Selecting an optimal ground support system for rockbursting conditions

Louchnikov,; Sandy, M.P.

doi:10.36487/acg_rep/1704_41_louchnikov

Cited by 7 publications

(4 citation statements)

References 3 publications

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“…Several authors have contributed to the industries understanding of energy-absorbing rockbolts resulting in the collation of designs charts facilitating the comparison between different rockbolt types (Jager 1992;Villaescusa et al 2004;Simser 2007;Hadjigeorgiou & Potvin 2011;Li & Doucet 2012;Louchnikov & Sandy 2017;Potvin & Hadjigeorgiou 2020). Except for the worked published by Jager (1992), all published data consists of a single loading method providing valuable insight into the performance of the rockbolts for comparison.…”

Section: Impact Testing Of Rockboltsmentioning

confidence: 99%

Dynamic testing: determining the relationship between rockbolt diameter and the residual dynamic capacity of an axially strained tendon

Crompton¹,

Knox²

2022

Caving 2022: Fifth International Conference on Block and Sublevel Caving

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The specification of a tendon is stated as the capacity of the tendon in new condition on the day it was produced. Rock support tendons are discretely tested quasi-statically (replicating closure) or dynamically (replicating seismicity) depending on the conditions expected with the mine environment. Although this testing is valuable, it is likely that a tendon subjected to rapid ground movement (seismicity) would first be subjected to some level of slow closure. Previous research investigated the possible correlation between the quasi-static elongation of a rockbolt prior to dynamic loading and residual dynamic capacity. The results from this research indicated that a correlation exists between the residual dynamic capacity and the energy absorbed quasi-statically when the tendon is elongated axially. It was proposed that a conservative approach would be to consider the total energy capacity of a tendon as the energy absorbed by a tendon in pristine condition during a single dynamic impulse resulting in the rupture of the tendon. The research sample set was limited to a single rockbolt configuration of fixed length and diameter, therefore it was noted that the results should not be extrapolated to other versions of this system or other ground support systems. This research will build on the previous work by repeating the testing regime on a larger diameter of the same configuration rockbolt. The results will be analysed to identify how the diameter of a rockbolt affects the energy and elongation capacity of the rockbolts under combined quasi-static and dynamic loading. This information will greatly assist geotechnical practitioners with support system design, product selection and decisions on when to rehabilitate an installed support system.

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Section: Impact Testing Of Rockboltsmentioning

confidence: 99%

Dynamic testing: determining the relationship between rockbolt diameter and the residual dynamic capacity of an axially strained tendon

Crompton¹,

Knox²

2022

Caving 2022: Fifth International Conference on Block and Sublevel Caving

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“…This also leads to a weakness in the fourth step namely that there is inadequate integration been the methods for areal support and the individual yielding support units. Louchnikov and Sandy 35 emphasised that "…the weakest link in a ground support system is often the surface support, including the connections with the rockbolts. "…”

Section: The Need For Robust Areal Support Systems In Tabular Stopesmentioning

confidence: 99%

Rockburst support in shallow-dipping tabular stopes at great depth

Malan

Napier

2018

International Journal of Rock Mechanics and Mining Sciences

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This paper investigates the unique problems associated with the design of rockburst support for shallow-dipping tabular excavations. These designs are particularly problematic when the stoping width is very small. In steep dipping orebodies, the layouts and mining methods can be selected to ensure that miners never enter the stopes. Only the access drives need to be protected by rockburst resistant support. In shallow-dipping orebodies, this problem is more difficult as miners enter the stopes and the entire hanging wall needs to be supported. A simple analytical model is used to investigate the implications for support design as a result of the convergence associated with the tabular geometry and the possibility of rocks being ejected during a rockburst. This illustrates that a support system is required that is initially stiff, but it should also be yieldable to survive the convergence in the back areas. By trial and error, the historic support solutions in the South African gold mines evolved into a system of timber packs and elongates to meet these requirements. When considering the three accepted key functions of modern rockburst support methodology namely, reinforce, retain and hold, the typical support design for these shallow-dipping orebodies does not meet all these requirements. The rock is highly fractured and fallouts occur between roofbolts during rockbursts as areal support is difficult to implement. Steel mesh is not used as it is often destroyed during cleaning operations. Solving this problem is of critical importance to ensure the viability of deep South African gold mines in future.

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“…A good introduction to the topic is available in the 'Canadian Rockburst Research Program Handbook' (Mining Research Directorate 1996). Examples of the application of this approach are provided by Scott et al (2008) and Louchnikov and Sandy (2017). Interested readers are also referred to the update on this topic provided by Kaiser and Cai (2013) in their Keynote address to Ground Support 2013.…”

Section: Current Practices For Ground Supportmentioning

confidence: 99%

Ground control methods in squeezing and rockburst-prone ground in mining — case studies and benchmarking

Stephenson¹,

Sandy²

2017

Proceedings of the International Conference on Deep and High Stress Mining

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Underground mines with high rock stress to rock strength ratios tend to experience squeezing ground conditions or rockbursting conditions, or a combination of both. The ground control methods and strategies that have evolved to manage such conditions have some similarities and some differences. Mining can continue successfully in such adverse conditions provided appropriate ground control methods are applied. This paper discusses various aspects of ground control in high stress environments and presents a literature review to discuss (1) the rock mass response to high stress conditions, and (2) the implications for ground support requirements and the effectiveness of support systems over the service life of development. Case studies are presented to describe examples of ground control methods in both squeezing and rockburst-prone ground conditions. Information describing the current practices for ground control at a number of high stress underground mines is also presented.

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Selecting an optimal ground support system for rockbursting conditions

Cited by 7 publications

References 3 publications

Dynamic testing: determining the relationship between rockbolt diameter and the residual dynamic capacity of an axially strained tendon

Dynamic testing: determining the relationship between rockbolt diameter and the residual dynamic capacity of an axially strained tendon

Rockburst support in shallow-dipping tabular stopes at great depth

Ground control methods in squeezing and rockburst-prone ground in mining — case studies and benchmarking

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