Nordqvist, A & Quinteiro, C 2024, 'Preliminary results from tests using SLC with 40 and 50 m sublevel height at LKAB with focus on gravity flow', in Daniel Johansson & Håkan Schunnesson (eds), MassMin 2024: Proceedings of the International Conference & Exhibition on Mass Mining, Luleå University of Technology, Luleå, pp. 480-491.
(https://papers.acg.uwa.edu.au/p/2435_D-01/)
Abstract: LKAB operates two underground iron ore mines located in the northern part of Sweden, both using sublevel caving as the mining method. Common sublevel heights vary between 25-30 m. Tests with 40 and 50 m sublevel height is on-going in a fairly small orebody called Konsuln located close to the main Kiruna orebody. LKAB has developed three sublevels (436, 486 and 536) in Konsuln to test sublevel caving with 40 and 50 m sublevel height. The objective with these tests is to assess the applicability of large sublevel heights in some of the LKAB future production areas. The production started in March 2021 at level 436 and May 2022 at level 486, level 486 still on-going. About 2,6 Mton has been produced from blasted rings at level 436 and 2,2 Mton so far at level 486. Production at level 536 has just started and scheduled to end 2025. Preparations necessary for planning and for the assessment of the performance of these large sublevel heights includes: (1) measurements of blasthole deviations, (2) measurements of raise hole deviations, (3) measurements of iron grades in selected blastholes, (4) installation of smart markers and (5) opening blast tests. Follow up of the performance of the rings involves collection of data from loaded buckets, recovered markers, blast function (vibrations) and visual inspections as well as laser scanning when appropriate. This paper summarizes results on gravity flow achieved so far.