A small piece of slag (top) and a copper alloy ( brass) rod fragment (bottom, SF 08-053). The greenish hue of the rod is a product of weathering. These artifacts were found next to one another in unit 48N 4W in an area (mound 6) that archaeologists interpret as a metallurgical workshop. They were found adjacent to and below a large grinding stone (GS 08-04). Site Ngre Kataa. 1 July 2008.