Safety and Health Engineering Solutions to HISLO Vibrations in Surface Mining

Surface mining comprises complex geometries, dangerous operations and human controlled machines. Due to human errors, unstable layouts, geological deformations, and design problems, safety and health hazards including fatal accidents occur. The 2016 fatal accidents review by the Mine Safety and Health Administration (MSHA) showed that mobile machines accounted for 58.3% (2012), 36.4% (2013), 39.1% (2014), 57.1% (2015) and 59% (2016) fatalities [1]. Previous MSHA data shows that, out of 250 fatalities in surface mining, 40% was attributed to powered haulage. An average of 675 accidents and 21 powered haulage fatalities occur each year in surface mining and 20% of these accidents involve dump trucks [1]. The use of large shovels to load large trucks in surface mining has resulted in HISLO. HISLO generates high-frequency shockwaves that cause extreme vibrations exposing operators to high WBV levels and injuries. Aouad [2] and Frimpong and Aouad et al. [2] showed that the vertical RMS acceleration of the operator’s seat was equal to 3.56 m/s2 during the loading of the CAT 793D in oil sands formation. This RMS value exceeds the ISO 2631-1 limits [3] for extremely uncomfortable zones (> 2.5 m/s2), and may cause short-term and long term injuries. The most common type of accidents was jarring (37.7%), which results in back injuries. ISO 2631-1 also shows that operators exposed to WBV with RMS values ≥ 1.0 m/s2 over 8-hour durations have a high probability of experiencing sacrum, lumbar and cervical problems [3]. Kittusamy [4] undertook an ergonomic evaluation of excavations for understanding musculoskeletal epidemiology. Using pilot experiments, he showed that digging and hauling had higher levels of total weighted acceleration than idling. They also showed that the seats were not designed to protect against high WBV levels. Kittusamy et al. [4] extended the study into awkward postures. They showed that operators are afflicted by musculoskeletal injuries of the arms, shoulders, neck and lower back. This research was undertaken to provide engineering solutions to HISLO problems. The primary objective was to reduce significantly (below 0.315 m/s2 RMS acceleration) or completely eliminate the impact of RMS accelerations on operators. The 0.315 m/s2 value is the upper threshold for the “Comfortable” region of the ISO 2631-1 Limits [3]. The elements of this objective were to develop: