Development of a model for economic control of loading in sublevel caving mines

Shekhar, Gurmeet; Gustafson, Anna; Hersinger, Anders; Jonsson, Kristina; Schunnesson, Håkan

doi:10.1080/25726668.2019.1586371

Cited by 12 publications

(14 citation statements)

References 10 publications

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“…The field tests were performed at LKAB's Malmberget mine, the second largest underground iron ore mine in the world (Shekhar et al 2019). It is located in Gällivare municipality in northern Sweden.…”

Section: Site Descriptionmentioning

confidence: 99%

Rock fragmentation measurements in sublevel caving: field tests at LKAB’s Malmberget mine

Manzoor¹,

Gustafson²,

Schunnesson³

et al. 2022

Caving 2022: Fifth International Conference on Block and Sublevel Caving

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Ground vibrations from blasting are one of the main challenges faced by mines located near populated areas. To confront this challenge, Luossavaara-Kiirunavaara Aktiebolag's Malmberget underground iron ore mine in Sweden tested a change in blast design. Specifically, it tested production holes with smaller diameter to decrease the explosive detonated per delay and thereby lower the ground vibrations. However, smaller holes normally increase hole deviation and may also influence the chargeability of the holes, both of which have a negative effect on fragmentation. Therefore, a detailed evaluation was required before a final decision could be made. To evaluate the fragmentation, field tests were carried out in two drifts of an orebody in the mine. Cameras were mounted in both drifts to record the fragmentation in every loaded bucket. The recording was configured to start by a motion detection parameter; consequently, every movement underneath the cameras was captured. The recording process continued for over a year and resulted in more than 15,000 videos. To analyse such an enormous data for fragmentation, an internally developed quick rating system (QRS) was used to evaluate a total of 7,258 loaded buckets. Blasted rock in the load-haul-dump buckets was classified as fine, medium, coarse, or oversize based on the median fragment size (X50). This paper explains the experimental setup of the test and the analysis procedures. The test results showed that smaller diameter boreholes tend to reduce the median fragment size slightly, and therefore favour the reduction of borehole diameter to deal with the ground vibration problem. The influence of borehole deviation and chargeability was not specifically investigated in this test and need further research to better understand subsequent fragmentation variations.

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Section: Site Descriptionmentioning

confidence: 99%

Rock fragmentation measurements in sublevel caving: field tests at LKAB’s Malmberget mine

Manzoor¹,

Gustafson²,

Schunnesson³

et al. 2022

Caving 2022: Fifth International Conference on Block and Sublevel Caving

Self Cite

View full text Add to dashboard Cite

show abstract

“…The iron content of pure magnetite ore is 72.36% and that of pure hematite ore is 69.90% [11,12]. In the grade control system, the percentage of the iron ore inside the LHD bucket is assumed to be 71% [12] even though it slightly differs from the theoretical values of pure magnetite and hematite. The grade control system used in both mines uses the density difference between the ore and waste [13].…”

Section: Current Practicementioning

confidence: 99%

Challenges with Density-Based Grade Estimation at LKAB’s Underground Iron Ore Mines

Manzoor

Gustafson

Schunnesson

2022

Mining, Metallurgy & Exploration

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Sublevel caving operation relies on the estimation of ore grade at drawpoints, as the mine management uses grade to decide whether the material at a certain ring should be loaded or abandoned. Grade is estimated in various ways, including visual estimation, density-based calculation, and sampling and assay methods. The grade estimation at the world’s two largest underground iron ore mines owned by LKAB in northern Sweden is based on the density difference between ore and waste. The calculations assume a constant swell factor, a theoretical fill of 100%, and a linear relationship between bucket weight and material grade. This study evaluated these assumptions in detail based on the loading data for 12,237 buckets and concluded that the method has some shortcomings which render the assumptions invalid. Further research is required to deal with these shortcomings to improve estimation of the material grade.

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“…The general trend is for the waste rock proportion to increase with the extraction ratio, the latter defined as the total weight of material removed from a drawpoint of a blasted ring divided by the planned tonnage calculated from the ring geometry (Shekhar, 2018). However, it can vary considerably between successive LHD bucket loads (Shekhar et al, 2019) and factors such as the ring geometry and composition of caved rock from the adjacent production area above. If waste rock dilution exceeds a certain level, the material becomes uneconomical to process.…”

Section: Impact Of Waste Rock On the Mining Processmentioning

confidence: 99%

Modelling stochastic behaviour in simulation digital twins through neural nets

Reed

Löfstrand

Andrews

2021

Journal of Simulation

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In discrete event simulation (DES) models, stochastic behaviour is modelled by sampling random variates from probability distributions to determine event outcomes. However, the distribution of outcomes for an event from a real system is often dynamic and dependent on the current system state. This paper proposes the use of artificial neural networks (ANN) in DES models to determine the current distribution of each event outcome, conditional on the current model state or input data, from which random variates can then be sampled. This enables more realistic and accurate modelling of stochastic behaviour. An application is in digital twin models that aim to closely mimic a real system by learning from its past behaviour and utilising current data to predict its future. The benefits of the approach introduced in this paper are demonstrated through a realistic DES model of load-haul-dump vehicle operations in a production area of a sublevel caving mine.

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Development of a model for economic control of loading in sublevel caving mines

Cited by 12 publications

References 10 publications

Rock fragmentation measurements in sublevel caving: field tests at LKAB’s Malmberget mine

Rock fragmentation measurements in sublevel caving: field tests at LKAB’s Malmberget mine

Challenges with Density-Based Grade Estimation at LKAB’s Underground Iron Ore Mines

Modelling stochastic behaviour in simulation digital twins through neural nets

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