{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T21:59:52Z","timestamp":1791583192905,"version":"4.3.4"},"reference-count":41,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2022,6,9]],"date-time":"2022-06-09T00:00:00Z","timestamp":1654732800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>The drill-and-blast method is widely used for the excavation of hard rock tunnels. Toxic gases such as carbon monoxide and nitrogen oxides are released immediately after blasting by the detonation of explosives. To provide a safe working environment, the concentration of noxious gases must be reduced below the threshold limit value according to health and safety regulations. In this paper, one-dimensional mathematical models and three-dimensional CFD numerical simulations were conducted to analyze the concentration, propagation and dilution of the blasting fumes under different operating conditions. Forced, exhaust and mixed ventilation modes were compared to determine the safe re-entry times after blasting in a 200 m-long tunnel excavated using the top-heading-and-benching method. Based on the numerical simulations, carbon monoxide was the most critical gas, as it required a longer ventilation time to reduce its concentration below the threshold limit value. The safe re-entry time reached 480 s under the typical forced ventilation mode, but was reduced to 155 s when a mixed ventilation system was used after blasting, reducing the operating costs. The reduction of the re-entry time represents a significant improvement in the excavation cycle. In addition, the results obtained show that 1D models can be used to preliminary analyze the migration of toxic gases. However, to reliably determine the safe re-entry times, 3D numerical models should be developed. Finally, to verify the accuracy of the CFD results, field measurements were carried out in a railway tunnel using gas sensors. In general, good agreements were obtained between the 3D numerical simulations and the measured values.<\/jats:p>","DOI":"10.3390\/ijerph19127092","type":"journal-article","created":{"date-parts":[[2022,6,10]],"date-time":"2022-06-10T02:25:33Z","timestamp":1654827933000},"page":"7092","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["Concentration, Propagation and Dilution of Toxic Gases in Underground Excavations under Different Ventilation Modes"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8181-4054","authenticated-orcid":false,"given":"Javier","family":"Men\u00e9ndez","sequence":"first","affiliation":[{"name":"Mining and Civil Department, SADIM Engineering, 33005 Oviedo, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Noe","family":"Merl\u00e9","sequence":"additional","affiliation":[{"name":"Mining and Civil Department, Duro Felguera, Parque Cient\u00edfico Tecnol\u00f3gico, 33203 Gij\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4270-7552","authenticated-orcid":false,"given":"Jes\u00fas Manuel","family":"Fern\u00e1ndez-Oro","sequence":"additional","affiliation":[{"name":"Fluid Mechanics Department, University of Oviedo, 33271 Gij\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7582-6734","authenticated-orcid":false,"given":"M\u00f3nica","family":"Galdo","sequence":"additional","affiliation":[{"name":"Fluid Mechanics Department, University of Oviedo, 33271 Gij\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2448-5973","authenticated-orcid":false,"given":"Laura \u00c1lvarez","family":"de Prado","sequence":"additional","affiliation":[{"name":"Department of Mining Technology, Topography and Structures, University of Le\u00f3n, 24071 Le\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jorge","family":"Loredo","sequence":"additional","affiliation":[{"name":"Mining Exploitation Department, University of Oviedo, 33004 Oviedo, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2277-9003","authenticated-orcid":false,"given":"Antonio","family":"Bernardo-S\u00e1nchez","sequence":"additional","affiliation":[{"name":"Department of Mining Technology, Topography and Structures, University of Le\u00f3n, 24071 Le\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,9]]},"reference":[{"key":"ref_1","unstructured":"Mainiero, R.J., Harris, M.L., and Rowland, J.H. (2007, January 28\u201331). Dangers of toxic fumes from blasting. Proceedings of the 33rd Annual Conference on Explosives and Blasting Technique, Nashville, TN, USA."},{"key":"ref_2","unstructured":"(2022, February 23). OSHA Permissible Exposure Limits, OSHA Annotated Table Z-1, Available online: https:\/\/www.osha.gov\/dsg\/annotated-pels\/table-z-1.html."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"122094","DOI":"10.1016\/j.jclepro.2020.122094","article-title":"Migration characteristics of CO under forced ventilation after excavation roadway blasting: A case study in a plateau mine","volume":"267","author":"Huang","year":"2020","journal-title":"J. Clean. Prod."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Yang, B., Yao, H., and Wang, F. (2022). A Review of Ventilation and Environmental Control of Underground Spaces. Energies, 15.","DOI":"10.3390\/en15020409"},{"key":"ref_5","first-page":"513","article-title":"Evaluation of postblast re-entry times based on gas monitoring of return air","volume":"36","author":"Bahrami","year":"2019","journal-title":"Min. Metall. Explor."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/j.tust.2012.11.003","article-title":"Conventional and numerical models of blasting gas behaviour in auxiliary ventilation of mining headings","volume":"34","author":"Torno","year":"2013","journal-title":"Tunn. Undergr. Space Technol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"104871","DOI":"10.1016\/j.jweia.2021.104871","article-title":"Study on CO diffusion law and concentration distribution function under ventilation after blasting in high-altitude tunnel","volume":"220","author":"Feng","year":"2022","journal-title":"J. Wind Eng. Ind. Aerodyn."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"103194","DOI":"10.1016\/j.tust.2019.103194","article-title":"On the prediction of toxic fumes from underground blasting operations and dilution ventilation. Conventional and numerical models","volume":"96","author":"Torno","year":"2020","journal-title":"Tunn. Undergr. Space Technol."},{"key":"ref_9","first-page":"8857947","article-title":"Simulation study on the effect of forced ventilation in tunnel under single-head drilling and blasting","volume":"2020","author":"Pu","year":"2020","journal-title":"Shock Vib."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1016\/j.jclepro.2014.08.083","article-title":"Environmental impact of drill and blast tunnelling: Life cycle assessment","volume":"86","author":"Huang","year":"2015","journal-title":"J. Clean. Prod."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1016\/0167-9031(91)91355-L","article-title":"On the prediction of blasting toxic fumes and dilution ventilation","volume":"13","author":"Katsabanis","year":"1991","journal-title":"Min. Sci. Technol."},{"key":"ref_12","unstructured":"Stewart, C.M. (2014, January 2\u20138). Practical prediction of blast fume clearance and workplace re-entry times in development headings. Proceedings of the 10th International Mine Ventilation Congress, Sun City, South Africa."},{"key":"ref_13","unstructured":"Agson Gani, P.H., Widodo, N.P., and Sitorus, T. (May, January 28). Study of re-entry time post blasting at ciguha PT ANTAM UBPE pongkor underground gold mine. Proceedings of the 17th North American Mine Ventilation Symposium (NAMVS 2019), Montreal, QC, Canada."},{"key":"ref_14","unstructured":"Sirait, S.H., Widodo, N.P., and Simanjuntak, M. (2013, January 3\u20134). Study on estimation of re-entry time after blasting in underground mining PT Cibaliung Sumberdaya, Indonesia. Proceedings of the International Symposium on Earth Science and Technology, Fukuoka, Japan."},{"key":"ref_15","unstructured":"Gillies, A., Wu, H., and Shires, D. (2004, January 16\u201319). Development of an assessment tool to minimize safe after blast re-entry time to improve the mining cycle. Proceedings of the Tenth US\/North American Mine Ventilation Sm, Anchorage, AK, USA."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1393","DOI":"10.1016\/j.ssci.2007.10.003","article-title":"Monitoring and removal of CO in blasting operations","volume":"46","author":"Harris","year":"2008","journal-title":"Saf. Sci."},{"key":"ref_17","first-page":"49","article-title":"Field Studies of CO Migration from Blasting","volume":"Volume II","author":"Harris","year":"2005","journal-title":"Proceedings of the 31st Annual Conference on Explosives and Blasting Technique"},{"key":"ref_18","unstructured":"Lawrence, D.L. (1995, January 2\u20135). A Study of Post Blast Generation of Nitrogen Dioxide. Proceedings of the 22nd Annual Conference on Explosives and Blasting Technique, Orlando, FL, USA."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1016\/j.jclepro.2016.01.002","article-title":"Assessment of mine ventilation systems and air pollution impacts on artisanal tanzanite miners at Merelani, Tanzania","volume":"116","author":"Mayala","year":"2016","journal-title":"J. Clean. Prod."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1016\/j.undsp.2018.07.002","article-title":"Air flow and gas dispersion in the forced ventilation of a road tunnel during construction","volume":"4","author":"Fang","year":"2019","journal-title":"Tunn. Undergr. Space Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1016\/j.tust.2015.11.009","article-title":"Numerical simulation of air ventilation in super-large underground developments","volume":"52","author":"Li","year":"2016","journal-title":"Tunn. Undergr. Space Technol."},{"key":"ref_22","first-page":"1994","article-title":"Distribution of harmful gas concentration of plateau tunnel under the forced ventilation mode","volume":"13","author":"Zhang","year":"2016","journal-title":"J. Railw. Sci. Eng."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"012111","DOI":"10.1088\/1757-899X\/741\/1\/012111","article-title":"Monitoring study on CO and dust diffusion in high altitude tunnel under blasting operation","volume":"741","author":"Zou","year":"2020","journal-title":"IOP Conf. Ser. Mater. Sci. Eng."},{"key":"ref_24","first-page":"3948","article-title":"Migration characteristics of poisonous gas during construction stage in railway tunnels at high altitude areas","volume":"47","author":"Cao","year":"2016","journal-title":"J. Cent. South Univ. (Nat. Sci.)"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"106902","DOI":"10.1016\/j.buildenv.2020.106902","article-title":"Tunnel ventilation during construction and diffusion of hazardous gases studied by numerical simulations","volume":"177","author":"Chang","year":"2020","journal-title":"Build. Environ."},{"key":"ref_26","first-page":"10222","article-title":"Comparative studies on control of thermal environment in development headings using force\/exhaust overlap ventilation systems","volume":"38","author":"Xin","year":"2021","journal-title":"J. Build. Eng."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.jlp.2013.05.002","article-title":"CFD analysis of the dispersion of toxic materials in road tunnels","volume":"28","author":"Bubbico","year":"2014","journal-title":"J. Loss Prevent. Proc."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1016\/j.psep.2019.10.012","article-title":"Long-duct forced and short-duct exhaust ventilation system in tunnels: Formation and dust control analysis of pressure ventilation air curtain","volume":"132","author":"Liu","year":"2019","journal-title":"Process Saf. Environ. Protect."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1342","DOI":"10.1007\/s11771-021-4704-z","article-title":"Ventilation control of tunnel drilling dust based on numerical simulation","volume":"28","author":"Jiang","year":"2021","journal-title":"J. Cent. South Univ."},{"key":"ref_30","unstructured":"Agasty, A., Clausen, E., Kellner, M., and Langefeld, O. (2013, January 1\u20133). After blast re-entry time for a room and pillar operation. Proceedings of the Australian Mine Ventilation Conference, Adelaide, Australia."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Roman, W.N., Guthrie, J., and Ndhlovu, W. (2002, January 8\u201312). Upgrading ventilation systems at Konkola mine, Zambia. Proceedings of the North American\/Ninth US Mine Ventilation Symposium, Kingston, ON, Canada.","DOI":"10.1201\/9781439833742.ch12"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Caliendo, C., Russo, I., and Genovese, G. (2021). Risk Analysis of One-Way Road Tunnel Tube Used for Bi-Directional Traffic under Fire Scenarios. Appl. Sci., 11.","DOI":"10.3390\/app11073198"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Khattri, S.K., Log, T., and Kraaijeveld, A. (2019). Tunnel Fire Dynamics as a Function of Longitudinal Ventilation Air Oxygen Content. Sustainability, 11.","DOI":"10.3390\/su11010203"},{"key":"ref_34","unstructured":"Rowland, J.H., Mainiero, R., and Hurd, D.A. (2001, January 28\u201331). Factors Affecting Fumes Production of an Emulsion and ANFO\/Emulsion Blends. Proceedings of the 27th Annual Conference on Explosives and Blasting Technique, Orlando, FL, USA."},{"key":"ref_35","unstructured":"Brake, D.J. (2015, January 21\u201323). A review of good practice standards and re-entry procedures after blasting and gas detection generally in underground Hardrock mines. Proceedings of the 15th North American Mine Ventilation Symposium, Blacksburg, VA, USA."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1098\/rspa.1953.0139","article-title":"Dispersion of soluble matter in solvent flowing slowly through a tube","volume":"219","author":"Taylor","year":"1953","journal-title":"Proc. R. Soc. Lond. Ser. A"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1098\/rspa.1954.0130","article-title":"The dispersion of matter in turbulent flow through a pipe","volume":"223","author":"Taylor","year":"1954","journal-title":"Proc. R. Soc. Lond. Ser. A"},{"key":"ref_38","unstructured":"Widodo, N., Sasaki, K., Sugai, Y., and Sayoga, R. (2008, January 9\u201312). Turbulent diffusion coefficient in mine airways. Proceedings of the 12th U.S.\/North American Mine Ventilation Symposium, Reno, Nevada."},{"key":"ref_39","unstructured":"De Souza, E., Katsabanis, P., Roberts, W., and Heidrich, H. (1993, January 21\u201323). Blasting fume prediction and control as a means of reducing ventilation costs. Proceedings of the 6th US Mine Ventilation Symposium, Salt Lake City, UT, USA."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2878","DOI":"10.1021\/ie0300676","article-title":"Explicit Friction Factor Correlation for Turbulent Flow in Smooth Pipes","volume":"42","author":"Goudar","year":"2003","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"306","DOI":"10.1016\/j.psep.2019.08.016","article-title":"Comparison of k-\u03b5 models in gaseous release and dispersion simulations using the CFD code FLACS","volume":"130","author":"Moen","year":"2019","journal-title":"Process Saf. Environ."}],"container-title":["International Journal of Environmental Research and Public Health"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1660-4601\/19\/12\/7092\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:27:08Z","timestamp":1760138828000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1660-4601\/19\/12\/7092"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,6,9]]},"references-count":41,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2022,6]]}},"alternative-id":["ijerph19127092"],"URL":"https:\/\/doi.org\/10.3390\/ijerph19127092","relation":{},"ISSN":["1660-4601"],"issn-type":[{"value":"1660-4601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,6,9]]}}}