Evaluation of Post-blast Re-entry Times Based on Gas Monitoring of Return Air
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Blasting is the main method of production in many non-coal underground mining operations and produces multiple toxic gases as a result. The Mine Safety and Health Administration (MSHA) requires mine operators to measure the level of toxic gases in mines as frequently as necessary to ensure they are below regulatory safety limits. The current practice uses portable gas monitors to check the concentrations of toxic gases after a fixed post-blast time. This paper studies the application of a gas monitoring system in the return entry of a limestone mine to determine a safe re-entry time. The National Institute for Occupational Safety and Health (NIOSH) conducted such a monitoring program in a limestone mine from September 2016 through May 2018. NIOSH/PMRD (Pittsburgh Mining Research Division) is endeavoring to develop workplace solutions to improve detection of and reduce the risk of hazardous conditions. This study showed that the use of gas monitoring in the return air can be a useful tool at the mine operator’s disposal to detect and reduce the risk of hazardous conditions and also to reliably estimate the re-entry time.
KeywordsVentilation Blasting Re-entry time Gas monitoring Contaminant spread
The authors wish to thank John Soles of the Pittsburgh Mining Research Division for conducting measurements during this study.
Compliance with Ethical Standards
The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention.
Conflict of Interest
The authors declare that they have no conflict of interest.
- 1.MSHA (2018) 30 CFR 57.5002 - Exposure Monitoring - Safety and Health Standards - Underground Metal and Nonmetal Mines. https://www.ecfr.gov/cgi-bin/text-idx?SID=0bcad0e6ebc19aadf8510f191ea706e9&mc=true&node=se30.1.57_15002&rgn=div8
- 2.Cash DA (1999) Introduction to operator air sampling. Mine Safety and Health Administration, ArlingtonGoogle Scholar
- 3.MSHA (2018) Metal/nonmetal operator monitoring requirements guidance. https://arlweb.msha.gov/S&HINFO/ExposureGuidance/ExposureGuidance.asp
- 4.OSHA permissible exposure limits, OSHA annotated table Z-1. https://www.osha.gov/dsg/annotated-pels/tablez-1.html. Accessed 13 Oct 2017
- 5.Agasty A, Clausen E, Kellner M, Langefeld O (2013) After blast re-entry time for a room and pillar operation. Paper presented at the the Australian Mine Ventilation Conference, Adelaide, SAGoogle Scholar
- 7.Taylor G (1954) The dispersion of matter in turbulent flow through a pipe. Proc R Soc Lond A Math Phys Sci 223(1155):446–468Google Scholar
- 8.Sirait SH, Widodo NP, Simanjuntak M (2013) Study on estimation of re-entry time after blasting in underground mining PT Cibaliung Sumberdaya, Indonesia. Paper presented at the Proceedings of International Symposium on Earth Science and Technology 2013Google Scholar
- 9.Widodo N, Sasaki K, Sugai Y, Sayoga R (2008) Turbulent diffusion coefficient in mine airways. Paper presented at the 12th U.S./North American Mine Ventilation Symposium 2008, Reno, NevadaGoogle Scholar
- 10.Stewart C (2014) Practical prediction of blast fume clearance and workplace re-entry times in development headings. Paper presented at the 10th International Mine Ventilation CongressGoogle Scholar
- 11.Rowland J, Mainiero R (2000) Factors affecting ANFO fumes production. Paper presented at the Proceedings of the Annual Conference on Explosives and Blasting TechniqueGoogle Scholar
- 12.Sapko M, Rowland J, Mainiero R, Zlochower I (2002) Chemical and physical factors that influence Nox production during blasting-exploratory study. Paper presented at the Proceedings of the Annual Conference on Explosives and Blasting TechniqueGoogle Scholar
- 13.Mainiero R, Rowland J, Harris M, Sapko M (2006) Behavior of nitrogen oxides in the product gases from explosive detonations. Paper presented at the Proceedings of the Annual Conference on Explosives and Blasting TechniqueGoogle Scholar
- 14.Brake DJ (2015, June 2015) A review of good practice standards and re-entry procedures after blasting and gas detection generally in underground Hardrock mines. Paper presented at the 15th North American Mine Ventilation Symposium, Blacksburg. Virginia:20–25Google Scholar
- 15.NIOSH (2010) NIOSH pocket guide to chemical hazards. Pocket guide to chemical hazards. Cincinnati, OH : U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 2010Google Scholar
- 16.Roman WN, Guthrie J, Ndhlovu W (2002) Upgrading ventilation systems at Konkola mine, Zambia. Paper presented at the Proceedings of the North American/Ninth US Mine Ventilation Symposium, Kingston, Canada, 8–12 June 2002Google Scholar
- 17.Gillis D, Counter D, Roberts M, Jahir T, Younes C (2016) Decreasing post blast re-entry time with battery-powered wireless monitoring of gas and ground movement. Canadian Institute of Mining, Metallurgy and PetroleumGoogle Scholar
- 18.De Souza E, Katsabanis P, Roberts W, Heidrich H (1993) Blasting fume prediction and control as a means of reducing ventilation costs. Paper presented at the Proceedings of the 6th US Mine Ventilation Symposium: June 21–23, 1993, University of Utah, Salt Lake City, UtahGoogle Scholar
- 21.Friel G, Edwards J, Morrow G (1994) Effect of dead-end crosscuts on contaminant travel times in mine entries. Report of investigations/1994. U.S. Bureau of Mines, Pittsburgh, PA (United States). Pittsburgh Research CenterGoogle Scholar