A Study On Application Of Coal Dust Occupational Health Risk Assessment Methods

Objective:Collecting,sorting and researching the main occupational health risk assessment methods both in China and abroad.According to the applicable scopes,method types,advantages and disadvantages of the occupational health risk assessment methods;I will select three kinds of coal dust occupational health risk assessment methods.And combined with results of field investigation and test,the actual situation of our country enterprises,I will research and improve appropriately for the selected risk assessment methods.And using the three methods carry out occupational health risk assessment for the main coal dust working posts of producing dust enterprises(including coal mine,coal preparation plant,coal terminal,coal transportation station and coal-fired power plant).According to comparing and analyzing the risk assessment results,I will research the three occupational health risk assessment methods for applicability of coal dust occupational health risk assessment again.In order to provide suitable methods for coal dust occupational health risk assessment and also provide bases for the establishment of occupational health risk assessment standards in our country.Methods:Choosing the main coal dust working posts of three coal mines(large,medium and small each one),one coal preparation plant,one coal terminal,one coal transportation station and one coal-fired power plant as the research objects randomly.Field investigation:investigation contents include the production process,the overall layout and equipment layout,the exposure situation of coal dust working posts(including coal dust exposure concentration,exposure time,exposure number of people,etc.),engineering hygiene facilities,personal protective equipments and occupational health examination,etc.Field test:according to the standards,including“Specifications of air sampling for hazardous substances monitoring in the workplace”(GBZ 159-2004),“Determination of dust in the air of workplace-Part 2:Respirable dust concentration"(GBZ/T 192.2-2007),and“Determination of dust in the air of workplace-Part 4:Content of free silica in dust”(GBZ/T 192.4-2007),etc.I will carry out field test of the coal dust working posts.Statistical analysis methods:in this study I will use Excel 2007 to input the field test and investigation datum.The normality tests of risk assessment results use K-S test method.Differences comparing of every enterprise' three kinds of risk assessment results use the pairwise comparison method,if the two assessment results are accorded with requirements of parametric test,their differences comparing use paired t-test,correlation analysis use Pearson correlation analysis method.If two assessment results are accorded with requirements of nonparametric test,their differences comparing use Wilcoxon paired singned-rank test,correlation analysis use Spearman correlation analysis method.Using SPSS 17.0 software to carry out statistic analysis,with a=0.05 as test level.Results:The choices of coal dust occupational health risk assessment methods:according to the applicable scopes,method types,advantages and disadvantages of occupational health risk assessment methods,choosing three kinds of coal dust occupational health risk assessment methods,including quantitative classification method(GBZ/T 229.1-2010),occupational health risk assessment quantitative method provided by the International Council on Mining and Metals(ICMM quantitative model)and occupational hazard risk index method.And combined with results of field investigation and test,the actual situation of our country enterprises,I improve the quantitative classification method(GBZ/T 229.1-2010)and ICMM quantitative model appropriately.Results of field investigation and test:The main coal dust working posts of coal mines(large,medium and small)are distributed in six systems:the coal mining production system,tunneling production system,underground coal transportation system,underground auxiliary production system,ground production system and boiler system.The main coal dust working posts of the coal preparation plant are distributed in four systems:the screening crushing workshop,jigging workshop,enrichment workshop and filtering workshop.The main coal dust working posts of the coal terminal are distributed in three systems:the coal unloading department,coal loading department,water department and maintenance crew.The main coal dust working posts of the coal transportation station are distributed in three systems:the coal receiving system,loading system and auxiliary system.The main coal dust working posts of the coal-fired power plant are distributed in three systems:the coal transportation systems,combustion milling system and maintenance system.According to field test,qualified rates of respirable coal dust concentration of the main coal dust working posts in the large coal mine,medium coal mine,small coal mine,coal preparation plant,coal terminal,coal transportation station and coal-fired power plant are 37.3%,38.1%,40.1%,50.0%,83.3%,58.3%,90.0%.Medical reports of the enterprises' workers show that the coal terminal finds one abnormal chest X-ray,the rest of the enterprises are not found the patients of occupational injury and occupational contraindication related to coal dust.Results of coal dust occupational health risk assessment:High-risk coal dust working posts of coal mines(large,medium and small)mainly concentrate in the coal mining and tunneling production systems,especially coal mining machine drivers and tunneling machine drivers.High-risk coal dust working posts of the coal preparation plant mainly concentrate in the screening crushing workshop,especially screeners and crusher drivers.High-risk coal dust working posts of the coal terminal mainly concentrate in the coal unloading department,especially the dumper drivers and dumper inspectors.High-risk coal dust working posts of the coal transportation station mainly concentrate in the coal receiving system and loading system,especially flat coal area operators.High-risk coal dust working posts of the coal-fired power plant mainly concentrate in the coal transportation system,especially bucket wheel drivers and crusher drivers.Statistics analysis results:statistics analysis results of three coal mines(large,medium and small)are consistent:according to the test level(?=0.05),risk assessment results of quantitative classification method(GBZ/T 229.1-2010,modified version)and occupational hazard risk index method have no signigicant difference(P>0.05),have good and significant correlation(P<0.05),the credibility of assessment results are verified.Risk assessment results of ICMM quantitative and modified model and the other two methods have signigicant difference(P<0.05).ICMM quantitative and modified model is easy to overestimate its perniciousness for posts of higher coal dust concentration;the three risk assessment results are basically consistent for posts of lower coal dust concentration.But risk assessment results of ICMM quantitative and modified model and the other two methods have good and significant correlation(P<0.05).It explains that they have higher close degree,similar changing trends and ICMM quantitative and modified model also points out high-risk coal dust working posts well.Statistics analysis results of the rest of enterprises are consistent:according to the test level(a=0.05),three kinds of risk assessment results all have no signigicant difference(P>0.05),have good and significant correlation(P<0.05),the credibility of assessment results are verified.Conclusion:Quantitative classification method(GBZ/T 229.1-2010,modified version),occupational hazard risk index method and ICMM quantitative and modified model all can carry out occupational health risk assessment for coal dust working posts of coal mines(large,medium and small),coal preparation plant,coal terminal,coal transportation station and coal-fired power plant.The three methods are all suitable for coal dust occupational health risk assessment.Among them,quantitative classification method(GBZ/T 229.1-2010,modified version)and occupational hazard risk index method are recommended to use for posts of higher coal dust concentration;three kinds of risk assessment methods are all recommended to use for posts of lower coal dust concentration.