Engineering & Mining Journal

MAY 2018

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NIOSH VIBRATION 42 E&MJ; • MAY 2018 www.e-mj.com Cumulative exposure to whole-body vibration (WBV) adverse- ly impacts the health and safety of exposed mine workers. Mining equipment-induced vibration depends on factors such as equipment type, task and operator skill. Generally, it is time-variant and widely broadband in frequency content. Ex- posure to such vibration can also cause fatigue or reduce fine motor skills. Moreover, WBV may contribute to the develop- ment of musculoskeletal disorders (MSDs) of the spine among exposed workers. Off-road mining equipment operating on rough surfaces un- der harsh conditions can produce WBV and mechanical-shock exposure to equipment operators. Until recently, the only meth- ods to measure WBV were through expensive vibration measure- ment systems that may cost $4,000 to $50,000 or more and require significant technical expertise to analyze the data and arrive at meaningful results. University of Queensland research- ers have investigated the use of a personal electronic device as a means for providing an uncomplicated and economical method to estimate WBV exposure in a mining environment. The whole-body vibration measurement application (WBV app) uses the built-in triaxial accelerometer of an iPod touch (mod- el A1509, iOS version 9.3.5) to collect acceleration data and calculate frequency-weighted estimates of WBV exposure. The National Institute for Occupational Safety and Health (NIOSH) recently conducted a study focusing on the measure- ment accuracy of the WBV app. The NIOSH field study involved data collection for 13 mobile machines (seven front-end wheel loaders and six haul trucks) operating at one sandstone mine and three limestone mines in central and southwestern Penn- sylvania and northern Virginia. A major objective of the NIOSH research study was to assess the accuracy of the WBV app and determine if it can be a useful low-cost tool for monitoring WBV exposure on mobile mine and quarry equipment. Through field evaluations, the exposure levels measured with the WBV app collected with an iPod touch device were compared to exposure levels measured simultaneously with the Siemens/LMS SCADAS data recording system. Approach NIOSH researchers measured WBV in three directions, X (fore-aft), Y (side-to-side), and Z (vertical) for operators of mo- bile mining equipment as they performed their normal work. NIOSH used a Siemens SCADAS–SCR05 16-channel data re- corder with 24-bit resolution as the reference, high-quality precision system to which the iPod touch device running the WBV app was compared. To measure WBV, NIOSH used a PCB 356B40 seat-pad accelerometer with the SCADAS recorder. Collected data were stored in flash memory on a SD card. The iPod touch device was placed under the front-most portion of the circular seat pad according to the WBV app User Manu- al (downloadable from University of Queensland website at http://ergonomics.uq.edu.au/WBV/WBVpod/Index.html). Measures of Interest Explained Weighted-root-mean-square acceleration (a w ) is frequency- weighted acceleration, expressed in m/s 2 , and used to describe New, Inexpensive Methods Monitor Off-road Vibration Exposure NIOSH researchers use an iPod app to assess whole-body vibration By A.G. Mayton and Bryan Kim Figure 1—A typical setup of the instrumentation on the operator seat with the iPod placed 'face down on the seat …with the long axis of the iPod perpendicular to the direction of travel,' as stated in the WBV v2.1 User Manual.

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