It is also well to remember that the engineering in many of the mines was often hit or miss to begin with, so that many of the mines may not have been safe when they were originally opened up. The best advice is to never enter an abandoned mine. Decayed timbers and open shafts are only two of the many hazards. Many of the old mines are wet, and pools can sometimes be deceptively deep. It is not unheard of for someone to drown in a mine.
Bad air is another possibility.
Suffocation is not worth the pursuit of anything the mountain may have to offer. One thought should keep any sane person out of such danger. The mine had a warning posted cautioning people to stay out due to bad air. These signs are not to be treated frivolously. Children, of course, must be watched constantly.