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

Abstract

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.

Test mining with raise caving mining method: one-time chance to prove the concept?

“…The massive pillars in the slot-pillar system are identified as being decisive for a successful application of the de-stressing variant of raise caving; compare Ladinig et al (2021Ladinig et al ( , 2022aLadinig et al ( , 2022b). In the de-stressing phase, these pillars must be able to transfer considerable stresses to enable the safe extraction of de-stressing slots.…”

“…Figures 2 and Figure 3 show the layout and sequence, as it is currently planned in Kiruna mine. The layout and sequence replicate the individual steps of the raise caving method; compare Ladinig et al (2021Ladinig et al ( , 2022aLadinig et al ( , 2022b.…”

“…A detailed description of the raise caving method, its variants, its advantages, key issues and conducted research and development is given by Ladinig et al (2021Ladinig et al ( , 2022a. Furthermore, a paper submitted for the conference provides additional background information on the raise caving method (Ladinig et al 2022b). The following section provides a brief description of the de-stressing variant, which concentrates on relevant aspects for the present paper, namely the active stress control approach and the corresponding slot-pillar system.…”

Development of an unsophisticated numerical simulation model for caving systems

“…Sensitivity tests are performed to analyse the weight of the mechanical parameters involved in the caving processes, as well as to optimise the reduction rate of the mechanical properties of the rock mass.The calibration of the caving algorithm is the current stage of the development. The calibration is carried out by analysing the results obtained in the numerical models and the outcome of the semi-empirical methods available in the literature.The unsophisticated caving predicting tool is being developed for its application on the novel raise caving mining method (Ladinig et al 2022). The caving tool will supply understanding regarding the caving initiation and propagation for the novel raise caving method.…”

“…The unsophisticated caving predicting tool is being developed for its application on the novel raise caving mining method (Ladinig et al 2022). The caving tool will supply understanding regarding the caving initiation and propagation for the novel raise caving method.…”