An in situ monitoring campaign of a hard rock pillar at great depth within a Canadian mine

Forbes, Bradley; Vlachopoulos, Nicholas; Diederichs, Mark S.; Hyett, A. J.; Punkkinen, Allan

doi:10.1016/j.jrmge.2019.07.018

Cited by 22 publications

(7 citation statements)

References 29 publications

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“…Routine measurement and monitoring of deformation in the roadway profiles has been challenging. Current practices still often involve manual in-field measurement approaches or include in-situ movement loggers such as extensometers [60,61] and closure meters [62]. These approaches are limited to provide a spatially sparse sampling of rock mass movement patterns.…”

Section: Future Application Of 3duidmentioning

confidence: 99%

Three-Dimensional Unique-Identifier-Based Automated Georeferencing and Coregistration of Point Clouds in Underground Mines

2021

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Spatially referenced and geometrically accurate laser scans are essential for mapping and monitoring applications in underground mines to ensure safe and smooth operation. However, obtaining an absolute 3D map in an underground mine environment is challenging using laser scanning due to the unavailability of global navigation satellite system (GNSS) signals. Consequently, applications that require georeferenced point cloud or coregistered multitemporal point clouds such as detecting changes, monitoring deformations, tracking mine logistics, measuring roadway convergence rate and evaluating construction performance become challenging. Current mapping practices largely include a manual selection of discernable reference points in laser scans for georeferencing and coregistration which is often time-consuming, arduous and error-prone. Moreover, challenges in obtaining a sensor positioning framework, the presence of structurally symmetric layouts and highly repetitive features (such as roof bolts) makes the multitemporal scans difficult to georeference and coregister. This study aims at overcoming these practical challenges through development of three-dimensional unique identifiers (3DUIDs) and a 3D registration (3DReG) workflow. Field testing of the developed approach in an underground coal mine has been found effective with an accuracy of 1.76 m in georeferencing and 0.16 m in coregistration for a scan length of 850 m. Additionally, automatic extraction of mine roadway profile has been demonstrated using 3DUID which is often a compliant and operational requirement for mitigating roadway related hazards that includes roadway convergence rate, roof/rock falls, floor heaves and vehicle clearance for collision avoidance. Potential applications of 3DUID include roadway profile extraction, guided automation, sensor calibration, reference targets for a routine survey and deformation monitoring.

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Section: Future Application Of 3duidmentioning

confidence: 99%

Three-Dimensional Unique-Identifier-Based Automated Georeferencing and Coregistration of Point Clouds in Underground Mines

2021

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“…Not only can movement be measured inside boreholes, a hydraulic pressure cell (Figure 8a) can be used to directly measure the stress in the rock mass. Forbes et al (2019) describes their use among other instruments in a monitoring campaign of hard rock pillars. In their study, they used a flat jack type instrument grouted in boreholes.…”

Section: Strata Monitoringmentioning

confidence: 99%

Ground support and strata monitoring: what is needed?

Vallati¹,

Roach²,

Weaver³

2020

Proceedings of the Second International Conference on Underground Mining Technology

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With the ever-moving challenge to increase safety and productivity in mines, the ability to understand what your strata is doing in 'real-time' is incredibly important. New technologies need to be developed to allow time efficient monitoring of strata behaviour over the excavations desired life, along with the condition of ground support systems and how effectively they are functioning. Monitoring systems play an important function in maintaining the safe operation of underground mines. This paper will review technologies currently available; those being utilised and the effectiveness of such systems. Key desired outputs will be investigated along with the constraints of available technologies. To assist the underground mining industry to continue evolving in this area, an overview of digital trends will be provided as a guide to the direction for current and future technology developments.

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“…Therefore, the shear fracture characteristics of deep rock mass are of great significance to the safety and stability of engineering, and it is one of the hot topics of research at home and abroad. [6][7][8] Shear test is an effective means to study the mechanical properties of rock mass. Many scholars have conducted extensive and in-depth research on it, and have made remarkable achievements in shear strength model and deformation characteristics.…”

Section: Introductionmentioning

confidence: 99%

“…It will cause huge damage and serious consequences to the underground engineering of deep rock mass. Therefore, the shear fracture characteristics of deep rock mass are of great significance to the safety and stability of engineering, and it is one of the hot topics of research at home and abroad 6–8 …”

Section: Introductionmentioning

confidence: 99%

Investigations on the macro‐meso mechanical properties and energy dissipation mechanism of granite shear fracture under dynamic disturbance

Wang

Luo

Gong

et al. 2023

Num Anal Meth Geomechanics

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To explore the mechanical characteristics and failure mechanisms of rock shear fracture under dynamic disturbance, the laboratory shear test and numerical simulation based on particle flow code (PFC) were carried out, and the mesoscopic degradation characteristics and energy dissipation mechanisms of rock shear fracture were analyzed. The results show that: (1) The crack initiation stress of rock under the disturbance condition is relatively reduced by 20%–29%, and there is a “shear fracture weakening effect.” The frequent alternating effect of stress concentration and release at the post‐peak failure stage is more obvious. (2) The number of cracks in rock under shear action shows the evolution of “calm → low speed growth → rapid increase → decrease of amplification → stabilization” with the increase of shear displacement. Compared with the conventional shear test, more cracks, and wider debris zones are formed. The number of cracks increases by 53%–106%, and the number of debris increases by 31%–138%. (3) The energy change trend of disturbance shear fracture test is basically consistent with that of conventional shear test. With the increase of normal stress, the input energy, elastic strain energy and dissipation energy of rock failure point show a certain linear growth feature. Compared with the conventional shear test, the input energy and stored strain energy of the failure point in the disturbance shear test are smaller, with relative reduction of 16.5% and 22.1%. Namely, the normal frequent disturbance reduces the energy storage capacity and failure resistance of rock.

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An in situ monitoring campaign of a hard rock pillar at great depth within a Canadian mine

Cited by 22 publications

References 29 publications

Three-Dimensional Unique-Identifier-Based Automated Georeferencing and Coregistration of Point Clouds in Underground Mines

Three-Dimensional Unique-Identifier-Based Automated Georeferencing and Coregistration of Point Clouds in Underground Mines

Ground support and strata monitoring: what is needed?

Investigations on the macro‐meso mechanical properties and energy dissipation mechanism of granite shear fracture under dynamic disturbance

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