Dockside Extortionist in hand or in your graveyard.
All other permanents on the battlefield.
You have at least three additional cards in your graveyard if Dockside Extortionist is in your graveyard.
Opponents control at least three artifacts and/or enchantments.
({1} magic symbol) ({R} magic symbol) available.
Steps
Cast Dockside Extortionist either from your hand by paying ({1} magic symbol) ({R} magic symbol) or from your graveyard for its escape cost by paying ({1} magic symbol) ({R} magic symbol) and exiling three other cards from your graveyard.
Dockside Extortionist enters the battlefield, creating at least three Treasure tokens.
The Treasures enter the battlefield, triggering Grinding Station that many times, untapping Grinding Station.
Activate Grinding Station by sacrificing a Treasure, causing you to mill three cards.