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Schunnesson, Håkan
Publications (10 of 78) Show all publications
Shekhar, G., Gustafson, A., Hersinger, A., Jonsson, K. & Schunnesson, H. (2019). Development of a model for economic control of loading in sublevel caving mines. Mining Technology
Open this publication in new window or tab >>Development of a model for economic control of loading in sublevel caving mines
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2019 (English)In: Mining Technology, ISSN 1474-9009, E-ISSN 1743-2863Article in journal (Refereed) Epub ahead of print
Abstract [en]

This paper presents an economic model for optimizing loading at the draw point in sublevel caving (SLC) operations. The input data consist of estimated bucket grades based on bucket weights from Load Haul Dump machines. This information, together with average operational mining costs, was used to create an economic model providing a real-time economic assessment of the draw point performance for SLC rings. The results demonstrate the importance of continuous draw point monitoring to optimize SLC operations. The proposed model provides an economic assessment of operating draw points and will help mine personnel to decide when to stop loading from a blasted ring. It can also help mine management understand the complexity of material flow in SLC operations. Finally, it provides operational flexibility for the mine to optimize loading at the draw point by increasing ore recovery while maintaining operational control of draw point performance.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
Draw control, mine economics, sublevel caving (SLC), draw point performance, Load Haul Dump (LHD)
National Category
Engineering and Technology Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-73175 (URN)10.1080/25726668.2019.1586371 (DOI)
Funder
Vinnova, 1832144
Available from: 2019-03-12 Created: 2019-03-12 Last updated: 2019-04-12
Ittner, H., Olsson, M., Johansson, D. & Schunnesson, H. (2019). Multivariate evaluation of blast damage from emulsion explosives in tunnels excavated in crystalline rock. Tunnelling and Underground Space Technology, 85, 331-339
Open this publication in new window or tab >>Multivariate evaluation of blast damage from emulsion explosives in tunnels excavated in crystalline rock
2019 (English)In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 85, p. 331-339Article in journal (Refereed) Published
Abstract [en]

Blast damage in tunnels is usually regulated in Swedish infrastructure contracts as it can influence the quality and lifecycle cost for tunneling projects. The topic is important for underground constructions with a long operation period such as tunnels for public transport, permanent access tunnels in mines or underground repositories for nuclear waste. This paper aims to evaluate the influence of design and geology variables on the resulting blast fracture length and frequency by means of multivariate data analysis. The analysis was based on data from five field investigations carried out at tunnel sites in Sweden and Finland where emulsion explosives were used. Data was compiled and analyzed using Principal Component Analysis (PCA). Charge concentration was found to be the most influential design variable and hole spacing had limited influence on blast fracturing. Results from the PCA suggest that blast fractures length could be dependent also on geology and natural fractures. Three main groups of fracture patterns were identified, one group with relatively few and short blast fractures, a group with several longer blast fractures and a group with few or a single long blast fracture. The result shows differences in fracture length between the column and bottom charge part of the contour holes, with blast fracture lengths up to approx. 40 cm for the column charge and up to approx. 60 cm for the bottom charge.

Keywords
Blasting, Blast damage, Emulsion explosives, Mechanized charging, Principal Component Analysis
National Category
Geotechnical Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-67454 (URN)10.1016/j.tust.2018.12.021 (DOI)000457512000031 ()2-s2.0-85059473074 (Scopus ID)
Funder
Rock Engineering Research Foundation (BeFo)
Note

Validerad;2019;Nivå 2;2019-01-10 (svasva)

Available from: 2018-02-01 Created: 2018-02-01 Last updated: 2019-02-21Bibliographically approved
Ghosh, R., Gustafson, A. & Schunnesson, H. (2018). Development of a geological model for chargeability assessment of borehole using drill monitoring technique. International Journal of Rock Mechanics And Mining Sciences, 109, 9-18
Open this publication in new window or tab >>Development of a geological model for chargeability assessment of borehole using drill monitoring technique
2018 (English)In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 109, p. 9-18Article in journal (Refereed) Published
Abstract [en]

In the mining industry, the ability to charge and blast a production borehole is fundamental. However, if rock mass conditions are challenging, with cavities, fracture zones or even unstable boreholes, the charging crew may fail to insert the required amount of explosives, resulting in bad fragmentation and significant production disturbances in the downstream process. Prior detailed knowledge of the chargeability of each production fan or ring will improve both the planning and execution of the charging work in a mine. The paper describes a study using the drill monitoring technique to assess the chargeability of production boreholes. For the study, data were collected on four drill parameters, penetration rate, rotation pressure, feed pressure and percussive pressure, from 23 drill fans with a total of 186 boreholes. A parameter called fracturing was calculated based on penetration rate variability and rotation pressure variability. Sixty-three boreholes were filmed to establish different rock mass conditions: solid rock, cavities, fractured zones and cave-ins. Principal Component Analysis (PCA) was performed to model the relationship between drill monitoring data and the geological features. The developed model shows high potential by identifying charging problems directly from drill monitoring data, and has been verified and validated in a real charging operation in an operating mine.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-70266 (URN)10.1016/j.ijrmms.2018.06.015 (DOI)000440458000002 ()2-s2.0-85049528017 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-08-08 (andbra)

Available from: 2018-08-08 Created: 2018-08-08 Last updated: 2018-08-21Bibliographically approved
Shekhar, G., Gustafson, A., Boeg-Jensen, P., Malmgren, L. & Schunnesson, H. (2018). Draw control strategies in sublevel caving mines: A baseline mapping of LKAB's Malmberget and Kiirunavaara mines. The Southern African Journal of Mining and Metallurgy, 118(7), 723-733
Open this publication in new window or tab >>Draw control strategies in sublevel caving mines: A baseline mapping of LKAB's Malmberget and Kiirunavaara mines
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2018 (English)In: The Southern African Journal of Mining and Metallurgy, ISSN 2225-6253, E-ISSN 1543-9518, Vol. 118, no 7, p. 723-733Article in journal (Refereed) Published
Abstract [en]

The Malmberget and Kiirunavaara mines are the two largest underground iron ore operations in the world. Luossavaara-Kiirunavaara AB (LKAB) uses sublevel caving (SLC) to operate the mines while maintaining a high level of productivity and safety. The paper enumerates the loading criteria and loading constraints at the mines and outlines details of mine design, layout, and geology affecting the draw control. A study of the various draw control strategies used in sublevel caving operations globally has also been done to establish the present state-of-the-art. An analysis of the draw control and loading operations at the Malmberget and Kiirunavaara mines is summarized using information collected through interviews, internal documents, meetings, and manuals. An optimized draw control strategy is vital for improving ore recovery and reducing dilution in SLC. Based on the literature review and baseline mapping study, a set of guidelines for designing a new draw control strategy is presented. The draw control strategy at Malmberget and Kiirunavaara is guided by a bucket-weightbased drawpoint monitoring system that is part of the overall framework. Both mines employ a draw control strategy that considers the production requirements and mining constraints while regulating the loading process through an empirical method based on bucket weights and grades. However, in the present scenario of fluctuating metal prices and increasing operational costs a new draw control strategy is needed which is probabilistic in nature and can handle the uncertainties associated with caving operations.

Place, publisher, year, edition, pages
The Southern African Institute of Mining and Metallurgy, 2018
Keywords
Sublevel caving, draw control, optimization, draw point monitoring
National Category
Engineering and Technology Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-71770 (URN)10.17159/2411-9717/2018/v118n7a6 (DOI)000442393900006 ()2-s2.0-85053623244 (Scopus ID)
Projects
SIP-STRIM
Funder
VINNOVA, 1832144
Note

Validerad;2018;Nivå 2;2018-12-07 (johcin)

Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2018-12-07Bibliographically approved
Danielsson, M., Johansson, D. & Schunnesson, H. (2018). The Influence of Blast Fragmentation on Loadability in Sublevel Caving. In: Kevin Hachmeister (Ed.), Proceedings of the forty-forurth annual conference on explosives and blasting technique: . Paper presented at 44th Annual Conference on Explosives and Blasting Technique, San Antonio, Texas, Jan. 28–31 2018.
Open this publication in new window or tab >>The Influence of Blast Fragmentation on Loadability in Sublevel Caving
2018 (English)In: Proceedings of the forty-forurth annual conference on explosives and blasting technique / [ed] Kevin Hachmeister, 2018Conference paper, Published paper (Refereed)
Abstract [en]

In sublevel caving, blasted material flows gravitationally into the drawpoint from above in a periodical manner. This type of flow behavior entails muck pile conditions that are variable along the course of extraction. The effect of this variability on the LHD (Load-Haul-Dump) operation in terms of loading efficiency and ability to undermine the blasted ring is not fully understood as of today. This paper presents results from a field test in LKABs Malmberget mine in Sweden, where the influence of fragmentation on the loading operation has been studied in detail. Drawpoint filming was conducted for extraction of two rings equivalent of roughly 10000 metric tons (~9842 long tons) of material each. The analysis includes fragmentation measurements, muck pile classification, and general estimations in terms of loadability. Further, an evaluation of LHD machines from two different manufacturers was conducted to identify and highlight differences. The results show that fragmentation, muck pile compactness, and flow characteristics are all interdependent. Flow disturbances and the subsequent loading of compacted fine material in the back of the ring have been identified as the main reason for occurring problems and prolonged digging times. However, the ability to sufficiently undermine the blasted ring has been identified to primarily depend on digging depth which is only observed to be high during flow disturbances. An absence of flow disturbances seem to promote high loading efficiency but simultaneously limit the maximum digging depth. A mid-range particle size distribution with a low amount of fines has proven beneficial for overall loading efficiency. The various LHDs employed showed significant variations in terms of ability to handle difficult loading situations (e.g. compactness, boulders, etc.).

National Category
Other Engineering and Technologies not elsewhere specified Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-70536 (URN)
Conference
44th Annual Conference on Explosives and Blasting Technique, San Antonio, Texas, Jan. 28–31 2018
Available from: 2018-08-22 Created: 2018-08-22 Last updated: 2018-08-28
Ghosh, R., Danielsson, M., Gustafson, A., Falksund, H. & Schunnesson, H. (2017). Assessment of rock mass quality using drill monitoring technique of Hydraulic ITH drills (ed.). International Journal of Mining and Mineral Engineering, 8(3), 169-186
Open this publication in new window or tab >>Assessment of rock mass quality using drill monitoring technique of Hydraulic ITH drills
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2017 (English)In: International Journal of Mining and Mineral Engineering, ISSN 1754-890X, Vol. 8, no 3, p. 169-186Article in journal (Refereed) Published
Abstract [en]

A rock drilling system always responds to variations in the mechanical properties of the penetrated rock mass. Combining the drill response with a detailed understanding of the drill system has the potential to give a detailed and high-resolution characterisation of the penetrated rock mass along the borehole. This paper analyses 186 boreholes, drilled using a water powered in-the-hole (ITH) drilling technique considering drill parameters; penetration rate, rotation pressure, feed pressure and percussive pressure. In addition, it suggests, calculates and uses a parameter reflecting rock fracturing. Sixty-three of the holes were filmed with a borehole camera to reveal the geo-mechanical features. The results show that the responses from the drill monitoring system can distinguish between solid rock, fracture zones, cavities and damaged rock. The ability to extract this information directly from the drilling operation provides unique prior information and can be useful to adjust production planning before charging and blasting boreholes.

Place, publisher, year, edition, pages
InderScience Publishers, 2017
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-14546 (URN)10.1504/IJMME.2017.10006862 (DOI)2-s2.0-85027419669 (Scopus ID)deb3ea8d-3a3b-4f92-a89c-67863f4661bf (Local ID)deb3ea8d-3a3b-4f92-a89c-67863f4661bf (Archive number)deb3ea8d-3a3b-4f92-a89c-67863f4661bf (OAI)
Note

Validerad;2017;Nivå 1;2017-08-16 (rokbeg)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-11-20Bibliographically approved
Gustafson, A., Paraszczak, J., Tuleau, J. & Schunnesson, H. (2017). Impact of technical and operational factors on effectiveness of automatic load-haul-dump machines. Mining Technology, 126(4), 185-190
Open this publication in new window or tab >>Impact of technical and operational factors on effectiveness of automatic load-haul-dump machines
2017 (English)In: Mining Technology, ISSN 1474-9009, E-ISSN 1743-2863, Vol. 126, no 4, p. 185-190Article in journal (Refereed) Published
Abstract [en]

The use of automatic load-haul-dump (LHD) machines in underground metal mines is a promising way to overcome some of the challenges now facing mining companies. They offer several potential benefits over man-operated units, mostly in terms of safety and health of the workers, but also in terms of higher availability, increased productivity, and reduced mining cost. That said, using such systems at their full capacity is a challenging and complex task. In this context, after describing some commercially available equipment and systems, the paper examines factors affecting reliability, availability and productivity of automatic LHDs and notes several technical and operational concerns.

Place, publisher, year, edition, pages
Taylor & Francis, 2017
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-62122 (URN)10.1080/14749009.2017.1285980 (DOI)2-s2.0-85038357365 (Scopus ID)
Note

Validerad;2018;Nivå 1;2017-12-21 (andbra)

Available from: 2017-02-22 Created: 2017-02-22 Last updated: 2018-04-16Bibliographically approved
Shekhar, G., Gustafson, A. & Schunnesson, H. (2017). Loading Procedure and Draw Control in LKAB’s Sublevel Caving Mines: Baseline Mapping Report. Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Loading Procedure and Draw Control in LKAB’s Sublevel Caving Mines: Baseline Mapping Report
2017 (English)Report (Other academic)
Abstract [en]

Sublevel caving (SLC) is an underground mass mining method used to extract iron ore from the Kiirunavaara and Malmberget mines. Although both mines use SLC as the mining method, their implementation varies in terms of mine design, ring design and draw control strategy. The Kiirunavaara mine has a continuous and massive ore deposit which allows a standard mine design layout, while the Malmberget mine has scattered ore bodies with varying mine design parameters. The two mines also employ different opening techniques for production drifts.

Luossavaara-Kiirunavaara AB (LKAB) uses different information systems to run these highly mechanized mines. The information generated by the various systems is transferred between the different unit operations and is used to optimize the mining process. The mines use GIRON to create, store and display different information related to the mining operation. Information on all unit operations is stored in a number of databases inside GIRON. The two loading related information systems which support the loading operation are the Wireless Loader Information System (WOLIS) and the Loadrite system. The Loadrite system measures the bucket weights being loaded by the Load Haul Dump (LHD) machines at the draw point. This information, along with information on planned ring tonnage etc., is displayed to the LHD operator inside the LHD machine using WOLIS. WOLIS provides online data on the ring performance such as grades, tonnage extracted etc. to the LHD operators and the production team.

In SLC, the different aspects of loading at the draw point include loading procedures, loading issues, loading criteria and loading constraints. Loading procedures include the practices and precautions taken during loading at the draw point. Loading issues include events observed at both mines, such as brow failure, ring freeze, hang-ups etc. Although most loading issues are handled in a similar manner, hang-up handling techniques are different at the Kiirunavaara and Malmberget mines. Loading criteria and constraints along with the nature of material flow collectively provide a complete understanding of the draw control strategy. Loading criteria comprise a set of rules or guidelines for loading and closing a draw point. LKAB uses WOLIS to enforce the loading criteria for its SLC operations. Loading constraints include production constraints, grade control and mining constraints which must be followed for a safe and sustainable mining operation.

A baseline analysis of the draw control and loading operations at the Kiirunavaara and Malmberget mines is summarized in this report using information collected through internal documents, meetings, e-mails and manuals.  

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2017. p. 60
Series
Research report / Luleå University of Technology, ISSN 1402-1528
Keywords
Draw control, Kiirunavaara, Kiruna, Malmberget, Sublevel caving, SLC, LHD, Loading, Drawpoint, loading constraints, Drill design, mining, underground mining, Information systems in Mining
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-61938 (URN)978-91-7583-807-6 (ISBN)978-91-7583-943-1 (ISBN)
Projects
Improved Resource Efficiency through Dynamic Loading Control
Funder
VINNOVA, 1832144
Available from: 2017-02-10 Created: 2017-02-10 Last updated: 2018-04-16Bibliographically approved
Ghosh, R., Schunnesson, H. & Gustafson, A. (2017). Monitoring of Drill System Behavior for Water-Powered in-the-hole (ITH) drilling. Minerals, 7(7), Article ID 121.
Open this publication in new window or tab >>Monitoring of Drill System Behavior for Water-Powered in-the-hole (ITH) drilling
2017 (English)In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 7, no 7, article id 121Article in journal (Refereed) Published
Abstract [en]

A detailed understanding of the drilling system and the drilling control is required to correctly interpret rock mass conditions based on monitored drilling data. This paper analyses data from hydraulic in-the-hole (ITH) drills used in LKAB’s Malmberget mine in Sweden. Drill parameters, including penetration rate, percussive pressure, feed pressure, and rotation pressure, are monitored in underground production holes. Calculated parameters, penetration rate variability, rotation pressure variability, and fracturing are included in the analysis to improve the opportunity to predict rock mass conditions. Principal component analysis (PCA) is used to address non-linearity and variable interactions. The results show that the data contain pronounced hole length-dependent trends, both linear and step-wise linear, for most parameters. It is also suggested that monitoring can be an efficient way to optimize target values for drill parameters, as demonstrated for feed force. Finally, principal component analysis can be used to transfer a number of drill parameters into single components with a more straightforward geomechanical meaning

Place, publisher, year, edition, pages
Basel: MDPI, 2017
National Category
Mineral and Mine Engineering Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-63802 (URN)10.3390/min7070121 (DOI)000407363800015 ()2-s2.0-85026226267 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-08-15 (andbra)

Available from: 2017-06-08 Created: 2017-06-08 Last updated: 2018-11-26Bibliographically approved
Ghodrati, B., Kumar, U. & Schunnesson, H. (Eds.). (2017). Proceeding of the 26th International Symposium on Mine Planning and Equipment Selection: MPES 2017. Paper presented at 26th International Symposium on Mine Planning and Equipment Selection, Luleå, Sweden,August 29-31, 2017. Luleå University of Technology
Open this publication in new window or tab >>Proceeding of the 26th International Symposium on Mine Planning and Equipment Selection: MPES 2017
2017 (English)Conference proceedings (editor) (Refereed)
Place, publisher, year, edition, pages
Luleå University of Technology, 2017. p. 570
Series
MPES 2017
Keywords
Mining, Reliability, Maintenance, Machinery, Environment
National Category
Engineering and Technology Environmental Engineering Mineral and Mine Engineering Reliability and Maintenance
Research subject
Mining and Rock Engineering; Operation and Maintenance; Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-65007 (URN)978-91-7583-935-6 (ISBN)978-91-7583-936-3 (ISBN)
Conference
26th International Symposium on Mine Planning and Equipment Selection, Luleå, Sweden,August 29-31, 2017
Available from: 2017-08-11 Created: 2017-08-11 Last updated: 2018-05-31Bibliographically approved
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