Good info. I think some of the answers are in that book Anansi recommended a while back called
A Fistfull of Shells. Was going to get it from library before COVID shut down services. But
could be several things in the mix like the dust, cowries, iron, and in some places salt bars.
Given that African technology produced adequate results for local use and was sometimes even
superior to European methods (like some African steel production), it seems that European "volume
strategy" might have enabled them to undercut local producers with cheap iron product in 18/19th cen.
Also if I remember a thread, suitable wood for charcoal smelting was a problem in some areas, (desert
for example), but even more wooded zones, because not just any kind of wood produced suitable
results. Europe, particularly Britain, had easy access coal deposits to get around this problem
aiding the "volume undercut" strategy. But cant remember that exact thread that broke down some issues.
As for the cowries, a "volume flood" strategy by Europeans shipping billions of shells from the
Maldives seems to have taken over the cowrie currency and eventually caused it to collapse, per
Anansi's book on Gbook Preview.
Re da gold the African technology seems to have enabled Mali to become a world leader in gold
production, one-third per one source I seen. What I haven't yet figured is the gold flows to
Europe. We know the Mansa hauled so much gold north it depressed gold markets in Cairo for years.
So the Maghreb/Levant was doing pretty well. But not so much detail on how EUrope benefited,
perhaps because a lot of the gold moved as gold dust and not as coins that could be collected centuries
later. We know the Portuguese were desperate to bypass the Islamic world and get directly to the
West African gold sources, so they must have been eyeing Africa for quite some time.