Rock Products

OCT 2014

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in order to perform other duties and tasks not performed on the first day. Case Study This section details a case study to im‐ plement an automated device to re‐ move wet sand when a screening process was started. When production was down for an extended period of time, it was common to encounter wet material which is problematic for the screening process. Wet or damp material can cause screens to clog or glaze over. This situ‐ ation creates undesirable maintenance and productivity difficulties. Histori‐ cally, to prevent wet material from reaching the screening process, a process helper would manually place a diverter on the screen house feed con‐ veyor belt until the product was dry. With this process helper wearing the Helmet‐CAM technology, it was deter‐ mined that his respirable dust expo‐ sure was greatly elevated while performing this task. In order to elim‐ inate this respirable dust exposure, the operator installed an automated system that allowed the process oper‐ ator, from his control room, to: (a) de‐ termine the moisture content of the material going to the screen house, and (b) engage a remote‐control di‐ verter to keep wet material from reaching the screening process. Once the material was determined to be at an acceptable moisture content, the process operator would remotely deactivate the diverter and the prod‐ uct would be directed to the screening house. Figure 3 shows a screenshot of the process operator's exposure while performing this task manually, as well as the new automated device which eliminated the need to for the worker to perform the task manually. Through use of the Helmet‐CAM tech‐ nology, the operator was able to effec‐ tively and efficiently determine the process operator's exposure to res‐ pirable dust which resulted in system automation and reduction of process operator exposure to respirable dust over the course of his shift. Through additional field studies, many other examples of respirable dust reduc‐ tion were achieved through implementa‐ tion of engineering, administrative or work practice interventions. Conclusions Despite developments in technology, the ability to determine a miner's ex‐ posure to various types of respirable contaminants has not advanced sub‐ stantively over the past few decades. With mobile workers performing many different types of tasks and func‐ tions in many different locations throughout the workday, it can be ex‐ tremely difficult and resource inten‐ sive to determine where a worker is being exposed to respirable dust through traditional time study meth‐ ods. The Helmet‐CAM technology has proven to be a viable tool to perform this assessment and determine where and when a mobile mine worker is being exposed to respirable dust. Although this assessment tool was orig‐ inally developed for respirable dust, it is in the process of being expanded to assess other contaminants, and is cur‐ rently being investigated by NIOSH for diesel exhaust (elemental carbon), noise exposure, and chemical assess‐ ments. It is envisioned that future ver‐ sions of the EVADE software may be able to simultaneously evaluate expo‐ sures to multiple contaminants using the same video footage. The Helmet‐CAM technology is cur‐ rently available for the assessment of worker's respirable dust exposure in mining. To utilize the technology, an in‐ terested mining operation has to pur‐ chase a video camera and a real‐time instantaneous dust monitor. The EVADE software package and user's manual are available for free at NIOSH's website, Acknowledgments NIOSH would like to thank the following companies who participated in testing the Helmet‐CAM technology: Unimin Corp., U.S. Silica Co., Badger Mining Co., 3M Corp., Sidwell Limestone Mine and Shelly Materials Co. Disclaimer Mention of any company or product does not constitute endorsement by the Na‐ tional Institute for Occupational Safety and Health. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occu‐ pational Safety and Health. E Andrew B. Cecala is with NIOSH, Pitts- burgh, and Andrew D. O'Brien is with Unimin Corp., Winchester, Va. References Cecala, A.B., Reed, W.R., Joy, G.J., Westmore- land S.C., and O'Brien, A.B. 2013. Helmet- CAM : Tool for Assessing Miners' Respirable Dust Exposure. Mining Engineering, 65(9): 78-84. Gressel, M.G., Heitbrink, W.A., Jensen, P.A., Cooper, T.C., O'Brien, D.M., McGlothlin, J.D., Fischbach, T.J., and Topmiller, J.L. 1992. Analyzing Workplace Exposures Using Direct Reading Instruments and Video Exposure Monitoring Techniques. Mine Safety and Health Administration (MSHA). 1990. Metal, Nonmetal Health Procedures Manual (PH90-IV4), Chapter D, Arlington, Virginia. Reed, W.R., Potts, J.D., Cecala, A.B., and Archer, W.J. 2012. Use of the pDR-1500 for gravimetric respirable dust meas- urements at mines. Preprint #: 12-001, 2012 SME Annual Meeting & Exhibit, Feb. 19-22, 2012, Seattle, Washington. Reed, W.R., Kwitowski, A.J., Helfrich, W., Cecala, A.B., and Joy, J.G. Guidelines for Performing a Helmet-CAM Respirable Dust Survey and Conducting Subsequent Analysis with Enhanced Video Analysis of Dust Exposures (EVADE) Software. NIOSH RI9696, 2014, 92 pp. Rosen, G., Andersson, I., Walsh, P.T., Clark, R.D.R., Saamanen, A., Heinonen, K., Riip- inen, H., and Paakkonen, R. 2005. A Re- view of Video Exposure Monitoring as an Occupational Hygiene Tool. Ann. Occup. Hyg., 49(3):201-217. ROCK products • OCTOBER 2014 30 DUST MONITORING

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