Cache Excavation? (probably stupid question)

Where could I get the lust items and incubus shard from the cache excavation investment? Automatically, or did I just screw up big time?

Follow Thosha's Playthrough. You have better uses for your money than the cache excavation.

cgh
I already bought them long ago; I can't really un-buy the cache. I'm asking where could I get the cache?

Miner's Junction.