Graveyard Keeper 2 Porter Station

Iron Smithing (50 red) leads to Zombie Mining (60 red, 10 blue), which unlocks both the Zombie Miner and the Porter Station. Zombie Stone Mining (70 red, 10 blue) also unlocks it for quarry lines.

One zombie works at the source: a Zombie Miner in the Old Mine or a quarry station on a stone node. A second zombie staffs the Porter Station and hauls the output home.

Build the Porter Station close to the producer and its chest. Loads end up in the matching stockpile at base, such as the Yard's stone stockpile, where the Smithy or Furnace can use them.

A mining zombie without a pickaxe never starts, so the porter idles. Also check your zombie limit: each porter is one more zombie, and the cap is easy to hit.