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

Research output: Contribution to journalArticleResearch

Authors

External Organisational units

  • LKAB

Abstract

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.

Details

Original languageEnglish
Pages (from-to)177-186
Number of pages10
JournalBerg- und hüttenmännische Monatshefte : BHM
Volume167.2022
Issue number4
DOIs
Publication statusPublished - 11 Mar 2022