Steel is a raw resource, crucial throughout the game for different purposes, such as construction of various structures, and production of weapons and armor.
Steel can be mined out of compacted steel on the map, purchased from bulk goods traders, extracted from Steel slag chunks using an electric smelter, or salvaged by disassembling mechanoids. Research and construction of deep drills in mid-late game allows extraction of large deposits underground. Although steel is common on most maps, it is still a limited resource, and should not be used carelessly.
Compacted steel tiles have 1,500 HP each, making them one of the faster ores to mine. They can be found in large veins, ranging from 20 to 40 tiles in size. Each mined block yields 35 steel, although miners with less than 8 skill in mining will produce significantly less.