The caves that Early Woodland miners had used intensively were left.

The knowledge of the cave routes may or may not have persisted in the communities that succeeded the mining communities — but even if it did, no one used that knowledge to continue mining on anything like the previous scale.

One plausible hypothesis: the cultural role played by cave gypsum and related minerals in Early Woodland ceremonial and practical life was taken over by other materials during the Middle Woodland period.

The Hopewell exchange network was bringing in mica, copper, obsidian, and other exotic materials from distant sources.