The Impact of Ergonomic Interventions on the Whole Body Vibration of Mining Machinery Drivers in Sarcheshmeh Copper Complex

Abstract

The existence of mechanical vibrations inside and around the industrial machinery and the constant exposure of the operators to these vibrations, increase the risk of musculoskeletal disorders in the operators and gradually affect their general health. The research is an attempt to investigate the effects of ergonomic interventions on the whole body vibration (WBV) of heavy machinery drivers in Sarcheshmeh Copper Complex in southern Iran. To evaluate the drivers’ exposure to WBV, a total number of 25 drivers, out of 45 drivers working in the complex, were selected. The vibration level was measured for each operator before and after the intervention using Bruel & Kjaer 4447 HAVS – Hand-Arm and Whole Body Vibration Meter. The measurements were conducted simultaneously in three axes (X, Y, and Z) in accordance with ISO 2631-1:1997. The obtained results were compared with the occupational exposure limits, recommended by the Iranian Ministry of Health and Medical Education (MoHME) of Iran, as a national standard. The data analysis was done by the independent t-test in SPSS software version 19. The obtained results revealed that prior to the intervention; the highest exposure to WBV was in the z-axis, which was the main axis of vibration entry into the drivers’ body. The results also showed that the equivalent acceleration of all vehicles exceeded the permissible limits (0.65 m/s2). The mean and maximum exposure levels were 0.66 and 0.56 m/s2 before the interventions and  0.88 and 0.63m/s2 after the interventions, which were significantly different (P<0.001). The application of engineering and administrative interventions, such as seat replacement, modification of the suspension system, work pace control, and training the operators to properly control the vehicle, can play a meaningful role in reducing the exposure to the vibration from heavy mining machinery.