Early experiences from the Grasberg block cave: A rock mechanics perspective

Campbell, Ryan; Mardiansyah, Ferric; Banda, H; Tshisens, Jacques; Griffiths, Christopher; Beck, David

doi:10.36487/acg_repo/2063_03

Cited by 3 publications

(4 citation statements)

References 2 publications

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“…These problems comprise stress related damage to pre-developed infrastructure (e.g. Fernandez et al 2010;Gomes et al 2016;Campbell et al 2020) and the occurrence of mining-induced seismicity and associated rockburst damage (e.g. Araneda & Sougarret 2008;Dahnér et al 2012).…”

Section: Specific Challenges Faced In Cave Miningmentioning

confidence: 99%

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Raise caving: a novel mining method for (deep) mass mining

Ladinig¹,

Wimmer²,

Wagner³

2022

Caving 2022: Fifth International Conference on Block and Sublevel Caving

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Raise caving is a novel mining method, which is based on the raise mining method. Raises are central and utilised for different purposes. Here only those directly related to the extraction of the orebody will be discussed. The main objective of raises is to utilise them for creating de-stressing slots, large drawbells and large stopes in an efficient manner. Remote-controlled or automated machinery is operated in raises. Further objectives of raises comprise monitoring and preconditioning. Depending on the field of application two different variants of raise caving can be distinguished, namely a de-stressing variant and a block caving variant.In the de-stressing variant, narrow slots are created first with the objective of providing stress shadows for mining activities in the subsequent production phase. Creating the slots in the de-stressing phase is high stress mining. Hence, massive pillars are left between slots to control the stress situation for de-stress raise development and mining-induced seismicity. After the de-stressing phase is completed, large-scale mineral extraction commences in de-stressed zones. In the production phase large drawbells are developed from raises and large stopes are extracted. During stope blasting only the swell of each blast is mucked so that blasted rock mass provides temporary support to the stope walls. After blasting is completed, the stope is drawn empty and the hanging wall is allowed to cave and caved hanging wall rock mass fills up the stope successively. The massive pillars are extracted in the course of large-scale stoping in the production phase too.In the block caving, variant raises are utilised for drawbell development, undercutting, preconditioning and monitoring purposes. Large drawbells are developed from raises. As drawbells are developed in upward direction, the roof area of the drawbells is enlarged constantly until continuous caving is initiated. Due to the integration of several key activities the block caving variant of raise caving is also referred to as integrated raise caving. This paper highlights the background and motivation for raise caving and it describes both raise caving variants. Steps for the implementation of the methods are outlined and advantages of the individual methods are outlined briefly. Key issues for the implementation of raise caving are highlighted and discussed, and an outlook on currently ongoing research and development activities, which include in situ tests of the method and machinery, is provided. Dedicated accompanying papers provide more information on the ongoing research and development.

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Section: Specific Challenges Faced In Cave Miningmentioning

confidence: 99%

“…• Installation of very heavy support and reinforcement systems (e.g. Jacobsson et al 2013;Campbell et al 2020).…”

Section: Initiativesmentioning

confidence: 99%

Raise caving: a novel mining method for (deep) mass mining

Ladinig¹,

Wimmer²,

Wagner³

2022

Caving 2022: Fifth International Conference on Block and Sublevel Caving

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“…Problems experienced comprise amongst others production level instability during undercutting and production (e.g. [2][3][4]), mining induced seismicity and associated rock burst damage (e.g. [5][6][7]), or difficulties in cave initiation and in ensuring continuous cave advance (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…1: Distribution of major principal stress near a deep tabular slot [26] installation of heavy support and reinforcement systems (e.g. [3,24,25]). Moreover, the trend to more competent rock masses calls for larger undercut areas.…”

Section: Introductionmentioning

confidence: 99%

Raise Caving—A Hybrid Mining Method Addressing Current Deep Cave Mining Challenges

Ladinig

Wagner

Karlsson

et al. 2022

Berg Huettenmaenn Monatsh

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Cave mining progresses to depths exceeding 1000 m and ore bodies situated in competent and strong rock masses are nowadays extracted by different cave mining methods. Widely applied caving methods in massive deposits are block and panel caving, inclined caving, and sublevel caving. All caving methods have in common that rock mass caves during extraction of an ore body in a controlled way. As a result, regional stress changes occur, considerable abutment stresses form, and large-scale subsidence and significant seismic energy releases occur. Experience shows that these rock mechanics effects become especially critical at great depths, where primary stress magnitudes reach and exceed rock mass strength, as well as in strong competent rock masses, which require large footprints to enable continuous caving. The presented raise caving method addresses previously mentioned rock mechanics issues. Initially, de-stressing slots are developed from raises with a minimum amount of pre-development. Substantial pillars separate neighboring slots in order to control stress magnitudes and seismicity near slots. The slots provide a stress shadow for production infrastructure so that large-scale mineral extraction can take place in de-stressed ground. As mining progresses, pillars are extracted and hanging wall is allowed to cave. Results of a pre-study conducted together with LKAB have highlighted advantages of raise caving from a rock mechanics, safety, and cost point of view.

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Numerical Modelling Challenges in Rock Engineering with Special Consideration of Open Pit to Underground Mine Interaction

Shapka-Fels

Elmo

2022

Geosciences

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This paper raises important questions about the way we approach numerical analysis in rock engineering design. The application of advanced numerical models is essential to adequately analyze and design different geotechnical aspects of pit-to-cave transitions. We present a critical review of numerical methods centered around the hypothesis that a model is not, and cannot be, a perfect imitation of reality; therefore, numerical modelling of large-scale mining projects requires the real problem to be idealized and simplified. The discussion highlights the dichotomy of continuum vs. discontinuum modelling and the important question of whether continuum models can effectively capture dynamic continuum-to-discontinuum processes typical of cave mining. The discussion is complemented by examples of hybrid continuum-discontinuum models to analyze the important problem of transitioning from surface (open pit) mining to underground mass mining (caving). The results demonstrate the hypothesis that forward modelling should be performed in the context of a risk-based approach, with numerical models becoming investigative tools to assess risk and evaluate the impact of different unknowns, thus classifying modelling outputs in terms of expected consequences.

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Early experiences from the Grasberg block cave: A rock mechanics perspective

Cited by 3 publications

References 2 publications

Raise caving: a novel mining method for (deep) mass mining

Raise caving: a novel mining method for (deep) mass mining

Raise Caving—A Hybrid Mining Method Addressing Current Deep Cave Mining Challenges

Numerical Modelling Challenges in Rock Engineering with Special Consideration of Open Pit to Underground Mine Interaction

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