The Cobalt Mines of Shokan, aka the Cobalt Mines, is a location in Outworld which is often used as a prison for "the lowest scum of all realms" by Shao Kahn and the Shokan race (the latter is the reason why they are named as such). Unlike real-world cobalt mines, these mines contain pure cobalt embedded into the rock walls of the mines. The cobalt is blue in color rather than silver.
The cobalt mines themselves seem to be an original creation for the show and comic book, and so far, have made no official appearances in any of the games. In Undying Dream, the Mines are revealed to be "as big as some realms" and have at least one-hundred countable levels. It is also referred to as a "Cobalt Prison" and a "blue hell" by various characters.
Theme song: Cobalt Mines - RE-recorded version (Mortal Kombat: Conquest, Paul Unfaces)
Mortal Kombat: Shinnok's Uprising[]
Sonya and Johnny were escaping from the overwhelming Army of Darkness led by Quan Chi, and the duo fell thru loose ground and rolled down a steep slope to an abyss! Luckily, they stopped themselves and the army never followed. He found a skinny ledge to the slope's side and followed it to the Mines themselves where the Shokan were busy wielding armor. One of the beasts came up to them, dreading they belonged to the aforementioned army, but only they were Earthrealmers. He backed down and he explained the Shokan escaped while some went back to Kuatan. The Centaurs, unexpectedly, joined the cause to fight back the invaders and reclaim their lands. He also stated unlike many mines, the Cobalt Mines' walls were formed in blue and according to legend, Quan Chi may have his sorcery negated by that compound! At least it went back over 500 years ago, back in the Great Kung Lao's time. The two accepted and soon, cobalt armor was forged for everyone excepting the hasty, reckless Tarkatans.