Dangers of Abandoned Mines


Many of the dangers posed by these sites are not visible from the outside. Below is an overview of the numerous hazards that these abandoned mine sites pose. 

Horizontal openings: The mine opening (known as a portal or adit) may seem stable, but rotting timbers and unstable rock formations make cave-ins a real danger. The darkness and debris in old mines make it difficult to identify the hazards.

Vertical shafts: These can be hundreds of feet deep. At the surface, openings can be hidden by vegetation, or covered by rotting boards or timbers. Inside old mines, shafts can be camouflaged by debris or hidden by darkness in the mine.

Explosives and toxic chemicals: Blasting caps, dynamite and chemicals were often left behind when the workings were abandoned. Explosives become unstable with age and can be detonated by the vibration of footsteps. Abandoned chemicals such as cyanide, arsenic, mercury and other deadly toxins may be present in leaking and deteriorating containers.

Dangerous gases: Lethal concentrations of methane, carbon monoxide, carbon dioxide and hydrogen sulfide may accumulate in underground passages. Oxygen deficient air may cause suffocation. People have died within a few feet of mine openings.

Water: Impounded water may be highly alkaline or acidic (resulting in skin burns), as well as deep and cold (contributing to hypothermia).

Spoils (rock and dirt) piles: These loose piles can collapse or slide, burying an unsuspecting victim.

Equipment and buildings: Abandoned surface structures and old mine equipment may collapse on bystanders.

Highwalls: These are the excavated vertical cliffs in surface pits and quarries. They can be unstable and prone to collapse. Highwalls may not be visible from the top, presenting a danger to off-road drivers.

Radon: Radon is a natural radioactive decay product and is known to be a factor in some lung cancers. Radon can accumulate in high concentrations in poorly ventilated mines.

Wildlife: Rattlesnakes, bears, mountain lions and other wildlife frequent old mine sites.

Disorientation: There is no natural light inside mine workings. Many workings meander randomly because the miners who dug them followed an ore vein. It is easy to become lost and disoriented in a maze of mine workings, especially if lighting equipment fails.

Mine Fires: Mine fires create surface hazards in abandoned coal mine areas. As fires burn within the seam, fissures can open to the surface delivering deadly gases into the atmosphere. The area around the fissure may not be capable of supporting the weight of a human or vehicle, and may collapse into the burning coal or the mine void.

For more information on mine safety, visit the U.S. Department of Labor’s Mine Safety and Health Administration Stay Out! Stay Alive! website.