To grasp the present situation of occupational hazards of coal dust in our country, understand our country coal dust workers' occupational health risks, provide information based on evidence and analysis for the government and organize to effectively deal with the current status of high coal workers pneumoconiosis incidence in China, and protect coal dust workers' occupational health.

The research object is the " mining-transportation-use" of coal industrial chain, referring to 33 units. Use field investigation to obtain the coal dust exposure, dust prevention measures and the occupational health data of study object. Use quantitative evaluation method of International council on mining and metals occupational health risk assessment model (ICMM method) and occupational hazard risk index method (index method) , with coal workers pneumoconiosis as health outcomes, to evaluate the coal dust occupational health risks of coal industrial chain.

The free silica content of partial coal dust in China is more than 10%, and even to 19.5%. coal dust concentration in workplaces, such as excavating system of dust coal mining (total dust: 22.1~46.5 mg/m³, respiratory dust: 8.4~17.7 mg/m³) , dumper (total dust: 25.2 mg/m³, respiratory dust: 6.9 mg/m³) , transfer tower (total dust: 35.4 mg/m³) of coal transportation and belt coal plough device of coal use (total dust: 36.3 mg/m³, respiratory dust: 14.0 mg/m³) , are much higher than those in other workplaces, and coal dust concentration of workers in these places (2.6~9.3 mg/m³) are much higher than those in other places, which are statistically significant. ICMM method evaluation results show that the risk value of excavating system is between 504~1 089, and the risk value of comprehensive mining system is between 347~2 040, which are far statistically significant higher than that of other systems. Index method evaluation results (excavating system risk value between 3.1~9.7, fully mechanized system risk value between 3.7~9.3) , are basically identical with ICMM method (correlation coefficient r=0.857, P<0.01) . The new cases of coal worker pneumoconiosis are distributed in three post of coal mining, excavating and coal mine mixing.

Coal-dust hazards are widely distributed in the coal "mining, transportation, and use" industrial chain, which of the underground coal mine is as serious as intolerable, meanwhile the risk of other industrial chain is basically can tolerable. The high coal dust concentration and the high risk of coal dust occupational hazard are concentrated in the excavating system and the comprehensive mining system. It is recommended to start the study on risk assessment and risk response of coal dust health hazard at the national level, and the occupational exposure limit of coal dust should be established according to the content of free silica.

Coal industry chain; Coal dust; Occupational health; Risk assessment.