Study on Dust Migration Law and Spray Dedusting Technology in Parallel Double Belt Transportation

To effectively solve the problem of dust pollution caused by the parallel double-belt transportation of coal in a coal preparation plant, taking the Huangyuchuan coal preparation plant as an example, a numerical model of the air flow-dust distribution was established by means of simulation. The flow lines between the strips of tape and the tail of the tape machine will gather, and there will be backflow on the right side of the 3001 tape and left side of the 3002 tape. Under the action of wind current, most of the dust particles larger than 10 μm are distributed in the range of 0~5 m on both sides of the tape; dust particles smaller than 10 μm spread to the entire preparation workshop. Combined with field test verification, dust pollution is mainly concentrated at the guide trough, the feed inlet, the rear of the machine, and the joint of the belt corridor. Based on this, a targeted spray dust reduction treatment plan is proposed. By measuring the dust concentration before and after the treatment of dust-polluted areas, it is proven that the dust reduction efficiency of this plan can reach more than 90%.

Analysis of the Factors Affecting Fine Dust Concentration Before and After COVID-19

This study conducted a comparative analysis of the factors affecting the concentration of fine dust before and after COVID-19. Of these, the dominant factor was CO, and the influence between variables increased even after COVID-19. In the case of PM10, the influence of wind direction and wind speed variables decreased, which is thought to be due to the reduction of westerly-based foreign air pollutants following China’s containment policy. Comparative analysis by season showed that the influence of temperature and humidity was higher in winter. In spring, the influence of wind direction and speed decreased with changes in the westerly wind and the influence of China’s containment policy. In summer and autumn, when the concentration of fine dust is relatively low, the influence of CO after COVID-19 was rather high, indicating that continuous CO management is necessary. Considering the relationship between these air pollutants and the meteorological environment, it is judged that fine dust reduction measures should be implemented.

Study on Dust Control Technology in Artillery Working Face

Aiming at the serious problem of dust pollution in blasting work, the dust generation law and dust-bearing air flow time and space evolution law of blasting working face is analyzed and studied, and the optimal dust-exhausting wind speed of blasting work was 1.5 m/s. Combining with the dust production characteristics and wind speed conditions of the 107 blasting face in Dongling Coal Mine, Chongqing, Comprehensive dust prevention measures such as high-efficiency water cannon mud, high-pressure spray dust reduction, and dust concentration over-limit spray dust reduction are adopted to control the dust from the source and cut off the dust diffusion path, and the total dust reduction efficiency reached 94.8%, the respirable dust reduction efficiency reached 92%, and a good dust reduction effect has been achieved, which provides a basic basis for the control of dust in the blast mining work.

Dust Concentration Changing Regularities and Dust Reduction Technology by Spray Negative Pressure in Fully Mechanized Mining Face

The dust concentration changing regularities are the basis to take dust depression measures, which is greatly influenced by the airflow. In the software of FLUENT, the value of ventilation velocity is set as a constant, which cannot express the real ventilation. According to the flow characteristics of the sublayer and data from Nicholas’ experiment, the ventilation velocity distribution formula of sublayer in the inlet section of fully mechanized caving coal face is deduced. The boundary condition of velocity is given by UDF. Taking the 3top1110 fully mechanized caving coal face as an example, the dust distribution in the process of coal mining and hydraulic support shifting was studied. According to the dust-spray coupling experiment, three types of nozzle are chosen based on the efficiency of dust suppression. Combining the dust migration rule and the characteristics of nozzles, the negative pressure-secondary dust suppression devices of spray were developed and applied. And the above measures have lowered the dust concentration effectively.

Blockchain-Based Network Concept Model for Reliable and Accessible Fine Dust Management System at Construction Sites

In total, 44.3% of particle matter 10 (PM10) is fugitive dust, and one of the main sources of fugitive dust generation in Korea is construction work (22%). Construction sites account for 84% of the total business places that have reported fugitive dust generation. Currently, the concentration of fine dust at construction sites is being remotely monitored by government inspection agencies through IoT sensors, but it is difficult to trust that appropriate fine dust reduction measures are being taken, because contractors can avoid taking these measures by submitting false reports or photos. In addition, since the fine dust monitoring system under government management is not an open platform and centralized system, residents near construction sites encounter difficulties in accessing information about fine dust. Therefore, in this study, we designed and constructed a blockchain network model to transparently and reliably provide network participants with the information associated with IoT data and fine dust reduction measures. To operate the blockchain network, we designed the chaincode, DApp, and network architecture. In addition, information on fine dust concentration and reduction measure photos were shared with the participants via the blockchain search tool (Hyperledger Explorer). The proposed blockchain network is expected to form a trust protocol among contractors, government inspection agencies, and citizens.