Mine blasting is to remove the ore from the ore body and blast it into a certain explosive pile according to the engineering requirements, and break it into a certain block degree to create conditions for subsequent mining, loading and transportation work.
Mine explosives include ammonium nitrate explosives, water gel explosives, nitrifying sweeteners, and emulsified fried drugs. The most widely used explosives in mines in China are ammonium nitrate explosives, including ammonium ladder explosives, ammonium explosives, ammonium pine wax explosives, and aqueous ammonium nitrate explosives. There are in danger of methane or coal mine working face or coal dust explosion workplace should use approved by the competent authorities, in line with the provisions of the national coal mine safety regulations permissible explosives.
Commonly used detonating devices are detonators (fire detonators, electric detonators), detonating cords, detonating tubes, fuses, and the like. According to the type of detonating equipment used, the detonating method includes a detonator detonation method, an electric detonator detonation method, a detonating cord detonation method, a detonating tube detonation method, and a joint detonation method. The underground coal mine is statically fired with an open flame, and only electric detonators excited by electric energy can be used. In order to ensure the safety and reliability of the blasting operation and prevent the explosion, the combined detonation method is used to detonate in the large-scale blasting, and two kinds of detonation networks are laid at the same time.
(2) Main safety regulations for blasting operations
(1) All kinds of blasting operations must use blasting equipment that conforms to national standards or industry standards, and is not allowed to use unauthorized explosives.
(2) For the group of mining mountains and mines where the blasting work is carried out, the person in charge of the blasting work, the blasting staff and the warehousing equipment clerk must be set up. These personnel should be aware of the performance of the blasting equipment used, blasting techniques and related safety knowledge.
(3) All personnel engaged in blasting work must undergo training, pass the examination and hold a certificate of conformity.
(4) For medium, 4, and 3 mines, when performing shallow blasting, there should be a blasting manual. The contents include the amount of charge, the structure of the charge, the length of the plug, and the method of detonation.
(5) When one of the following conditions occurs, the blasting operation is prohibited: there is danger of falling roof or slope falling; the passage is unsafe or the passage is blocked; when the medium-deep hole or deep-hole blasting is performed, the blasting parameters or construction quality are not in conformity with the design. Requirements; there is a danger of water inrush on the working surface or abnormal temperature in the blasthole; there is no warning on the boundary of the danger 1i2; there is insufficient light or no illumination. (6) It is forbidden to wear chemical fiber clothes for blasting equipment processing and blasting operations; open blasting is prohibited in foggy weather, thunderstorms, dusks and nights.
(7) When charging, the following rules must be observed:
Use wooden guns; when loading explosive kits, it is strictly forbidden to throw or impact; once the primer is not in place, it is forbidden to pull out or hard pull the fuse, detonating cord, detonating tube or electric mine in the explosive kit. The pin line shall be handled in accordance with the relevant regulations for handling the blind cannon.
(8) When filling work, the following rules must be observed:
After filling, it is necessary to ensure the quality of packing, and it is forbidden to use non-filling blasting; in shallow hole blasting, the general filling length is 1/3 of the hole depth; it is forbidden to use stone and flammable materials to fill the blasthole; the blockage should be very careful and must not be destroyed. Detonation line; it is forbidden to tamper directly to the packing material of the medicine bag or to impact the detonating medicine bag with the stuffing material.
(9) After the gun is fired, it is allowed to enter the blasting operation site after sufficient ventilation.
(10) Before the commencement of the blasting work, the boundary of the danger zone must be determined and no obvious signs are placed. Underground blasting should be set up on the relevant passages. There should be a roadblock in the return airway, and the sign of “Blasting danger zone, not allowed to enter†should be hung.
(11) Acoustic and visual signals must be emitted simultaneously before blasting to enable personnel in the danger zone to hear and see. After the blast, the warning signal can be released when it is checked for safety.
(12) After the blaster enters the shooting position, he shall check whether there is any roof, dangerous stone, damage to the support and blind gun. If these phenomena are found, they should be dealt with in a timely manner. If it cannot be handled, a hazard warning or sign should be established. Commonly used methods for handling blind cannons include re-explosion method, trapping method, parallel eye charge blasting method, and water washing method.
(3) Detonation safety technology
1. Safety technology for detonation of fire detonators
The causes of accidents caused by the detonation of fire detonators include the quality problems of fuses and detonators, the early explosion of detonators, the delay of detonation of detonators, and the detonation of detonators. The main preventive measures include:
(1) Strengthen the management of the manufacture, storage and transportation of fuses and detonators, carefully purchase and inspect fuses and detonators, and strictly control the quality of fuses and detonators.
(2) Establish and improve the inspection system, avoid excessive bending or breaking of the fuse in operation, and listen to the sound of the gun and the number of guns, or several guns. When there is a cannon or may have a cannon, the time to enter the cannon should be doubled.
(3) Strengthen the training of blasters, improve their professional knowledge and improve their operational skills.
2 Safety technology detonated by detonators
The cause of accidents caused by the detonation of electric detonators is the early explosion, detonation, and delayed explosion of electric detonators. Stray current, lightning and static electricity are the main factors causing the explosion of electric detonators. The main measures to prevent stray current are: electric blasting network with stray-proof current; electric detonator with anti-stray current; non-electric detonation method; strengthening blasting circuit insulation without bare wire connection. Measures to prevent early explosion caused by lightning include: prohibiting electric detonator blasting in thunderstorms; setting up lightning protection system in blasting area; using shielded line blasting; using non-electrical detonation method. Measures to prevent static premature explosions include: increase the moisture of explosives; use antistatic detonators; use non-electric detonation methods.
In order to reduce the occurrence of detonation and delayed explosion of electric detonators, in addition to strictly testing blasting equipment and ensuring the quality of blasting equipment, it is necessary to adopt an accurate and reliable detonation network to eliminate errors in network design and strictly enforce operational procedures. .
3. Safety technology for the detonation of detonating tubes and the detonation of detonating cords
When designing the detonating tube to detonate the network, the ring network cannot be used, that is, the initial position of the explosion cannot be too close to the final position. In the case of gas, the use of a detonating tube is prohibited. Special attention should be paid to the use of the correct connection method to prevent the occurrence of a detonation accident in the detonating cord network.
(4) Storage, transportation and management of blasting equipment
The location, structure and facilities of the blasting equipment warehouse shall be in accordance with the provisions and requirements of the Blasting Safety Regulations, and shall be approved by the competent department and reported to the local public security bureau for approval. The management, storage, transmission, transmission and transportation of blasting equipment must comply with the relevant provisions of the Blasting Safety Regulations.
After inspection, the failure of the blasting equipment or the failure to comply with national standards or technical conditions shall be destroyed. When destroying blasting equipment, it is necessary to register the book and prepare a written report indicating the name, quantity, cause of destruction, method of destruction, location and time of destruction of the destroyed blasting equipment, and report it to the relevant department.
(5) Prevention of blasting accidents
To prevent the occurrence of blasting accidents, the main measures are as follows.
(1) Maintaining blasting safety distance Blasting earthquakes, air shock waves, debris scattering and harmful gases will inevitably occur, thus endangering the safety of personnel, equipment, buildings and wells in the vicinity of the explosion area. Therefore, the blasting hazard must be determined and the safety distance specified. The safety distance mainly includes the safety distance of blasting earthquake, the safety distance of blasting air shock wave, the safety distance of individual gravel scattering, the safety distance of electric detonation, and the safe distance of blasting harmful gas diffusion.
(2) Careful design must be made clear before design; the maximum allowable dose should be determined during design, then the blasting parameters should be selected reasonably, the reasonable delay time should be selected, a feasible blasting plan should be made, and the blasting accident prevention measures should be formulated; The design documents should be reviewed and checked carefully.
(3) Carefully constructing personnel at all levels to hold certificates and form a strict management system; according to the characteristics of the project, formulate various safety systems, post responsibilities, and key technical operation rules; perform blasting equipment inspection according to the regulations; ensure the charging, Construction quality of three key processes of blockage and connection; safety inspection and treatment after explosion.
(4) Strengthen safety management to report to the management department for approval and filing according to the requirements of the regulations; establish and improve strict command management organization; establish quality assurance system, formulate quality assurance outline and quality maintenance procedures for each process.
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