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BLM>California>What We Do>Abandoned Mine Lands>Safety and Education>Types of Hazards
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Types of Hazards


Shaft left behind by one of many abandoned mines

Shafts are vertical mine openings that can extend hundreds of feet to the lower level of a mine. Open shafts can be concealed by mine debris, dirt, rock, and even water. 

 

An adit prebid walk with a contractor

Adits are horizontal mine opening that can extend hundreds of feet.  Both shafts and adits tend to follow the original ore veins.  Within a short distance of the entrance there is no light, and these openings can be the cause of becoming lost and disoriented inside a mine. 

 

An abandoned mine entrance collapse

Unstable Rock and Decayed Support includes once solid beams and frameworks that have been decaying for more than a hundred years.  In many cases, there may be no support beams at all and the fractured roof or walls of the mine tunnel eventually collapse in response to vibrations and/or the force of gravity .

Deadly Gases and Lack of Oxygen can be presented in abandoned mines that are not ventilated. Pockets of methane, carbon dioxide, and other deadly gases can form or simply displace oxygen with no visible sign. When these gases enter the body, muscles stop responding normally thinking clouded, and unconsciousness and death can occur.

Stick of Dynamite  ound in 2010 at an abandoned mine

Explosives and Toxic Chemicals were often left behind when an active mining operation was abandoned. Explosives such as dynamite and blasting caps become very unstable over time, and can explode if disturbed. Storage containers, boxes, barrels, and drums deteriorate allowing toxic chemicals to leak or combine into highly dangerous mixtures. 

 

Open mine pit with high walls

Highwalls and Open Pits are located where large areas of the surface have been disturbed to get at minerals near the surface. Open pits can be filled with water that can be highly acidic or laden with harmful chemicals.  Highwalls can be unstable at the top and the bottom and are prone to collapse. When approached from the top, the vertical edge of a highwall may not be seen in time or may crumble, leading to a fatal fall. 

 

Speckled rattle snkane found in an abandoned mine More subtle hazards associated with AML’s include encounters with wild animals (e.g., rattlesnakes, bears, mountain lions); exposure to bat droppings, hantavirus, radon and radiation; and toxic soil, water, and air contaminated with cyanide, lead, arsenic, mercury, and other toxins which may be inhaled through dust and particles or through contact with impounded acidic water. 

 

Water Quality Sites are those sites where a hazardous substance release has occurred, is suspected, or the threat of release exists.  BLM generally uses CERCLA authority to address these sites, and can address physical safety hazards concurrently with the environmental remediation under CERCLA. 


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