Knowledge of Conservation and Restoration

Mining and Ancient Metalworking Studies in Cultural Heritage: Values and Necessities

Amin Allah Kamali,
Volume 5, Issue 1 (3-2022)

Abstract

Iran, with a history spanning over 7,000 years, is considered one of the pioneers of ancient mining and metallurgy in the world. Ancient mining and metallurgy, as part of Iran's engineering and cultural heritage, play a crucial role in understanding the history of these technologies and advancing related knowledge. The study of this field contributes to the preservation of this historical and cultural legacy. Since the 1990s, organized efforts in the field of ancient mining and metallurgy have been initiated in Iran, leading to significant achievements, including the implementation of national and international projects. This research reviews key studies conducted in the field of ancient mining and metallurgy, presenting the outcomes of activities in this area. Moreover, it highlights the values embedded in the heritage of ancient mining and metallurgy, emphasizing the need to preserve this valuable legacy and register significant ancient mining and metallurgy sites as national heritage assets.

Investigation of Metal Smelting Remains at the Dehneh Lashkar Site (Robat Posht-e Badam) with Emphasis on Petrographic and Geochemical Analysis of Slags

Aminallah Kamali,
Volume 7, Issue 4 (2-2025)

Abstract

Yazd Province, with its diverse mineral resources and long history of metallurgical activities from prehistoric to contemporary times, is considered one of the primary centers of ancient metalworking in the Central Iranian Plateau. The Dehneh Lashkar metal smelting site, located near Robat Posht-Badam village, was identified during regional geological surveys and studied for the first time. From this site, covering an area of 140 square meters, 10 slag samples were collected, with 4 samples subjected to petrographic analysis and 4 samples analyzed chemically using ICP-OES. The examined samples exhibited distinct macroscopic characteristics, including dark green to black coloration, irregular morphology, porous to dense textures, and dimensions ranging from 2 to 7 cm. Petrographic studies revealed that the slags primarily consist of fayalite (Fe₂SiO₄), pyroxene, and glassy phases, with spinifex and porphyritic textures indicative of rapid cooling and incomplete melt crystallization. Polished section analyses further confirmed the presence of copper sulfide phases, including bornite (Cu₅FeS₄), covellite (CuS), and native copper (Cu) within the slags. Chemical analyses indicated an average copper concentration of 1.96 wt% and zinc concentration of 0.88 wt%, suggesting the use of Cu-Pb-Zn polymetallic ores as the primary raw material. The average calcium oxide (CaO) content of 24 wt% points to the use of carbonate rocks (likely limestone and dolomite) as fluxes to adjust viscosity and lower the melting temperature. The chemical composition of the slags suggests an average smelting temperature of 1100–1200°C, consistent with the use of siliceous and carbonate fluxes to enhance metal separation. This study provides evidence of an ancient metalworking industry at the site based on petrographic and chemical analyses of the slags. The main research questions addressed the types of metals extracted and the metallurgical processes employed. Based on the findings, the site was primarily exploited for copper extraction. Although insufficient surface evidence was available for precise dating, petrographic and chemical studies indicate the use of advanced metallurgical technologies capable of achieving temperatures of 1100–1200°C and employing combined siliceous-carbonate flux systems to optimize the reduction and metal separation processes.

Investigation of Metal Smelting Remains at the Dehneh Lashkar Site (Robat Posht-e Badam) with Emphasis on Petrographic and Geochemical Analysis of Slags

Aminallah Kamali,
Volume 8, Issue 1 (6-2025)

Abstract

Yazd Province, with its diverse mineral resources and long history of metallurgical activities from prehistoric to contemporary times, is considered one of the primary centers of ancient metalworking in the Central Iranian Plateau. The Dehneh Lashkar metal smelting site, located near Robat Posht-Badam village, was identified during regional geological surveys and studied for the first time. From this site, covering an area of 140 square meters, 10 slag samples were collected, with 4 samples subjected to petrographic analysis and 4 samples analyzed chemically using ICP-OES. The examined samples exhibited distinct macroscopic characteristics, including dark green to black coloration, irregular morphology, porous to dense textures, and dimensions ranging from 2 to 7 cm. Petrographic studies revealed that the slags primarily consist of fayalite (Fe₂SiO₄), pyroxene, and glassy phases, with spinifex and porphyritic textures indicative of rapid cooling and incomplete melt crystallization. Polished section analyses further confirmed the presence of copper sulfide phases, including bornite (Cu₅FeS₄), covellite (CuS), and native copper (Cu) within the slags. Chemical analyses indicated an average copper concentration of 1.96 wt% and zinc concentration of 0.88 wt%, suggesting the use of Cu-Pb-Zn polymetallic ores as the primary raw material. The average calcium oxide (CaO) content of 24 wt% points to the use of carbonate rocks (likely limestone and dolomite) as fluxes to adjust viscosity and lower the melting temperature. The chemical composition of the slags suggests an average smelting temperature of 1100–1200°C, consistent with the use of siliceous and carbonate fluxes to enhance metal separation. This study provides evidence of an ancient metalworking industry at the site based on petrographic and chemical analyses of the slags. The main research questions addressed the types of metals extracted and the metallurgical processes employed. Based on the findings, the site was primarily exploited for copper extraction. Although insufficient surface evidence was available for precise dating, petrographic and chemical studies indicate the use of advanced metallurgical technologies capable of achieving temperatures of 1100–1200°C and employing combined siliceous-carbonate flux systems to optimize the reduction and metal separation processes.

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