Archaeometallurgical studies on slags of the Middle Bronze Copper Smelting Site S1, Styria, Austria (original) (raw)
Related papers
Hauptmann, A. & Modaressi-Tehrani, D. (eds.), Archaeometallurgy in Europe III: Proceedings of the 3rd International Conference Deutsches Bergbau-Museum Bochum, June 29 – July 1, 2011, Der Anschnitt, Beiheft 26, 301-308, 2015
The copper smelting site S1 in the Eisenerzer Ramsau Valley, Styria, is the largest Bronze Age copper smelting site excavated in the Eastern Alps. The site was almost completely excavated from 1992 to 2006 and ten roasting hearths, six double furnaces, a number of pits of variable size, form and function, and three separate slag dumps have been recorded. The use of this smelting site covers the whole period of the Middle Bronze Age from the 16th to the 13th century BC and might extend as far as the 11th century BC. The aim of this archaeometallurgical study is the reconstruction of the smelting process at this site and the discovery of possible diachronic changes or developments in the technology of smelting during the different phases of use. Therefore slags of the different archaeological phases were analysed for their chemical and mineralogical composition. A few slags were analysed with Mössbauer spectroscopy to obtain further information about the conditions during the smelting process. The results of the analyses show that nearly all slags belong to one particular step of the smelting process which was the production of raw copper or copper matte under reducing conditions at temperatures around 1250 °C.
In the Late Bronze Age, the extractive metallurgy of copper in north-eastern Italy achieved a peak of technological efficiency and mass production, as evidenced by the substantial number of metallurgical sites and the large volume of slags resulting from smelting activities. In order to define the technological features of the Late Bronze Age metallurgical process, more than 20 slags from the smelting site of Luserna (Trentino, Italy) were fully analysed by means of optical microscopy, X-ray powder diffraction, X-ray fluorescence spectrometry and scanning electron microscopy. Three different slag types were identified based on mineralogical and chemico-physical parameters, each being interpreted as the product of distinct metallurgical steps. A Cu-smelting model is proposed accordingly.
Journal of Archaeological Science, 2015
A number of slags of all known sites in the Italian Eastern Alps showing occurrences of copper smelting activities in the Copper Age have been characterized by lead isotope analysis. All the investigated smelting slags from Trentino (Romagnano Loc, La Vela, Gaban, Acquaviva di Besenello, Montesei di Serso) and Alto Adige/Sud Tyrol (Millan, Gudon, Bressanone Circonvallazione Ovest) have been recently characterized by thorough mineralogical, petrographical and chemical analysis and demonstrated to be the product of copper smelting activities of chalcopyrite-based mineral charges, with an immature technological extraction process referred as the "Chalcolithic" smelting process. Revision of the available radiocarbon dates show that the metallurgical activities pertaining to the analysed slags can be attributed to the third millennium BC. The lead isotope analysis indicates clearly that the mineral charge use for the smelting process was extracted from nearby mineral deposits. The detailed analysis of the spatial distribution of ores and slags allows for the first time to define the local organization of the metallurgical operations.
Der Anschnitt. Beiheft 42, 2019
Since the 1990s, archaeological investigations of prehistoric copper mines have been conducted in the famous mining district of Schwaz/Brixlegg in the Lower Inn Valley, North Tyrol (Austria). A large number of sites (mainly from the Late Bronze Age and up to the Early Iron Age) have been investigated so far with the aim to record and to analyse this extraordinary prehistoric mining landscape. A focal point of research is the reconstruction of the process chain connected to the prehistoric copper production comprising ore mining, beneficiation, and smelting processes. This paper discusses the final step of metal production, the smelting of copper ores. Whereas dozens of prehistoric mines and several sites with traces of mechanical ore treatment have been examined in the last years, only two smelting sites from the period under consideration are known so far. One of these sites, the smelting site Rotholz (municipality of Buch in Tyrol), could be prospected by geophysical methods (geomagnetic) and partly excavated during several campaigns in 2010 and 2015-2017. A detailed documentation of the archaeological remains could be performed in the frame of the DACH-project “Prehistoric copper production in the eastern and central Alps - technical, social and economic dynamics in space and time” (supported by the Austrian Science Fund FWF, the German research foundation DFG and the Swiss National Research Foundation SNF, 2015-2018). The Rotholz smelting site dates into the 12th/11th cent. BC (Late Bronze Age, Urnfield culture, dated by 14C-analysis). The basic raw material used for the local copper production were fahlores which occur in considerable quantities in the Devonian dolomitic hostrock (Schwazer Dolomit). As a result of the excavations a multiphase roasting bed, a battery of four furnaces, a slag heap (crushed slag, slag sand) and many other informative structures could be uncovered and documented. The findings (ceramic, slags, ores, stone tools, animal bones,…) have been furnished to archaeological and archaeometrical analysis.
The Raxgebiet (Lower Austria) is a large region in the Alps with abundant archaeological remains of copper smelting (structures, by-products, finished objects). This potentially indicates a high volume of metallurgical activity, which mainly consisted of primary smelting from sulphidic ores. The most abundant of the slag types is cake-shaped with plenty of un-decomposed quartz within a fully crystallised silicate matrix. This is in stark contrast to the other two types of slag that clearly reached a completely liquefied state. Based on the morphology, composition and microstructure of the slag and analyses of other by-products (matte, furnace lining) we have attempted a reconstruction of the copper smelting process. This includes roasting the ore, smelting it to get matte and, finally, smelting the matte to obtain copper metal.
Archaeometry, 2009
Slags from the Pb/Ag medieval (14th century) smelting plant located at Bohutín, Příbram district, Czech Republic, were studied from the mineralogical and geochemical points of view. Two types of slags were distinguished: (i) quenched slags formed mainly by Pb-rich glass and unmelted residual grains of SiO 2 and feldspars, and (ii) crystallized slags mainly composed of Fe-rich olivine (fayalite) and glass. The mean log viscosity value of the slags calculated for 1200°C was 2.119 Pa s. The morphology of olivine crystals was used to estimate the cooling rates of the melt, for some slags indicating rates > 1450°C/h. The projection of the bulk composition of slags onto the SiO 2-PbO-FeO ternary system was used for rough temperature estimates of slag formation, lying probably between 800 and 1200°C.
Metallurgical Slags as Traces of a 15 th century Copper Smelter
The research focuses on assessing the metal content, mainly copper, lead, iron and also silver in metallurgical slag samples from the area where historical metallurgical industry functioned. In the smelter located in Mogiła, near Krakow (southern Poland), whose operation is confirmed in sources from 1469, copper was probably refined as well as silver was separated from copper. Based on the change of chemical and soil phase content and also taking cartographic and historical data into account, considering the restrictions resulting from the modern land use the area was determined whose geochemical mapping can point to the location of the 15 th century Jan Thurzo's smelter in Mogiła near Krakow. Moreover, using the same approach with the samples of this kind here as with hazardous waste, an attempt has been made to assess their impact on the environment. Thereby, taking the geoenvironmental conditions into account, potential impact of the industrial activity has been assessed, which probably left large scale changes in the substratum, manifested in the structure, chemical content and soil phase changes. Discovering areas which are contaminated above the standard value can help to identify historical human activities, and finding the context in artefacts allows to treat geochemical anomalies as a geochronological marker. For this purpose the best are bed sediments, at present buried in the ground, of historical ditches draining the area of the supposed smelter. Correlating their qualities with analogical research of archeologically identified slags and other waste material allows for reconstructing the anthropopressure stages and the evaluation of their effects. The operation of Jan Thurzo's smelter is significant for the history of mining and metallurgy of Poland and Central and Eastern Europe.
The smelting copper slags from the archaeological sites of Transacqua and Segonzano in Trentino (Italy) were fully analysed to study the extraction of copper from copper and iron sulphide minerals that were carried out in the southeastern Alps during the Late Bronze Age. A combined approach involving physical, chemical, mineralogical and petrographic analyses was applied on over 130 copper slags from Transacqua and Segonzano. Three different types of slags were distinguished from the mineralogical and chemical points of view, differing in the size and relative amount of the unreacted sulphides and matte, the size of metallic copper prills, the ratio between unreacted quartz and newly formed silicate phases and viscosity. By combining all the observations, it is suggested that the three types of slags are the product of a Cu-smelting process formed by three main operations: slagging, matting and refining, which were standardised in the southeast Alps between the fourteenth and the eleventh century BC.
In: R. Turck, Th. Stöllner, G. Goldenberg (eds): Alpine Copper II. New Results and Perspectives on Prehistoric Copper Production. Der Anschnitt Beiheft 42, Bochum 2019, 229-244., 2019
Mining archaeologists and archaeometallurgists have attempted to decipher the prehistoric multistage process of copper smelting from chalcopyrite for a number of decades. For this purpose, various examinations of archaeological remains, historical and ethnographical comparisons and archaeological experiments have been carried out. Apart from archaeological structures such as furnaces, very little if any of the original raw materials (copper ore) or final products (matte/raw copper) remain from which the process could be reconstructed. Only smelting slag is usually available in vast quantities. By conducting geochemical and mineralogical analyses of this by-product, information can be gained concerning the raw material, charge composition, process temperature, furnace atmosphere and even the resulting (intermediate) product. Despite these efforts, a number of questions remain unsolved, e.g. the much-debated association of different slag types with different process steps or reactors. From an archaeological point of view, this is due in part to the fact that slag samples are usually described and discussed in insufficient detail, if at all. They are often generally classified as one of only two tentatively defined types: “slag cakes” and “plate slags”. This paper aims to demonstrate the additional value of a detailed archaeological evaluation of macroscopic characteristics of smelting slag using finds from the Oberhalbstein region (Canton of Grisons, Switzerland) as an example. The typology and morphology of smelting slag must be taken into account in addition to, and not instead of, further investigations, particularly of geochemical and mineralogical analyses.
The Earliest Copper Metallurgy in Northern Italy: Study of Copper Smelting Slags of Bronze Age
2011
The present Ph.D. project attempts to clarify the metallurgical knowledge achieved at the end of the Bronze Age in Northern Italy starting with the study of the Trentino area slags. In archaeology, this area is well known for its protohistoric copper smelting sites dated to Late Bronze Age, such as Luserna, Transacqua and Segonzano. During the second year of activity, the huge amount of Luserna and Transacqua slags was investigated in order to understand: 1) the technological development of the smelting processes performed, 2) the possible use of different working-steps in the metal production process and the copper extraction efficiency, 3) the ore source of the smelted minerals. Therefore a multianalytical approach has been applied and besides the minero-petrographic analyses, the research has involved lead isotopes analyses and metallurgical smelting experiments. These experiments were carried out in order to directly explore the roasting and the slagging processes, which are fun...