardaillon, E. "Les mines de dans l'antiquite," Paris: classical periods of Greek history, operations related Fondemoing Ed., 1897. to mining and metallurgy undoubtedly played an Campesy, A. "Le Laurium," Paris: Rev. Univ. des Mines, important role in the creation of ancient civilization, No.6, 1889. and at the same time helped Greece to confront its various enemies successfully. It is well known that a Conophagos C. "Le Laurium antique et Ia technique Crecque de la production del'argent," Athenes, 1980. sudden peak in the production of silver in Lavrion . helped , for example, to build a naval Cordellas, A. "Le Laurium," Marseilles, 1869. fleet that won the Battle of Salamis in 480 BC. This Crosby, M. ''The leases of the Laurium Mines," Hesperia v. great sea victory eventually contributed to the creation 19 (1950). of the Athenian Empire. Healy, J. "Mining and Metallurgy in the Greek and Roman It must also be noted that by the middle of the 4th World," London: Thames and Huston, 1978. century BC, Philip, king of Macedonia, initiated the intensive exploitation of the gold and silver deposits Ledoux, C. "Le Laurium et les mines d'argent en Grece," of Paggaion Mountain. This great wealth allowed him Revu des deux Mondes v. 13 (1872). to create his own empire that he handed down to his Mussche, H. "Thorikos: A guide of the excavations," more famous son, Alexander the Great, who Bruxelles, 1974. conquered expansive kingdoms in the Near East from Negris, P. H. "Laveries anciennes du Laurium," Annales des 334 to 323 BC. The influence of mining on the Mines Paris (1881). development of Classical Greece was overwhelming. Rangabe, M. "Du Laurium," Paris: Imprimerie Nationale, The wealth allowed for the creation of the Golden 1870. Age of Pericles' Athens, the construction of the tern-