Application of two occupational health risk assessment methods for dust hazards in non-coal underground mines

Background The mining of non-coal underground mines may come into contact with various types of dust, such as lead, zinc, copper, and non-metallic minerals. Dust of various kinds commonly exists in all aspects of mining and selection, and is one of the main occupational hazard groups in non-coal underground mines.

Objective To compare the application of two risk assessment methods in the occupational health risk assessment of productive dust in non-coal underground mines, and to provide a reference for the selection of dust hazard health risk assessment methods and the management of dust hazards in non-coal mines.

Methods A field investigation of the dust hazards of three typical non-coal underground mining enterprises (lead-zinc mines, copper mines, and fluorite mines) was carried out, and the comprehensive index method and the occupational health risk assessment method from the International Council on Mining and Metals (ICMM) were used to perform risk assessments. The comprehensiveindex method considers the following factors: dust monitoring data, the aerodynamic diameter of dust, hazard control measures, occupational health management, daily usage, and daily exposure time to determine exposure levels. The ICMM method determines the risk level based on the consequences caused by dust, exposure probability, exposure time, and uncertainty coefficient. Kendall consistency test was used to compare agreement between the results generated by the two methods.

Results The results generated by the comprehensive index method were as follows: level 3 (medium risk) or level 4 (high risk) for silica dust or lead dust; level 1 (negligible risk) or level 2 (low risk) for other dust (dust with free SiO₂ content<10% and containing lead, zinc, and copper, using other dust limit values for comparison), fluorspar mixed dust, fluorine and its compounds, zinc oxide, and copper dust. The risk levels graded by the ICMM method were as follows: level 4 (very high risk) and level 3 (high risk) for exposure to silica dust and lead dust, respectively, and level 1 (tolerable risk) or level 2 (potential risk) for exposure to other dust (dust with free SiO₂ content <10% and containing lead, zinc, and copper, using other dust limit values for comparison), fluorspar mixed dust, fluorine and its compounds, zinc oxide, and copper dust. The consistency level between the results graded by the two methods was very high (Kendall W coefficient=0.974, P < 0.05).

Conclusion For the occupational health risk assessment of productive dust in non-coal underground mines, the consistency level of risk assessment results between the ICMM method and the comprehensive index method is very high. The ICMM method is more convenient to operate and should be preferred in assessing health risks of dust hazard in non-coal underground mines.