Technology. Playable during the sit phase if one of your companies enters the Deep Mines site and you have more Delver's Harvest cards in play than you have Earth-eater cards. Tap Earth-eater to take a minion non-unique weapon/armor/shield/helmet major item from your sideboard or discard pile to your hand.
"'...they delved too greedily and too deep...'"
-LotRII