Archaeological excavations of Mound 6 at Ngre Kataa in 2009 expose a workshop where blacksmiths produced iron and copper-alloy tools and ornaments. The mound is being excavated in 2 x 2 meter units named for the coordinates of their northeast corner. In unit 50N 0W (foreground), an area of burned soil marks the location where blacksmiths heated metals. A pottery jar sits in place to the right. In surrounding units (50N 2W, 48N 0W, 48N 2W) are large anvil stones where the hot metals would have been hammered and shaped through forging. The mound's stratified deposits suggest that the workshop area was used for many decades, and perhaps centuries, between the years of about 1350 and 1520 CE (Common Era). View across the mound from the northeast looking towards the southwest. Site Ngre Kataa. 27 June, 2009.
Finger ring made from twisted copper alloy wire. From Ngre Kataa, Mound 6, Unit 44N 4W, Level 5. Width: 2.3 cm. Weight: 1.6 g. Ngre Kataa, 8 July, 2009.
Several grinding stones, a whole pot and a cluster of pottery sherds have been exposed in situ at the base of level 3, unit 44N 4W at Mound 6, Ngre Kataa. The large grinding stone in the foreground (grinding stone 1, NK-08-112) is oriented with its grinding surface facing down. Another smaller stone rests on a soil pedestal created as archaeologists excavated surrounding soil to a lower level. Upper right, a whole pottery jar (NK-08-176) sits next to a large grinding stone (grinding stone 3, NK-08-173) oriented with its grinding surface up. To the far left, above the photo scale in centimeters, archaeologists have exposed the edges of a pottery jar, broken in half and lying on its side. As excavations extended into the adjacent unit (42N 4W, to the left), this broken pot was found to be associated with two tuyere fragments. This cluster of grindstones, tuyeres and nearby burned features is interpreted as part of a larger metal-working workshop, the activities of which led to the build up of mound 6. The soil on the right side of the unit is darker because it is moister than that on the left. View to west. Site Ngre Kataa. 1 July, 2008.
Excavations in unit 42N 4W have exposed clusters of pottery, grinding stones, tuyeres and an area of burned soil associated with metal working at Mound 6, Ngre Kataa. Foreground, left, a grinding stone (GS 08-10) rests with its working surface face down. It sits at a slightly higher level than a nearby (left) whole pottery jar (NK 08-406). To the right of these, a partial pot (NK 08-282) and a tuyere fragment (NK 08-284) are clustered together with two halves of a broken pottery jar, lying with its exterior surface facing down. To the south (behind), near the sign board and framed by photo scales, is a burned feature. Next to it sits a hand-held hammerstone (GS 08-11). Another partial pottery jar (NK 08-520) and a small flat grinding stone (GS 08-12) have been exposed to the left of the sign board at 77 cm below the unit's datum. The narrow dark bands visible in the soil are the traces of animal burrows. Photo scale adjacent to the sign board in centimeters. View looking south. Site Ngre Kataa. 7 July 2008.
A twinned lost wax cast copper alloy figurine from Ngre Kataa, Mound 6, Unit 44N 6W, Feature 5 cluster. Archaeologists interpret the Feature 5 cluster as a shrine placed among metalworking facilities. Height: 5.9 cm. Weight: 31.3 g. Ngre Kataa, 19 July, 2008.
The circular outline of a burned basin (Feature 3) is bracketed by photo scales (center) in unit 50N 4W (130 cm below the unit datum) at Mound 6. A pottery jar sits to the right side of the basin, its opening covered by a potsherd lid. To the left, a grinding stone sits, grinding surface down, over top of another pottery jar. Burned features like these were associated with metal working in this Mound 6 workshop area. Photo scale at bottom in centimeters. Site Ngre Kataa. 29 June, 2009.
The circular outline of a burned basin (Feature 3) is bracketed by photo scales (left of center) in unit 50N 4W (130 cm below the unit datum) at Mound 6. A pottery jar sits to the right side of the basin, its opening covered by a potsherd lid. To the left, a grinding stone sits, grinding surface down, over top of another pottery jar. Another grinding stone (far left) sits at a higher level in unit 50N 6W. A second burned feature is associated with a grinding stone tipped on its side, far right. Another pottery jar sits nearby, also lidded with a broken sherd. Burned features like these were associated with metal working in this Mound 6 workshop area. Photo scale at bottom in centimeters. Site Ngre Kataa. 29 June, 2009.
A finger ring made of twisted copper alloy wire is photographed in situ. Base of level 5, unit 44N 4W, Mound 6, Ngre Kataa. Scale in 5 centimeter increments. Ngre Kataa, 8 July, 2009.
The mouth of a perforated shrine pot (left) is covered with the pedestaled base of another pot. It remains in situ as the surrounding areas of unit 46N 2W are excavated to lower levels. Behind, the stratified layers of Mound 6 are visible in the unit's north wall. Center (back) are a series of anvil and grinding stones exposed at higher mound levels in other excavation units. During excavations in 2008, a cluster of four anvil/grinding stones was found at a level slightly higher than but adjacent (left/west) to the perforated pot. At right, in lower levels, two grinding stones rest at an angle in association with a burned feature. Archaeologists interpret Mound 6 as a metallurgical workshop at which stratified levels built up through repeated use of the same location. Photo scale in centimeters. Site Ngre Kataa. 2 July, 2009.
Iron slag is formed as a byproduct of iron smelting. Here a large slag nodule has broken in half, revealing its interior texture. At the archaeological site of Ngre Kataa, large chunks of 'bubbly' slag like this were occasionally found in household and other contexts, away from areas otherwise associated with metal-working activities. Potters at the time of the site's occupation had begun to use crushed iron slag as a tempering agent in their potting clays, which may explain why large nodules were being carried and cached in areas away from metal-working locations. Ngre Kataa, June, 2008.