Mining Project: Improving Prevention and Suppression of Equipment Fires in Metal/Nonmetal Mines
| Principal Investigator |
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|---|---|
| Start Date | 10/1/2019 |
| Objective |
This project will evaluate and develop effective measures to prevent hot surface ignitions on mining equipment, improve fire suppression techniques for equipment fires, and develop a diagnostic tool to identify and evaluate the impacts of mine fires on a mine’s ventilation system. Mine fires remain one of the biggest threats to the health and safety of miners in metal and nonmetal (M/NM) mines. Most of the reportable mine fires are equipment fires caused by ignitions of combustible fluids such as hydraulic fluid released from a hose rupture onto hot engine surfaces. To reduce the number of equipment fires, NIOSH is developing effective measures to limit or prevent hot surface ignitions on mine equipment as well as to improve the effectiveness of suppression systems through research. The project intends to reach mine operators, fire suppression manufacturers, and the Mine Safety and Health Administration (MSHA), all of which will benefit from this work’s advanced design and mitigation techniques. |
| Topic Areas |
Research Summary
Approach
Large-scale experiments in the NIOSH fire test facility determined the minimum hot surface temperatures for the ignition of various fluids commonly used on mining equipment. These fluids include diesel fuel, hydraulic fluid, and engine oil. Such tests assessed the effects of air velocity around the hot surface, the composition of the hot surface material, and fluid type on the occurrence of hot surface ignition. A variable-speed fan was used to control airflow speed. The hot surface materials identified for testing are cast iron alloy, carbon steel, and stainless steel. Hot surface ignition results were presented to the MSHA Approval and Certification Center (A&CC) to help improve equipment fire prevention.
Large-scale experiments conducted in the NIOSH fire test facility will be used to evaluate the effectiveness of different fire suppression systems for fires caused by a hot surface ignition. Various fire suppression systems—water mist, dry chemical, wet chemical, dual agent (dry chemical and wet chemical), and carbon dioxide—have been installed based on the manufacturers’ guidelines. The effectiveness of the suppression systems will be assessed based on whether a fire is extinguished, how long it takes to extinguish the fire, and whether a re-ignition occurs after the application of the fire suppressant. Based on experimental results, recommendations and guidelines will be developed for the M/NM mining sector to prevent hot surface ignitions and extinguish mine equipment fires. Large-scale fire suppression tests will be conducted to examine the effect of nozzle locations on the suppressive effect of each system. Based on the test results, appropriate fire suppression nozzle locations will be identified.
The MATLAB Machine Learning Toolbox was used to develop a predictive/diagnostic tool for assessing the response of an underground mine ventilation system to an equipment fire. Mine ventilation simulations using the MFIRE software will be employed to identify a ventilation network’s responses or sensitivities to various anomalies that can impact ventilation flow (i.e., fire). The data from these sensitivity analyses will then be used as inputs to train a diagnostic tool to recognize the potential consequences of an equipment fire on ventilation networks. A tool will be developed to use network sensitivities as part of a diagnostic tool for identifying the location of an abnormal airflow source. This tool will take the significant airflow changes from the user and provide potential airways as the source location. The diagnostic tool can also be used to solve for the flow distribution in the network and sensitivity to resistance changes.
Milestones and Accomplishments
| Description | Audience | Year |
|---|---|---|
| Set up a multi-project fire facility to conduct various fire-related experiments | Equipment manufacturers, MSHA, and mine operators |
2019 |
| Developed an approach to determine fire size and location using the post-fire airflow data | Equipment manufacturers, MSHA, and mine operators | 2021 |
| Conducted and evaluated a series of hot surface ignition tests for three metal types, three fuel types, and four airflows | Equipment manufacturers, MSHA, and mine operators | 2020-2021 |
| Conducted and evaluated a series of engine fire suppression tests | Equipment manufacturers, MSHA, and mine operators | 2022 |
Planned Impacts and Outcomes
This project will deliver recommendations and guidelines for the prevention of hot surface ignitions on mine equipment. The research will also provide recommendations on fire suppression system selection and installation for mine equipment. It is expected that equipment manufacturers, MSHA, and mine operators will use these recommendations and guidelines to reduce the risk of hot surface ignitions and improve fire suppression system designs for mine equipment. The research findings will help prevent equipment fires by providing a better understanding of controlling parameters. Mine operators will also benefit from the results of this project by having better control of their ventilation networks in cases of an equipment fire emergency or an unplanned flow disturbance caused by an unknown source.
Outputs
Bahrami D, Zhou L [2022]. A novel methodology to locate an abnormal airflow in underground mine ventilation networks. 2022 SME Preprint 22-018, Salt Lake City, February 27-March 2, 2022.
Xue Y, Bahrami D, Zhou L [2022]. Identifying the location and size of an underground mine fire with simulated ventilation data and random forest model. 2022 SME Preprint 22-026, Salt Lake City, February 27-March 2, 2022.
Zhou L, Thomas RA, Yuan L [2022]. Experimental study of improving a mine ventilation network model using continuously monitored airflow. Min Metal Expl 39:887-895.
Zhou L, Bahrami D [2022]. A derivative method to calculate resistance sensitivity for mine ventilation networks. Min Metal Expl 39:1833-1839.
Tang W, Bahrami D, Yuan L et al. [2022]. Hot surface ignition of liquid fuels under ventilation. Min Metal Expl 39:961–968.
Bahrami D, Zhou L, Xue Y, Yuan L [2023]. Determination of underground hazard location using machine learning techniques, CIM Journal 14(1):56-63.
Supporting Visual
Photo of hot surface experiments in the NIOSH fire facility to determine ignition temperatures of selected fuel types, airflow speeds, and surface material types. This work concluded that the fuel type has a significant effect on ignition temperature, followed by surface material type. Engine fire suppression tests are being conducted to evaluate the efficacy of commonly used suppression systems under various test conditions.
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