Hutomaru Kanmitei

Suzu, a mineral researcher, suddenly loses consciousness at work!! When she wakes up, she finds herself in the world of an otome game, reincarnated as the villainess, Mahalia!? If this continues, her life will fall apart just like in the game!! She escapes from the royal palace and makes her way to a coal mine, where she meets Abel, the leader of the mine. In order to survive, Suzu proposes that they make steel using coke, a type of coal that does not yet exist in this world... (Source: Pocket Magazine, translated)