| 1. |
- Gustafson, Anna, et al.
(author)
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Operator influence on the loading process at LKAB's Iron ore mines
- 2020
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In: Journal of the Southern African Institute of Mining and Metallurgy. - : The Southern African Institute of Mining and Metallurgy. - 2225-6253 .- 2411-9717. ; 120:3, s. 191-202
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Journal article (peer-reviewed)abstract
- The loading process in sublevel caving mines entails loading material from the drawpoint using load haul dump machines that transport the material to orepasses or trucks, depending on the mine conditions. When each bucket is drawn from the drawpoint, a decision must be made as to whether loading should continue or be stopped and the next ring blasted. The decision to abandon the drawpoint is irrevocable, as it is followed by the blasting of the next ring. Abandonment of the drawpoint too early leads to ore losses and inefficient use of ore resources. Loading beyond the optimal point increases dilution as well as mining costs.The experience of the LHD operators is an important basis for manual drawpoint control. However, it has been difficult to establish which specific factors manual drawpoint control is based on. To try to shed more light on these factors we analysed the operators' experiences at LKAB's Kiirunavaara and Malmberget iron ore mines. The operators in the two mines completed a questionnaire on the current loading practices and the process of deciding to abandon 'normal' rings, opening rings, and rings with loading issues.It was found that in both case study mines, most decisions on the abandonment of drawpoints are made by the operators. The more experienced operators tend to make more decisions themselves rather than rely on support from the existing support functions.
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| 2. |
- Manzoor, Sohail, et al.
(author)
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Predicting rock fragmentation based on drill monitoring: A case study from Malmberget mine, Sweden
- 2022
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In: Journal of the Southern African Institute of Mining and Metallurgy. - : The Southern African Institute of Minning and Metallurgy. - 2225-6253 .- 2411-9717. ; 122:3, s. 155-165
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Journal article (peer-reviewed)abstract
- 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.
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| 3. |
- Mwandawande, I, et al.
(author)
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Investigation of the mixing characteristics of industrial flotation columns using computational fluid dynamics
- 2022
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In: Journal of the Southern African Institute of Mining and Metallurgy. - : Academy of Science of South Africa. - 2225-6253 .- 2411-9717. ; 122:5, s. 245-257
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Journal article (peer-reviewed)abstract
- The mixing characteristics of industrial flotation columns were investigated using computational fluid dynamics (CFD). Particular emphasis was placed on the clarification of the relationship between the liquid and solids mixing parameters such as the mean residence time and axial dispersion coefficients. The effects of particle size and bubble size on liquid dispersion in the column were also studied. An Eulerian-Eulerian method was applied to simulate the multiphase flow, while additional scalar transport equations were introduced to predict the liquid residence time distribution (RTD) and particle age distribution inside the column. The results obtained show that particle residence time decreases with increasing particle size. The residence time of the coarser particles (112.5 ??m) was found to be at least 60% of the liquid residence time, while the finer particles (19 ??m) had a residence time similar to the liquid. The results also show that an increase in the particle size of the solids results in a decrease in the liquid vessel dispersion number, while a decrease in the bubble size increases liquid axial mixing. Finally, the simulated axial velocity profiles confirm the similarity between the liquid and solids axial dispersion coefficients in column flotation.
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| 4. |
- Skawina, Bartlomiej, 1985-, et al.
(author)
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Automatic closed-loop scheduling in underground mining using discrete event simulation
- 2021
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In: Journal of the Southern African Institute of Mining and Metallurgy. - : South African Institute of Mining and Metallurgy. - 2225-6253 .- 2411-9717. ; 121:6, s. 277-282
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Journal article (peer-reviewed)abstract
- Today's mining operations require fast reporting and rapid rescheduling based on updated information. An automatic mine scheduling system could not only quickly reschedule but also propose alternative solutions. To avoid the financial and physical risks associated with testing such a system directly in operation, it could be first evaluated via discrete event simulation models. This would offer a safe environment to evaluate different operating rules and algorithms. In this study, this is achieved by integrating automatic scheduling software with a discrete event simulation model.
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