The black walls reflecting almost an oily shine along this tunnel are unrefined salt deep underground. Salt deposits as normally viewed can be seen accumulating near bottom. Though it's heavily toured I was fortunate enough to cross these two solitary friends.
As I haven't had time to sit down and process anything while traveling and I really love this image. I want to give it more notice and will post a follow up to the Salina Turda Mine later in the week.