Introduction

The sensational finds of mummified remains of ancient miners in the opencast salt mine of Douzlakh (Figure 1) have been attracting scientific and scholarly interest since their discovery in 1994 (RCCCR 1998; Reference AaliAali 2005; Reference ShokouhiShokouhi 2005; Vatandoust & Hadian-Dehkordi 2005). In the following years rescue excavations have been conducted by the Zanjan branch of the Miras Farhangi (Zanjan Cultural Heritage, Handicrafts and Tourism Organisation) and in 2008 an initial conference was held in Zanjan. This resulted in the setting up of an international, multidisciplinary research project whose main partners are Abolfazl Aali (Miras Farhangi Zanjan), Mark Pollard (University of Oxford), Frank Rühli (Universität Zürich) and Thomas Stöllner (Deutsches Bergbau-Museum & Ruhr Universität Bochum). The project comprises scholars and scientists from Iran, France, Germany, Great Britain and Switzerland.

Figure 2.

Map of Iran, showing the location of the salt mine. Source: http://en.wikipedia.org/wiki/File:Iran_topo_en.jpg, originally uploaded by Captain Blood).

The site

The Chehrabad salt mine is located in north-western Iran, 75km north-west of the city of Zanjan, close to the villages of Hamzeli and Chehrabad (Figure 2). The area belongs to the Ghezel Ozan basin, and consists of a range-like series of hills between two narrow valleys, running from north-west to south-east. The mine is located on one of the slopes at around 1350m asl.

The interpretation of the various features and structures (Figure 3) combined with recent results of 14C analyses has led to a better understanding of the different phases of extraction and abandonment of the area investigated (Aali et al. 2012). The excavation seasons of 2010 and 2011 have produced data indicating that mining activities took place over a long time span, with the first period of mining dated to the fifth century BC (Achaemenid period). The end of this phase is marked by several cave-ins, which caused the deaths of a number of miners. This catastrophe most probably occurred around 400 BC, based on the dating of three mummified bodies (nos. 3–5) (Pollard et al. 2008). Reuse is dated to the fifth century AD (Sassanian period), from straw and dung layers found on top of layers of rock fall and erosion deposits.

Figure 3.

Detailed map of the site (graphics: Deutsches Bergbau-Museum).

Figure 4.

Iron pick with wooden handle, length c. 210mm, Archaeological Museum Zanjan (photograph: Deutsches Bergbau-Museum).

Examination of the extraction techniques through the study of tools (Figure 4) and the well-preserved mining traces show that the miners extracted salt by pillar-and-chamber mining, using metal picks and adzes. Timbering techniques seem not to have been used. It is highly likely that modes of production differed through the periods represented, perhaps in relation to trade and social conventions.

Research objectives

Apart from the fundamental task of establishing a solid chronology, and recording the mining techniques used on site, the aim of the project is to analyse the social and economic background of individuals involved in the mining activities. The finds show an extraordinary state of preservation, thanks to being embedded in salt-enriched deposits, thus offering great potential for a variety of scientific approaches to answer questions concerning mining activity, interregionality, palaeolandscape and socio-cultural aspects. An international team has been assembled to conduct research in the disciplines of:

• • Archaeobotany

• • Archaeozoology

• • aDNA analysis

• • Geomorphology

• • Isotope analysis

• • Mining archaeology

• • Palaeoparasitology

• • Palaeopathology, including computed tomography, histology and experimental work

• • Physical anthropology, with a main focus on osteology

• • Textile research

Results and prospects

Figure 5.

Salt mummy no. 4, Archaeological Museum Zanjan (photograph: Deutsches Bergbau-Museum).

Results from the detailed anatomical analysis of the salt mummies (Figure 5) have led to a revision of the presumed number of individuals found at the site: some body parts, previously thought to belong to a single individual, come in fact from different bodies, thus raising their number to at least eight individuals. Isotopic analyses have shown that not all miners came from the Iranian Central Plateau (the Tehran-Qazvin Plain) but from the more arid steppe regions of north-eastern Iran and central Asia, as well as from the coastal areas around the Caspian Sea.

Palaeoparasitology, histological, and isotopic analyses provide us with information on taphonomic and palaeopathological questions related to the state of health, sanitary conditions and diet during the individuals' lifetime, while DNA studies shed light on ancestry and kinship, as well as medically relevant genes. In this context, the mummies will be investigated in an interdisciplinary archaeozoological and archaeobotanical study of the large number of human and animal faeces found inside the mine, providing clues for the subsistence of the miners. The animal bone remains indicate that the miners consumed sheep and goat, though the consumption of cattle (horn containers at the site point to the presence of cattle) and pig cannot be excluded; the consumption of the latter is certainly possible, as they were widely consumed on the Iranian Plateau in the periods under study. Archaeobotanical records indicate that different cultivated plants were used, hinting at a well-established agricultural background. Deforestation was less severe than today and several tree species found their way inside the mine as tools. The excellent condition of the textiles and other organic artefacts inside the mine has allowed comprehensive analyses to be undertaken, ranging from the resources used for fibre production, via processing, to the dyes used for colouring different parts of the garments (Figure 6). The diachronic nature of the textile finds, which are well-excavated and radiocarbon dated, gives insight into changes in garment types, weave patterns and the morphology of fibre through time.

Figure 6.

Textile fragment, length c. 520 mm, Archaeological Museum Zanjan (photograph: Miras Farhangi/Deutsches Bergbau-Museum).

The integration of the results obtained so far has produced a first holistic view of the salt mine and its miners. Examining the various artefacts and ecofacts in their stratigraphic and chronological setting has allowed the research team to differentiate between the Achaemenid and Sassanian mining phases. During the Sassanian period mining was established within the surrounding landscape, and isotopic data indicate that supply was organised on a regional scale. In the Achaemenid period mining seems to have been organised on a different basis: there are indications that foreign miners were present (Ramaroli et al. 2010) and the lack of settlements in the vicinity, as well as the goods supplied and the high amount of ceramic vessels, suggest access from areas further away.