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    Evaluation of Whole-Body Vibration Exposure of Dozer Operators, a Task-Based Approach
    (Springer Heidelberg, 2022) Erdem, Bulent; Dogan, Tugba; Duran, Zekeriya
    The objective of this study was to evaluate the potential health risk associated with exposure of dozer operators to whole-body vibration. Measurements were made on 31 dozers used in different surface mines in Turkey. Predictions of adverse health effects of vibration were based on the standards BS 6841:1987, ISO 2631-1:1997, ISO 2631-5:2004, and the EU Vibration Directive:2002. Operators experienced high and comparable levels of vibration acceleration and dose during all dozer tasks: pushing the material (DOZE), moving forward (FORWARD), moving backward (REVERSE), and ripping (RIP). Specifically, DOZE, FORWARD, REVERSE, and RIP showed high potential of adverse health effects in terms of vibration dose according to the worst-case axis and vector sum criteria and a moderate adverse health effect for acceleration according to the worst-case axis criterion. Operators of large dozers were exposed to lower levels of vibration. However, no statistically significant relationship between vibration exposure levels and the propelling mechanism and the service time of dozers, operator experience, operator age, and ground type was found.
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    A model for extended bench casting in dipping coal seam
    (NATL INST SCIENCE COMMUNICATION, 2007) Erdem, Bulent; Duran, Zekeriya
    This paper deals with extended bench casting with draglines in surface coalmines. A computer model, developed for panel design, covers three fundamental operating modes: i) level casting for flat-lying coal seam; ii) downhill casting; and iii)uphill casting for inclined coal seam conditions. Influence of pit width on critical pit dimensions such as cut length, dragline reach on key cut and main cut positions, swing angles on key cut and main cut positions and rehandle percentage is critically studied. The model is equipped with a device to determine total number of points within a cut on which dragline is placed. With another module, walking pattern of dragline between adjacent cuts is decided. The model indicates that coal seam inclination significantly influences dragline productivity. All things being equal, the uphill operation mode demands larger dragline dimensions. Extended bench construction in uphill casting is easier and faster as less material is required. Besides, dragline operates on a safe bench. As coal seam gets inclined, a large dragline may switch from extended benching in downhill mode to direct casting owing to the room available for spoil piles increases with coal seam inclination. However, a small dragline would likely fail to operate in downhill mode as the size of the extended bench would expand faster than the waste available in the cuts. Besides, dragline would not be adversely affecte by failures occuring in spoil piles. It has been observed that in extended benching practice with an inclined coal seam downhill casting should be considered first.
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    Phase-based evaluation of whole-body vibration exposure for hydraulic excavator operators
    (Inderscience Enterprises Ltd, 2023) Dogan, Tugba; Erdem, Bulent; Duran, Zekeriya
    Hydraulic excavator operators' whole-body vibration exposure was studied with the guidelines set by several approaches. The most jolty and quiet phases were FORWARD and WAIT, respectively. Vibration magnitudes were inversely proportional to bucket capacity. Excavator service year and vibration exposure were positively correlated. Younger operators were exposed to higher levels of vibration. Vibration acceleration was negatively correlated to operator experience. Handling of large-sized rocks resulted in more vibration than soillike material. The most conservative method in estimating the hazard potential was the ISO 2631-1 'vector sum' while the probability of an adverse health effect was generally low according to the ISO 2631-5.