Browsing by Author "Schafrik, Steven J."

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    Coal Mining Outlook: International, National, and Virginia Trends
    Karmis, Michael E.; McDowney, Preston; Ripepi, Nino; Schafrik, Steven J.; Weisiger, Sean; Walton, Daniel; Kostic, Dennis (Virginia Tech. Virginia Center for Coal and Energy Research., 2000-11)
    Coal mining serves an important role as the economic catalyst for Southwest Virginia, providing high paying jobs in an area crippled by unemployment. There are numerous support industries in existence only because of coal mining. The ripple effects of mining are experienced throughout the state. Every ton of coal mined in Virginia contributes $27.11 to Virginia's economy, while every dollar paid to a miner has a $4.64 impact on Virginia's economy. The tax credit has had a pronounced effect on coal production in Virginia. After the tax credit was enacted, the declining trend in coal production has slowed down, and the production levels are higher than projected. As a result of these higher production levels, an additional $394 million in total impact has been generated, millions in severance and income taxes have been produced, and numerous coal mining jobs have been preserved.
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    Development and Application of a Risk-Based Online Body-of-Knowledge for the U.S. Underground Coal Mining Industry: RISKGATE-US COAL
    Restrepo, Julian Alexander (Virginia Tech, 2017-02-16)
    The occurrence of multiple fatality events in the U.S. underground coal mining industry, such as the Upper Big Branch mine explosion, illustrates the need for improved methods of major safety hazard identification and control. While many solutions to reducing the risk of mine disasters have been proposed, including stricter regulation and improved technology, a comprehensive risk management approach has yet to be fully integrated in the U.S. mining industry. Comprehensive risk management systems have been developed and implemented across a multitude of heavy industries, most notably the Australian minerals industry. This research examines the successful application of risk management in these industries, along with barriers towards U.S. implementation of risk management, which include the existence of competing safety models (e.g. behavior-based safety) and compliance regulation which consumes company resources, and limits incentive for beyond compliance safety measures. Steps towards the risk-based approach, including increased regulatory pressure and proactive initiation by high-ranking industry individuals, begin with the development of risk-based knowledge within the U.S. mining community. This research reviews the development of mine safety regulation in the U.S., and identifies regulatory constraints which have affected the diffusion of risk management. The development of a risk-based online platform which could complement the existing safety systems of U.S. underground coal operations, based on the Australian RISKGATE tool, is the central work of this research. This online platform has been developed by the research participants and industry professionals whose total underground coal mining experience exceeds 1,290 years. This joint effort has yielded a body-of-knowledge which may be used as a complementary safety control reference for U.S. mine operators who wish to employ risk management policies and practices at their own operations, or identify gaps within their own safety control systems.
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    Effects of Dust Controls and Dust Sources on Respirable Coal Mine Dust Characteristics
    Animah, Festus Ayinimi (Virginia Tech, 2024-10-14)
    Respirable coal mine dust (RCMD) continues to pose serious health hazards to workers. Over the past few decades, new regulations, monitoring technologies, and improved dust controls have emerged, and all are based on the presumption that limiting RCMD on the basis of mass will effectively mitigate the exposure hazards. Given the latency of exposure outcomes, it will be some time before the full impact of these strategies can be evaluated. In the meantime, there is increasing awareness that RCMD particle characteristics, in addition to mass, might be important. This dissertation comprises four separate studies which explore the effects of primary RCMD sources and/or engineering controls on particle size and constituents. To enable a direct comparison of dust generation from primary dust sources, a field study was conducted to investigate the dust generation and particle characteristics between coal and the rock strata. Results indicated that finer and more dust was generated when mining predominantly into the rock strata versus the coal strata, while the operation of a flooded bed scrubber and an increase in water sprays pressure and volume generally suppressed dust. Prior government research, conducted within the Mining Research Division of the National Institute of Occupational Safety and Health (NIOSH) evaluated the dust mass concentrations removal efficiency of different dust controls (i.e., a dry and wet scrubber, canopy air curtain, and a wet versus dry dust collection boxes). In the second and third studies, preserved samples from these prior NIOSH dust control studies were re-analyzed and evaluated to understand their effects on dust characteristics. Results indicated that the efficiency of dust controls was particle size dependent, as these controls mostly showed no appreciable effects on dust constituents. Generally, the cleaning of dust from a novel wet dust collection box versus a traditional dry dust box led to a reduction in operator exposure to hazardous dust. In the final study, a laboratory prototype flooded bed scrubber was evaluated to understand its efficiency on dust between different particle size bins (i.e., by particle count) ranging from 0.3-10 µm. From the results, removal efficiencies were generally low – and sometimes negative, for dust particles mostly in each of the size bins less than 2 µm. The results presented here highlight the need to holistically evaluate dust controls to understand their efficiency on dust of different particle sizes and constituents, so that informed decisions can be made on the best controls to adopt in mine operations.
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    Evaluation and Design of Atmospheric Monitoring Interfaces and Approaches for Improved Health and Safety in Underground Coal Mines
    Dougherty, Heather N. (Virginia Tech, 2018-06-29)
    A majority of underground coal mine disasters in the United States are due to explosions. Current atmospheric monitoring system (AMS) practices in the US could be enhanced to facilitate data sharing and learning of the entire work force. With the inclusion of additional atmospheric monitoring and data collecting, meaningful analysis can be realized and shared with the workforce. AMS data can be utilized to advance the understanding of underground atmospheres for the entire workforce along with adding to the knowledge base for preventative planning. An AMS interface ADAMAS is suggested to facilitate this conglomeration and sharing of the data visually, so that it can be quickly processed and applied in their daily decisions. An emerging sensor technology for underground mining, fiber optics is explored and tested in emergency, or fire and explosion situations. The fiber optic methane sensor performed well in smoke only showing a slow in response time due to soot on the filter. The ADAMAS interface was tested in a large population of underground coal miners. The population varied in age, job, classification, and experience. They all primarily found it to be easy to use and helpful to them. Concerns arose when asked how this will facilitate an improved relationship with regulatory agencies. There is trepidation when it comes to additional atmospheric information sharing, that it may not be used advance understanding of mine atmospheres. The AMS data collected is individual to each mine site but can assist in the understanding of underground atmosphere as a whole. Moving forward, regulatory bodies should use this as a stepping point to consider how this information can be used to advance the field of mine ventilation and also the health and safety of the miner.
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    Evaluation and Simulation of Wireless Communication and Tracking in Underground Mining Applications
    Schafrik, Steven J. (Virginia Tech, 2013-04-25)
    In an underground coal mine, the measure of a communication system is the coverage area it can provide at a quality that ensures a miner can communicate with other miners in and out of the mine during normal and emergency operations.  The coverage area of a wireless mesh communication system can be calculated using the tool, COMMs, developed and discussed in this document.  This tool can also be used to explore emergency operations, or operations where the mesh infrastructure is degraded or destroyed.  Most often, the communication system is also capable of transmitting data from sensors including a set of sensors, such as Radio Frequency Identification readers, described as the tracking system. An underground tracking system is described as a system that calculates a location in a useful coordinate when a tracked device is underground.  The tracked device is a representative of a miner, group of miners or equipment, depending on state law and the mine's deployment.  The actual location of the miner or equipment being tracked is the Ground Truth Position (GTP) and the tracking system's representation in the same coordinate system at the same time is the Tracking System Position (TSP).  In an excellent tracking system the actual location, GTP, and TSP will be very close to each other.  This work also develops a set of calculated metrics that describe tracking system performance. The Tracking Coverage Area metric refers to the area within the mine that the tracking system either actively measures a tracked device's location or infers it based on the spatial limitations of the mine and information other than active measurements. Average Accuracy is the arithmetic mean of a set of distances from the TSP to the GTP associated with a tracking system. The Average Cluster Radius metric is the average distance a set of TSPs are from their center point, which is determined by the average location of a TSP relative to the GTP.  A 90% Confidence Distance is the distance from a tracked device's actual location (i.e., GTP) that is greater than 90% of the collected distance from GTP to TSP magnitudes ("90th percentile"). Regulatory guidelines in the United States currently define different tracking qualities at locations in the mine.  These can be classified in location categories of Working Face, Strategic Areas, and Escapeways and Travel-ways. All direct paths via escapeway or travel-way from the mine portal to the working face should be simplified into a one-dimensional path that is subdivided by the three regulatory categories.  Each of these subdivisions should be described using the metrics defined above. These metrics can be predicted using COMMs for a tracking system that is utilizing an underground wireless mesh system that uses Received Signal Strength Indicators (RSSI) to calculate the TSP.  Because the tracking system's algorithm to convert RSSI into a TSP is proprietary to the manufacturer, in order to develop predictions the engineer must collaborate with the manufacturer.  In this document, the predictions and calculations were obtained in conjunction with the manufacturer and proved to be accurate describing the tracking system that was designed and tested.
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    Fire Simulation Cost Reduction for Improved Safety and Response for Underground Spaces
    Haghighat, Ali (Virginia Tech, 2017-10-16)
    Over the past century, great strides have been made in the advancement of mine fire knowledge since the 1909 Cherry Mine Fire Disaster, one of the worst in U.S. history. However, fire hazards remain omnipresent in underground coal mines in the U.S. and around the world. A precise fire numerical analysis (simulation) before any fire events can give a broad view of the emergency scenarios, leading to improved emergency response, and better health and safety outcomes. However, the simulation cost of precise large complex dynamical systems such as fire in underground mines makes practical and even theoretical application challenging. This work details a novel methodology to reduce fire and airflow simulation costs in order to make simulation of complex systems around fire and mine ventilation systems viable. This study will examine the development of a Reduced Order Model (ROM) to predict the flow field of an underground mine geometry using proper orthogonal decomposition (POD) to reduce the airflow simulation cost in a nonlinear model. ROM proves to be an effective tool for approximating several possible solutions near a known solution, resulting in significant time savings over calculating full solutions and suitable for ensemble calculations. In addition, a novel iterative methodology was developed based on the physics of the fluid structure, turbulent kinetic energy (TKE) of the dynamical system, and the vortex dynamics to determine the interface boundary in multiscale (3D-1D) fire simulations of underground space environments. The proposed methodology was demonstrated to be a useful technique for the determination of near and far fire fields, and could be applied across a broad range of flow simulations and mine geometries. Moreover, this research develops a methodology to analyze the tenable limits in a methane fire event in an underground coal mine for bare-faced miners, mine rescue teams, and fire brigade teams in order to improve safety and training of personnel trained to fight fires. The outcomes of this research are specific to mining although the methods outlined might have broader impacts on the other fields such as tunneling and underground spaces technology, HVAC, and fire protection engineering industries.
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    A New Style of Simulation Model for Mining Systems
    Schafrik, Steven J. (Virginia Tech, 2001-09-26)
    The algorithms for the mathematical modeling to predict productivity of underground room-and-pillar mining systems are well-known and documented. These algorithms consider the time-varying relationships between mining equipment for a given geometry of operations as well as other constraints. This study presents a newly developed, user-friendly visual simulation computer tool for the Windows environment. This tool can be easily customized and utilized by field engineers and will help mine operators plan the optimum mining sequence for different mine geometries and equipment layouts. Program output includes monitoring of shift data, equipment utilization indices, and so forth. The simulation technique can be used with any environment. Use of the system is demonstrated in different mining equipment configurations. Development and validation of the system was aided by the Peabody Group.
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    Predicting the Dynamics of Injection-Induced Earthquakes
    Schlosser, Charles Stewart (Virginia Tech, 2023-05-24)
    Human activities associated with the injection of fluids at depth are known to trigger earthquakes. Fluid injection increases the internal pore pressure of the host rock, which in turn reduces the effective stress and frictional resistance of faults that maintain the fractured rock system in a state of mechanical equilibrium. Under certain conditions, sufficiently high pore pressure can lower this frictional resistance below a critical threshold and initiate an earthquake – the relative motion of rock on either side of the fault plane. Many of these earthquakes are small and imperceptible without the aid of specialized instruments, but some may be large enough to pose a significant risk to life and property. Several emerging technologies that have the potential to shape the future of low-carbon energy production, including carbon capture and storage and enhanced geothermal energy production, are inextricably linked to large-scale injection of fluids into the subsurface. The risk of injection-induced earthquakes is a primary concern and potential barrier to widespread adoption of these technologies. New tools are required to help operators manage these risks and meet stakeholder expectations. Current knowledge enables operators to predict the conditions that would trigger such an earthquake, but few or no tools exist to predict the severity of the earthquakes, precluding a complete description of the risk associated with operating a large-scale injection well. This dissertation details the theoretical justification and initial validation of a methodology and software to simulate the motion of an earthquake as it occurs and quantify the severity in terms that are germane to experts in earthquake science. Specifically, this work utilizes the finite element method to solve the equations of motion dictated by the three-dimensional linear elastic constitutive equation. Novel aspects of this research include the treatment of friction at the fault interface as a constraint on the motion of the system, and the numerical methods necessary to solve this problem. This software was created exclusively with free and open source software, so that every aspect of its internal machinery may be scrutinized, replicated, and improved by future workers.
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    Proceedings of the 15th North American Mine Ventilation Symposium
    (Virginia Tech, Department of Mining and Minerals Engineering, 2015-06-20)
    These conference proceedings consist of 70 peer-reviewed technical papers representing subjects related to underground mine ventilation. All were presented at the 15th North American Mine Ventilation Symposium (NAMVS) from June 20, 2015 to June 25, 2015, held on the Virginia Tech campus in Blacksburg, Virginia. The included papers were selected by Symposium organizers because they reflect both present day critical challenges that underground mine ventilation professionals face as well as new innovative ideas that will propel the profession into the future. The content in the proceedings represents topics that include diesel exhaust and other contaminants in the mine atmosphere, dust in the underground mine environment, mine atmospheric monitoring, mine fans, mine fires, mine gases, mine heating and cooling, case studies, ventilation planning, and ventilation system design.
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    Underground Wireless Mesh Communication Infrastructure Design Prediction and Optimization
    Schafrik, Steven J. (Virginia Tech, 2013-04-27)
    In an underground coal mine, the measure of a communication system is the coverage area it can provide at a quality that ensures a miner can communicate with other miners in and out of the mine during normal and emergency operations.  The coverage area of a wireless mesh communication system can be calculated using the tool, COMMs, developed and discussed in this document.  This tool can also be used to explore emergency operations, or operations where the mesh infrastructure is degraded or destroyed.  Most often, the communication system is also capable of transmitting data from sensors including a set of sensors, such as Radio Frequency Identification readers, described as the tracking system. An underground tracking system is described as a system that calculates a location in a useful coordinate when a tracked device is underground.  The tracked device is a representative of a miner, group of miners or equipment, depending on state law and the mine's deployment.  The actual location of the miner or equipment being tracked is the Ground Truth Position (GTP) and the tracking system's representation in the same coordinate system at the same time is the Tracking System Position (TSP).  In an excellent tracking system the actual location, GTP, and TSP will be very close to each other.  This work also develops a set of calculated metrics that describe tracking system performance. The Tracking Coverage Area metric refers to the area within the mine that the tracking system either actively measures a tracked device's location or infers it based on the spatial limitations of the mine and information other than active measurements. Average Accuracy is the arithmetic mean of a set of distances from the TSP to the GTP associated with a tracking system. The Average Cluster Radius metric is the average distance a set of TSPs are from their center point, which is determined by the average location of a TSP relative to the GTP.  A 90% Confidence Distance is the distance from a tracked device's actual location (i.e., GTP) that is greater than 90% of the collected distance from GTP to TSP magnitudes ("90th percentile"). Regulatory guidelines in the United States currently define different tracking qualities at locations in the mine.  These can be classified in location categories of Working Face, Strategic Areas, and Escapeways and Travel-ways. All direct paths via escapeway or travel-way from the mine portal to the working face should be simplified into a one-dimensional path that is subdivided by the three regulatory categories.  Each of these subdivisions should be described using the metrics defined above. These metrics can be predicted using COMMs for a tracking system that is utilizing an underground wireless mesh system that uses Received Signal Strength Indicators (RSSI) to calculate the TSP.  Because the tracking system's algorithm to convert RSSI into a TSP is proprietary to the manufacturer, in order to develop predictions the engineer must collaborate with the manufacturer.  In this document, the predictions and calculations were obtained in conjunction with the manufacturer and proved to be accurate describing the tracking system that was designed and tested.