BACKGROUND: Workers who stand on platforms or equipment that vibrate are exposed to foot-transmitted vibration (FTV). Exposure to FTV can lead to vibration white feet/toes resulting in blanching of the toes, and tingling and numbness in the feet and toes. OBJECTIVES: The objectives are 1) to review the current state of knowledge of the health risks associated with foot-transmitted vibration (FTV), and 2) to identify the characteristics of FTV and discuss the associated risk of vibration-induced injury. PARTICIPANTS: Workers who operated locomotives (n=3), bolting platforms (n=10), jumbo drills (n=7), raise drilling platforms (n=4), and crushers (n=3), participated. METHODS: A tri-axial accelerometer was used to measure FTV in accordance with ISO 2631-1 guidelines. Frequency-weighted root-mean-square acceleration and the dominant frequency are reported. Participants were also asked to report pain/ache/discomfort in the hands and/or feet. RESULTS: Reports of pain/discomfort/ache were highest in raise platform workers and jumbo drill operators who were exposed to FTV in the 40 Hz and 28 Hz range respectively. Reports of discomfort/ache/pain were lowest in the locomotive and crusher operators who were exposed to FTV below 10 Hz. These findings are consistent with animal studies that have shown vascular and neural damage in exposed appendages occurs at frequencies above 40 Hz. CONCLUSIONS: Operators exposed to FTV at 40 Hz appear to be at greater risk of experiencing vibration induced injury. Future research is required to document the characteristics of FTV and epidemiological evidence is required to link exposure with injury.

Operators of load-haul-dump (LHD) vehicles are commonly exposed to whole-body-vibration (WBV) levels above ISO 2631–1 and EU Directive 2002/44/EC guidelines. WBV was measured at the floor and seat while the same operator drove two LHDs on a controlled test track while driving speed, bucket load, ride control, terrain type, driving task, and seat optimization were varied. Frequency-weighted RMS acceleration was calculated and A(8) values were modeled for six driving scenarios. Vibration exposure was lowest when the LHD was driven at the lowest speed, forward, over smooth terrain, with ride control on and the bucket loaded (0.20 m/s²). The A(8) decreased from 0.84 m/s² when driving with ride control off, over mixed terrain using all gears, to 0.53 m/s² when driving with ride control on and an optimized seat. The estimated daily exposure decreased but remained just above the ISO 2631–1 and EU Directive 2002/44/EC guidelines.

Exposure to foot-transmitted vibration (FTV) can lead to pain and numbness in the toes and feet, increased cold sensitivity, blanching in the toes, and joint pain. Prolonged exposure can result in a clinical diagnosis of vibration-induced white foot (VIWFt). Data on the biomechanical response of the feet to FTV is limited; therefore, this study seeks to identify resonant frequencies for different anatomical locations on the human foot, while standing in a natural position. A laser Doppler vibrometer was used to measure vertical (z-axis) vibration on 21 participants at 24 anatomical locations on the right foot during exposure to a sine sweep from 10-200Hz with a peak vertical velocity of 30 mm/s. The most notable differences in the average peak frequency occur between the toes (range: 99-147Hz), midfoot (range: 51-84Hz), and ankle (range: 16-39Hz). The biomechanical response of the human foot exposed to foot-transmitted vibration, when standing in a natural position, was measured for 21 participants. The foot does not respond uniformly; the toes, midfoot, and ankle regions need to be considered independently in future development of isolation strategies and protective measures.

The purpose of this study was to evaluate health risks to operators of large and small load-haul-dump (LHD) vehicles exposed to whole-body vibration (WBV), based on criteria established in ISO 2631-1, ISO 2631-5, and EU Directive 2002/44 EC. Studies simultaneously evaluating health risks based on all three standards are limited. Operator WBV exposure was measured in accordance with ISO 2631-1 using a tri-axial seat pad accelerometer. According to ISO 2631-1, four of the seven large LHD vehicle operators and three of six small LHD vehicle operators were exposed to WBV above the 8-hour vibration dose value (VDV) health guidance caution zone (HGCZ). According to the EU Directive 2002/44/EC criteria one of the seven large LHD vehicle operators and one of the six small LHD vehicle operators were exposed to WBV above the VDV daily exposure limit. However, health risks predicted by ISO 2631-5 criteria only placed one of seven large LHD vehicle operators and one of the six small LHD vehicle operators in the high probability of an adverse health effect category. Thus, the probability of adverse health effects, associated with WBV exposure during LHD vehicle operation, is suggested to be greatest based on the ISO 2631-1 8-hour VDV HGCZ and lowest based on ISO 2631-5 S_ed criterion values.

Documented whole-body vibration (WBV) exposure levels at the operator/seat interface are limited for underground mining load-haul-dump (LHD) vehicles. Therefore, WBV exposure during the operation of eight small and nine large LHD vehicles, under loaded and empty haulage, was measured in accordance with ISO 2631–1 guidelines. Vibration exposure was also measured for a subsample of LHD vehicles equipped with a feature designed to reduce vibration exposure (ride-control). Operator health risks were predicted according to ISO 2631–1 health guidance caution zone (HGCZ) limits for daily vibration exposure. Vibration exposure was not significantly different for vehicle size or ride control but was significantly lower when driving with a loaded haulage bucket. All operators of small LHDs and one large LHD operator were exposed to vibration levels above the HGCZ.