Saltpeter Mine Construction Kit Detail tab: Use to build a saltpeter mine to solve quests. This buff is only usable in the Twin Town adventure. It’ll be deleted when the adventure is no longer active. Cost: x 2000 x 2000 Production Time: 3 d Instant Upgrade: 420 Objective: Adventure: Buildings Delete Item: Yes Trade: No Type: Instant Upgrade Recipe 14 h 24 m x 2000 x 2000 x 1 x 2000 x 2000 x 1