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Guest editorial-special issue on ground control in mining in 2018

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International Journal of mining Science and Technology 2019年第1期29卷 1-2页

作者： michael m.murphy ted klemetti Heather Lawson Brijes mishra Kyle Perry Pittsburgh mining Research Division NIOSH Spokane mining Research Division NIOSH mining Engineering West Virginia University mining&Nuclear Engineering Missouri S&T

Ground control is the science of studying and controlling the behavior of rock strata in response to mining operations. Ground control-related research has seen significant advancements over the last 37 years, and these accomplishments are well documented in the proceedings of the annual International Conference on Ground Control in mining (ICGCm)(1)The ICGCm is a forum to promote closer communication among researchers, consultants。

关键词： NIOSH Guest editorial-special issue on ground control in mining in 2018

Analysis of gateroad stability at two longwall mines based on field monitoring results and numerical model analysis

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International Journal of mining Science and Technology 2019年第1期29卷 35-43页

作者： Gabriel S.Esterhuizen David F.Gearhart ted klemetti Heather Dougherty mark van Dyke National Institute for Occupational Safety and Health

Coal mine longwall gateroads are subject to changing loading conditions induced by the advancing longwall face. The ground response and support requirements are closely related to the magnitude and orientation of the stress changes, as well as the local geology. This paper presents the monitoring results of gateroad response and support performance at two longwall mines at a 180-m and 600-m depth of cover.At the first mine, a three-entry gateroad layout was used. The second mine used a four-entry, yieldabutment-yield gateroad pillar system. Local ground deformation and support response were monitored at both sites. The monitoring period started during the development stage and continued during first panel retreat and up to second panel retreat. The two data sets were used to compare the response of the entries in two very different geotechnical settings and different gateroad layouts. The monitoring results were used to validate numerical models that simulate the loading conditions and entry response for these widely differing conditions. The validated models were used to compare the load path and ground response at the two mines. This paper demonstrates the potential for numerical models to assist mine engineers in optimizing longwall layouts and gateroad support systems.

关键词： Coal mining Longwall Gateroad Support Numerical models

Guest editorial-special issue on ground control in mining in 2019

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International Journal of mining Science and Technology 2020年第1期30卷 1-2页

作者： michael m.murphy ted klemetti Heather Lawson Brijes mishra Kyle Perry Pittsburgh mining Research Division NIOSHPittsburghPA 15228USA Spokane mining Research Division NIOSHSpokaneWA 99207USA mining Engineering West Virginia UniversityMorgantownWV 26506USA mining&Nuclear Engineering Missouri S&TRollaMO 65409USA

Ground control is the science of studying and controlling the behavior of rock strata in response to mining operations.Ground-control-related research has seen significant advancements over the last 39 years,and these accomplishments are well documented in the proceedings of the annual International Conference on Ground Control in mining(ICGCm)[1].The ICGCm is a forum to promote closer communication among researchers,consultants,regulators,manufacturers,and mine operators to expedite solutions to ground control problems in mining[2–7].Fundamental research and advancements in ground control science define the central core of the conference mission.Providing information to mine operators is a priority,as the conference goal is to offer solutions-oriented information.In addition,the conference has included innovative technologies and ideas in miningrelated fields such as exploration,geology,and surface and underground mining in all commodities.many new ground control technologies and design standards adopted by the mining industry were first discussed at ICGCm.Therefore,this conference is recognized as the best international forum for introducing new groundcontrol-related research and products.

关键词： operators closer accomplishment

Analysis of the current rib support practices and techniques in U.S. coal mines

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International Journal of mining Science and Technology 2016年第1期26卷 77-87页

作者： mohamed Khaled m. murphy michael m. Lawson Heather E. klemetti ted Office of mine Safety and Health Research Ground Control Branch Pittsburgh PA USA

Design of rib support systems in U.S. coal mines is based primarily on local practices and experience. A better understanding of current rib support practices in U.S. coal mines is crucial for developing a sound engineering rib support design tool. The objective of this paper is to analyze the current practices of rib control in U.S. coal mines. Twenty underground coal mines were studied representing various coal basins,coal seams,geology,loading conditions,and rib control strategies. The key findings are:(1) any rib design guideline or tool should take into account external rib support as well as internal bolting;(2) rib bolts on their own cannot contain rib spall,especially in soft ribs subjected to significant load—external rib control devices such as mesh are required in such cases to contain rib sloughing;(3) the majority of the studied mines follow the overburden depth and entry height thresholds recommended by the Program Information Bulletin 11-29 issued by the mine Safety and Health Administration;(4) potential rib instability occurred when certain geological features prevailed—these include draw slate and/or bone coal near the rib/roof line,claystone partings,and soft coal bench overlain by rock strata;(5) 47% of the studied rib spall was classified as blocky—this could indicate a high potential of rib hazards; and(6) rib injury rates of the studied mines for the last three years emphasize the need for more rib control management for mines operating at overburden depths between 152.4 m and 304.8 m.

关键词：地下煤矿肋骨美国技术分析支撑技术矿山安全设计工具控制策略

A case study of the stability of a non-typical bleeder entry system at a U.S.longwall mine

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International Journal of mining Science and Technology 2020年第1期30卷 25-31页

作者： T.m.klemetti m.A.Van Dyke I.B.Tulu D.Tuncay NIOSH Pittsburgh mining Research Division Pittsburgh 15236USA Department of mining Engineering West Virginia UniversityMorgantown 26505USA

Longwall abutment loads are influenced by several factors,including depth of cover,pillar sizes,panel dimensions,geological setting,mining height,proximity to gob,intersection type,and size of the gob.How does proximity to the gob affect pillar loading and entry condition?Does the gob influence depend on whether the abutment load is a forward,side,or rear loading?Do non-typical bleeder entry systems follow the traditional front and side abutment loading and extent concepts?If not,will an improved understanding of the combined abutment extent warrant a change in pillar design or standing support in bleeder entries?This paper details observations made in the non-typical bleeder entries of a moderate depth longwall panel—specifically,data collected from borehole pressure cells and roof extensometers,observations of the conditions of the entries,and numerical modeling of the bleeder entries during longwall extraction.The primary focus was on the extent and magnitude of the abutment loading experienced due to the extraction of the longwall panels.Due to the layout of the longwall panels and bleeder entries,the borehole pressure cells(BPCs)and roof extensometers did not show much change due to the advancing of the first longwall.However,they did show a noticeable increase due to the second longwall advancement,with a maximum of about 4 mPa of pressure increase and 5mmof roof deformation.The observations of the conditions showed little to no change from before the first longwall panel extraction began to when the second longwall panel had been advanced more than 915 m.Localized pillar spalling was observed on the corners of the pillars closest to the longwall gob as well as an increase in water in the entries.In addition to the observations and instrumentation,numerical modeling was performed to validate modeling procedures against the monitoring results and evaluate the bleeder design.ITASCA Consulting Group’s FLAC3D numerical modeling software was used to evaluate the bleeder entries.The results of the models indicate

关键词： Abutment loading Longwall Instrumentation Bore hole pressure cells Pillar loading Yield pillar Bleeder pillar

Single atom Cu-N-C catalysts for the electro-reduction of CO_(2) to CO assessed by rotating ring-disc electrode

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Journal of Energy Chemistry 2024年第1期88卷 169-182,I0004页

作者： S.Pérez-Rodríguez m.Gutiérrez-Roa C.Giménez-Rubio D.Ríos-Ruiz P.Arévalo-Cid m.V.martínez-Huerta A.Zitolo m.J.Lázaro D.Sebastián Instituto de Carboquímica(CSIC) Miguel Luesma Castán 450018 ZaragozaSpain Instituto de Catálisis y Petroleoquímica(CSIC) Marie Curie 228049 MadridSpain Synchrotron SOLEIL L’Orme des MerisiersDépartementale 12891190France

The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient CO_(2)RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for CO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly CO selective at low overpotentials(from -0.6 to -0.8 V vs.RHE) in 0.1 m KHCO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N_(4) moieties exhibits a CO_(2)-to-CO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/CO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from CO_(2)RR.

关键词： Cu-N-C Carbon xerogel Rotating ring disc electrode Carbon dioxide reduction reaction Carbon monoxide

Analysis of global and local stress changes in a longwall gateroad

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International Journal of mining Science and Technology 2018年第1期28卷 127-135页

作者： I.B.Tulu G.S.Esterhuizen D.Gearhart T.m.klemetti K.m.mohamed D.W.H.Su Department of mining Engineering West Virginia University NIOSH Pittsburgh Mining Research Division

A numerical-model-based approach was recently developed for estimating the changes in both the horizontal and vertical loading conditions induced by an approaching longwall face.In this approach, a systematic procedure is used to estimate the model's inputs.Shearing along the bedding planes is modeled with ubiquitous joint elements and interface elements.Coal is modeled with a newly developed coal mass model.The response of the gob is calibrated with back analysis of subsidence data and the results of previously published laboratory tests on rock fragments.The model results were verified with the subsidence and stress data recently collected from a longwall mine in the eastern United States.

关键词： Longwall mining Gateroad design Flac3D Horizontal angle Gob loading Hollow inclusion cells

Simulating hydrodynamics of hot and large Group A particle systems at cold conditions to obtain data for scale-up

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Particuology 2010年第6期8卷 501-502页

作者： ted m.Knowlton Particulate Solid Research Inc.4201 W.36th StreetChicagoILUSA

Scaling laws based on the concept of dimensional similitude are proposed to simulate the hydrodynamics of hot and large particle systems at conditions of cold and small particle systems. This technique uses the concept of dimensional similitude to accomplish this by maintaining certain dimensional groups constant in the large, hot and small, cold systems. However, there are certain limitations with this technique. One of them is that the particle size in the small, cold system is usually smaller than in the large, hot system. Because particle size is such a dominant parameter in fluidized systems, this can certainly affect the simulation. An alternative method of simulating hot hydrodynamics in ambient-temperature Group A particle systems has been proposed. In this method, the same calculated drag force is maintained between the two systems. The drag force is varied by changing the gas density of the cold system so that it matches the drag force in the hot system.

关键词： Drag Drag force Simulation modeling

GSTARS computer models and their applications, Part Ⅱ: Applications

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International Journal of Sediment Research 2008年第4期23卷 299-315页

作者： Francisco J.m.SIm■ES Chih ted YANG Research Hydrologist US Geological Survey Geomorphology and Sediment Transport Laboratory4620 Technology Drive Suite 400 Golden CO 80403 USA Borland Prof. of Water Resources and Director of Hydroscience and Training Center Department of Civil and Environmental Engineering Colorado State UniversityFort Collins CO 80523-1372 USA

In part 1 of this two-paper series, a brief summary of the basic concepts and theories used in developing the Generalized Stream Tube model for Alluvial River Simulation (GSTARS) computer models was presented. Part 2 provides examples that illustrate some of the capabilities of the GSTARS models and how they can be applied to solve a wide range of river and reservoir sedimentation problems. Laboratory and field case studies are used and the examples show representative applications of the earlier and of the more recent versions of GSTARS. Some of the more recent capabilities implemented in GSTARS3, one of the latest versions of the series, are also discussed here with more detail.

关键词： Computer model Reservoir River Sediment transport Unit stream power