Pollution Characteristics And Diffusion Law Of Dust At The Pit Bottom In Haerwusu Open-Pit Coal Mine In Winter

Dust pollution in open-pit coal mines in northern my country is serious in winter,and the prevention and control of dust pollution in winter is one of the important problems in the construction of green mines in open-pit coal mines in northern China.The characteristics and diffusion law of dust pollution under the combined influence of mining operations and regional climate are the key and urgent problems to be solved in the prevention and control of dust pollution in winter.In response to this problem,this paper takes the winter pit bottom dust of the Haerwusu Open-pit Coal Mine as the research object.Through on-site testing,data statistical analysis and numerical simulation,the characteristics of the winter pit bottom dust pollution change are clarified,and the diffusion law of dust in the stope and surrounding areas is revealed.The main results obtained are as follows:(1)Based on on-site measured data and meteorological data over the same period,the change characteristics of meteorological parameters in the stope of Haerwusu Open-pit Coal Mine were analyzed,and the influence of meteorological parameters on dust concentration was clarified;correlation analysis and factors were used to obtain dust particles at pit bottom in winter is significantly correlated with wind speed,solar radiation,boundary layer height and relative humidity.Among them,wind speed and boundary layer height have the most significant influence on the particle concentration.Dust concentration is affected by multiple meteorological factors and production intensity,and small particles of dust are more significantly affected by meteorological factors.(2)The diurnal variation of the dust concentration at the pit bottom in Haerwusu Open-pit Coal Mine in winter is characterized by a single peak distribution,and the concentration of particulate matter reaches the peak before sunrise;it is more obvious that the concentration of small particles in the pit exceeds the national limit,and the main pollutant at pit bottom is PM10;the particulate matter concentration changes have significant consistency,and the correlation coefficient exceeds 0.9;the power function can be used to fit the relationship between different particulate matter concentrations.Through data fitting,the air stagnation criterion for the stope of Haerwusu Open-pit Coal Mine is obtained:MLH<913.33e^-0.592WS;the air stagnation day/event frequency has shown an upward trend in recent years.(3)There are multiple circulation areas at the pit bottom of the Haerwusu Open-pit Coal Mine,which are mainly distributed on the side of the pit bottom close to the dump;the dust is affected by the vortex effect and accumulates in the circulation area and is difficult to spread out of the pit bottom;the staff should reduce the exposure time in the circulation area,and at the same time,it is necessary to take dust reduction measures in the circulation area to effectively reduce the dust concentration at the pit bottom.During the study period,the airflow passing through the Haerwusu Open-pit Coal Mine was relatively divergent,and the monthly clusters were 4,7,and 5respectively;through PSCF and CWT analysis,the winter pollution time of the Haerwusu Open-pit Coal Mine to the surrounding area was mainly distributed in December and January.The main polluted areas are in the southeast and east directions of the Haerwusu Open-pit Coal Mine,and the transmission distance is long.It is necessary to focus on preventing and controlling dust pollution in these directions.There are 34 figures,19 tables,and 91 references in this thesis.