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  • 1.
    Chelgani, Saeed Chehreh
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Exploring relationships of gross calorific value and valuable elements with conventional coal properties for North Korean coals2019Inngår i: International Journal of Mining Science and Technology, ISSN 2095-2686, Vol. 29, nr 6, s. 867-871Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Coal in North Korean (NKC) is one of the most important products; however, based on various strategic policies its detail properties remain opaque even for general researchers. Since there are some signs for opening of the North Korea economy, this investigation as a modest effort is going to explore principle relationships among some essential parameters of NKCs such as gross calorific value (GCV), valuable elements and conventional properties by different statistical methods. Correlations indicated that ultimate parameters (carbon, nitrogen, and hydrogen) are the best GCV predictors for NKCs in comparison with proximate parameters (ash, moisture and volatile matter). Multivariable regression demonstrated that predicted GCV based on ultimate properties has a quite accuracy when correlation of determination was 0.99. Descriptive statistics processes showed that on average, the contents of valuable elements such as Ga and V for NKCs are higher than the world coal ranges and they can be considered as byproducts of combustion of NKCs. Pearson correlations indicated that Y may have a mixed organic-inorganic affinity while Ga and V mainly occur in the inorganic part (mineral matter) of NKCs. High inter-correlations between Ga-V and Al showed that aluminosilicates can be considered as their main bring minerals.

  • 2.
    Chelgani, Saeed Chehreh
    et al.
    University of Michigan, Ann Arbor, USA.
    Hart, B.
    University of Western Ontario, Ontario N6G0J3, Canada.
    Explaining surface interactions for common associated gangues of rare earth minerals in response to the oxalic acid2018Inngår i: International Journal of Mining Science and Technology, ISSN 2095-2686, Vol. 28, nr 2, s. 343-346Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the flotation of rare earth minerals (REMs), oxalic acid is reportedly acting both as a depressant and pH modifier. Although results of testing have established the significance of oxalic acid in the flotation process, its specific role in either the recovery or selectivity of REMs over their common gangue minerals is not well understood. Pulp pH reduction trials with alternative acids have not shown the same effect on the REMs recovery or the depression of gangue phases. This work studies the effect of oxalic acid on the surface of common REMs gangue minerals (quartz and carbonates (dolomite and calcite)) in a series of conditioning tests. Gangue surface analyses by time of flight secondary ion mass spectroscopy (TOF-SIMS) indicate that oxalic acid inhibits the transfer of secondary ions generated during the conditioning process from one mineral to another. In this regard, the oxalate anion acts to fix ions in solution through chelation, limiting their participation in surface adsorption.

  • 3.
    Chelgani, Saeed Chehreh
    et al.
    Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Germany.
    Rudolph, M.
    Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Germany.
    Leistner, T.
    Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Germany.
    Gutzmer, J.
    Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Germany.
    Peuker, U. A.
    Institute of Mechanical Process Engineering and Minerals Processing, TU Bergakademie Freiberg, Germany.
    A review of rare earth minerals flotation: Monazite and xenotime2015Inngår i: International Journal of Mining Science and Technology, ISSN 2095-2686, Vol. 25, nr 6, s. 877-883Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper reviews rare earth minerals (monazite and xenotime) separation by flotation. A wide range of monazite and xenotime flotation test results are summarized including: reasons of variation in the point of zero charges on these minerals, the effects of various flotation conditions on zeta potential of monazite and xenotime, interactions of collectors and depressants on the surface of these minerals during flotation separation, relationship between surface chemistry of the minerals and different types of collector adsorptions and effects of the conditioning temperature on flotation of rare earth minerals. This review collects various approaches for the selective separation of monazite and xenotime by flotation and gives perspectives for further research in the future.

  • 4.
    Lanke, Amol
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Hoseinie, Hadi
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ghodrati, Behzad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Mine production index (MPI)-extension of OEE for bottleneck detection in mining2016Inngår i: International Journal of Mining Science and Technology, ISSN 2095-2686, Vol. 26, nr 5, s. 753-760Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Although mining production depends on various equipments, significant amount of production loss can be attributed a specific equipment or fleet. Bottleneck is defined not only by production loss but also by our satisfaction from the equipment. The user satisfaction could be measured as machine effectiveness. Mining literature on performance improvement and optimization of equipment operations assert importance of availability, utilization and production performance as key parameters. These three parameters are useful for evaluating effectiveness of equipment. Mine production index (MPI), which can represent the effect of these factors, has been applied for continuous operation in mining. MPI uses Fuzzy Delphi Analytical Hierarchy Process to determine importance of each three parameter for individual equipment. A case study in a Swedish open pit mine was done to evaluate the field application of MPI. The results reveal that crusher is the bottleneck equipment in studied mine. As a methodical approach, an algorithm which uses MPI and detects bottleneck in continuous mining operation has been proposed.

  • 5.
    Rahimdel, Mohammad Javad
    et al.
    Faculty of Mining Engineering, Sahand University of Technology, Tabriz.
    Ataei, Mohammad
    Faculty of Mining Engineering, Geophysics and Petroleum, Shahrood University of Technology.
    Khalokakae, Reza
    Faculty of Mining Engineering, Geophysics and Petroleum, Shahrood University of Technology.
    Hoseinie, Hadi
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Reliability-based maintenance scheduling of hydraulic system of rotary drilling machines2013Inngår i: International Journal of Mining Science and Technology, ISSN 2095-2686, Vol. 23, nr 5, s. 771-775Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydraulic system has a critical and important role in drilling machines. Any failure in this system leads to problems in power system and machine operation. Since the failure cannot be prevented entirely, it is important to minimize its probability. Reliability is one of the most efficient and important method to study safe operation probability of hydraulic systems. In this research, the reliability of hydraulic system of four rotary drilling machines in Sarcheshmeh Copper Mine in Iran has been analyzed. The data analysis shows that the time between failures (TBF) of Machines A and C obey the Weibull (2P) and Weibull (3P) distribution, respectively. Also, the TBF of Machines B and D obey the lognormal distribution. With regard to reliability plots of hydraulic systems, preventive reliability-based maintenance time intervals for 80% reliability levels for machines in this system are 10 h.

  • 6.
    Rai, Piyush
    et al.
    Department of Mining Engineering, Indian Institute of Technology (BHU), Varanasi, Banaras Hindu University, Varanasi.
    Schunnesson, Håkan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Lindqvist, Per-Arne
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Measurement-while-drilling technique and its scope in design and prediction of rock blasting2016Inngår i: International Journal of Mining Science and Technology, ISSN 2095-2686, Vol. 26, nr 4, s. 711-719Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With rampant growth and improvements in drilling technology, drilling of blast holes should no longer be viewed as an arduous sub-process in any mining or excavation process. Instead, it must be viewed as an important opportunity to quickly and accurately measure the geo-mechanical features of the rock mass on-site, much in advance of the downstream operations. It is well established that even the slightest variation in lithology, ground conditions, blast designs vis-à-vis geologic features and explosives performance, results in drastic changes in fragmentation results. Keeping in mind the importance of state-of-the-art measurement-while-drilling (MWD) technique, the current paper focuses on integrating this technique with the blasting operation in order to enhance the blasting designs and results. The paper presents a preliminary understanding of various blasting models, blastability and other related concepts, to review the state-of-the-art advancements and researches done in this area. In light of this, the paper highlights the future needs and implications on drill monitoring systems for improved information to enhance the blasting results.

  • 7.
    Salama, Abubakary
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Nehring, Micah
    School of Mechanical and Mining Engineering, The University of Queensland.
    Greberg, Jenny
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Analysis of the impact of increasing mining rate in underground mining using simulation and mixed integer programming2016Inngår i: International Journal of Mining Science and Technology, ISSN 2095-2686Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper challenges the traditional notion that mine planners need to plan production at mining rates that result in a low mining cost. For a given mine configuration, a mine that considers increases to its mining rate most often increases mining costs. In an environment in which operations are fixated on cost reduction, a proposal to increase costs may be very difficult to implement. Such a proposal may need to be justified financially because the increase in costs might not be recuperated by the extra production gained. This paper evaluates the net present value (NPV) of the selected range of copper prices for two underground orebodies located at different depths using a production rate of 300,000 tonnes and one that introduces additional costs at 450,000 tonnes per quarter. Discrete event simulation combined with mixed integer programming was used for the analysis. The results shows that, for the low mining rate at the final copper price, an NPV of $755.65M is achieved, whereas an NPV of $773.45M is achieved at a high mining rate. Therefore, even though pushing mining rates beyond traditional limits increases mining costs, pursuing this option at certain commodity prices may be beneficial, particularly when prices are elevated.

  • 8.
    Salama, Abubakary
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Nehring, Micah
    School of Mechanical and Mining Engineering, The University of Queensland.
    Greberg, Jenny
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Evaluation of the impact of commodity price change on the mine plan of deep underground mining2015Inngår i: International Journal of Mining Science and Technology, ISSN 2095-2686, Vol. 25, nr 3, s. 375-382Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The fluctuations in commodity prices influences mining operations to continually update and adjust their mine plans in order to capture additional value under the new market condition. Some of the adjustments could include changes to the production sequencing, changes to the point at which the open pit transitions to the underground, and the time for changing or modifying the existing ore handling systems as a result of an increase in mine depth. This paper seeks to present a method for quantifying the net present value component of optimal mine plans that may be directly attributed to the change in commodity prices, and more importantly the changes in the mine plan itself. The evaluation is conducted on a deep underground copper deposit amenable to sublevel stoping whereby optimal mine plans were generated across a total of ten copper price scenarios ranging between $5250/t Cu and $9750/t Cu. Discrete event simulation in conjunction with mixed integer programming was used to attain a viable production strategy and then to generate optimal mine plans. The analysis indicates that the increase in prices results in an increase in net present value from $96.57M to ultimately reach $755.65M. In an environment where mining operations must be looking to gain as much value as possible from the rights to exploiting a finite resource, it is simply not appropriate to keep operating under the same mine plan if commodity prices have altered during the course of operation.

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