Analysis of the causes and countermeasures of dust pollution in mine production

For open-pit mine production, the dust generated in the mine production process has become an important control factor affecting the environment, operation efficiency, transportation safety and production cost. The dust in the air worsens the working conditions of mining and transportation, and brings great harm to the physical and mental health of the workers working on the site every day, so the dust prevention work is becoming more and more important. Therefore, dust prevention has become a very important work in mine production. This paper analyzes the causes of dust pollution in the production of open-pit mines and its countermeasures.

The hazards of mine dust are mainly manifested in the following aspects:

① Polluting the working environment of the stope, stimulating the mucous membranes of the operators, causing eye damage, causing inflammation and affecting vision;

② make the skin dry, itching, severe will cause acne, chapped skin and a lot of hair loss;

③ Entering the external ear canal, affecting hearing;

(4) Enter the lungs, promote the occurrence of acute and chronic inflammation, long-term operation and even cause silicosis;

⑤ The visibility around the stope is low, and the probability of industrial accidents is high.

Causes of dust pollution sources

Dust pollution sources are almost produced in every link of production in open-pit mining area, such as perforation, blasting, shovel loading, transportation, crushing, soil discharge and so on. In addition, the construction of auxiliary vehicles and mining projects in the mining area (such as the construction of slopes, slope cleaning, etc.) will also produce dust pollution sources, but in comparison, the former will produce much more serious pollution.

01 Dust from perforating operation

The hand-held, air-leg or rock drill used by the roller drill or secondary crushing machine in the working face process is broken into particles of different sizes due to the impact, extrusion, cutting and peeling, and friction of the drill bit on the rock, and some of them form dust after discharging the hole. The dust production in rock drilling is characterized by long time and continuous, and the diameter of a large number of dust particles is less than micron, which is one of the main sources of fine mine dust in open pit mining area. In particular, the cone drill is widely distributed and scattered, resulting in more dust production points and scattered, and more people are exposed to such dust operations, contact time is longer, and the harm to workers is greater.

02 Dust from blasting operations

During the blasting operation, the rock is crushed by the great pressure, high temperature and stress wave of the charge blasting, and the dust is formed after displacement. The instantaneous dust production is very large, and the dust production is greatly damaged by the number of holes, parameters of holes, types of explosives, mineral and rock properties, and geological structures of a blasting.

03 Shovel loading operation produces dust

First of all, when the electric shovel excavates the ore and rock, the dust produced by friction and collision on the surface of the ore and rock is raised by vibration and forms secondary dust. Secondly, when the bucket is unloading the mineral rock to the electric wheel vehicle, it will produce huge dust due to the drop. In addition, the shovel will also produce dust when cleaning the explosion.

04 Dust from transportation operations

The dust deposited on the transport road is affected by the compression, vibration and airflow produced by the electric wheel vehicle when it passes by, and it moves up irregularly, resulting in secondary dust. At the same time, the air quality monitoring of the open-pit mine shows that the road traffic dust is the biggest dust pollution source in the open-pit mining area, accounting for 70%~90% of the total dust production.

05 Dust production in dumping operation

The dust in the dump is produced by the collision and friction of the rock when the electric wheel vehicle is unloading the rock. In particular, the high section of the mining area of the waste dump, the drop is large, and the discharge is large, the formed secondary dust is large, and the surrounding environment is seriously polluted.

06 Secondary dust from slope cleaning, road construction and working face leveling

When the dust in these parts is subjected to vibration and airflow, it flies into the air to produce secondary dust.

07 Dust from crushing operation

When the crusher is working, the ore is squeezed and hit, so that the air in the ore gap is violently squeezed out. When these air flows outward at high speed, due to the shear compression of the air flow and dust, the dust is discharged outward through the feeding port.

08 screening operation dust

In the screening process, dust is generated due to the rapid vibration of the material in the direction perpendicular to the screen surface with the vibrating screen.

09 Belt transport operation dust

After the ore is screened, it is discharged through the chute to the lower belt conveyor. Due to a drop between the dust flow and the surrounding air have a shearing effect, the air is rolled into the material, and the mutual enrolling effect instantly raises the dust at the discharge port and flies around.