Hello Olta,

Working mainly in Central Asia and Iran I can really not confirm your idea that prehistoric copper slags are difficult to find or that they are rarer than Iron slags - it is certainly not true for that area!

At the Arisman metallurgical site in Iran, the copper slag was visible immediately on the surface, as heaps of up to 25 m diameter and 2 m height! This is published already: Abdolrasool Vatandoust, Hermann Parzinger, Barbara Helwing (Hrsg.), Early mining and metallurgy on the western Central Iranian Plateau. The first five years of work. Archäologie in Iran und Turan 9. Verlag Philipp von Zabern (Mainz 2011).

The same is also true for proper mining and processing sites in Europe - see for examples: Jan Cierny, Prähistorische Kupferproduktion in den südlichen Alpen, Region Trentino Orientale. Veröffentlichungen aus dem Deutschen Bergbau-Museum Bochum 163 (Bochum 2008) or .Craig Merideth, An archaeological survey for ancient tin mines and smelting sites in Spain and Portugal. Mid-central western Iberian geographical region 1990-1995. British Archaeological Reports. International Series 714 (Oxford 1998). [the latter mainly for tin mining, but with many sites of copper as well - tin slags are indeed very rare, but as has been written many times already the main tin-ore - cassiterite - could be added to a smelt directly so that no slag would be produced].

At the Bronze Age site of Gonur Depe in Turkmenistan we actually find copper slags, althought the site lies far away from any ore sources and could only process imported metal.

Perhaps it would be useful to check geologic maps first and start looking for copper slags near actual copper occurences, although the Turkmen example shows that copper slags are also found far away from the ore deposits.

It gets weathered faster than iron under some conditions,,, and the crust that forms around it makes it difficult to distinguish it from oxidized iron,,, also the iron slag can be separated from sediments by attraction to magnetic field,, while copper shows no response for magnetic fields.

In early copper production prehistoric metallurgists could use quite rich copper carbonates which led only few amount of slag (S. Rovira has made some experimental coper smelting and have observed that). Moreover, slag was crushed to get the copper prills trapped in the slaggy matrix (due to low efficiency) so big slag lump are not common. But this is true for the earliest copper productions, I am not sure that copper technology in Early Iron Age is to be the same

Thank you very much

Along the Araba Valley, on both Jordanian and Israeli sides, and in Sinai, there are tens of copper smelting camps with thousands of tons of slag, clearly visible. There might be a difficulty identifying copper industry if was based on crucible smelting, which produces little amount of slag.