Underground blasting
I. General regulations
(1) When underground blasting may cause surface subsidence and rolling stones on the slopes, warnings must be placed on the roads leading to the subsidence area and the rolling stone area to establish eye-catching signs to prevent personnel from entering.
(2) When the distance between the working surface exceeds the value specified in the design (or work procedure), no blasting is allowed.
(C) when the power detonate main blasting, wire zone, the suspension cable must not be in contact with a conductive object metal tubes and the like, nor close to cables, wires, signal lines
Second, the tunnel, tunnel blasting
(1) Using the blasting method to penetrate the roadway, there should be an accurate measurement map, and each shift should be filled in on the map. When the two working faces are separated by 15m, the geological surveying personnel should not give notice. After that, they should only be excavated from the front of a work, and should be alerted at a safe place where both sides lead to the working face. The personnel on both sides of the work are all evacuated to a safe place before they are allowed to start. After the roadway is penetrated, the excavation faces on both sides shall coordinate the shooting time.
(2) When one of the two parallel roadways with a spacing of less than 20 m needs to be blasted, the personnel of the adjacent working surface must be evacuated to a safe place.
(3) Blasting is prohibited within the area within 30m from the explosives store. When blasting is carried out in the area of ​​30~100m from the explosives warehouse, no personnel are allowed to stay in the warehouse.
(4) During the blasting of the heading roadway, the work must be kept open between the roadway and the fresh airflow roadway. After the blasting personnel enter the work surface, they must be sprayed with water and fully ventilated.
(5) When the well excavation adopts the deep hole segmental charge blasting, the precaution must be sent to the safe place leading to the access passage at the bottom of the patio before the charge, and the bottom is confirmed to be detonated.
(6) Excavation and blasting of shafts, blind shafts, inclined shafts, blind inclined shafts or patios. There shall be no people in the wellbore during detonation.
(7) To transport the explosive charge in the wellbore, the explosive charge must be placed in a special wooden box or bag. Do not use the bottom bucket. It is forbidden to transport both the explosive charge and the explosive at the same time.
(8) When transporting blasting equipment to the working face of the wellbore, no one shall remain in the wellbore except for the blaster, the pumper and the signal worker.
There shall be no other personnel on the work plate and the steady rope tray except the blasters who escort the bucket. It is forbidden to perform other operations on the two hanging plates when charging.
(9) When drilling the wellbore, the insulated flexible wire must be used as the blasting wire; the length of the electric detonator should be more than 1m longer than the depth of the blasthole; all the joints of the blasting network must be tightly covered with insulating tape and higher water surface.
(10) All manhole covers must be opened before detonation. Personnel unrelated to the blasting operation must evacuate the wellhead.
(11) When drilling a wellbore by drilling, the blasting operation of the bottom of the broken pot and the opening of the head must be taken with special safety measures and reported to the chief engineer of the unit for approval.
When the shaft well is drilled by the freezing method, it is generally not allowed to use the blasting method to open the frozen section of the topsoil. If it is necessary to blast, safety technical measures shall be formulated and reported to the chief engineer of the unit for approval.
(12) When drilling wells with counter-wells, the blasting operations must comply with the following regulations:
1. Anti-well mining and wooden raft support, support must be timely, the distance from the last plate to the working surface before blasting shall not exceed 1.6m;
2. Before the blasting, the pedestrian compartment and the material must be covered tightly; after the shot is fired, the road should be ventilated first. After blowing off the gun smoke, the inspection shall be carried out, and the number of inspectors shall not be less than two. After the inspection and confirmation of safety, the operation can be carried out;
3. When using the hanging tank method, the hanging tank must be taken off before blasting and placed in a safe place in the horizontal roadway. After the shot is fired, special personnel must be designated to check that the lifting wire rope and the hanging crane have no damage, and other operations are prohibited under the counter well;
4. When cleaning the well, there must be safety measures to prevent falling people; before blasting, the wooden raft plate within 0.3m below the bottom of the blasthole must be returned, otherwise it shall not be blasted.
(13) When using nitroglycerin explosives in wellbore blasting, all blastholes must be arranged offset from the positions of the previous blastholes.
(14) When blasting in a tunnel with biogas explosion hazard, the relevant provisions of 4.4 of this regulation shall be observed.
(15) When excavating roadways or tunnels under unfavorable geological conditions, rivers, lakes or reservoirs, blasting shall be carried out in accordance with the special design.
(16) When tunneling with a compressed air shield method, it is strictly forbidden to place the blasting equipment in the area with compressed air.
(17) When blasting in a caisson (including a sunken caisson and a tunnel caisson), the blasting operation must be allowed under the condition that the rock of the caisson working face is vertical and the distance from the bottom plate to the caisson roof is greater than 2 m.
Third, underground mining blasting
(1) When a underground hole or a dike chamber is blasted, all personnel must be evacuated from the danger zone before detonation. The extent of the danger zone is determined by design.
(2) A warning sign must be set at each entrance to the location of the secondary blasting (broken block). Only when it is confirmed that there is no one in the blasting danger zone, the standard is detonated.
Fourth, under coal mine blast
(1) The underground blasting work must be performed by a full-time blaster who has been trained and holds a certificate. In coal seams where coal (rock) and biogas are at risk, special personnel must be blasted.
(2) Mines that are in danger of biogas or coal dust explosion must have the following conditions to be allowed to perform blasting operations:
1. The working face has fresh air flow, and the air volume and wind speed meet the special requirements of the coal mine;
2. The indicators of the blasting equipment and auxiliary blasting equipment used are inspected by the inspection department designated by the Ministry of Coal Industry and obtained the certificate of conformity;
3. Before charging and before detonation, the concentration of biogas in the airflow within 20m of the blasting site must be checked, and its value should be less than 1%;
4. In the coal seam with the danger of coal dust explosion, the roadway within 20m of the working surface must be sprinkled and dusted before the blasting of the working face.
(3) The coal mine explosives of the corresponding safety level shall be selected according to the degree of danger:
1. Non-coal mine permitted explosives can be used in the excavation work face without biogas rock roadway;
2. For low-biogas mines, for mining face with biogas or coal dust explosion hazard, it is necessary to use explosives approved by coal mines of Class I or above;
3. For high-biogas mines, there is a mining face with biogas or coal dust explosion hazard, and it is necessary to use explosives approved by coal mines of Grade II or above;
4. For mining face with gas and biogas hazard, it is necessary to use explosives for mines of Grade III or above;
5. It is strictly forbidden to use black powder.
(4) When using underground electric blasting in coal mine blasting, the following provisions shall be observed:
1. Low biogas mines allow the use of universal instantaneous power detonators or millisecond electric detonators;
2. High-biogas or mining face with prominent dangers of coal and biogas must use the instantaneous power generation detonator or millisecond electric detonator allowed by the coal mine;
3. For mining face with biogas or coal dust explosion hazard, when the millisecond electric detonator and the millisecond electric mine allowed by the coal mine are used, the total delay time shall not exceed 130ms. It is strictly forbidden to use the second and half second deferred electric detonators.
(5) When digging a well or deepening a wellbore in a rock formation, a non-coal safety explosive and a deferred electric detonator may be used. These wells must be 10m away from the coal seam (rock formation) with biogas. When the working face is close to the geological fracture zone, the chief engineer of the mine should extend this distance according to the specific conditions.
(6) Explosion-proof detonators must be used for underground blasting. When drilling or deepening the wellbore that passes through the ground, the bottomless working face without biogas can be detonated using other power sources. At this time, the voltage must not exceed 380V. There must be an explosion-proof power-initiating junction box. The power supply, line connection method, switch structure and installation location of the junction box should be designed and submitted to the competent department for approval.
(7) Explosives and electric detonators must be stored separately in the locked blasting equipment box. It is strictly forbidden to throw or throw them. The blasting equipment box must be placed in a stable top, complete bracket, avoiding mechanical and electrical equipment. At each detonation, the blasting equipment box must be placed in a safe location outside the cordon.
(8) Fill the blasthole with water cannon mud or a non-combustible, malleable loose material such as clay or a mixture of clay and sand. When using water cannon mud, the blasthole must be filled with blockage at the rear with a cannon of not less than 0.15m. Blast holes that are not filled or have insufficient length are strictly prohibited from blasting.
(9) One of the following circumstances shall be banned from blasting, and the team and the squad leader shall be reported immediately and dealt with in a timely manner.
1. The bracket of the mining face is behind the provisions of the operating regulations, or the bracket is damaged, or there is an umbrella;
2. The concentration of biogas in the wind flow within 20m near the blasting site reaches or exceeds 1%;
3. The water in the blasthole is found to be abnormal in water, the temperature is suddenly high, the gas is rushing out, the coal is loose, and the old is empty;
4. There is no reliable protection for equipment, tools and cables near the blasting site;
5. There is no warning.
(10) In order to prevent explosives from deflagrating, the following provisions must be observed:
1. Thoroughly remove the coal (rock) powder in the blasthole before charging.
2. Gently push the medicine roll with wooden or bamboo gun sticks so that the medicine rolls are in close contact with each other, and the force should be appropriate and must not be collided;
3. Do not use ammonium nitrate powder explosives with water content greater than 0.5%;
4. The distance between adjacent blastholes in the coal seam shall not be less than 0.4m.
(11) The charge and packing length of the blasthole must meet the following requirements:
1. Blasting of coal seam or rock formation, the depth of the blasthole shall not be less than 0.65m;
2, in the coal seam blasting, the filling length should be at least one-half of the depth of the blasthole; when using the coal cutting machine, the filling length should not be less than 0.5m;
3. When blasting in the rock formation, when the depth of the blasthole is below 0.9m, the length of the charge shall not exceed one-half of the depth of the blasthole; when the depth of the blasthole is above 0.9m, the length of the charge shall not exceed three points of the depth of the blasthole. Second; the remaining part of the blasthole is filled with packing material;
4. When blasting a working surface with several free faces, the length of the minimum resistance line shall not be less than 0.5m; when blasting large blocks, the minimum resistance line shall not be less than 0.3m.
(12) For the heading face with biogas and coal dust blasting danger, full-section blasting shall be carried out with millisecond detonator. The longwall mining face is not allowed to be blasted at the same time.
(13) In the underground blasting operation, it is strictly forbidden to use two different kinds of explosives in one blasthole.
(14) The joint main line and foot line, inspection line, conduction and detonation operations must be operated by a designated blaster.
(15) The blaster must finally leave the blasting site and must detonate at a safe place with cover. The distance from the shelter to the blasting face shall be prescribed by the competent department of the unit.
(16) After blasting, the blasting staff, the class and the team leader must patrol the venting site for ventilation, biogas, coal dust, roof, brackets, blind cannons, residual explosions, etc. In case of danger, they should be dealt with immediately. Only when the guns on the working surface are blown away, the blasting and alerting personnel are personally withdrawn by the guards and the team leader before entering the work surface.
(17) Using the blasting method to penetrate the well and alleys, in addition to complying with the provisions of 4.2.1, the other working face shall be provided with fences and warning signs to maintain normal ventilation. Only when the biogas concentration of both working faces is below 1% blasting.
(18) The coal seam with severe impact pressure, the blasting retreat distance of the mining face and the time of entering the working face after blasting shall be determined according to the actual inspection results.
(19) Excavation working face with prominent dangers of coal (rock) and biogas. All waste cannons before blasting are also filled with non-combustible materials. The filling depth of large diameter boreholes should exceed the depth of rod hole charge and strengthen at the same time. Support the mining face and back the top.
(20) When Shimen uses vibration blasting to uncover coal seams with coal (rock) and biogas hazard, the minimum distance between the coal seams of the working face is 2m for steeply inclined coal seams and 1.5m for inclined and gently inclined coal seams.
(21) It is forbidden to use the vibration blasting in Shimen to uncover coal seams with a greater degree of danger or biogas pressure greater than 10 atmospheres.
(22) The use of vibration blasting to uncover the coal seam with the danger of biogas is necessary to be specially designed and reported to the competent department of the enterprise for approval. The blasting parameters, the position of the reverse damper at the detonation site, the route of avoidance, and the range of power outages, evacuation distances, and warnings shall be specified in the special design. Supports near the location of the vibration blasting should be strengthened before blasting.
In order to reduce the protruding strength, a barrier measure can be employed.
(XXIII) The first blasting of the vibration blasting If the rock pillar and coal seam of the full section of the Shimen gate have not been broken, the second blasting must still be carried out in accordance with the relevant provisions of the vibration blasting, and the roadway support shall be strengthened to set the oncoming bracket. There are special personnel to observe the obvious signs, and full-time gas inspectors often check the concentration of biogas before they can carry out operations. If a prominent omen is found in the operation, the staff member should immediately evacuate to a safe place.
(24) When excavating roadways in coal seams with prominent dangers of gas and biogas, special design must be carried out when loose blasting is carried out. With the approval of the chief engineer of the mine, the blasting operation is under the command of a special person. The full-time blaster is implemented and recorded. The distance between the loose front and the working face shall not be less than 5m.
(25) When performing blasting operations under complex geological conditions such as faults, fractured layers, calluses, and carbon-free columns, technical measures must be prepared to prevent biogas and water from escaping.
(26) The blasting of the comprehensive mechanized mining (excavation) working face must be approved by the chief engineer of the mine to protect the hydraulic supports and other equipment.
(27) In the high-biogas and its mining face with coal and biogas outburst, a biogas automatic detection and alarm power-off device shall be installed.
(28) The blastholes that have been charged must be blasted on duty. In special cases, when there is an unexploded charge blasthole, the blaster on duty must clarify and clearly mark the next blaster on the scene.
(29) It is strictly forbidden to blast (exposed guns).
5. High-sulfur high-temperature mine blasting
(1) When blasting a mine with a risk of explosion of sulfur dust or sulphide dust, the following provisions must be observed:
1. Regularly measure the dust concentration;
2. It is forbidden to use an open flame to detonate or detonate a cord to blast outside the hole;
3. It is forbidden to use shallow-hole blasting, bare drug pack and unfilled blasthole blasting and blasthole filling length of blasthole depth less than 0.65m, not to be one-third of the total length of the blasthole, and not less than 30cm;
4. Before the filling, the working surface should be sprinkled with water. In the shallow blasting, the space and the surface within 10m from the working surface shall be sprinkled. When the deep hole is blasted, the full space and surface within the 30m of the working surface shall be sprinkled;
5. Persons who break the blast should carry self-rescuer and explosion-proof battery lights with them, and must not use other lighting;
6. After each blast, it must be inspected by a professional ambulance team. After confirming the safety, the authorized personnel enter the work surface.
(2) In the high-sulfur mine using ammonium nitrate explosives for blasting, the iron ion concentration and sulfur content of the sulfide ore powder must be determined in advance. When the sulphur content of the ore exceeds 30%, the sum of the iron ion concentrations of the mineral powder containing iron sulphate and iron sulphite (trivalent and ferrous iron) exceeds 0.3%, the working surface is moist and watery, and when blasting with ammonium nitrate explosives, The ore powder must be removed from the hole; the explosive should not be in direct contact with the hole wall; the explosive should be packaged intact; the slag hole should not be filled with sulfur slag; the charge time and the number of holes should be strictly controlled.
(3) When blasting at a high temperature mine exceeding 60 °C, the following regulations must be observed:
1. The working surface and the bottom temperature of the hole must be measured before charging;
2. Ventilation must be strengthened before and after explosion, and cooling measures such as spray watering should be adopted;
3. When the temperature at the bottom of the hole is 60~80°C, the explosive should be packaged in asphalt kraft paper and must not be in contact with the hole wall; the time from charging to the detonation should not exceed 1 hour;
4. When the temperature at the bottom of the hole is 80~140°C, the explosive must be tightly packed with asbestos fabric or other insulating materials. The detonator is not allowed in the hole, and the anti-heat treatment black-black gold can be used to detonate the coal; the charge to the detonation Time should be determined by simulation test;
5. When the temperature at the bottom of the hole exceeds 140 °C, high temperature blasting materials should be used.
(4) In the case of mine blasting with high temperature, high sulfur and sulfur dust explosion hazard, effective safety protection measures shall be formulated. After approval by the person in charge of the unit, the blasting operation shall be carried out.
Sixth, potassium mine underground blasting
(1) The concentration of hydrogen and biogas in the air must be determined at important locations such as the blasting surface and nearby roadways, electrical equipment, and detonation stations. When it is confirmed that there is no danger, the blast preparation shall be carried out.
(2) The detonation station should be located in the fresh air current in the safe area.
(3) Before charging, the power supply and lighting power supply of the mining area must be cut off. Before the detonation, the insulation of the blasting network should be checked.
(4) The design of the blasting network shall be such that the sequence of the cannons is sequentially detonated against the direction of the wind flow.
(5) After 15 minutes of fire, the gas inspector should check the concentration of gas (hydrogen, biogas, etc.) in the vicinity of the blasting operation surface and electrical equipment to confirm the danger of no gas explosion, and check that the power grid, lighting grid and electrical equipment are not When the damage is good and the insulation is good, the power can be restored. After the ventilation is normal, the personnel are allowed to enter the work surface.
(6) When mines with hydrogen and gas explosion hazards are blasted, only blasting equipment that meets the safety requirements for potassium mine blasting shall be used.
7. Underground blasting of petroleum and swaddle mines
(1) The working surface that is allowed to perform blasting operations shall be determined according to the concentration of toxic gases, gas and oil vapors in the air in the mine, and approved by the chief engineer of the mine. Blasting is strictly prohibited in unauthorised locations.
(2) When blasting is carried out at the place where the blasting operation is approved, the following provisions must be observed:
1. Ensure that there is fresh air flow on the blasting operation surface, and the concentration of flammable gas does not exceed the dangerous standard;
2. Use safe explosives;
3, the use of mine-approved detonators, it is strictly prohibited to open fire or detonate tube detonation;
4. It is strictly forbidden to use the bare pack to blast, and it is strictly forbidden to use the blasthole blasting less than 1m deep;
5. Only use the detonating cord to detonate in the case where the wellbore is excavated in the rock layer containing no petroleum and ceresin, and no gas is deposited;
6. When the depth of the blasthole is 1~1.5m, the packing length should not be less than one-half of the depth of the hole. When the blasthole depth exceeds 1.5m, the packing length should not be less than one-third of the hole depth, and not less than 0.75m, no blasting without tamping;
7. When there are several free faces, the minimum resistance line of each drug pack shall not be less than 0.5m.
(3) For the blasting of petroleum mines, the gas and oil vapor concentrations of all roadways and detonation stations within 20 m of working and working faces shall be measured before and before detonation.
(4) The oil on the bottom of each roadway within 20m of the working face and working face shall be removed and covered with sand.
(5) A safety officer with a post not less than the length of the mining section (or class) shall supervise the blasting operation at the blasting site.
(6) After each blasting, a special person must check the condition of the working face and the ventilation of the working face. Finally, the squad leader or the section chief approves the personnel to enter the working face.
(7) For mines where gas and rock are suddenly ejected, the blasting operation shall comply with the provisions of 4.4 of this regulation and take corresponding measures.
(8) There are blastholes that are strongly sprayed by light oil and gas. It is forbidden to blast the charge. Only a small amount of blastholes are formed by the drop of oil. After carefully clearing out the oil droplets, it can be blasted.
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