The Subtropolis Mine is a room-and-pillar mine extracting the Vanport limestone near Petersburg,Ohio,U.S.In February of 2018,mine management began implementing a heading re-orientation to better control the negative e...The Subtropolis Mine is a room-and-pillar mine extracting the Vanport limestone near Petersburg,Ohio,U.S.In February of 2018,mine management began implementing a heading re-orientation to better control the negative effects of excessive levels of horizontal stress.The conditions in the headings improved,but as expected,stress-related damage concentrated within crosscuts.The mine operator has worked to lessen the impact of the instabilities in the outby crosscuts by implementing several engineering controls.With the implementation of each control,conditions were monitored and analyzed using observational and measurement techniques including 3D LiDAR surveys.Since the heading re-orientation,several 3D LiDAR surveys have been conducted and analyzed by researchers from the National Institute for Occupational Safety and Health(NIOSH).This study examines(1)the characteristics of each 3D LiDAR survey,(2)the change in the detailed strata conditions in response to stress concentrations,and(3)the change detection techniques between 3D LiDAR surveys to assess entry stability.Ultimately,the 3D LiDAR surveys proved to be a useful tool for characterizing ground instability and assessing the effectiveness of the engineering controls used in the heading re-orientation at the Subtropolis Mine.展开更多
The Subtropolis room-and-pillar mine extracts the Vanport Limestone(Allegheny Formation,Pennsylvanian System)near Petersburg,Ohio.Strata instability problems associated with excessive concentrations of lateral stress ...The Subtropolis room-and-pillar mine extracts the Vanport Limestone(Allegheny Formation,Pennsylvanian System)near Petersburg,Ohio.Strata instability problems associated with excessive concentrations of lateral stress caused the mine operator to implement a change in layout design.This mining method has been identified as a stress control layout and has been used by other underground stone mines in the past with varying degrees of success.Practical experience has shown that entry headings advance in the direction of the principal lateral stress,producing lower stress concentrations with better mining conditions.It is important to minimize stress concentrations along the mining front,so an arrowshaped advance is recommended.This technique advances more developments(headings)in a"good"direction and reduces developments(crosscuts)in the"bad direction."As is expected,the stress control layout enhances the potential for shear failures in crosscuts.It is,therefore,important to focus crosscut engineering interventions that either:(a)lower stress concentrations(for example,an arched roof)or(b)enhance strength of the strata containing the shears(for example,rock reinforcement).This study focuses on observing strata conditions on a regular basis and monitoring the response of these strata to changing geologic and mining conditions through 3D Dynamic LiDAR scans.展开更多
Over 600 longwall panels have been mined in Pennsylvania in the last 50 years. Of those 600 panels, 25 panels undermined interstates highways. Despite this quantity of panels, much is still unknown regarded the detail...Over 600 longwall panels have been mined in Pennsylvania in the last 50 years. Of those 600 panels, 25 panels undermined interstates highways. Despite this quantity of panels, much is still unknown regarded the detailed effects of undermining highways. The Gateway Mine, the Emerald Mine, and the Cumberland Mine undermined I-79 with 17 panels in 1982–1989 and in 2003–2008, respectively;Mine 84 undermined I-70 with 4 panels in 1987–2000. Through the examination of the panels that undermined I-70 and I-79, it is possible to determine which factors have most impacted the highway alignments. In some locations, the highway intersects with panels at angles ranging from 45° to 80°;and at the others, it runs between two panels, which simulates the effect of gateroads on the subsidence. The panel width to overburden ratio varies between 0.64 and 1.7, meaning that the interstates were influenced by both subcritical and supercritical subsidence basins. The face advance rates and overburden depths also vary between the panels. Unfortunately, specific information detailing highway impacts associated with unique characteristics of the subsidence basins are limited. In this paper, using the profile function model and influence function model within the surface deformation prediction system(SDPS), the effects of overburden,panel size, and orientation of the road on the highway can be indirectly assessed.展开更多
文摘The Subtropolis Mine is a room-and-pillar mine extracting the Vanport limestone near Petersburg,Ohio,U.S.In February of 2018,mine management began implementing a heading re-orientation to better control the negative effects of excessive levels of horizontal stress.The conditions in the headings improved,but as expected,stress-related damage concentrated within crosscuts.The mine operator has worked to lessen the impact of the instabilities in the outby crosscuts by implementing several engineering controls.With the implementation of each control,conditions were monitored and analyzed using observational and measurement techniques including 3D LiDAR surveys.Since the heading re-orientation,several 3D LiDAR surveys have been conducted and analyzed by researchers from the National Institute for Occupational Safety and Health(NIOSH).This study examines(1)the characteristics of each 3D LiDAR survey,(2)the change in the detailed strata conditions in response to stress concentrations,and(3)the change detection techniques between 3D LiDAR surveys to assess entry stability.Ultimately,the 3D LiDAR surveys proved to be a useful tool for characterizing ground instability and assessing the effectiveness of the engineering controls used in the heading re-orientation at the Subtropolis Mine.
文摘The Subtropolis room-and-pillar mine extracts the Vanport Limestone(Allegheny Formation,Pennsylvanian System)near Petersburg,Ohio.Strata instability problems associated with excessive concentrations of lateral stress caused the mine operator to implement a change in layout design.This mining method has been identified as a stress control layout and has been used by other underground stone mines in the past with varying degrees of success.Practical experience has shown that entry headings advance in the direction of the principal lateral stress,producing lower stress concentrations with better mining conditions.It is important to minimize stress concentrations along the mining front,so an arrowshaped advance is recommended.This technique advances more developments(headings)in a"good"direction and reduces developments(crosscuts)in the"bad direction."As is expected,the stress control layout enhances the potential for shear failures in crosscuts.It is,therefore,important to focus crosscut engineering interventions that either:(a)lower stress concentrations(for example,an arched roof)or(b)enhance strength of the strata containing the shears(for example,rock reinforcement).This study focuses on observing strata conditions on a regular basis and monitoring the response of these strata to changing geologic and mining conditions through 3D Dynamic LiDAR scans.
文摘Over 600 longwall panels have been mined in Pennsylvania in the last 50 years. Of those 600 panels, 25 panels undermined interstates highways. Despite this quantity of panels, much is still unknown regarded the detailed effects of undermining highways. The Gateway Mine, the Emerald Mine, and the Cumberland Mine undermined I-79 with 17 panels in 1982–1989 and in 2003–2008, respectively;Mine 84 undermined I-70 with 4 panels in 1987–2000. Through the examination of the panels that undermined I-70 and I-79, it is possible to determine which factors have most impacted the highway alignments. In some locations, the highway intersects with panels at angles ranging from 45° to 80°;and at the others, it runs between two panels, which simulates the effect of gateroads on the subsidence. The panel width to overburden ratio varies between 0.64 and 1.7, meaning that the interstates were influenced by both subcritical and supercritical subsidence basins. The face advance rates and overburden depths also vary between the panels. Unfortunately, specific information detailing highway impacts associated with unique characteristics of the subsidence basins are limited. In this paper, using the profile function model and influence function model within the surface deformation prediction system(SDPS), the effects of overburden,panel size, and orientation of the road on the highway can be indirectly assessed.
