About

Nino Ripepi is an associate professor and deputy director at Virginia Tech's Mining and Minerals Engineering department. His research focuses on coalbed methane and shale gas production, enhanced production from carbon sequestration, environmental and health & safety issues related to mining. He is involved in courses such as Underground Mine Design, Health, Safety and Risk Management, and Energy, Resources, Development and the Environment. Dr. Ripepi earned his Ph.D. from Virginia Tech in 2009 and his B.S. from Virginia Tech in 1999. His professional activities include leadership in mining engineering education and research, with a particular emphasis on safety, environmental impact, and resource development.

Research topics

• Geology
• Geotechnical engineering
• Materials science
• Mining engineering
• Engineering
• Composite material
• Chemistry
• Mechanics
• Soil science
• Petroleum engineering
• Chemical engineering
• Nanotechnology
• Organic chemistry
• Geomorphology
• Physics
• Geochemistry
• Structural engineering
• Mineralogy

Selected publications

• Southeast Regional CO<sub>2</sub> Utilization and Storage Acceleration Partnership (SECARB-USA): Final Closeout Meeting Presentation [Slides]

  2025-09-17

  reportOpen access
  PublisherOA PDFDOI

• A Risk-Based Pillar Design Approach Combining Stochastic Continuous and Discontinuous Modeling in an Underground Stone Mine

  Mining Metallurgy & Exploration · 2025-02-18 · 1 citations

  articleOpen accessSenior author

  The collapse of a mine pillar is a catastrophic event with great consequences for a mining operation. In spite of the low probability of occurrence for a pillar collapse in comparison to other ground control instability issues, these consequences make these events high risk. Therefore, the design of these structures should be considered from a risk perspective rather than from a factor-of-safety deterministic approach, as it has been traditionally done. This work presents a risk-based pillar design framework that enables to characterize discontinuities' effect in pillar strength, as well as accounting for the possible range of stresses that will be acting on pillars. The proposed methodology is based on the integration of stochastic discrete element modeling for pillar strength estimation, and stochastic continuous modeling for pillar stress determination. This approach was evaluated in an underground dipping stone mine. Using the reliability analysis method, results from the stress estimation model were integrated with those obtained from the stochastic DEM approach, thereby enabling the probability of failure estimation for the pillars throughout the mine. Finally, the methodology was validated by comparing numerical modeling results with LiDAR and photogrammetric surveys from the mine. Results from this design framework provide additional decision-making tools to prevent pillar failure from the design stages by reducing uncertainty. The proposed method enables the integration of pillar design into the risk analysis framework of the mining operation, ultimately improving safety by preventing future pillar collapses.

  PublisherOA PDFDOI

• Experimental and numerical investigation of fracture conductivity between non-smooth rock surfaces with and without proppant

  Geoenergy Science and Engineering · 2024-11-30 · 7 citations

  articleOpen access
  PublisherOA PDFDOI

• ASSESSING THE FEASIBILITY OF CARBON STORAGE IN THE VIRGINIA VALLEY AND RIDGE: RESULTS FROM RECENT DRILLING IN SOUTHWEST VIRGINIA

  Abstracts with programs - Geological Society of America · 2024-01-01

  article
  PublisherDOI

• Modified Design of Pillar Based on Estimated Stresses and Strength of Pillar in an Underground Limestone Mine

  Mining Metallurgy & Exploration · 2023 · 7 citations

  Senior authorCorresponding
  • Geotechnical engineering
  • Geology
  • Mining engineering
  PublisherDOI

• Field Laboratory for Emerging Stacked Unconventional Plays in Central Appalachia

  2023-03-03 · 1 citations

  reportOpen access1st authorCorresponding

  The goal of the Field Laboratory for Emerging Stacked Unconventional Plays (ESUP) in Central Appalachia project was to investigate and characterize the resource potential for multi-play production of emerging unconventional reservoirs in Central Appalachia. Project activities included drilling, logging and coring of a vertical characterization well drilled to basement to approximately 15,000 feet in depth. The data from drilling and well logs as well recovered core samples were used by the research team to support characterization of the geology and potential pay zones within the Nora Gas Field of southwestern Virginia and the greater Central Appalachian Basin. This project was led by Dr. Nino Ripepi of the Virginia Center for Coal and Energy Research (VCCER) in close collaboration with EnerVest Operating LLC (EnerVest). VCCER is housed in the Department of Mining and Minerals Engineering at Virginia Tech and was created by an Act of the Virginia General Assembly on March 30, 1977, as an interdisciplinary study, research, information, and resource facility for the Commonwealth of Virginia. EnerVest is a top tier, low-cost oil and natural gas company with a long history of traditional operating relationships with institutional investors as well as public and private companies. This report summarizes two major research activities: 1) Log and Core Analysis and 2) Numerical Modeling. Core analysis comprises the characterization efforts of the ESUP Field Laboratory and includes a discussion of the well logs run in the deep characterization wells, an initial analysis of those, the number, size and location of cores recovered, core testing and analysis done to date as well as plans for future analysis. Numerical modeling is comprised of seven major modeling efforts, including (1) Multiphysics shale transport modeling work, (2) the developed in-house compositional simulator studies, (3) reservoir modeling studies using GEM software, (4) fracture modeling work using EFRAC3D software and (5) numerical modeling efforts with ABAQUS software, (6) Numerical modeling efforts using FLAC3D and PFC3D, and (7) Automatic Machine Learning (AutoML) Studies.

  PublisherOA PDFDOI

• Analysis of Pillar Strength and Design in a Karst-affected Underground Stone Mine

  Proceedings 56th US Rock Mechanics / Geomechanics Symposium · 2022-09-28

  articleSenior author

  Underground stone mines are often prone to karst formations created by the gradual erosion of carbonate rocks due to groundwater flow. The prevalent fracture network in these stone deposits offers favorable conditions for acidic dissolution which leads to the formation of large karst cavities. The interaction of these cavities with the extensive presence of discontinuities is the major cause of ground control problems encountered during stone mining operations. This paper presents a case study of the effect of the karst cavity on the strength of a pillar in an underground stone mine. Numerical analyses show that presence of these voids in a pillar contributes to a considerable decrease in load-bearing capacity. Any excavation or blasting into the affected areas may pose a safety hazard to the miners. This may also disrupt production and burden the planned mine operations. The study for estimating pillar strength using numerical modeling could provide a pragmatic approach to designing future pillars affected by karsts. The shape and volume of the cavities inside the concerned pillar were approximated using ground-penetrating radar (GPR) surveys. LiDAR scans were used to map the discontinuity network around the pillars, and a Discrete Fracture Network (DFN) was created to simulate the joint network in the pillar’s rock mass. The behavior of the pillar with the increase in axial compressive stress was observed with the help of Distinct-element modeling (DEM) using 3DEC. The pillar model is simulated using Elastic and Mohr-Coulomb constitutive models. Two scenarios are presented to assess the pillar strength with and without the presence of karst. Pillar strength is compared to the estimated current stress levels to understand the potential for improvement in the pillar design. The research emphasizes the importance of pillar design while maximizing safety and production in underground stone mines with karst cavities to prevent pillar instability or local roof failures.

  PublisherDOI

• Analysis of Pillar Strength and Design in a Karst-Affected Underground Stone Mine

  2022-06-26 · 1 citations

  articleSenior author

  ABSTRACT: Underground stone mines are often prone to karst formations created by the gradual erosion of carbonate rocks due to groundwater flow. The prevalent fracture network in these stone deposits offers favorable conditions for acidic dissolution, which leads to the formation of large karst cavities. The interaction of these cavities with the extensive presence of discontinuities is the major cause of ground control problems encountered during stone mining operations. This paper presents a case study for analyzing the effect of the karst cavity on the strength of a pillar in an underground room-and-pillar stone mine. Numerical analyses show that the presence of these voids in a pillar contributes to a considerable decrease in load-bearing capacity. Any development through excavation or blasting into the affected areas may pose a safety hazard to the miners. Apart from that, this may also disrupt production and burden the pre-planned mine operations. The study for estimating pillar strength using numerical modeling could provide a pragmatic approach to designing future pillars affected by karsts. The shape and volume of the karst cavities inside the concerned pillar were approximated using ground-penetrating radar (GPR) surveys. LiDAR scans were performed to map the discontinuity network around the pillars, and Discrete Fracture Network (DFN) technique was implemented to simulate the joint network in the pillar’s rock mass. The behavior of the pillar with the increase in axial compressive stress was observed with the help of Distinct-element modeling (DEM) using 3DEC software. The pillar’s rock mass is simulated using Elastic and Mohr-Coulomb constitutive models. Two scenarios are presented to assess the pillar strength with and without the presence of karst. Pillar strength is compared to the estimated current stress levels to understand the potential for improvement in the pillar design. The research emphasizes the importance of pillar design while maximizing safety and production in underground stone mines with karst cavities to prevent pillar instability or local roof failures.

  PublisherDOI

• Experimental investigation of non-monotonic fracture conductivity evolution in energy georeservoirs

  Journal of Petroleum Science and Engineering · 2022-01-05 · 16 citations

  article
  PublisherDOI

• Estimating Strength of Pillars with Karst Voids in a Room-and-Pillar Limestone Mine

  Mining Metallurgy & Exploration · 2022 · 8 citations

  • Geology
  • Mining engineering
  • Geotechnical engineering
  PublisherDOI

Frequent coauthors

• Xu Tang

  16 shared

• Ming Fan

  10 shared

• Juan J. Monsalve

  Virginia Tech

  9 shared

• Ellen Gilliland

  8 shared

• Erik Westman

  Virginia Tech

  7 shared

• Aman Soni

  Indian Institute of Science Education and Research Pune

  7 shared

• Michael Karmis

  7 shared

• James E. McClure

  6 shared