Change search
Refine search result
1 - 10 of 10
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Dandotiya, Rajiv
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lundberg, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Wijaya, Andi
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Evaluation of abrasive wear measurement devices of mill liners2011In: International Journal of COMADEM, ISSN 1363-7681, Vol. 14, no 2, p. 3-17Article in journal (Refereed)
    Abstract [en]

    Measurement of the liner wear in the mill of an ore dressing plant is one of the critical parameters in the context of mill downtime and production performance. The total downtime cost during measurement can be reduced by a significant fraction by using appropriate measurement devices. Due to the different quality attributes of a measuring device, e.g. the cost, accuracy, reliability and accessibility, it is necessary to select an appropriate device based on the specific needs of the industry. The main aim of this study is to determine a unified measure or quality index for the service quality of the measurement device across selected attributes. Each quality index will then correspond to the total predicted usability of the particular measurement method based on the industry needs. Furthermore, this study includes test of selected measurement methods and discusses the advantages and disadvantages for the same. It also proposes a new concept of an indirect measurement method to reduce the downtime during inspection.

  • 2.
    Hamodi, Hussan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lundberg, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Wijaya, Andi
    Ghodrati, Behzad
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Downtime analysis of drilling machines and suggestions for improvements2014In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 20, no 4, p. 306-332Article in journal (Refereed)
    Abstract [en]

    Purpose– The purpose of this paper is to analyse and compare the downtime of four drilling machines used in two underground mines in Sweden. The downtime of these machines was compared to show what problems affect downtime and which strategies should be applied to reduce it.Design/methodology/approach– The study collects failure data from a two-year period for four drilling machines and performs reliability analysis. It also performs downtime analysis utilising a log-log diagram with a confidence interval.Findings– There are notable differences in the downtime of most of the studied components for all machines. The hoses and feeder have relatively high downtime. Depending on their downtime, the significant components can be ranked in three groups. The downtime of the studied components is due to reliability problems. The study suggests the need to improve the reliability of critical components to reduce the downtime of drilling machines.Originality/value– The method of analysing the downtime, identifying dominant factors and the interval estimation for the downtime, has never been studied on drilling machines. The research proposed in this paper provides a general method to link downtime analysis with potential component improvement. To increase the statistical accuracy; four case studies was performed in two different mines with completely different working environment and ore properties. Using the above method showed which components need to be improved and suggestions for improvement was proposed and will be implemented accordingly.

  • 3. Kumar, Rupesh
    et al.
    Wijaya, Andi
    Barabady, Javad
    Tromsø University.
    Markeset, Tore
    University of Stavanger.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ergonomic and maintainability design issues in mining2009Conference paper (Refereed)
    Abstract [en]

    Due to confined space and poor illumination in the mine the maintenance activities are difficult to perform which in turn leads to increased down time, cost and injuries. This also influences the productivity of maintenance personnel owing to stresses generated due to increased psychological and physiological demand on them. However, the industry has paid much less attention to the design of the mining machine in initial phase itself with respect to maintainability parameters leading to low productivity, increased maintenance time and increased likelihood of accidents during maintenance and operation of such equipment. The objective of the paper is to present ergonomics factors such as; anthropometery, human sensory, physiological and psychological application in relation to maintainability design issues in mining in order to reduce occupational risk factors and improved maintainability of the mining equipments leading to increased productivity.

  • 4.
    Rantatalo, Matti
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Wijaya, Andj
    Lundberg, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Thurley, Matthew
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Fredriksson, Håkan
    Project: HLRC Pre-study: Owner-specific methods for production-increasing improvements of mining machinery2012Other (Other (popular science, discussion, etc.))
  • 5. Wijaya, Andi
    et al.
    Kumar, Rupesh
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Implementing lean principle into mining industry issues and challenges2009Conference paper (Refereed)
    Abstract [en]

    The lean production concept has its origin in automotive industry and is widely used in manufacturing sectors. What makes its applicability in mining difficult is the dynamic nature of mining operations bringing high degree of uncertainty in various unit operations. To reduce the wastage of efforts, one needs to remove uncertainty and predict the process behaviour as correct as possible. Furthermore, to achieve lean approach in mining, the entire mining chain needs to be considered starting from Mine exploration, mine planning, drilling operation, blasting, loading and transportation, ore dressing processes, reclamation, etc. To be lean in mining is not only dependent on mine production systems consisting of equipments and machines but it also depends on quality and reliability of information flow in real time generating action plans. Also, the reliability and maintenance preparedness have major influence on the degree of waste being generated in the process. For example if ore body is not correctly delineated/characterised or drilling operations not performed correctly, wrong charging process and wrong loading process- all may lead to wastage of resources. In fact Lean production has its origin (leans on) in JIT, TQM and TPM. The common denominator of all these philosophies is the human in the process. To improve any process one needs to measure the current status so that any change in current status can be recorded. The paper presents issues and challenges associated with implementation of Lean Principles in Mining industries.

  • 6.
    Wijaya, Andi
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lundberg, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    The effect of the operator, the mine room and their interaction on the measured vibration level of a scaling machine2012In: International Journal of Systems Assurance Engineering and Management, ISSN 0975-6809, E-ISSN 0976-4348, Vol. 3, no 2, p. 145-152Article in journal (Refereed)
    Abstract [en]

    The objective of the present study is to find out the effect of the operator, the mine room and their interaction on the vibration measured on a scaling machine. Vibration measurements were conducted for three different mine rooms and three different drivers. The vector sum value of the root-mean-square acceleration, the vector sum value of the acceleration dose and the kurtosis sum were utilized to quantify the measured vibration. The unbalanced two-way ANOVA and the Kramer-Tukey test were utilized for the statistical analysis. The results show that the operating styles of the drivers in performing scaling activity and their interaction with the mine rooms have no significant effect on the vector sum value of the acceleration, the vector sum value of the acceleration dose and the kurtosis sum value. The mine rooms have a significant effect on the kurtosis sum value and the vector sum value of the acceleration dose, but not on the vector sum value of the acceleration

  • 7.
    Wijaya, Andi
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lundberg, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Downtime analysis of a scaling machine2012In: International Journal of Mining, Reclamation and Environment, ISSN 1748-0930, E-ISSN 1748-0949, Vol. 26, no 3, p. 244-260Article in journal (Refereed)
    Abstract [en]

    Scaling machines are identified as one of the major contributors to unplanned downtime. In general, to gain a better understanding of downtime, an analysis of the downtime should be performed. Downtime analysis usually involves a group consisting of many people with various backgrounds. The use of a visualisation method can act as a bridge that eliminates the knowledge gap within the group. The present study has two purposes: firstly to develop a method for visualisation of downtime and secondly to analyse the downtime of a scaling machine utilising the proposed visualisation method. The proposed method provides a visualisation of the downtime estimation and the precision and the uncertainty of the estimation at a given confidence level, as well as the factors influencing the failure. An analysis of the failures of the critical components of the scaling machine has also been conducted and suggestions for improvement have been proposed.

  • 8. Wijaya, Andi
    et al.
    Lundberg, Jan
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Graphical method for visualization of machine's downtime: case study of scaling machine2010In: Proceedings of the 1st international workshop and congress on eMaintenance, Luleå tekniska universitet, 2010, p. 99-106Conference paper (Refereed)
    Abstract [en]

    Visualization is the foundation for human to understand as human think and create in a graphic world. By nature, maintenance activity is a multi discipline approach, where maintenance engineer should be able to convey their idea to people with various backgrounds. In this situation, visualization is a powerful mode; it can act as a bridge to eliminate the knowledge gap within the group. Knight (2001) developed Jack-knife diagram for visualizing total downtime and factors influencing the failure (failure frequency and mean downtime) in a point estimation. As failure data is a probabilistic in nature, it is important to look not only point estimation but also interval estimation, so the precision and uncertainty of estimation can be identified. This paper proposes a way of visualizing total downtime and factors influencing the failure (failure frequency and mean downtime) in interval estimation. Case study from scaling machines is used for illustration.

  • 9.
    Wijaya, Andi
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lundberg, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Robust-optimum multi-attribute age-based replacement policy2012In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 18, no 3, p. 325-343Article in journal (Refereed)
    Abstract [en]

    Purpose - A common model in the age-based replacement policy is based on the cost attribute and assumes that the model parameters are known. In practice, the model parameters are estimated from limited historical data, which brings uncertainty into the model. Moreover, minimizing the cost is not the only goal of the maintenance activity. From the decision maker's point of view, the multi-attributes and the uncertainty of the age-based replacement policy are two important aspects to take into consideration in the decision-making process. The purpose of this paper is to propose an approach for a robust-optimum multi-attribute age-based replacement policy. Design/methodology/approach - The proposed approach is based on a combination of the multiattribute age-based replacement policy and robust design problem philosophy. A case study is provided for illustrating the application of the proposed method. Findings - It is found that the proposed approach can determine the interval time for preventive replacement that provides a robust and optimum solution for a multi-attribute age-based replacement policy. Practical implications - The proposed approach can be used by the decision maker in determining a robust-optimum interval time for preventive replacement of multi-attribute age-based replacement, a time interval which is not only optimum, but also robust. Originality/value - This paper presents an approach that simultaneously considers the multi-attributes and the uncertainty in the age-based replacement policy which is, to date, not available

  • 10.
    Wijaya, Andi Rahadiyan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Methods for availability improvements of a scaling machine system2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Scaling is the process of cleaning loose material from the roof, face and wall of the mine room in underground mining. The purpose of scaling is to make the mine room safe for the next operation. Due to the nature of the task, scaling has been identified as an operation with a high number of accident occurrences. The use of a scaling machine to replace hand scaling has successfully reduced the number of scaling-related accidents. However, due to the combination of a hostile environment (such as falling rock, dust, high humidity, etc.), the operation context (e.g. significant vibrations), and reliability and maintainability issues, the scaling machine is identified as one of the major contributors to unplanned downtime.The purpose of this research is to develop methods that can be used for identifying the availability related problems and improving the availability of the scaling machine system in a cost effective way. To achieve the purpose of this research, literature studies, case studies, and simulations study have been conducted. Empirical data have been collected from field measurements, document studies, interviews, and observations. For data analysis, theories and methodologies within reliability, availability and maintainability (RAM), ergonomics and optimization have been combined with the best practices from the related industry. A first result of this study is the development of a method for visualization of the downtime that provides a visualization of the downtime estimation and the precision and the uncertainty of the estimation at a given confidence level, as well as factors influencing the failure. Second result is the identification of components that significantly contribute to the downtime and the reason for that downtime (reliability and/or maintainability problem). Based on the failures analysis, suggestion for the improvement of the critical component is also proposed. Third result is the identification and analyzing of performance shaping factors (PSFs) that can affect to the reliability of scaling machine system. Fourth result is a proposed methodology that can help the design team to select which components of a system are needed to be improved and to which level the improvement should be done to optimize the availability of system in a cost effective way. Finally, the fifth result is a proposed method for a robust-optimum multi-attribute age-based replacement policy. The proposed approach can be used to determine the interval time for preventive replacement that provides a robust and optimum solution for a multi-attribute age-based replacement policy. These results are related to specific industrial challenges, and are expected to enhance the capability for improving the availability of the scaling machine system in a cost effective way. The results have been verified through interaction with experienced practitioners from both the manufacture and the user (i.e. mining company) of the scaling machine.

1 - 10 of 10
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf