ACCIDENT (EN: accident, emergency, break-down, failure; DE: Storung, Betriebsstorung, Havarie; FR: panne; ES: averia, emergencia; RU: авария, derived from the Italian word avaria, from the arabian word avar, which means the damage or the loss) is the sudden total or partial damage to the equipment, the mine workings, the built structures, and the various devices, accompanied by the long-term (typically more than the one working shift) breach of the production process, of the work in the sector or the whole enterprise. The accidents are always associated with the economic losses; in some cases they are accompanied by the injuries of the people.

The most characteristic types of the accidents at the mining enterprises are: the cave-ins in the mine workings; the explosions of the gas and dust; the breakdown of the equipment and the installations; the sudden breakthroughs of the quicksand, water, or slurry from the underground aquifers; the flooding of the goafs or of the water bodies and the water streams on the surface; the sudden outbursts of the gas, coal or rock; the rock bursts; the fires; the breach of the dams (embankments) of the tailings storage and the settlers for the waste waters; the landslides or the collapses of the open pit walls; the fires of the electrical cables and the electrical equipment; the collapses of the overpasses and other engineering structures; the collisions of the rolling stock; the ruptures of the belts of the trunk conveyors in the inclined shafts; the open gushing from the oil and gas wells; the breakdown, rupture, sticking of the drilling tool and the pumping pipes; the termination of the circulation of the drilling fluid; the breakdowns of the casing string; the leakage of the oil and gas pipelines, reservoirs for the oil and gas; the uncontrolled overflow of the oil, gas, water from some strata to the others as the result of the leak in the trunk of the wells (see the mud spring).

The accidents are mainly the consequence of the wrong actions of the staff of the enterprises: the violation (during the operation) of the modes, norms and parameters, which have been established by the regulations on the technical exploitation, by the safety regulations, by the instructions, manuals, normative documents; the out of time inspections and repairs. At the same time, the accidents occur because of the structural deficiencies of the equipment, its deficient reliability, the non-conformance of the equipment and materials with the requirements of the state standards. The cause of the accidents may also be the force majeure natural phenomena (earthquakes, avalanches, floods, etc.).

In the USSR and other socialist countries, the works to eliminate the accidents are assigned with not only the technical and economic, but also the social importance. The system of the prevention of the accidents, which has been approved by the government departments of the industries, is acting at the mining enterprises. In accordance with the regulations, it is mandatory to perform: the systematic implementation of the planned preventive inspections and repairs of the equipment, the mine workings, the built structures and installations; the teaching to the workers of the methods of the accident prevention, of the use of the accident protection, and of the systems of the accident notification and the rescue of the people.

The safety regulations, which are active in the USSR, stipulate the obligatory preparation in advance of the plans for the prevention of the accidents at the mines, quarries, beneficiation plants, oil and gas extraction enterprises. It is explained by the fact that the accidents, as a rule, evolve rapidly, thus it is not always possible to perform the rapid development of the effective actions for the rescue of the people, and of the accident response and the recovery activities. The specific obligations of the enterprise officials for the time of the accident situation are defined in the plans. The plans are kept by the dispatcher, the chief engineer, and the commander of the corresponding detachment of the rescue service. At the times of the construction, reconstruction, and operation, every mining enterprise is served by the specialized paramilitary mining rescue detachments (In Russian, VGSCh, Voenizirovannye Gorno Spasatelnye Chasti). In addition, there are created at the mines the voluntary auxiliary mine rescue teams, which are provided with the special equipment, and trained to perform the simple mine rescue actions.

Also, the gas rescue service acts at the enterprises of the oil and gas industry. The condition of the accident prevention at all the mining facilities is controlled by the Gosgortechnadzor of the USSR (the State Committee of the USSR on the Supervision for the Safe Performance of the Works in the Industry and for the Mining Supervision) and its local departments. The accidents, which have occured at the mining enterprises, and were accompanied by the injuries and the death of the people, are investigated in accordance with the "Instruction on the investigation and the recording of the casualties at the enterprises and facilities, which are controlled by the Gosgortechnadzor of the USSR", and other accidents are investigated according to the procedure, which is defined by the "Instruction on the investigation of the accidents, which have not caused the casualties, at the enterprises and facilities, which are controlled by the Gosgortechnadzor of the USSR."

The main goals of the investigation are the identification of the causes and the circumstances of the accident, the development of the actions for the prevention of them in the future. The responsibility of the persons, whose activities or actions have caused the accident, is defined by the laws of the USSR and of the republics of the union.