Causes and preventive measures of mine blasting accident
Drying Furnace,Fully Automatic Dryer,Fully Automatic Drying Oven,Drying Equipment Shandong Hengyi kaifeng Machinery Co.,Ltd , https://www.xhykf.com
In addition, the quality of the detonator may also cause premature explosion.
The effect of lightning on blasting is the largest and most abundant of various external electric fields. Most of the early explosion accidents caused by lightning occurred in open-pit blasting operations, such as chamber blasting, deep hole blasting and shallow hole blasting.
Stray current is the current clutter exists outside of the power supply circuit initiating network; induced current is caused by the alternating electromagnetic field, it exists in the vicinity of power lines, transformers, high-voltage switch and a ground rail iron feedback, if Electric explosion networks close to these devices may cause early explosions.
Static electricity refers to the relatively static charge carried on the insulating material. For example, when performing blasting work, if the operator wears chemical fiber or other protective overalls, the clothes will rub each other to generate static charge. When accumulated to a certain extent, it may be accumulated. Causes the electric detonator to explode.
Radio frequency power refers to electromagnetic waves of various frequencies generated by radio, lightning, television transmitters, high-frequency equipment, etc., such as electric detonators or electric explosion networks are in a strong radio frequency electric field, and may also cause early explosion accidents.
2. Accident prevention (1) The prevention and control measures of stray current include: reducing the source of stray current, checking all kinds of electrical equipment around the explosion area, preventing leakage; cutting off the power supply, electric conductor, etc. into the explosion area; The stray current in the explosion area should be detected. When the stray current exceeds 30 mA, it is forbidden to use ordinary electric detonators, electric anti-stray electric current detonators or electric blasting networks with stray-proof current, or non-electric detonation method; preventing metal objects into the conductor and other electric detonator with bore holes, to prevent the spread nitrate explosive plating fine wet ground; Nonel system employed.
(2) Prevention and control of static electricity Preventive measures against static premature explosion: Blasting workers are prohibited from wearing chemical-resistant clothing such as chemical fiber and wool; when mechanically charging, all equipment must be reliably grounded to prevent static electricity accumulation; antistatic detonators are used; Use a semiconductor delivery tube in a compressed gas charging system (which may generate static electricity when compressed gas is delivered to solid particles of explosives); use a detonating cord network or orifice in a dry area, especially when using compressed gas to fill a powdered nitrate-type explosive Detonation method, or use anti-static electric detonator; use detonating tube detonation system.
(3) Prevention of thunder and lightning In the thunderstorm season, a non-electric detonation system should be adopted for blasting operations; when an electric detonation system has to be used in an open-air explosion area, a lightning rod or an early warning system should be installed in the blasting area; lightning is coming in the charging connection operation. When signing or warning, stop the operation immediately, disassemble the main line and branch line of the electric blast network, bundle the exposed core wire with tape, and insulate the wire of the electric blast network from the ground, and prevent the network from forming a closed loop, and the operator immediately Withdrawal to a safe place; temporarily cut off all electrical conductors (wires or metal pipes) leading to the blast zone before the arrival of lightning, to prevent current from entering the blast zone; for blasting of the chamber, and when there is thunderstorm, it should be immediately The ends of the lead wires are insulated separately, placed in a suspended position at least 2 m away from the mouth, and all personnel are evacuated to a safe place; all charges are detonated before the lightning strikes.
(2) Blind Gun Accidents 1. Causes of Blind Gun Accidents Blind guns (also known as refusing explosives and smashing guns) refer to the phenomenon that explosives do not explode as designed. Reasons for blind cannons include detonators, detonating power or electric blasting network factors, explosive factors, and construction quality factors.
2. Handling of blind cannons (1) Before the blind cannon is handled, the blasting leader should set the warning range and set an alert at the boundary of the area. Unrelated personnel are not allowed to enter the warning zone when handling the blind cannon.
(2) When detonating after power-on, the blaster must first remove the handle or key, and remove the blasting busbar from the power supply, twist it into a short circuit, and wait for a certain period of time (at least 5 minutes when using the instant detonator; use the deferred detonator At least 15 minutes), you can check along the line to find out the cause of the explosion.
(3) If the blind cannon occurs due to poor connection, misconnection, leakage, etc., the power supply should be cut off immediately, and then re-wired.
(4) When the detonating cord and the detonating tube detonate the network, a blind cannon should be inspected first for damage or breakage. If it is found that there is damage or breakage, it should be repaired and re-initiated.
(5) It is strictly forbidden to use planing or picking up the explosive charge from the blasthole or pulling out the electric detonator from the explosive charge.
(6) Blind cannons of shallow hole blasting caused by other reasons can be blasted in parallel holes, and the parallel hole distance should not be less than 0.3m; for shallow hole medicine pot method, the parallel hole should not be the edge of the blind gun pot Less than 0.5m. To ensure the direction of the parallel blastholes, a portion of the tampon can be removed from the blind blasthole.
(7) For the blind cannon that handles deep hole blasting, the blasting network is not damaged, and the minimum resistance to the change of the line element can be re-wired and detonated; if there is a change in the minimum resistance line, the safety distance should be checked and the warning range should be increased. Then connect the line to detonation. Otherwise, the parallel blasthole charge can be detonated at a diameter of not less than 10 times the diameter of the blasthole from the blind cannon. The blasting parameters are determined by the blasting technician and approved by the blasting person in charge.
(8) It is strictly forbidden to continue to deepen the bottom of the blasthole with or without residual explosives; it is strictly forbidden to use the method of eye-catching to smear the drug; it is strictly forbidden to use the pressure wind to blow the blasthole.
(9) It is strictly forbidden to work at the location and deal with the refusal of the blast before the blasting treatment is completed.
(10) After handling the explosion of the blasthole, the blaster must inspect the bombed coal and the stone and collect the unexploded electric detonator.