Objective: To explore the occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mining enterprises.
Methods: Using typical sampling method, 44 non-ferrous metal mining enterprises were selected in seven provinces.37 non-ferrous metal mining enterprises were included, and most of them were underground enterprises(97.30%). Enterprises basic information and silica dust exposure data of key positions were collected by using on-site hygiene investigation and detecting method. Finally, the International Council on Mining and Metals'(ICMM) risk rating table method and occupational hazard risk index method(INDEX) were used to analyze the occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mines from total and respirable dust views, respectively. Meanwhile, the square weighted Kappa test was performed to analyze the consistency between two risk assessment method.
Results: Medium enterprises(64.69%(40.38%, 73.41%)), silver mining enterprises(84.69%(63.38%, 86.06%)) and antimony mining enterprises(72.22%) had relatively higher silica dust exposure rates. On-site hygiene detecting result showed that:(1) M(P25, P75) of free silica content was 21.18%(17.03%, 30.47%). (2) 1.60(0.86, 2.46)mg/m~3 for total dust concentration, 64.47% total dust concentration samples exceeding Chinese permissible concentration-time weighted average(PC-TWA), 0.68(0.30, 1.18) mg/m~3 for respiratory dust concentration, 50.00% respirable dust concentration samples exceeding Chinese PC-TWA. (3) Medium-sized enterprises, as well as rock drillers and crushers, had higher levels of silica dust exposure. Occupational health risk assessment result showed that:(1) The overall occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mining enterprises was medium:(1) In term of total dust, ICMM risk rating table method and INDEX method indicated high and medium risks, respectively(S_(weighted) were 3.52 and 2.79). (2) In term of respirable dust, both ICMM risk rating table and INDEX method indicated medium risks(S_(weighted) were 2.78 and 2.35). (2) Medium-sized enterprises risk level was higher than other two production scales enterprises. ICMM risk rating table method and the INDEX method consistency analyses showed that these two risk assessment method had strong consistencies in terms of total dust or respirable dust(both Kappa values ≥ 0.600).
Conclusion: The overall occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mining enterprises was medium, and the risk levels of medium production-scale mining enterprises, rock driller and crusher were higher.
Keywords: non-ferrous metal mine; occupational health risk assessment; silica dust; silicosis.