Dust hazard protection measures

The so-called "revolution" is to adopt a technological innovation method to fundamentally solve the dust generation process from the generation of dust. In recent years, occupational disease prevention and control work has gradually been paid more attention in the coal mining industry, from mining process, mining operation environment, personal protective equipment and facilities. large capital investment, and gradually transform and update production equipment and facilities, with the mechanization further improve the chances of workers in direct contact with dust gradually reduced, dust prevention and control work has made great breakthroughs and improve.

The so-called "wind" and "water" are mainly based on "water" and supplemented by "wind", and adopt dust control methods such as watering and dust reduction, ventilation and dust removal and purifying wind flow to reduce dust and dust. Specifically, there are the following:

Wet rock drilling

It refers to the pressure water passing through the rock drill to the bottom of the hole during the tunneling process, moisturizing and flushing the dust in the blasthole, so that it becomes a slurry in the blasthole and discharges the blasthole. This allows most of the dust to be controlled in the blasthole. After wet drilling, the dust concentration can be reduced from 500-1400 mg/m3 to 4-10 mg/m3 when the dry eye is dry, and the dust reduction rate can reach 90%-98%. Therefore, wet rock drilling is an effective dust control measure commonly used in rock drilling work. Dry drilling can be used and dry dust collector can be used to catch dust only when the water shortage site and the water-expanded rock cannot use wet drilling.

2. Ventilation and purification of airflow

Diluting and discharging the dust by ventilation is one of the important measures to reduce the concentration of dust in the mine. Therefore, it is necessary to strengthen the ventilation management work, reduce air leakage, increase the air volume at the outlet of the air duct, and reasonably control the wind speed. When the wind speed is too low, the coarse dust will separate from the air and will not be discharged. According to experimental observations, when the wind speed in the roadway reaches 0.15m/s, the dust below 5μm can be suspended and evenly mixed with the air and discharged with the wind. The "Procedure" stipulates that the minimum wind speed of the rock roadway in the excavation shall not be less than 0.15m/s, which can fully meet the requirements of the minimum dust exhaust wind speed. Increasing the dust speed, the dust particles with a slightly larger particle size can also be suspended and discharged, and the dilution effect is enhanced, and the concentration of the dust is also reduced. When the wind speed is increasing, the dust will be raised to increase the dust concentration in the wind flow. Therefore, the Regulations stipulate that the maximum allowable wind speed of the mining face is 4m/s.

In the working place where the dust production is high, the mine dust ratio is high, and the temperature is relatively high, the dust exhaust wind speed can be moderately increased.

Ventilation and dust removal is a reasonable wind speed to discharge the dust generated by the driving face, but the pollution range should be reduced. To this end, a water curtain purifying wind flow is provided in a roadway through which a wind flow having a high dust concentration is passed. The arrangement of the sprayer should be based on the principle that the water curtain is covered with the roadway section and as close as possible to the dust source to reduce the diffuse range of the dusty air. Another way is to add a water curtain in the dust-producing roadway, and the distance between them is every 20 meters. It is best to install three heads (heading heads). According to the field test results, the dust reduction rate reached 98.6%.

3. Cannon spray

Blasting is one of the main links in the production of dust, and it can make the dust fly again and pollute the air. Spraying water to reduce dust during shooting can get better results.

Spray watering is to spray the pressurized water through the sprayer under the action of rotation or impact, so that the water flow is atomized into fine water droplets and sprayed into the air. Its functions are as follows: (1) After the high-speed flowing water droplets collide with the floating dust in the range of the fog, the dust particles are wetted and sink under the action of gravity; 2 the high-speed flowing mist generates a negative pressure to pollute the surrounding dusty air. Attracting to the wet and sinking of the fog; 3 Wetting the dead dust particles to make it difficult to fly; 4 Increasing the moisture of the coal to reduce the explosiveness of the coal dust; 5 Preventing the spread of the explosion flame.

4. Install rock sprinklers, flush lanes, and transfer points to reduce dust

Rock-filling water is a way of artificially sprinkling water before and during the slag discharge. Washing the rock gang is a measure to prevent the dust on the wall of the roadway from flying again after the wind and the shock wave of the roadway to form multiple damages. The implementation of these two measures requires manual operation. According to the author's many on-site follow-up implementation results, most of the production is not normal. This is a gap in dust control. It is recommended that leaders and departments at all levels strengthen this work. Supervision and management efforts.

The unloading point at each transfer point is also another source of dust flooding. Article 150 of the “Safety Regulations for Coal Mines” has clearly stipulated that “the mine must establish a complete dust-proof water supply system. The mining face without the dust-proof water supply system pipeline shall not be produced. The main transportation lane, the return road of the mining area and All transporters must be equipped with sprinklers when reloading the nose and unloading ports."

5. Personal protection

After the implementation of the above-mentioned dust-proof measures, a small amount of fine dust is still diffused in the air, so strengthening the dust of the individual is also an important aspect of comprehensive dust prevention.

The main tool for personal dust prevention is dust masks. Currently, there are simple masks and special dust masks. According to the difference of working environment, different dust masks are selected and adhered to correctly, especially the workers who pick drivers and anchor sprays can not ignore the role of individual protection.

In short, the management of coal mine dust hazards is a long and complicated process. As long as we respect science and adhere to the spirit of putting people first, advancing with the times, pioneering and innovating, seeking truth and being pragmatic, we will strengthen technological innovation in strict accordance with the "Procedures" and in accordance with industry standards, combined with the "eight-character" guidelines, methods, standards and requirements for dust control. To ensure the investment of facilities, strengthen the combination of discipline and education, the governance of coal mine dust hazards will present a good situation.

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