If we accept that smelting was taken place in an ancient site, how is the ratio of ore/slag in the late antiquity sites? In my case study, this ratio is largely greater than 100.
I think it is unmeasurable to obtain a single ratio for the whole globe, since virtually every location in the world that was associated with ore smelting in ancient times (contemporary as well) has a different input parameters of the process, such as ore composition, technology, even when desired output (namely metal) is the same worldwide.