Mine exploration is a hobby in which people visit abandoned mines, quarries, and sometimes operational mines. Enthusiasts usually engage in such activities for the purpose of exploration and documentation, sometimes through the use of surveying and photography. In this respect, mine exploration might be considered a type of amateur industrial archaeology. In many ways, however, it is closer to caving, with many participants actively interested in exploring both mines and caves. Mine exploration typically requires equipment such as helmets, head lamps, Wellington boots, and climbing gear.
Mine exploration typically involves less crawling and more walking than caving, since mines were purposefully excavated to allow human access. Some disused mines have been adapted for tourism, or use by organized outdoor recreation groups. Conversely, gaining access to other mines may require technical skills such as rappelling or single rope technique. Such techniques may also be used inside a mine to explore a winze, shaft, or steep incline. Similarly, some traverses and slopes may be roped for safety, particularly if organized groups are taken into the mine.
Mine exploration shares some interests with Urban Exploration, primarily that of gaining access to abandoned or sometimes restricted locations. Mine explorers share an unspoken code of ethics, that of leaving sites in the same condition as they were found. A common phrase illustrating this viewpoint is the Baltimore Grotto caving society's motto: "take nothing but pictures, leave nothing but footprints." This is similar to the Leave No Trace ethos followed in much of modern outdoor recreation.
Like many hobbies or sports, mine exploration appeals to a specific subset of people. An interest in industrial archaeology may be a motivating factor for some enthusiasts. Relics and artifacts found in abandoned mine workings may include equipment such as pumps, cranes, drills, narrow gauge railway tracks, wagons and locomotives. Abandoned mines may occasionally contain larger features such as timber bridges, cable railways, or waterwheels.
Photography is often a significant component of enthusiasts' motivation for exploration. Underground photography requires specialized techniques such as light painting or an 'open flash.' Such techniques may require considerable practice for mastery.
There are many abandoned mines in the world – for example, it is estimated that there are approximately 500,000 abandoned mines in the United States alone, with Nevada having the largest percentage of this number. However, access to many of these is not possible for a variety of reasons, including:
Mine exploration is considered a dangerous activity by many. In the United States, the Mine Safety and Health Administration (MSHA) has run an annual "Stay Out-Stay Alive" national public safety campaign to warn children about the dangers of exploring and playing on mine property. They claim that since 1999, nearly 150 children and adults have died in recreational accidents at active and abandoned mine and quarry sites, although the majority of these were not related to mine exploration.
Many accidents by inexperienced curiosity-seekers cause reactions by government agencies to close mines. In most cases, a mine entrance will be fenced and warning signs erected, but the BLM, NPS and other organizations are increasingly resorting to bulldozing, plugging or gating mine entrances, denying everyone access. Most mine closures of this nature are done in areas near large population centers and parks that receive a large number of visitors, such as Death Valley.
Common features in a mine include drifts (horizontal tunnels), shafts (vertical tunnels) and winzes or air vents that are much smaller and can be at any angle underground. Climbing through these shafts, tunnels, and winzes can be very dangerous due to their unseen entrances and exits. A drift with a portal to the outside is called an adit.
Stopes (areas where ore was removed) usually follow the ore vein and are often at steep angles to horizontal. Many stopes are shored with wooden 2x4s or 4x4s. Contrary to what one might think, the wood isn't there to keep the stope from collapsing, but rather to hold loose rock in place. Some stopes are narrow and convoluted (explorers like to call them "spider holes"); others resemble giant rooms. Many stopes have a lot of loose material on or around them.
Raises are often used to transit vertically between levels of a mine. A raise is often a 6–12 foot square vertical shaft divided into two sections. One half is a straight drop to the bottom and is used for haulage, and the other section is a series of platforms, 10 or more feet apart, with holes cut in them in an alternating manner. Beneath each hole is a ladder leading to the next platform. This style of construction affords safety: if one falls off the ladder, the fall is only to the next platform, not the bottom of the shaft.
Mines were generally constructed and maintained to be safe while they were operational. After they are abandoned, workings may decay to a point where they could become dangerous. For instance, some support structures may have been removed before abandonment for re-use elsewhere, or supporting pillars may have been quarried away, leaving the chambering unstable. Ventilation and water pumping systems that once maintained safe working conditions are removed.
There are a number of potential hazards that mine explorers face:
In spite of the potential risks involved in mine exploration, the danger to the experienced mine explorer is relatively low: as the MHSA state, the majority of accidents involve people who are unprepared.
There are thought to be approximately 500,000 mines within the United States. Listed below are regions containing a high number of both abandoned and operational mines:
Britain's man-made underground world is extensive. Some abandoned mines range as deep as 1.1 km. Some of the more extensive tunnel systems span mountain ranges or extend underneath populous cities.
Some typical mine exploration locations and type of mines are:
Some examples of mines frequented by explorers includes: