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Schunnesson, Håkan
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Publications (10 of 106) Show all publications
Manzoor, S., Gustafson, A. & Schunnesson, H. (2023). Dumping oversize rock fragments in orepasses: the impact on the production cycle of a sublevel caving operation. Mining Technology, 132(3), 215-224
Open this publication in new window or tab >>Dumping oversize rock fragments in orepasses: the impact on the production cycle of a sublevel caving operation
2023 (English)In: Mining Technology, ISSN 2572-6668, Vol. 132, no 3, p. 215-224Article in journal (Refereed) Published
Abstract [en]

Oversize rock fragments are highly undesired in a sublevel caving (SLC) operation as they affectthe production cycle, equipment, and infrastructure. In this study, afield test was carried out inMalmberget mine to analyse the impact of oversize fragments on the production cycle and thecosts of different procedures for handling such fragments. The tests involved monitoring ofdumping oversize fragments in two orepasses, one with a grizzly and the other one withouta grizzly, using cameras. The cycle times of load-haul-dump (LHD) machines weredetermined for both orepasses. The results indicate that the grizzly increased the availabilityand productivity of the orepass despite increasing the cycle time of the LHD machines.Moreover, installation of a boulder breaker system along with the grizzly can furtherincrease the productivity and the cost of such a system will be paid offin a shorter time interms of enhanced productivity.

Place, publisher, year, edition, pages
Taylor & Francis, 2023
Keywords
Sublevel caving (SLC), orepass, oversize fragment, grizzly, boulder breaker, Load-Haul-Dump (LHD) machines, hang-ups, orepass screening
National Category
Geotechnical Engineering
Research subject
Mining and Rock Engineering; Centre - Centre for Advanced Mining & Metallurgy (CAMM)
Identifiers
urn:nbn:se:ltu:diva-96670 (URN)10.1080/25726668.2023.2215560 (DOI)2-s2.0-85160944276 (Scopus ID)
Projects
Face-to-Surface II
Funder
Swedish Research Council FormasSwedish Energy AgencyVinnova
Note

Validerad;2023;Nivå 2;2023-11-07 (sofila);

Available from: 2023-04-19 Created: 2023-04-19 Last updated: 2023-11-07Bibliographically approved
Manzoor, S., Gustafson, A. & Schunnesson, H. (2023). Modelling the relationship between oversize fragments and nature of rock mass for a sublevel caving operation. International Journal of Rock Mechanics And Mining Sciences, 169, Article ID 105433.
Open this publication in new window or tab >>Modelling the relationship between oversize fragments and nature of rock mass for a sublevel caving operation
2023 (English)In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 169, article id 105433Article in journal (Refereed) Published
Abstract [en]

Rock fragmentation is vital in a sublevel caving operation. The oversize fragments are the most undesiredfragmentation category because of their challenges; as such, they require special attention. This study carried outa field test in one of the LKAB’s iron ore mines in northern Sweden to analyse the occurrence of oversizefragments. The analysis involved correlation and regression tests and was performed for different types of rockmasses. The results showed that an increase in the percentage of solid rock mass caused an increase in thepercentage of oversize fragments. The other rock types, including slightly fractured, highly fractured, and rockmass with minor and major cavities, tended to have a reduced percentage of oversize fragments. The resultsindicate that oversize fragments can be predicted using linear regression or partial least square regression modelswith R2 values of 0.78 and 0.73, respectively. 

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Oversize fragments, Measurement while drilling (MWD), Sublevel caving (SLC), Multiple linear regression, Partial least square (PLS) regression
National Category
Geotechnical Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-96669 (URN)10.1016/j.ijrmms.2023.105433 (DOI)2-s2.0-85161352616 (Scopus ID)
Funder
VinnovaSwedish Energy AgencySwedish Research Council Formas
Note

Validerad;2023;Nivå 2;2023-06-08 (joosat);

Licens fulltext: CC BY License

This article has previously appeared as a manuscript in a thesis.

Available from: 2023-04-19 Created: 2023-04-19 Last updated: 2023-10-11Bibliographically approved
Tariq, M., Gustafson, A. & Schunnesson, H. (2023). Training of load haul dump (LHD) machine operators: a case study at LKAB’s Kiirunavaara mine. Mining Technology, 132(4), 237-252
Open this publication in new window or tab >>Training of load haul dump (LHD) machine operators: a case study at LKAB’s Kiirunavaara mine
2023 (English)In: Mining Technology, ISSN 2572-6668, Vol. 132, no 4, p. 237-252Article in journal (Refereed) Published
Abstract [en]

Mining is a high-risk industry, so efficiency and safety are key priorities. Technological advancements, such as digitisation, digitalisation, and automation have made mines safer. These developments have also highlighted the need for operators with updated skills and improved education programs. This study analysed the training of semi-autonomous and manual Load Haul Dump (LHD) operators’ at LKAB’s Kiirunavaara mine, focusing on operators’ training, perspective and integration of more recent tool such as simulator training. The survey questionnaire was sent to all 120 LHD operators. 86 answers were received, giving response rate of 70%. Results showed that operators generally were satisfied with how the training was structured, organised, and delivered. However, they wanted to add more topics, including practical loading, spending time with departments of other sub-processes, etc. In addition, 36% of the operators, including 20% of those operating semi-autonomous LHDs, and 80% of those operating manual LHDs, found simulator training difficult.

Place, publisher, year, edition, pages
Taylor & Francis, 2023
Keywords
LHD, Mining education, Operator training, Simulators, Training, Training method, Underground, Underground mining equipment
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-98585 (URN)10.1080/25726668.2023.2217669 (DOI)001000867300001 ()2-s2.0-85161500912 (Scopus ID)
Funder
EU, Horizon 2020, 101003591
Note

Validerad;2023;Nivå 2;2023-11-07 (sofila);

Funder: Luossavaara-Kiirunavaara AB, Sweden

Available from: 2023-06-19 Created: 2023-06-19 Last updated: 2023-11-07Bibliographically approved
Yi, C., Iravani, A., Gómez, S., Johansson, D., Schunnesson, H. & Wimmer, M. (2023). Voronoi-based numerical investigation of fragmentation and gravity flow of SLC. In: : . Paper presented at ISEE 49th Annual Conference on Explosives and Blasting Technique, Sant Antonio, Texas, USA, February 4-8, 2023.
Open this publication in new window or tab >>Voronoi-based numerical investigation of fragmentation and gravity flow of SLC
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2023 (English)Conference paper, Published paper (Refereed)
National Category
Geotechnical Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-101614 (URN)
Conference
ISEE 49th Annual Conference on Explosives and Blasting Technique, Sant Antonio, Texas, USA, February 4-8, 2023
Projects
illuMINEation
Funder
EU, Horizon 2020, 869379Luleå University of Technology
Note

Funder: Swedish Mining innovation (SMI); LKAB Stiftels, Centre of Advanced Mining & Metallurgy (CAMM3); Swedish blasting research centre (Swebrec)

Available from: 2023-10-10 Created: 2023-10-10 Last updated: 2024-02-05Bibliographically approved
Manzoor, S., Gustafson, A. & Schunnesson, H. (2022). Challenges with Density-Based Grade Estimation at LKAB’s Underground Iron Ore Mines. Mining, Metallurgy & Exploration, 39(6), 2301-2310
Open this publication in new window or tab >>Challenges with Density-Based Grade Estimation at LKAB’s Underground Iron Ore Mines
2022 (English)In: Mining, Metallurgy & Exploration, ISSN 2524-3462, Vol. 39, no 6, p. 2301-2310Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Springer Nature, 2022
Keywords
Sublevel caving, Grade control, Fragmentation, Bucket weight, Bucket volume
National Category
Geotechnical Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-93634 (URN)10.1007/s42461-022-00688-9 (DOI)000869336800001 ()2-s2.0-85140017142 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-12-06 (joosat);

Funder: Luossavaara-Kiirunavaara AB (LKAB)

Available from: 2022-10-18 Created: 2022-10-18 Last updated: 2023-04-20Bibliographically approved
Varannai, B., Johansson, D. & Schunnesson, H. (2022). Crusher to Mill Transportation Time Calculation—The Aitik Case. Minerals, 12(2), Article ID 147.
Open this publication in new window or tab >>Crusher to Mill Transportation Time Calculation—The Aitik Case
2022 (English)In: Minerals, E-ISSN 2075-163X, Vol. 12, no 2, article id 147Article in journal (Refereed) Published
Abstract [en]

Comminution is a major contributor to the production costs in a mining operation. There-fore, process optimization in comminution can significantly improve cost efficiency. The mine-to-mill concept can be utilized to optimize the comminution chain from blasting to grinding. In order to evaluate the mill performance of the ore from a specific location of the deposit, a direct link needs to be established between the mill performance and the place of origin in the mine. Today, technology enables the accurate positioning of drilling, loading, and dumping points in the mine, making the ore flow between loading and crushing more transparent. However, the material flow from the crusher to the mill is not yet fully understood and monitored. This paper presents the development of an ore transportation model, based on the virtual silo concept, between the crusher and the mill for Boliden’s Aitik mine in northern Sweden. The proposed model helps to establish a link between in situ ore location and mill performance. Two transportation time calculations are used, one based on mass balance, and one based on momentary values. Historical data are used to test the capabilities of the model and the results are compared with the transportation time calculated from the mean capacity values, commonly used in previous studies to connect mill parameters with in situ ore location. The comparison of the results show that the mean parameter-based values can be as much as 50% lower than the transportation times, even in normal operation. In the tested times, the transportation time based on momentary values systematically underestimated the cumulated times. The developed model will also serve as a starting point to analyze the effect of geotechnical parameters, in addition to drill and blast design, on the mill performance of the blasted ore.

Place, publisher, year, edition, pages
MDPI, 2022
Keywords
Aitik mine, Mine-to-mill, Ore transport, Virtual silo
National Category
Metallurgy and Metallic Materials Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-89305 (URN)10.3390/min12020147 (DOI)000764340400001 ()2-s2.0-85123384252 (Scopus ID)
Funder
VinnovaSwedish Energy AgencySwedish Research Council Formas
Note

Validerad;2022;Nivå 2;2022-02-16 (joosat)

Available from: 2022-02-16 Created: 2022-02-16 Last updated: 2024-01-17Bibliographically approved
Yi, C., Johansson, D., Petropoulos, N. & Schunnesson, H. (2022). Experimental and Numerical Investigation of the Effects of Jointing on Fragmentation. In: Proceedings of the 48th Annual Conference on Explosives and Blasting Technique: . Paper presented at 48th Annual Conference on Explosives and Blasting Technique, Las Vegas, USA, January 28 - February 2, 2022.
Open this publication in new window or tab >>Experimental and Numerical Investigation of the Effects of Jointing on Fragmentation
2022 (English)In: Proceedings of the 48th Annual Conference on Explosives and Blasting Technique, 2022Conference paper, Published paper (Refereed)
National Category
Geotechnical Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-101615 (URN)
Conference
48th Annual Conference on Explosives and Blasting Technique, Las Vegas, USA, January 28 - February 2, 2022
Projects
illuMINEation
Funder
EU, Horizon 2020, 869379Luleå University of TechnologyIngaBritt and Arne Lundberg’s Research Foundation
Note

Funder: Centre of Advanced Mining & Metallurgy (CAMM3); Swedish blasting research centre (Swebrec)

Available from: 2023-10-10 Created: 2023-10-10 Last updated: 2024-02-06Bibliographically approved
Manzoor, S., Danielsson, M., Söderström, E., Schunnesson, H., Gustafson, A., Fredriksson, H. & Johansson, D. (2022). Predicting rock fragmentation based on drill monitoring: A case study from Malmberget mine, Sweden. Journal of the Southern African Institute of Mining and Metallurgy, 122(3), 155-165
Open this publication in new window or tab >>Predicting rock fragmentation based on drill monitoring: A case study from Malmberget mine, Sweden
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2022 (English)In: Journal of the Southern African Institute of Mining and Metallurgy, ISSN 2225-6253, E-ISSN 2411-9717, Vol. 122, no 3, p. 155-165Article in journal (Refereed) Published
Abstract [en]

Fragmentation analysis is an essential part of the optimization process in any mining operation. The costs of loading, hauling, and crushing the rock are strongly influenced by the size distribution of the blasted rock. Several direct and indirect methods are used to analyse or predict fragmentation, but none is entirely applicable to fragmentation assessment in sublevel caving mines, mainly because of the limitations imposed by the underground environment and the lack of all the required data to adequately describe the rock mass. Over the past few years, measurement while drilling (MWD) data has emerged as a potential tool to provide more information about the in-situ rock mass. This research investigated if MWD can be used to predict rock fragmentation in sublevel caving. The MWD data obtained from a sublevel caving mine in northern Sweden were used to find the relationship between rock fragmentation and the nature of the rock mass. The loading operation of the mine was filmed for more than 12 months to capture images of loaded load-haul-dump (LHD) buckets. The blasted material in those buckets was classified into four categories based on the median particle size (X50). The results showed a strongercorrelation for fine and medium fragmented material with rock type (MWD data) than coarser material. The paper presents a model for prediction of fragmentation, which concludes that it is possible to use MWD data for fragmentation predict ion.

Place, publisher, year, edition, pages
The Southern African Institute of Minning and Metallurgy, 2022
Keywords
rock fragmentation, measurement while drilling, quick rating system, partial least squares regression, sublevel caving
National Category
Geotechnical Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-80805 (URN)10.17159/2411-9717/1587/2022 (DOI)000785742700007 ()2-s2.0-85131238807 (Scopus ID)
Funder
Swedish Energy AgencyEU, Horizon 2020, 869379
Note

Validerad;2022;Nivå 2;2022-04-07 (hanlid);

Funder: Centre for Advanced Mining and Metallurgy (CAMM2), Luleå University of Technology

Available from: 2020-09-16 Created: 2020-09-16 Last updated: 2024-02-16Bibliographically approved
Manzoor, S., Gustafson, A., Schunnesson, H., Tariq, M. & Wettainen, T. (2022). Rock fragmentation measurements in sublevel caving: Field tests at LKAB’s Malmberget mine. In: Y. Potvin (Ed.), Caving 2022: Fifth International Conference on Block and Sublevel Caving Volume One. Paper presented at Caving 2022 - Fifth International Conference on Block and Sublevel Caving, Adelaide, Australia, August 30 - September 1, 2022 (pp. 381-392). Australian Centre for Geomechanics
Open this publication in new window or tab >>Rock fragmentation measurements in sublevel caving: Field tests at LKAB’s Malmberget mine
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2022 (English)In: Caving 2022: Fifth International Conference on Block and Sublevel Caving Volume One / [ed] Y. Potvin, Australian Centre for Geomechanics , 2022, p. 381-392Conference paper, Published paper (Refereed)
Abstract [en]

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 ore body 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.

Place, publisher, year, edition, pages
Australian Centre for Geomechanics, 2022
Keywords
borehole diameter, rock fragmentation, sublevel caving, quick rating system
National Category
Geophysics
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-93146 (URN)10.36487/ACG_repo/2205_26 (DOI)
Conference
Caving 2022 - Fifth International Conference on Block and Sublevel Caving, Adelaide, Australia, August 30 - September 1, 2022
Projects
Face-to-Surface II
Funder
VinnovaSwedish Energy AgencySwedish Research Council Formas
Note

ISBN för värdpublikation: 978-0-6450938-3-4

Available from: 2022-09-19 Created: 2022-09-19 Last updated: 2024-02-22Bibliographically approved
Manzoor, S., Gustafson, A., Johansson, D. & Schunnesson, H. (2022). Rock fragmentation variations with increasing extraction ratio in sublevel caving: a case study. International Journal of Mining, Reclamation and Environment, 36(3), 159-173
Open this publication in new window or tab >>Rock fragmentation variations with increasing extraction ratio in sublevel caving: a case study
2022 (English)In: International Journal of Mining, Reclamation and Environment, ISSN 1748-0930, E-ISSN 1748-0949, Vol. 36, no 3, p. 159-173Article in journal (Refereed) Published
Abstract [en]

Variations in rock fragmentation are very likely to occur in a sublevel-caving operation. This study conducted a comprehensive test in an iron ore mine to monitor rock fragmentation. The results show a clear trend in fragmentation variations from start to end of production from a ring. These variations suggest an increase in coarse and oversized fragments with increasing material extraction from the rings that can be linked to increased overburden and drill hole deviations in the upper part of the rings. These problems can be addressed by shortening the drill hole length or directional drilling but need further investigations.

Place, publisher, year, edition, pages
Taylor & Francis, 2022
Keywords
extraction ratio, quick rating system, Rock fragmentation, sublevel caving
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-88934 (URN)10.1080/17480930.2021.2000826 (DOI)000736802800001 ()2-s2.0-85122511409 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-01-28 (johcin)

Available from: 2022-01-26 Created: 2022-01-26 Last updated: 2023-04-20Bibliographically approved
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