Harmful factors in non-coal mines

Lifting injuries refer to accidents and electric shocks caused by squeezing, falling, objects (slings, lifting weights) in various lifting operations (including crane installation, maintenance and testing). In the production process of non-coal mines, there are a large number of lifting equipment in mineral processing workshops and machine maintenance workshops, and the probability of lifting injury is relatively high. The main risk factors are broken traction chain or sliding parts, collision, emergency stop, etc. The accidents caused by this include equipment destruction, casualties and production impact. The common causes of lifting injuries are: overload; The traction chain or product does not meet the specified quality requirements; Operating lifting equipment without a license or operating personnel violating regulations; Switch failure, unable to cut off the power supply in time, resulting in out-of-control operation; The operator can't stop in time due to inattention or visual impairment; The volume of the transported object is too large; Sudden power failure; Lifting equipment failure, etc. In the production process, there are still dangerous and harmful factors such as pressure vessel explosion, high temperature, corrosion, lightning strike, earthquake and poor lighting.

radiation

Radiation hazard: Generally, non-coal mining, even if it is not a mine that produces radioactive ores such as uranium, also contains trace radioactive substances, such as radon. Radon is the result of the decay of 226 radium atoms. This decay is natural, and people can't control it, so the generation of radon is continuous, and the process of radon running from rocks to the air is also continuous. The main route of radon entering human body is respiratory tract. Inhaled radon enters the lungs through the upper respiratory tract, penetrates into the alveolar wall, dissolves in the blood circulation system and distributes all over the body, and accumulates in organs or tissues containing more fat, decays according to its own inherent law, damages the lungs and upper respiratory tract, accelerates the development of some chronic diseases, and seriously harms the health of employees.

fire

Fire is sudden, although there are signs of accidents, but due to the imperfect monitoring and forecasting methods and people's lack of grasp of the law of fire occurrence, fires often occur at unexpected times. The consequences of fire accidents are often very serious, and it is easy to cause heavy casualties, especially catastrophic fire accidents. Therefore, it is necessary to strengthen the prevention of fire accidents. The causes of fire accidents are more complicated, because the three elements (ignition source, combustible material and combustion-supporting material) that constitute the combustion conditions generally exist in people's production and life. For example, ignition sources include naked flame, heat of chemical reaction, decomposition and spontaneous combustion of substances, thermal radiation, high-temperature surface, impact or friction, electric spark, electrostatic discharge, lightning, etc. Combustible substances include all kinds of combustible gases, combustible solids and combustible liquids. The general causes of fire accidents in non-coal mines are as follows:

(1) Careless use of fire in production. Through the investigation and analysis of a large number of fire accidents, it is shown that many accidents are caused by lack of relevant scientific knowledge, paralysis of thinking in the face of fire danger, luck, irresponsibility and illegal operation.

(2) Poor equipment. If the design is wrong and does not meet the requirements of fire prevention or explosion prevention, the design, installation, use and maintenance of electrical equipment are improper.

(3) the reason of the material. For example, spontaneous combustion of combustible materials, interaction of various dangerous goods, mechanical friction and impact heat generation, and violent vibration during transportation and loading and unloading.

(4) Environmental reasons. Such as humidity, high temperature, poor ventilation, lightning, static electricity, earthquake and other natural factors.

(5) management reasons.

(6) Unreasonable layout of building structure, improper selection of building materials and other factors.

Dust and noise

Non-coal mines will produce a lot of dust in the production process (such as drilling, blasting, shovel loading, ore drawing, transportation and crushing, etc.) ), and the tailings pond also has a certain amount of dust. The harmfulness of dust is related to the dispersion, free silica content, composition and concentration of dust, and generally increases with the increase of free silica content and harmful substances. Among the dust with different particle sizes, respirable dust is the most harmful to people. After long-term inhalation of human dust, lung tissue will be diseased, thus losing normal ventilation and ventilation functions and seriously damaging health.

Noise is an unpleasant sound, which not only affects people's hearing, psychology and physiology, but also causes occupational deafness and adversely affects production activities. Working in a high-noise environment will make people feel irritable, tired, unresponsive and inefficient, which will easily lead to accidents. Noise comes from the vibration of objects. Vibration is a common risk factor in production, which acts on human body in combination with noise. Vibration can act on the human body directly, or through the floor or other objects, and can be divided into local vibration and whole body vibration according to its action position. Vibration is more common in pneumatic tools, electric tools and other places with strong mechanical friction.

In the production process of non-coal mines, noise and vibration mainly come from pneumatic noise of pneumatic drilling tools, mechanical noise caused by vibration, friction and collision of various equipment during operation, and electromagnetic radiation noise caused by electrical equipment such as motors. The equipment and places that produce noise and vibration mainly include: air compressor and air compressor pump room; Fan and ventilator room; Water pump and water pump room; Winch and winch room; Blasting workplace; Crushing equipment and crushing workplace; Rock drilling equipment and rock drilling face; Roadways through which transportation equipment and equipment pass; Rock loader and rock loader workplace; Machine maintenance equipment (such as brazing machine) and machine maintenance workshop.

Flooding

(1) Causes of water damage. In the mining process of non-coal mines, there may be surface subsidence or cracks formed by geological structures, the harm of surface water entering the mine, the harm of "artificial water body" stored in goaf and abandoned roadway, and the harm of original rock water body in original rock caves and cracks. The main causes of water disasters may be: there is no water exploration in the mining process or the water exploration technology is unreasonable; Sudden encounter with water-bearing geological structure during mining; Exposing water bodies during blasting; Exposing water bodies during drilling; Ground pressure activities expose water bodies; Unreasonable design of drainage facilities and equipment; The construction of drainage facilities and equipment is unreasonable; Illegal operation in the mining process; No signs of water inrush were found in time; Found that the signs of water inrush did not take water exploration measures in time or did not explore water in time; Failing to take waterproof measures in time after discovering the signs of water inrush; When the signs of water inrush were found, proper water exploration and waterproof measures were not taken; Reasonable drainage and water guiding measures were not taken during mining, resulting in water accumulation in goaf and abandoned roadway; Roadway, working face and surface water are connected inside and outside; When the rainfall suddenly increases, the groundwater inflow suddenly increases.

(2) the form of harm and destruction. Mine, surface water or sudden rainfall may cause mine flood accidents, including:

(1) water inrush in coal mining face;

(2) The mining face or goaf is permeable. Because various channels connect the goaf with the water storage body, a large number of water bodies directly enter the goaf, thus forming goaf, roadway and even mine flooded;

(3) Surface water or sudden heavy rainfall enters the ground. A large number of water bodies pass through cracks, caves, abandoned roadways, permeable layers and surface outcrops, and then directly enter the goaf and then the workplace, or directly enter the workplace.

mechanical damage

Mechanical injury mainly refers to the attack, collision, shearing, entanglement, twisting, grinding, cutting and stabbing caused by the direct contact between moving (stationary) parts, tools and machined parts of mechanical equipment and human body. Exposed transmission parts (such as gears, shafts, rails, etc.). ) and various reciprocating parts of rotating machinery may cause mechanical damage to human body.

At the same time, mechanical injury is also one of the most common injuries in non-coal mine production. Mechanical equipment that is easy to cause mechanical damage includes: transportation machinery, tunneling machinery, loading machinery, drilling machinery, crushing equipment, ventilation and drainage equipment, mineral processing equipment and other rotating and transmission equipment.

Descending and lifting transportation

Falling danger refers to the casualty accidents caused by falling in aerial work. The main places or areas where falling accidents may occur in non-coal mines are: shafts, inclined shafts, patios, chutes, stopes and various operating platforms.

Lifting transportation is an important link in the production process of non-coal mines. Non-coal mines mainly include vertical shaft hoisting, inclined shaft hoisting and horizontal transportation (locomotive transportation and belt conveyor transportation). Transportation accidents are mainly manifested as:

(1) Shaft lifting: broken rope, overwinding, squatting, damaging things; Sudden tank sticking or sudden parking, tank sticking or misoperation of signalman and winch causes personnel to fall.

(2) Inclined shaft lifting: sports car, falling off the road, destroying things and hurting people; Falling rocks in inclined shafts hurt people. Among them, sports car accident is the most harmful accident in inclined shaft hoisting transportation, and the main reasons are as follows:

(1) harvesters are in poor running condition.

A. the wire rope is broken. When the strength of the wire rope is insufficient or the load exceeds the limit, the wire rope may break.

B.the hook has been untied. If the hook is not put down or decoupled prematurely, it will cause a sports car accident.

C. the brake device fails. The braking device mainly includes working braking or braking. If the working braking or braking fails, the braking device will fail.

D. winch driver's operation error. The driver was distracted and didn't charge "fly".

E. trailer violation. Overloaded vehicle, overloaded vehicle or disconnected vehicle.

② Anti-running car device.

A. design reasons. Mainly refers to the design of anti-running car device is not in line with the reality, and can not play the role of anti-running car.

B. installation defects. If it is not installed or improperly installed, it will not play its due role.

C. poor working conditions. Abnormal working condition or fault, unable to stop the sports car.

(3) Horizontal transportation.

① Motorcycle transportation: Common accidents include motorcycle collision, motorcycle collision, pedestrian crush, motorcycle falling off the road, etc. Among them, the locomotive hitting pedestrians is the most harmful accident. The main causes of locomotive collision accidents are as follows:

A. pedestrians. Pedestrians may be injured by locomotives if they walk in inappropriate places, such as between tracks, on tracks and on narrow sides of carriageways; Poor pedestrian safety awareness or inattention, pedestrians' failure to avoid in time, grabbing the road with the locomotive or jumping off the car may all cause accidents; The influence of the surrounding environment, such as no sidewalk, no escape room, equipment and materials accumulation, roadway compression deformation, insufficient lighting, loud noise, etc.

B. locomotive operation. Operating reasons, such as overspeed operation, illegal operation, misjudgment, out-of-control operation, etc. Braking device failure, etc.

C. other factors. If there is no signal or the signal doesn't work, it means that the operator driving without a license is inattentive and his driving sight is poor.

② Belt transportation: The main performance is strangulation injury, and the main reasons for strangulation injury of belt conveyor are:

A. Human factors: cleaning materials, oiling or troubleshooting during the operation of the belt conveyor; Fatigue mistakes, tripping and falling, sleeves not fastened properly; Crossing and riding illegally; The operator is inattentive.

B. physical factors: the protection device fails; The design does not meet the requirements; Signal device is faulty or not turned on, etc.

Electrical equipment or facilities

Non-coal mine production system uses a large number of electrical equipment, which is harmful to electrical accidents. Long-term overload of oil-filled transformers and power capacitors will generate a lot of heat, resulting in internal insulation damage. If the protection monitoring device fails, it will cause fire and explosion. In addition, distribution lines, switches, fuses, pin holders, electric heating equipment, lighting appliances, motors, etc. May cause electrical damage.

(1) Cause of electrical fire.

① Overheating is caused by unreasonable design, poor installation or short circuit, overload, poor contact, short circuit of iron core, poor heat dissipation and leakage during operation.

(2) Electric heating appliances and lighting lamps constitute the ignition source.

(3) Electric sparks and electric arcs, including electric sparks generated during normal operation or operation of electrical equipment, accidental electric sparks generated when electrical equipment or electrical lines fail, electric arcs generated by lightning discharge, electrostatic sparks, etc.

(2) Risk of electric shock.

① Distribution. In the power distribution room, power distribution lines, all kinds of electric drag equipment, mobile electrical equipment, hand-held power tools, lighting lines and lighting appliances or metal conductors communicating with charged bodies, there is the possibility of direct contact or indirect contact with electric shock.

(2) ways and means of injury.

A. the way of injury. Electric shock injury is caused by the energy of current. When electric current flows through the human body, the normal work of cells in the human body is damaged to varying degrees by local electric energy, resulting in biological effect, thermal effect, chemical effect and mechanical effect, which will cause oppression, shock, spasm, pain, dyspnea, abnormal blood pressure, coma, arrhythmia and so on. In severe cases, it even leads to suffocation and ventricular fibrillation and death.

B. the way of injury. Human contact with charged body; Human contact with a metal conductor (such as an equipment shell) that is not normally charged, but accidentally charged when the equipment or line fails (such as leakage); When the human body enters the electrified area on the ground, a step voltage is applied between the two feet.

③ The cause of electric shock.

A. There are defects in the design and installation of electrical lines or electrical equipment, or lack of necessary maintenance during operation, resulting in hidden dangers such as electric leakage, overheating, short circuit, loose connector, broken wire and shell collision, insulation aging, insulation breakdown, insulation damage, PE wire disconnection, etc. ;

B. Necessary safety technical measures (such as protective earthing, leakage protection, safe voltage, equipotential connection, etc.). ) is not set, or safety measures fail;

C improper operation and management of electrical equipment and imperfect safety management system;

D. Mistakes or illegal operations of electrician or electromechanical equipment operators, etc.

(3) Places that may cause electric shock.

① Distribution. Power distribution room, power distribution lines, etc.

(2) ways and means of injury.

A. the way of injury. The thermal effect, chemical effect and mechanical effect of current cause local damage to human body, forming arc burn, current burn, electric branding, electromechanical damage, electro-optic eye and so on.

B. the way of injury.

Direct burn: When an electric arc is generated between the charged body and the human body, current flows through the human body to form a burn. Direct arc burns occur simultaneously with electric shocks.

Indirect burns: When the electric arc occurs near the human body, it will cause burns to the human body, including those caused by splashing molten hot metal.

Electric current burn: the injury caused by the contact between human body and charged body and the conversion of electric energy into heat energy through human body.

③ Cause of electric shock: Turn on the bare knife switch with load (especially inductive load); Short circuit caused by misoperation; Working close to high-voltage charged body; When the line is short-circuited and the fuse is blown, hot metal particles splash; The human body is too close to the charged body, etc.

soil pressure

Ground pressure disaster is a major safety hazard in the mining process of non-coal mines. If prevention is improper and management measures are not in place, it will lead to accidents. Goaf, stope and roadway are all affected by ground pressure, which may cause ground pressure disaster.

(1) Cause of ground pressure disaster: unreasonable coal mining method; Crossing the active area of ground pressure; Crossing the geological structure area; The pillar was destroyed; The design of stope pillar is unreasonable or poorly protected; There is no support in the roadway or the support design is unreasonable; Failing to take timely measures when encountering new geological structures; The construction technology of stope or roadway is unreasonable; Illegal operation in stope or roadway construction; When encountering new rocks, the construction was not carried out according to lithology; The design of blasting parameters is unreasonable; The blasting technology is unreasonable; Illegal operation in blasting construction; Affect or destroy groundwater, rock weathering and other ground pressure activities.

(2) The hazards of ground pressure disasters. Ground pressure disasters are usually manifested as large-scale collapse, collapse and caving of stope roof, large-scale collapse or collapse of goaf, spalling, roof caving or floor heave of roadway or mining face, shaft lining rupture, sand gushing in shaft, rock spalling and surface subsidence.

① The roof of stope collapses, collapses and falls in a large area, and its main hazards are: destroying stope and surrounding roadway; Causing casualties in the mining area; Destroy the equipment and facilities in the mining area; Destroy the normal ventilation of the mine; Causing confusion in production order; Other hazards. If the drainage pipeline passes through the stope, it may damage the drainage system, cause water damage, and then destroy the power supply system of the mine.

(2) Roadway or coal mining face is in danger of spalling and roof caving. Rock pressure activity causes roof caving in roadway, and its hazards mainly include: casualties in roadway; Destroy the equipment and facilities in the roadway; Destroy the normal production system; Destroy the roadway, etc.

Poisoning and suffocation

Analysis of the causes of suffocation caused by (1) poisoning. According to the characteristics of production technology in non-coal mines, the main causes of poisoning and suffocation are gun smoke and other toxic smoke produced after blasting. Other toxic smoke and dust, such as the mixture of sulfide and air formed by ore body oxidation, caves and mined-out areas encountered during mining, toxic gases existing in roadway, toxic smoke generated after fire, etc.

Gun smoke formed after blasting is one of the main causes of personnel poisoning. The main causes of gun smoke poisoning are poor ventilation and illegal operation. Causes of personnel poisoning and suffocation include:

(1) illegal operation. After blasting, the ventilation time is insufficient, workers enter the working face to work, and personnel fail to evacuate to the roadway where gun smoke poisoning will not occur as required;

(2) The ventilation design is unreasonable, which makes the gun smoke stay in the working area for a long time, and there is no local ventilation when heading the single-headed roadway, and there is not enough air volume to dilute the gun smoke, so the design ventilation time is too short.

(3) Due to unreasonable warning signs or no signs, people accidentally enter blind alleys, mined-out areas, chambers, etc. Poor ventilation and long-term poor ventilation;

(4) Sudden encounter with geological structure containing a large amount of asphyxiating gas, toxic gas and dust, and a large amount of asphyxiating gas, toxic gas and dust suddenly gushed out to the mining face or other personnel's workplaces, and the personnel had no protective measures;

⑤ There is an accident. Such as accidental short circuit of airflow, accidental entry of personnel into smoke-polluted areas and long stay, unexpected wind stoppage, etc.

(2) Poisoning and suffocation places. The main places where poisoning and suffocation may occur are: blasting operation face, roadway where gun smoke flows, goaf where gun smoke accumulates, chamber where gun smoke enters, blind alley, blind well, poorly ventilated roadway, goaf, mineral processing workshop where toxic or corrosive chemicals are used, etc.

blasting operation

Blasting operation is an important process in the production process of non-coal mines. Its function is to use the energy released by the explosive in the instant of blasting to do work on the surrounding medium, so as to break the ore and rock and achieve the purpose of excavation and mining.

A large number of explosives must be used in the mining process of non-coal mines. The explosion may occur in the process of transporting explosives from the ground explosives depot to the underground, in the process of charging and detonating, and in the process of loading and unloading ores and rocks with unexploded or incomplete explosives. The vibration, shock wave and flying stones produced by the explosion have great destructive effects on people, equipment, facilities and structures. The common blasting hazards include blasting vibration, blasting shock wave, blasting slungshot, misfire, early explosion and late explosion.

(1) Several accidents in blasting operation.

(1) Fire (fire). ② Early explosion. ③ Self-explosion. (4) Delayed explosion.

(2) The harmful effects of blasting.

① Blasting seismic effect. After the explosive explodes in the rock and soil, it produces elastic vibration waves in the rock and soil within a certain range from the explosion source, that is, blasting earthquake; In chamber blasting, due to the large charge at one time and strong blasting earthquake, it will have a great impact on nearby structures, equipment and facilities, rock mass and so on. , and may lead to a wide range of roof caving and spalling accidents.

(2) Blasting slungshot. Flying stone is a single fragment that shoots from the surface of rock mass and flies far away during blasting. When blasting, the minimum resistance line of explosive charge is inaccurate, and the explosive charge is too large, which leads to the blasting flying stones exceeding the safe allowable range or underestimating the safe distance, resulting in personal injury and equipment loss, which is one of the harmful effects of blasting.

③ Blasting shock wave. During blasting, some explosive gas products rush out with the caving rock and soil, forming shock waves in the air, which may endanger nearby structures, equipment and facilities and rock mass.

(4) Explosive toxic gas. When blasting, it will produce a lot of toxic and harmful gases. If the discharge is not diluted in time and enters the working face prematurely, it will cause great harm to the health of workers and even lead to poisoning death.

(3) The main cause of blasting accident. The main causes of blasting accidents are: premature entry into the working face after blasting; Improper handling of blind guns or broken eyes; Strong vibration or friction during the transportation of explosives; Unreasonable charging process or illegal operation; Unreasonable startup process or illegal operation; The warning is not in place, the signal is not perfect, and the safety distance is not enough; The quality of blasting equipment is poor, the ignition is slow, and the ignition time is delayed; Non-blasting professionals operate, and blasting operators operate illegally; Using materials with unknown blasting performance; The management of explosive magazine is not strict.

(4) Places prone to blasting accidents. In the process of mining in non-coal mines, the workplaces where blasting accidents may occur mainly include: explosive depot, roadway for transporting explosives, roadway for transporting ore and rock, blasting working face, blasting working face, post-blasting working face, post-blasting stope and blasting equipment processing place.