Efficient Mine

The Efficient Mine is a mid/late-game production building that extracts Scrap Metal from Underground Ruins. It is built on top of an Underground Ruins tile and is intended to convert consumed inputs into large amounts of Scrap Metal for downstream metal production.

The Efficient Mine has two operating recipes. In the current iteration the recipes are: 1x Treated plank → 5x Scrap Metal, and 1x Treated Plank + 2x Extract → 10x Scrap Metal. Efficient Mines are configured to use up to 10 workers by default. The building was adjusted in Update 7 to change its basic recipe and to enable 10 workers by default; the update also increased the yield of the second recipe in the Iron Teeth variant.

• The Efficient Mine must be placed on an Underground Ruins tile; it cannot be built on ordinary ground.
• With a steady supply of Treated Planks and a fully staffed 10-worker crew, a single Efficient Mine using the 1x Treated Plank → 5x Scrap Metal recipe can supply about 2.77 Smelters. With the boosted recipe (1x Treated Plank + 2x Extract → 10x Scrap Metal) the same mine can supply about 5.55 Smelters.
• Prior updates altered the mine’s recipes and worker capacity; consult the game’s current patch notes or in-game tooltips for exact, up-to-date numbers if modded or if playing an older version.
• To maximize output, ensure continuous delivery of Treated Planks (and Extract if using the higher-yield recipe) and keep the mine staffed up to its 10-worker capacity. Continuous supply chains to Smelters allow scrap metal to be converted onward into metal blocks and components.