| Mineral resources are the indispensable material base in the process of social development and economic construction in China.With the increasing demand of people’s material life,the mining scale of open-pit mines is getting bigger and bigger.In the process of open pit mining,a large amount of dust will be generated,and it has the characteristics of rapid diffusion,high concentration and transient,which endangers the health of the site staff and brings pollution to the environment that cannot be ignored.At present,most of the domestic open pit mines do not adopt effective dust management methods in the blasting process,and the data testing of blasting dust reduction effect is tedious and not accurate enough,which leads to a relatively perfect quantitative evaluation system for the dust reduction effect of blasting dust reduction operation in open pit mines.To address this problem,this thesis takes the limestone mine in Tongling City,Anhui Conch Group as the research background.Firstly,the main sources and proportions of blasting dust were determined through on-site dust collection,and the process of dust generation to diffusion was analyzed through blasting operation images,and the key of dust management was determined.Secondly,the physical properties of blasting dust were detected,and the dust reduction scheme of water pre-wetting + water-sealed blasting was determined by combining theoretical analysis with the actual situation on site,and the dust reduction effect was determined to be as high as 67% through field tests,with significant dust reduction effect;in addition,MATLAB was used to process the on-site blasting dust images,and the quantified analysis of blasting dust reduction effect was carried out by means of image method,and the function relationship between dust concentration and dust Finally,based on the previous research results,a quantitative dust reduction analysis software was designed based on MATLAB APP Designer,and through field application and error analysis,it was determined that the software could meet the demand for quantitative analysis of blasting dust reduction effect in open pit mines.The details and conclusions are as follows.(1)Blasting dust generated from blasting operations in open pit mines can be divided into dust generated before blasting starts,during blasting and after blasting according to the time sequence,where dust generated before blasting starts and during blasting is mainly concentrated in the blasting area and dust generated after blasting is mainly concentrated in the material area.The results show that the dust generated during blasting in the blasting area of the open pit blasting operation accounts for about81% of the total dust from the blasting operation,and the secondary dust in the material area caused by the friction and collision of rock and soil after blasting accounts for about 19%,and the dust mainly comes from the blasting area.And through the analysis of blasting operation images,it can be found that the spatial location of dust in the blasting area is high and easy to spread,while the spatial location of dust in the material area is low,mostly settling in place and not easy to spread,so the blasting dust reduction work in the open pit mine should focus on the dust generated in the blasting area.(2)Collecting mine blasting dust and testing the physical properties of the dust,the test results show that: the particle size range of the dust is concentrated in 0～30μm,which is more hazardous,and the main components are calcite and a small amount of quartz and trace amount of Albite and potassium feldspar,which are all hydrophilic minerals with a good contact angle of about 17.5° and excellent wettability.According to the physical nature of blasting dust and the characteristics of large concentration and rapid diffusion,we chose the wet dust reduction technology means,and compared the advantages and disadvantages of several wet dust reduction means,and finally determined the water pre-wetting + water sealing blasting combined dust reduction means according to the actual situation of the mine.After designing the specific test program,we carried out on-site comparison tests and tested the dust concentration between conventional blasting and dust reduction blasting through equipment.The test data showed that the dust reduction effect of this dust reduction blasting program reached 67.3%,which is a significant dust reduction effect and can meet the demand of blasting dust management in open pit mines.(3)The blasting dust images were processed by MATLAB,and it was found that the pseudo-colorized images generated by the image grayscale values could clearly show the concentration size and distribution of blasting dust.The relationship between dust concentration and dust image grayscale is derived to quantify the blasting dust reduction effect,and field tests are conducted to collect dust concentration and image data to improve the formula(4)Aiming at the problems of insufficient accuracy and cumbersome process of blasting dust reduction data detection in open pit mines,it is difficult to carry out regular detection,etc.,a quantitative dust reduction analysis software based on MATLAB APP Designer design platform is designed by combining the characteristics of blasting dust in open pit mines and image processing methods.The software calculates the dust reduction efficiency through the function of dust concentration and image grayscale value,and visualizes the spatial distribution of dust concentration through pseudo-color images and grayscale histograms to analyze the dust reduction effect,which provides a reliable reference basis for the evaluation and optimization of blasting dust reduction operation.According to the field application verification,the relative error between the calculated and actual values of blasting dust reduction effect in this software is <8%,which can realize the quantitative analysis of blasting dust reduction effect,and the software is simple to operate and easy to obtain the required field image information,which is convenient to build a scientific and systematic quantitative evaluation system of blasting dust reduction and has a broad application prospect.Figure[37] Table[13]... |
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