Inside the Cave of Obscenity - Chapter Volume 1 26: Overrun

... doned mine made it slightly difficult to breathe, and visibility was poor.

Even though the light source generated by magic was illuminated, one could only see a little further.

Dark abandoned mine. It used to be a prosperous area where a large amount of mithril was mined and sold as a material for armor, but after the war with the Demon King ended and the amount of mithril mined decreased, the mine was abandoned and now covered in cobwebs and dust.

In the darkness, there ...