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This book presents a state-of-the-art analysis of energy efficiency as applied to mining processes. From ground fragmentation to mineral processing and extractive metallurgy, experts discuss the current state of knowledge and the nagging questions that call for further research. It offers an excellent resource for all mine managers and engineers who want to improve energy efficiency to boost both production efficiency and sustainability. It will also benefit graduate students and experienced researchers looking for a comprehensive review of the current state of knowledge concerning energy efficiency in the minerals industry.



Chapter 1. Introduction

The goal of this book is to present the current knowledge regarding energy efficiency implications of mining processes and future research directions. This introductory chapter explains the purpose and motivation for this book, provides highlights of the book, provides strategies that a reader can use to read the book, and identifies the key unanswered questions that require further research. It is my hope that this book will be a valuable resource for industry professionals and researchers and stimulate further discussions on energy efficiency in mining.
Kwame Awuah-Offei

Ground Fragmentation


Chapter 2. Energy Distribution in the Blast Fragmentation Process

The study of energy distribution in a blast fragmentation process is the subject of active research. The complexity of the phenomena and the high intensity and speed of some of the physical processes occurring during an explosion such as high pressures and temperatures make measuring of the energy distribution a very difficult task. Because of the limitation of current technologies to measure the actual energy released in an explosion, the assessment of energy distribution is done considering the balance between the ideal energy stored in the explosive and the effects of the released energy in the surrounding media. To study the ideal amount of energy in the explosive, it is necessary to use thermophysics and thermodynamic principles, while the effects in the surrounding media are explained using materials deformation theories, material fracture models, and dynamics. This chapter will review the basic principles behind the assessment of the ideal energy in the explosives and discuss the most accepted theories about the distribution of the energy in the surrounding media when an explosion takes place.
Braden Lusk, Jhon J. Silva

Chapter 3. Effect of Hole Stemming Practices on Energy Efficiency of Comminution

In order to increase the efficiency of explosive comminution, the borehole pressure must be maximized and pressure losses minimized. The majority of these pressure losses occur from premature borehole venting and through weak layers intersecting the borehole. With the use of proper stemming material and amount of stemming these pressure losses can be minimized, increasing the efficiency of explosive comminution. This chapter discusses the key considerations in the choice of stemming materials and methods calculate proper stemming size for different borehole sizes. In addition, the pressure models and methods to calculate stemming depth are discussed for both ideal and nonideal stemming material. Following the stemming design section, the chapter presents methods to improve stemming efficiency and reduce total stemming height including airdecks and stemming plugs. The chapter then addresses the issue of minimal fragmentation in the stemming zone. Practical design guidelines are presented for the use of a stem charge, allowing for breakage in the stemming zone.
Calvin J. Konya, Anthony Konya

Chapter 4. Effect of Wave Collision on Fragmentation, Throw, and Energy Efficiency of Mining and Comminution

The chapter presents a review of the current literature on shock and detonation wave collisions in bench blasting and discusses how the resulting fragmentation and throw can influence the energy efficiency of mining and comminution. Wave collisions are now possible in a typical bench blast using programmable delays and the accuracy of electronic detonators. The objectives of this chapter are to: (i) explain how shock and detonation waves are created during a bench blast; (ii) provide a review of current literature on shock and detonation wave collisions with relevance to fragmentation and throw; and (iii) present the results of a recent study at a full-scale mine, which investigated the effect of shock and detonation wave collisions on fragmentation and throw at a granite quarry. This review chapter demonstrates how shockwave collisions can have a negative effect on fragmentation while detonation wave collisions can have a positive effect on fragmentation and throw and, therefore, overall mine efficiency.
Catherine Johnson

Chapter 5. Energy Efficiency of Drilling Operations

This chapter presents a review of the literature on energy efficiency of drilling operations in mineral industries. It introduces the drilling systems, factors affecting drilling work, and general relations between type of drilling systems and rock properties. First, the basic features of rock drilling and the role of drilling work in energy efficiency of mineral industry are generally described. Then the importance of energy concept which is usually expressed in terms of specific energy and related approaches as well as the related studies is reviewed. The author makes recommendations for future research directions to enhance the energy efficiency of drilling operations in mineral industries. The papers included in the review were mainly selected through searches in major abstract databases of web of science.
Celal Karpuz

Chapter 6. Energy Efficiency in Rock Blasting

Ten production blasts and one single-hole confined blast were monitored in two quarries in order to assess the measurable forms in which the energy delivered by the explosive is transformed in rock blasting. The seismic wave energy, the kinetic energy, and the fracture energy transferred in the blasting process were determined using the seismic field from seismograph records, the initial velocity of the blasted rock face obtained from high-speed video footages, and the fragment size distributions from image analysis of the muck pile material, respectively. The maximum total energy measured accounts for not more than 26% of the available explosive energy, if this is rated as the heat of explosion, though lower figures are usually obtained. The values measured for each of the energy components range from 2 to 6% of the total energy available for the fragmentation energy, 1–3% for the seismic energy, and 3–21% for the kinetic energy. For the confined shot hole, the seismic energy was 9% of the heat of explosion.
José A. Sanchidrián, Pablo Segarra, Lina M. López

Material Handling


Chapter 7. Energy-Efficient Loading and Hauling Operations

Approximately, 40% of the total energy used in surface mines is related to diesel consumption. Truck haulage is responsible for a majority of this. This chapter introduces the principal equipment used to load and haul materials in mines, namely trucks, electric rope shovels, hydraulic excavators and crushing and conveying systems. The chapter discusses factors that contribute to the energy-efficient operation of such equipment. Based on gross weight hauled per unit weight of payload, belt conveyors appear to be the most energy-efficient means of transporting material in surface mines. However, a number of factors, including large upfront capital expenditure and limited ability to relocate and scale up belt capacities, currently restrict their widespread applicability.
Ali Soofastaei, Elnaz Karimpour, Peter Knights, Mehmet Kizil

Chapter 8. Energy Efficiency in Cable Shovel Operations

This chapter seeks to establish the current knowledge on energy efficiency of cable shovel operations. Additionally, the chapter uses a review of the literature to make recommendations for industrial best practices and for future research to address identified gaps in the literature. The chapter first presents the fundamentals of cable shovel operations and the factors that affect the energy efficiency of shovel operations. Subsequently, the chapter presents an overview of the latest research on cable shovel energy efficiency, which is used as the basis for the recommendations. The chapter recommends that industry practitioners should use the right drive systems for their cable shovels, use data analytics to understand shovel energy efficiency, and carefully evaluate the costs and benefits of energy efficiency initiatives. The chapter also recommends that future research on shovel energy efficiency should: (i) establish theoretical benchmarks for cable shovel operations; (ii) account for human factors in the design of operator guidance systems to assist operators during shovel operations; and (iii) evaluate how effective operator training programs are in improving shovel energy efficiency.
Kwame Awuah-Offei

Chapter 9. Benchmarking Energy Consumption of Truck Haulage

Haul trucks are used for material handling in most surface mines and consume about 32% of the total energy usage in mines that use them. This chapter deals with benchmarking approaches applicable to haul truck operation in mines. The specific fuel consumption (SFC) is used as the energy performance index for benchmarking energy consumption of haul trucks. Benchmarking using a statistical approach estimates the minimum SFC based on the comparison of past aggregate time series data and disaggregate data on fuel consumption and the production rate of haul trucks. A model-based approach calculates the minimum SFC using a mathematical model derived from vehicle dynamics, mass balance, and engine and mine characteristics. This chapter presents an analysis of two case studies of haul trucks operations at different surface mines (coal and limestone) to illustrate the benchmarking methods. The studies revealed that benchmarking of energy consumption in haul trucks using the model-based approach is appropriate for setting the fuel consumption target in an opencast mine and assess the fuel saving potential. The model-based approach results in minimum SFC of 89 g/t and fuel saving potential of 17% for multiple haul trucks operating in a limestone mine. The model-based approach shows a direction for setting rational targets for fuel consumption in haul trucks and result in more energy efficient mines.
Lalit Kumar Sahoo, Santanu Bandyopadhyay, Rangan Banerjee

Chapter 10. Role of the Operator in Dragline Energy Efficiency

Dragline operators, as controllers of one the most energy-intensive equipments in surface coal mines, play a significant role in dragline energy efficiency and thus mine profitability. The literature lacks work that explores monitoring system data and applies data-driven methods to gain a better understanding of dragline operation and develop more effective training approaches. This chapter provides a framework for assessing dragline energy efficiency performance using monitoring data and using such work to improve operator training. The first step in improving dragline performance is the assessment using data from dragline monitoring systems to estimate an overall performance indicator. Next, the analyst should apply a comprehensive algorithm to quantify the relationship between different operating parameters and the overall performance indicator. Finally, operators’ performance can be improved by using the results to optimize operator training.
Maryam Abdi-Oskouei, Kwame Awuah-Offei

Mineral Processing and Extractive Metallurgy


Chapter 11. Energy-Efficient Comminution: Best Practices and Future Research Needs

The mining energy value chain starts at the face and extends to smelting and refining. System designs that conserve energy and apply energy-efficient technologies can result in significant reductions in overall energy usage. A main component of the energy value chain involves comminution, which accounts for about 50% of all energy used by mines. This chapter summarizes innovations of the state of the art with respect to energy-efficient comminution technologies and process circuit designs. The chapter will also present practices to measure and benchmark energy efficiency.
Bern Klein, Chengtie Wang, Stefan Nadolski

Chapter 12. Energy Efficiency of Electrowinning

The winning of high purity metal from aqueous solutions through electrodeposition is the final processing recovery step for many nonferrous metals. Direct electrical current/voltage provides the necessary driving force to promote the necessary reactions at an industrially relevant rate. Energy, especially electrical, is often the highest cost for electrowinning operations. Therefore, energy efficiency is a paramount concern for modern facilities. This chapter discusses electrical energy consumption in aqueous electrowinning with a specific focus on cell voltage and current efficiency. It also presents potential improvements.
Michael S. Moats

Chapter 13. Plant Automation for Energy-Efficient Mineral Processing

Mineral processing is one of the most energy-intensive stages of the overall mining beneficiation chain, with an increasing share of the industry footprint. This chapter examines how automation represents a practical means to significantly improve energy efficiency in mineral processing operations. It introduces the fundamentals of automation, hierarchical framework of automation systems, and how the multiple functions can be integrated into an energy management information system. The discussion also explains the rationale of process control and real-time optimization approaches that facilitates lower specific energy requirements from lower variability of key process variables, and determining more appropriate operating points. Case studies are presented to illustrate the current state of the art.
Jocelyn Bouchard, Daniel Sbarbaro, André Desbiens

Chapter 14. Energy Management Systems in Copper Smelting: The Atlantic Copper Case Study

Copper smelters play an important role in the extractive metallurgy of copper, with 80% of mining output processed in primary smelters to produce copper cathodes, while the remaining 20% is refined at hydrometallurgical plants at the mines. Energy represents more than one-third of operating costs for copper smelting and refining, so good energy management is of vital importance to guarantee energy sustainability in an increasingly competitive economic setting, not to mention the ever-increasing demands for environmental protection. In 2009, Atlantic Copper launched a new energy management strategy for its copper smelter and refinery with the implementation of an Energy Management System, and it became the world’s first copper smelter to receive the ISO 50001 (Int Organ Stand 16, 2011 [1]) certificate. This system can accurately monitor consumption, and shapes production planning in accordance with energy criteria in order to achieve continuous improvement in all company processes, based on the following:
  • Integration of energy efficiency in the organization’s scorecard.
  • Assimilation of energy criteria in daily work decisions.
  • Implementation of projects that can reduce specific energy consumption.
  • Investment in projects that recover and utilize residual heat from the metallurgical processes.
This policy carried out between 2009 and 2014 enabled Atlantic Copper to become one of the copper smelters with the lowest specific energy consumption worldwide, achieving reductions of over 20% of the energy consumption, together with cuts in direct greenhouse gas emissions of more than 30%.
José Maria Tejera, Guillerno Rios, Tasio Martínez, Miguel Palacios

Renewable Energy and Miscellaneous Topics


Chapter 15. Solar Energy Applications in Mining: A Case Study

In these times when sustainability is so crucial, clean energy resources have become increasingly important in the mining sector. Typically, about 30% of operational costs can be attributed to energy in mining activities. A mining company able to successfully embrace an integrated program that uses available renewable energy resources is often more successful. Renewable Energy Integration (REI) involves production, as well as managing the environmental and regulatory conditions. Renewable energy technologies are most attractive to mining projects in remote regions with little or no access to established electric grids. Inadequate energy supply has shifted the dynamic of solar energy development, as firms increasingly turn to renewable energies as one component of a basket of energy options used to maintain stable power at mining operations. The broad objective of the chapter is to foster a deeper understanding of solar technology and its integration in mines that enable them to address energy and sustainability issues more proactively and tactically. This chapter outlines recent developments in solar energy in the mining industry. It also discusses case studies where this framework has been applied and highlights the key emerging themes, such as energy management and environmental considerations, with benefits, weaknesses and future challenges.
José Pablo Paredes Sánchez

Chapter 16. Energy-Efficient Mine Ventilation Practices

Energy efficiency in mine ventilation, which is responsible for a substantial amount of total energy consumption, is of paramount concern in underground mining. Achieving energy-efficient mine ventilation practices is not only important for reducing total operating and energy costs but is also potentially the most effective means of reducing greenhouse gas emissions and environmental and occupational health and safety. This chapter presents a comprehensive review of the literature on energy-efficient mine ventilation practices and approaches to provide the current knowledge and research frontiers on energy efficiency in mine ventilation. Successful case studies, which resulted in efficiency increases, are also included to illustrate already existing energy efficiency alternatives and energy-saving opportunities. This review is expected to provide mining professionals a tool for improving current operations and achieving best practices.
Nuray Demirel

Chapter 17. Technology Selection and Sizing of On-Board Energy Recovery Systems to Reduce Fuel Consumption of Diesel-Electric Mine Haul Trucks

Installing an energy recovery system (ERS) on a mining haul truck has the potential to save a significant amount of fuel by recovering energy while descending into the pit and reinjecting this energy to reduce fuel usage for acceleration and ascent out of the pit. This chapter presents an initial investigation into the technical and economic feasibility of such an ERS for diesel-electric drive mine haul trucks. A simulation model incorporating the haul route, the truck and drive system characteristics, and the ERS is employed to evaluate the changes to fuel used and impact on payload for an ERS of a specific technology and size on a given pit depth, from which cost savings and fuel savings per tonne of material moved are inferred. Lithium-ion batteries and electrolytic double-layer capacitors were found to be generally infeasible due to, respectively, poor charging rate and cycle life, and low energy density. Both lithium-ion capacitors and electromechanical flywheels promise fuel efficiency improvements of greater than 10% for a large range of pit depths. Electromechanical flywheels are judged the most cost-effective option, with an expected payback period of less than 1.2 years.
Petrus J. Terblanche, Michael P. Kearney, Clay S. Hearn, Peter F. Knights
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