CIM Bulletin, Vol. 97, No. 1082, 2004
J. Berezan, T.G. Joseph and V. del Valle
The effects of whole body vibration (WBV) on equipment operators have historically gone unnoticed as a major occupational health and safety concern. Recently, however, research has shown that WBV can have a serious effect on the human body, causing both physiological and psychological health problems.
Early studies carried out on light and heavy haul trucks as well as earth movers showed that all vehicles exceeded ISO 2631 guidelines for vibration exposure, and that vibration levels from rigid frame haul trucks can exceed safe limits in merely four hours.
In Canada, a study by the Workers Compensation Board of British Columbia reported that operators of heavy equipment in the mining industry were found to have high rates of exposure to WBV. Where vibration levels exceeded the ISO guidelines there was a corresponding high incidence of back problems. British Columbia has adopted the ISO standard for new mining equipment.
For companies working in Alberta’s oil sands sector the challenge of operating large mobile equipment is compounded by soft underfoot conditions. In-pit haul roads can rapidly deteriorate within a few haul truck-driving cycles, producing large ruts and hummocks that significantly degrade driving conditions and increase the vibration exposure of the operator. Modification of haul trucks by introducing high dampening or semi-active suspension concepts could provide a solution to reducing vibration. However, this is a longer term vision requiring significant mechanical research.
A more short-term solution is to focus on the driver’s participation in reducing vibration through reacting to an onboard feedback system. The premise for such a system is that operators who are aware of driving patterns, road conditions or operational situations that cause high vibration exposure can initiate remedial action to reduce exposure levels.
This paper proposes such an onboard vibration warning system, based on the ISO 2631-1 standard. The system would consist of a screen that displays the instantaneous vibration in the form of three lights: green (safe zone), yellow (cautious zone), and red (danger zone), as well as an overall vibration exposure or cumulative dose level for the entire shift. The use of such a warning system is anticipated to reduce WBV exposure, resulting in improved operator health, a reduction of vibration-induced maintenance, and improved haul roads through reduced impact loading. Operator feedback to road maintenance crews will enable timely repair of localized trouble areas.
Preliminary testing results indicate that the system is functional and user-friendly, and that WBV exposures and vibration-induced frame damage can be reduced while maintaining cycle times. Further testing is required to verify the approach, but more importantly to provide evidence as to whether or not an on-board vibration feedback system will effectively reduce whole body vibration experienced by operators.
The effects of whole body vibration (WBV) on equipment operators have historically gone unnoticed as a major occupational health and safety concern. Recently, however, research has shown that WBV can have a serious effect on the human body, causing both physiological and psychological health problems.
Early studies carried out on light and heavy haul trucks as well as earth movers showed that all vehicles exceeded ISO 2631 guidelines for vibration exposure, and that vibration levels from rigid frame haul trucks can exceed safe limits in merely four hours.
In Canada, a study by the Workers Compensation Board of British Columbia reported that operators of heavy equipment in the mining industry were found to have high rates of exposure to WBV. Where vibration levels exceeded the ISO guidelines there was a corresponding high incidence of back problems. British Columbia has adopted the ISO standard for new mining equipment.
For companies working in Alberta’s oil sands sector the challenge of operating large mobile equipment is compounded by soft underfoot conditions. In-pit haul roads can rapidly deteriorate within a few haul truck-driving cycles, producing large ruts and hummocks that significantly degrade driving conditions and increase the vibration exposure of the operator. Modification of haul trucks by introducing high dampening or semi-active suspension concepts could provide a solution to reducing vibration. However, this is a longer term vision requiring significant mechanical research.
A more short-term solution is to focus on the driver’s participation in reducing vibration through reacting to an onboard feedback system. The premise for such a system is that operators who are aware of driving patterns, road conditions or operational situations that cause high vibration exposure can initiate remedial action to reduce exposure levels.
This paper proposes such an onboard vibration warning system, based on the ISO 2631-1 standard. The system would consist of a screen that displays the instantaneous vibration in the form of three lights: green (safe zone), yellow (cautious zone), and red (danger zone), as well as an overall vibration exposure or cumulative dose level for the entire shift. The use of such a warning system is anticipated to reduce WBV exposure, resulting in improved operator health, a reduction of vibration-induced maintenance, and improved haul roads through reduced impact loading. Operator feedback to road maintenance crews will enable timely repair of localized trouble areas.
Preliminary testing results indicate that the system is functional and user-friendly, and that WBV exposures and vibration-induced frame damage can be reduced while maintaining cycle times. Further testing is required to verify the approach, but more importantly to provide evidence as to whether or not an on-board vibration feedback system will effectively reduce whole body vibration experienced by operators.
Research is progressing toward more active suspension systems that are able to react to the dynamic ground conditions of the mining environment. Simple mechanical adaptation systems such as the rapid dampening poled suspension (RDPS) approach being developed by the Alberta Equipment-Ground Interactions Syndicate (AEGIS) are being proven as potential retrofit approaches to existing suspension systems, rather than moving to complete suspension re-design. In the meantime, the operator vibration feedback system provides employers and operators with the opportunity to prevent damage to themselves, the equipment they operate, and the surfaces on which they run.
