1wt% to 22.4wt% and represent losses of this metal during the metallurgical operations developed inside these crucibles. Additionally, F11 has considerably higher FeO, but this enrichment appears to derive from the ic (see below). Other elements are potentially indicative of the charge. Sporadic As2Ostep step 3 (G10 and H12) and PbO (E13) in the slag ( Table 5 ) must be related to the impurities of the ore or metal charge. Slag layers in crucibles G10, G11 and F12 are the thickest in the assemblage ( Desk 8 , Fig 5 ), showing more interaction with the ceramic and large bloating pores. They also form a distinct compositional group, particularly noticeable in the much higher levels of CaO, MgO and P2O5 ( Table 5 ). Slag in H12 is also relatively thick and enriched in CaO, although to a lesser extent.