Documents Stevenson, Jim 2 results

"Driving posture and whole-body vibration (WBV) (reported in Part 1) were measured during the operation of seven load-haul-dump (LHD) mining vehicles. Simultaneous exposure to WBV and non-neutral postures could increase an LHD operator's risk of developing a musculoskeletal injury. The percentage of work time spent in neutral, moderate and severe neck rotation, trunk rotation, trunk flexion and trunk lateral bend postures was determined via a 3DMatch analysis of 1 h of videotaped driving for each LHD operator. Peak and cumulative spinal loads at the L4/L5 level also were estimated using 3DMatch. Operators averaged 89% of the time with their necks rotated more than 40°, 3% of the time with the trunk rotated more than 30°, 24% of the time with the trunk in forward flexion between 20° and 45°, and 16% of the time with the trunk in lateral bend between 15° and 30°. The average maximal compressive force (based on static measure estimations associated with posture only) at the L4/L5 level of the spine was 2176 N, and the cumulative compressive load for an 8-h work shift was 34 MN. A total injury risk score, which considered vibration exposure, working postures and spinal loading, was correlated with LHD operator musculoskeletal injury reports. Therefore, exposure to vibration and non-neutral working postures appears to increase musculoskeletal injury risk amongst LHD operators."

"Predicted health risks, associated with the operation of load-haul-dump (LHD) vehicles, based on ISO 2631-1 criteria are limited and have not yet been determined according to ISO 2631-5 criteria. Therefore, health risks predicted by ISO 2631-1 and 2631-5 criteria are reported and compared in this paper. Whole-body vibration (WBV) exposure was measured according to procedures established in ISO 2631-1. A tri-axial seat pad accelerometer was used to measure vibration exposure at the operator/seat interface. According to ISO 2631-1 criteria, calculated 8-h equivalent vibration dose values placed three of the seven LHD operators above the health guidance caution zone (HGCZ) boundaries and four LHD operators within the HGCZ. However, health risks predicted by the ISO 2631-5 criteria were always lower than the risks predicted by ISO 2631-1 criteria."