National Park Service Visitor Information.

Dangers In and Around Old Mines

U.S. Department of the Interior
National Park Service


Shafts Falling
A mine shaft is deceptive to the uninitiated because there is little or no light down a dark hole. The feeling of height and normal reaction to "pullback" is not evident in most persons. Many people who would hesitate to look over the side of a tall building do not show any fear when looking into a mine shaft. The fall down a mine shaft is just as lethal as the fall from a tall building - with the added disadvantage of bouncing from wall to wall in a mine shaft and the likelihood of having falling rocks and timbers for company.

The timber in abandoned mines are unsafe. Ladder rungs are often missing or broken. Some will fall under the weight of a child because of dry rot. Vertical ladders are particularly dangerous. It is impossible to climb down a vertical ladder and examine each rung before placing weight upon it. Use of a rope will protect the climber from falling - but will also act to dislodge rocks and timbers above the climber.

The timber in abandoned mines is usually decayed. This danger is not apparent as the lumber often looks very solid - when it actually can be crushed with the squeeze of a hand. Other timber, although in good condition. becomes loose and will fall at the slightest touch. Unfortunately, the timber does not always fall until the person descending the shaft is below the timber.

Loose Rock
A mine shaft will weather in much the same way as a cliff. There are always loose rocks on timbers or on the walls. A rock the size of a peanut, when falling a hundred feet, can easily penetrate a person's skull. Larger rocks are not necessarily more lethal - they only make a tougher job for the mortician, if the body is ever recovered.

Collar Cave-ins
The collar or top of a shaft is perhaps the most dangerous area to the layman. The rock is already decomposed - the timbers are more likely to have decayed - and conditions, in general, allow for rapid disintegration of the shaft wall. Carbon dioxide can be detected by a match or candle - as both will refuse to burn. Carbon monoxide can not be readily detected, and is lethal in very small amounts.

Many mine shafts contain pools of water at the bottom. Drowning is an obvious danger in such situations.

Any protected hole or ledge is a natural habitat for snakes. This is a particular hazard in shallow shafts and in shafts with near-surface work levels.


Cave-ins are a danger in any mine. An experienced miner can often detect areas that are likely to cave. A layman stands little chance of making a proper evaluation. Minor disturbances, such as vibrations caused by walking or speaking, may cause a cave-in in an abandoned mine. If a person is caught in a cave-in, his troubles are soon over as he will usually be crushed to death or suffocate. A less cheerful possibility is to be trapped behind a cave-in with no one knowing that you are trapped. Death may come through starvation, thirst, gradual suffocation, or sheer fright.

The timber in horizontal workings is subject to decay. A well-timbered mine opening can give a sense of security when in fact the timber can barely support its own weight. There is the constant danger of inadvertently brushing against a timber and causing the entire area to collapse.

Bad Air
Carbon monoxide and carbon dioxide often collect in low areas or along the floor in horizontal workings, particularly when there is only a single opening. A person can walk into these areas and safely breathe the good air above the gases. However, the motion of the air caused by walking will mix the gases with the good air, and, when walking out of the tunnel, the gases will be mixed in lethal quantities with the good air. There are many cases where experienced miners have been killed while walking out of a mine after safely walking in.

Winzes were sunk in the floor of tunnels - and then boarded over. If these boards have decayed, a perfect trap is waiting for the first person that steps on the boards.

Many tunnels have water standing in them or small streams flowing out of them. When water is standing or flowing on the bottom of a tunnel, it is usually impossible to see the bottom and there is always the danger of stepping into a winze or other deep hole.

Old miner tunnels are among their favorite haunts - to cool off in summer - or in search of rodents and small animals.

Good miners never carelessly discard explosives, however, many abandoned mines, both shafts and tunnels, contain old explosives left by careless workers. This is illegal and very dangerous. Explosives found in old mines include dynamite and fuses and caps. Explosives should never be handled by anyone not thoroughly familiar with them. Even experienced miners hesitate to handle old explosives as they are extremely dangerous. Old dynamite often contains free nitroglycerine and will explode with the slightest disturbance. Dynamite caps are perhaps the most dangerous. Mice and rats, common in all mines, scatter dynamite caps on the floors. If these caps are stepped upon they will explode. Such dynamite caps are often covered with dust and difficult to see. The only way to avoid this danger is not to enter mine workings in the first place. In fact, there is only one safe way for any inexperienced person to deal with abandoned mines and tunnels — STAY OUT!

Rescue Problems
Rescuing a person from a mine accident is usually difficult and dangerous for both the rescuee and the rescuer. A rescuer must avoid dislodging any lumber or rock that might fall on the victim - and this is an almost impossible job. One of the cardinal rules in mine rescue is to avoid all unnecessary risk. It makes no sense to kill one man to rescue another. Death or injury faces any professional rescue team that takes chances and these teams are trained to know the odds. However, it is mathematically certain that in making a given number of rescues, rescuers face the inevitable unknown factor that results in serious injury or death. Anyone, adults as well as children, should consider this when tempted to enter abandoned mines.

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