Study On Integrated Monitoring Technology And Application Of Air Space Ground For Dust In Open Pit Coal Mine

Mineral resources are indispensable material basis for the survival and development of human society.The development and utilization of these mineral resources have promoted economic development,but have also caused different degrees of ecological damage and environmental pollution,which has become an important factor restricting the long-term development of economy and society.The open pit mining is carried out in an open space,the operation equipment is large-scale and the operation points are scattered,These factors/characteristics led to a large amount of open pit mineral dust,many production points of dust,a wide range of diffusion as well and exacerbated air quality in a certain range.Therefore,it aroused the general concern of the government and society.However,the systematic research are few concerning the dust emission,diffusion and distribution law of the open pit mine and the impact on the surrounding ambient air quality is extremely limited.It is not possible to objectively and scientifically evaluate the dust pollution of the open pit mining,let alone simply formulate the policy of limiting the development of the open pit mine,nor give the open pit mine the punishment of stopping production without quantitative standards.Therefore,it is of great theoretical significance and practical value to carry out academic research on open pit mine dust and systematically answer the key problems such as reliable monitoring technology,dust distribution law,concentration prediction and dust reduction measures of main dust sources,especially whether the diffusion of productive dust in open pit mine aggravates the pollution degree of air quality in the surrounding area.Taking the anjialing open pit mine as the research object,this thesis establishes a new dust monitoring technology and implementation scheme suitable for the"air space ground"in the semi open space of the open pit mine by using the methods of on-site monitoring,theoretical analysis,numerical simulation and example verification.It takes one year to collect a large number of data on the concentration of suspended particles（PM2.5,PM10,TSP）in the air and on the meteorological environment（pressure,wind direction,wind speed,temperature and humidity,etc.）in the on-site open pit,over the stope and the surrounding air and space environment.On this basis,the distribution laws of dust generation and diffusion in open pit mines with different observation scales,seasons and periods are studied and obtained;Then,the dust diffusion model of main equipment and operation links of open pit mine is established.Through numerical simulation and example verification,the prediction algorithm of open pit mine dust concentration is put forward;Finally,based on the above research results and field preliminary test,the dust reduction measures of the main equipment and operation links of the open pit mine are determined.The major findings and innovative achievements of this thesis are as follows:（1）Taking advantage of the wide range of satellite monitoring and the strong mobility of UAV monitoring,and combined with the advantages of long-term fixed monitoring on the ground.A set of"air space ground"dust monitoring technology and its implementation scheme suitable for the production and operation space of open pit mine and the organic combination of ground and space,fixed and mobile technology are proposed and implemented,and a large amount of data from ground monitoring,UAV monitoring and satellite monitoring are obtained.（2）Through the ground monitoring in the pit,it is determined that the minerals in the dust in the pit of the anjialing open pit mine mainly include Si O₂ and Al₂O₃,and the main pollutant is PM10.The dust concentration in the links of blasting,mining,loading,transportation and disposal in the open pit sometimes exceeds the standard,and the dust production in the links of mining,loading and transportation is the most.The dust concentration is the highest in winter,followed by autumn and spring,and the lowest in summer.The change of dust concentration is high in the evening and morning（4-8 o’clock）and low in the afternoon（13-14 o’clock）.which is mainly affected by wind speed.（3）Through the analysis of satellite monitoring data,The concentration of PM2.5,PM10 and TSP in pingshuo mining area are not higher than those in the surrounding cities and counties,and the dust concentration in the mining area is not significantly higher than that in the surrounding areas;the PM2.5,PM10 and TSP of the anjialing open pit mine are sometimes slightly higher than those around the pit,but the concentration of open pit mine dust is not higher than that in the surrounding area all year round.According to the analysis of UAV monitoring information,most of the particles above PM10 in the open pit mine diffuse to about 200m above the air,and mainly settle in the open pit mine or mining area.The ratio of dust to standard in winter is 1.4 times;the proportion of standard in spring is 1.2 times;the dust concentration of open pit mine in summer and autumn did not exceed the standard.（4）Through numerical simulation analysis,there is a consistent line distribution law in different wind speeds.When the wind direction of the open pit mine is westerly,the turbulent flow is formed near the waste dump and the wind speed is the largest,and the wind flow at the bottom of the pit near the waste dump forms a local re circulation and the wind speed is the smallest;When the wind direction of the open pit mine is north wind,the wind speed at the junction of the surface and the north slope is the largest,and the wind flow at the bottom of the north slope of the open pit mine forms a local double circulation and the wind speed is the smallest.By analyzing the vertical and horizontal stress of dust in open pit mine,the dust settlement model and horizontal diffusion model are deduced.The PM10 and TSP diffusion models of blasting link,mining and loading link,transportation link,waste discharge link and open pit mine under the influence of no wind and different wind speed are proposed and deduced,and the practical application and verification are carried out.（5）The LSTM attention model for predicting TSP concentration in open pit mine is proposed.Combine the LSTM model with Attention,the historical process of input time series is reflected through LSTM model,and the inherent characteristics of input parameters are extracted to achieve the purpose of weighting value according to the importance of influencing factors.The model can better predict dust concentration,facilitate the formulation of dust reduction plan in advance,and has expansibility and wide practical application value.According to the research results of dust diffusion law,based on the actual situation of the anjialing open pit mine and the existing dust reduction technology,the dust reduction measures for blasting,mining and loading,transportation and waste disposal are put forward and implemented.