Interestingly there's technologies we might not be able to replicate if needed, as we've mined out the purest resources that we know of.

Particularly nuclear technology, since so much early experimentation was dependent on ores like from the Shinkolobwe mine in Congo with 65% uranium. These days finding ore with 1% uranium is considered a good find.

https://en.wikipedia.org/wiki/Shinkolobwe

Maybe our nuclear waste will fill the same niche in a post apocalyptic reconstruction of society?