SCY021 : Mitsero Kouloupakhis 1

Slag Heaps

Grid reference: 511600/3878400
Cadastral plan: XXIX/53
Aerial photo: 1993, Run 177, No. 43
SIA: SIA 3 (Mitsero Kouloupakhis)

Like all other slag heaps on the island, Kouloupakhis has suffered from modern exploitation: a substantial part of it has been quarried for use as road metal. Its full extent can only be approximated from 1948 aerial photographs (Hellenic Mining Company) and from earlier publications. The slag heap was drilled and found to be 80 feet (24 m) deep, which led to an estimate of 600,000 tons of slag.

Modern quarrying has divided the slag heap into three components and created artificial terraces within each of these. The largest component, which we defined as SCY021W, has an estimated diameter of 60 m and a height of 5 m. To the east lies the second largest component (SCY021E), with an estimated diameter of 35 m and a height of 5 m at the exposed face. Most of the southern section of the original slag heap has been quarried away or removed during the construction of the road.

The sections created by the quarrying enabled us to inspect and record the stratigraphy of the heap. Permission was obtained from the Cypriot Department of Antiquities to clean back the sections, and systematically to record and collect samples from each one.

SCY021W-1: Building Section within Slag Heap

Slag layers and earlier structure in Section SCY021W-1

SCY021W-1 is the most widely exposed section of the slag heap, in which substantial architectural remains were incorporated (see figure). The section clearly shows distinct layers consisting either entirely or partly of slag, furnace material, slagged stones and refractory ceramics, layers rich in ash and charcoal, layers of limestone fragments and mixed material which may have come from collapsed walls and the like.

A point of major cultural interest is that substantial architectural remains were found beneath all this industrial waste. In SCY021W-1, the removal of large quantities of slag has exposed the corner and part of the face of a rectangular structure built of limestone blocks and lined with a mixture of stone and mortar. What appears to be an opening may in fact have been created by the partial collapse of the wall. The exposed walls are almost 2 m high and 50 cm wide, but their full height is unknown because the present ground level is artificial. Most of the slag that fills the cavity does not have a ropy surface typical of the tap slag from the rest of the heap; instead it has a rough, somewhat friable surface in which small pieces of charcoal were incorporated.

More walls, some of which were at least 15 m long, protruded from other exposed sections of the slag heap. Moreover, according to Konstantinos Ttaouxis, who worked for the Hellenic Mining Company on the construction of the road that dissected this slag heap, there was a substantial wall (ca. 1.5-2.0 m across) running from the slag heap under what is now the road. Unfortunately, the remaining evidence is so fragmentary that it is difficult to understand the relationship between all these architectural remains and consequently to ascertain the shape of the building of which they were part.

Nonetheless, because most of the exposed walls have an east-west orientation, we assume that they form part of the same, rather substantial, building complex. We also assume that the construction and use of the buildings predates the creation of the slag heap, although some of the walls seem to be associated with some of the archaeometallurgical features.

 

 
Successive workshop floors seen in Section SCY021W-2.

SCY021W-2: Workshop Floors (Unit 2002)

SCY021W-2 is located at the eastern extension of the exposed slag heap (see figure - right). The sub-unit consists of a series of nine plastered floors, presumably the working surfaces of metallurgical activities, interspersed with accumulated debris of varying composition which lies between two limestone walls set obliquely to the section. Once again, the lower levels were never reached as they lay below the present ground level of the quarried terrace.

Between the work-floors were compacted layers consisting of charcoal, ash, ore and finely crushed slag. This material is characteristic of foundry workshops, where large waste materials are removed to the dump while the finer material, usually fine black dust, accumulates on the floor. On one work-floor was found a smooth, diabase grinding stone. Fragments of small mortar stones with cavities of 10 cm diameter were also found in the direct proximity of this section. A much thicker layer consisted largely of furnace wall fragments made of coarse organically tempered clay, slagged stones, and large pieces of charcoal. Samples of slag and charcoal were collected from all layers in this section for analysis.

SCY021W-3: Lower Terrace, West Section (Unit 2003)

This section of the lower terrace provided clear evidence of constructional phases and the abandonment of buildings prior to the advent of copper smelting at the site.

Beneath the layers of slag were at least five layers of sediment, two of which could in fact be floors. Each of these layers has cultural material, in particular material related to building construction: chips of limestone, mortar and tile mixed with some pottery. The fact that we found no slag or other metallurgical debris in any of these earlier levels may indicate that they predated smelting activities.

SCY021E-1: Eastern Slag Heap (Units 2004, 2006)

A second somewhat smaller section of the original slag heap (SCY021E) is located approximately 50 m east of SCY021W. At the bottom of the exposed section was a series of working floors but no architectural remains (Figure 4.28). These floors are not dissimilar to the workshop floors of SCY021W-2, and consist of a dark brown/black dust rich in charcoal, ore and slag fragments. As in the previous section, among the slag remains we found fragments of pottery indicating the date of the smelting activity.

SCY021: Archaeometallurgical Finds

The most striking archaeometallurgical finds from SCY021 were the complete slag cakes, weighing between 40 and 55 kg. A typical slag cake from SCY021E-1 is about 42 cm long, 62 cm wide and 17 cm thick; the standard weight is about 55 kg. These slag cakes have a fan-like shape with the typical flows on the surface and a convex base, indicating that they were tapped into a pit. Some of the slag fragments have multiple layers that may result from continuous or serial tapping.

In his description of Kouloupakhis, Koucky (1982: 243) describes the layers according to the type of slag they contained. What is striking about the slag heaps, however, is not that the layers are composed of different types of slag (probably indicative of different conditions in the furnace and not necessarily a significantly different technology), but rather that the size of the slag pieces differs in each layer. For example, in SCY021W-1 there are concentrations of complete slag cakes, as well as layers of small crushed fragments of slag. Clearly this phenomenon is not coincidental or natural. In other words, these layers cannot possibly have formed haphazardly when the large pieces of slag were dumped on the pile. Rather it seems to indicate that a specific method was followed for disposing of the waste produced in the smelting workshops.

The large quantities of crushed slag require explanation. Because the chemical and microscopic analyses carried out on these slag samples revealed very little copper, we can dismiss the possibility that metallic copper was mechanically removed by crushing the slag. Even if this were the reason behind the crushing of the slag, what workshop activity could explain its sorting into different sizes?

Amongst the finds from this POSI are a number of stone mortars and grinding stones, some of which are broken and thus may have been thrown as waste on the slag heap. Other mortars or grinding stones, however, seem to be in situ (for example, one found in SCY021W-2). The size of the slag cakes is related to the size of the smelting furnaces, which must have been quite large. Remains of these smelting furnaces were found among the slag pieces. In Kouloupakhis we found slagged rocks (igneous rocks such as diabase and gabbro able to withstand high temperatures) and slagged pottery tiles, as well as fragments of slagged refractory clay - the last either a clay lining over a stone structure or part of a furnace wall entirely made from refractory clay. Unfortunately none of these is preserved well enough to enable us establish the shape or to calculate the diameter of the furnace. Only excavation could resolve some of the manifold questions raised by the archaeometallurgical remains of Kouloupakhis.

Dating

In an effort to substantiate and refine the dates provided by the pottery assemblage, samples of charcoal were selected from several points in this POSI for radiocarbon dating. The earliest date stems from a sample collected on the floor of the building remains in SCY021W-5. The calibrated date of Cal AD 74-241 (1 sigma) falls within the Early Roman period. As suggested above, it provides a terminus ante quem for the construction of the buildings. It may also be related with the beginning of smelting activities in this area. The three other samples derive from the stratified slag deposits and are therefore associated with the period during which the smelting workshops were active. The calibrated dates fall within the Late Roman period and correspond well with the relative dating of the strata based on the pottery. The two samples collected from the workshop floors of SCY021W-2 are dated to Cal AD 263-431 (1 sigma), while the third sample - from the higher layers of SCY021W-1 and associated with furnace wall fragments - dates to Cal AD 435-599 (1 sigma). This final sample is perhaps the most significant of the four, as it provides solid evidence for the continuation of smelting activities on the island after the 5th century AD.