Optimising Shovel-Truck Fuel Consumption using Stochastic Simulation

Stochastic simulation was conducted to analyse the fuel consumption of a shovel-truck system. An example shovel-truck system, comprising a single shovel and four trucks was considered. At 95% confidence interval, the monthly simulated fuel consumption by the shovel-truck system was found to be about 198 127 litres against the actual fuel consumption of 203 772 litres, registering a variance of -2.70%. About 22 000 litres of fuel was consumed per month due to truck waiting. Optimising the fuel consumption and truck waiting time can result in significant fuel savings. The paper demonstrates that stochastic simulation is an effective tool for optimising the utilisation of fossil-based fuels in mining and related industries. Keywords: Stochastic, Simulation Modelling, Mining, Optimisation, Shovel-Truck Material Handlin

Применение метода Нелдера–Мида для оптимизации одноименнополюсного синхронного двигателя для карьерного самосвала

The relevance of the study is in the increasing need for the use of mining dump trucks with a diesel-electric (hybrid) drive for the development of minerals. Improving the operational and cost characteristics of the electric drive of mining dump trucks helps to reduce costs in the development of minerals. The main aim of the study is to find an effective approach to optimizing a synchronous homopolar motor for driving the rear wheels of a mining dump truck, which makes it possible to solve the problem of the high demand for computing resources when simulating a three-dimensional magnetic field of the motor; develop the recommendations for the design of a synchronous homopolar motor with an excitation winding on the stator; apply the optimization to reduce power losses and maximum motor current for a given traction characteristic of the drive, and to reduce the current rating and cost of the semiconductor inverter module of the electric drive of a mining dump truck with the type of motor under consideration. Object of the research is a design of a six-pole nine-phase synchronous homopolar motor with an excitation winding on the stator with a power rating of 370 kW. Methods: derivative-free optimization method; equivalent circuit method; mathematical modeling; two-dimensional finite element method. Results. A novel approach to optimization of a synchronous homopolar motor is proposed. This approach is effective from the point of view of the accuracy of calculating the characteristics and computational costs. As a result of optimization, the motor losses and the maximum current required by the motor from the inverter have been significantly reduced. The achieved reduction of the motor current allows reducing the cost of the semiconductor modules of the inverter by 1,4 times (by 2295 United States dollars), and also allows reducing the alternating component in the current of the direct current link of the inverter by the same amount. © 2022 Tomsk Polytechnic University, Publishing House. All rights reserved.The research was performed with the support of the Russian Science Foundation grant (Project No. 21-19-00696)

Design optimization of a traction synchronous homopolar motor

Synchronous homopolar motors (SHMs) have been attracting the attention of researchers for many decades. They are used in a variety of equipment such as aircraft and train generators, weld-ing inverters, and as traction motors. Various mathematical models of SHMs have been proposed to deal with their complicated magnetic circuit. However, mathematical techniques for optimizing SHMs have not yet been proposed. This paper discusses various aspects of the optimal design of traction SHMs, applying the one-criterion unconstrained Nelder–Mead method. The considered motor is intended for use in a mining dump truck with a carrying capacity of 90 tons. The objective function for the SHM optimization was designed to reduce/improve the following main characteristics: total motor power loss, maximum winding current, and torque ripple. One of the difficulties in optimizing SHMs is the three-dimensional structure of their magnetic core, which usually requires the use of a three-dimensional finite element model. However, in this study, an original two-dimensional finite element model of a SHM was used; it allowed the drastic reduction in the computational burden, enabling objective optimization. As a result of optimization, the total losses in the motor decreased by up to 1.16 times and the torque ripple decreased by up to 1.34 times; the maximum armature winding current in the motor mode decreased by 8%. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The research was performed with the support of the Russian Science Foundation grant (Project No. 21-19-00696)

Comparative Study of Induction and Wound Rotor Synchronous Motors for the Traction Drive of a Mining Dump Truck Operating in Wide Constant Power Speed Range

Motors with rare earth permanent magnets are the most compact and energy efficient in most applications. However, their use as traction motors for off-highway vehicles, such as mining dump trucks, is challenging not only because of the high cost of the magnets, but also because of the difficulty of providing a wide range of constant power speed control due to the unregulated permanent magnet flux. For this reason, induction motors remain the most popular type of motor for hybrid and all-electric mining dump trucks. However, the use of an induction motor results in increased power loss, increased current, and high temperature ripple of the power switches of the solid-state inverter when stopping on a slope with an electric brake. In this article, a theoretical comparison between an induction motor (IM) and a magnet-free wound rotor synchronous motor (WRSM) with a rotor DC-excitation in a mining dump truck drive is presented. Both motors have an identical stator outer diameter, and their geometry is optimized using the Nelder-Mead method. 2D finite element analysis in the time domain is used to calculate the IM characteristics. Steady-state characteristics of the motors such as efficiency, losses, torque ripple, required inverter power, dimensions, weight and cost of active materials are compared. In addition, losses and temperature ripples in the power modules of the semiconductor inverter, which affect the reliability of the drive, are compared when using the considered motors. The study demonstrates that the WRSM offers significant benefits such as reduced power loss, inverter power requirement, cost and mass of active materials, making it promising for use in mining trucks. © 2013 IEEE.Ministry of Education and Science of the Russian Federation, Minobrnauka: FSWF-2023-0017This work was supported by the Ministry of Science and Higher Education of the Russian Federation under Project FSWF-2023-0017

An Overview of Microgrids Challenges in the Mining Industry

Indexación: Scopus.The transition from fossil fuels to renewable energies as power sources in the heavy industries is one of the main climate change mitigation strategies. The carbon footprint in mining is related to its inherent extraction process, its high demand of electric power and water, and the use of diesel. However, considering its particular power requirements, the integration of microgrids throughout the whole control hierarchy of mining industry is an emergent topic. This paper provides an overview of the opportunities and challenges derived from the synergy between microgrids and the mining industry. Bidirectional and optimal power flow, as well as the integration of power quality have been identified as microgrid features that could potentially enhance mining processes. Recommendations pertaining to the technological transition and the improvement of energy issues in mining environments are also highlighted in this work.https://ieeexplore.ieee.org/document/9229426

Performance Improvement Study on High Horsepower Compression Ignition Diesel Engines in Mining Haul Trucks at High Altitude

Railways and mining operations are reaching new heights as end users break altitude barriers to increase efficiencies of their business and provide more goods. Diesel engines are the primary source of power used in both of these applications, whether it is for electricity generation or transportation of products. In particular, the copper and gold mining occurring in the Andes Mountains require diesel engines to operate at altitudes above 15,000 ft. At these altitudes the air density is low and the air temperature often falls below 0° F during the winter, providing a less than ideal atmosphere for the operation of a diesel engine. However, end users are demanding improved performance, fuel economy, and reliability as part of their push to optimize production and minimize costs.;As part of this effort to improve operation of diesel engines at high altitudes, engine manufacturers like Cummins are tailoring calibrations to oblige the customer. After making calibration modifications, a field test was conducted on a Komatsu 930E haul truck with a GE electric drive train at approximately 16,000 ft to assess the in-cylinder combustion events and compare them to an engine operating near 500 ft in a test cell.;Idiosyncrasies were identified for the Cummins QSK 60L engine incorporating a HPI fuel system. It was observed that the first cylinder on each bank was found to underperform when compared to the other instrumented cylinders. With respect to the maximum in-cylinder pressure, the greatest amount of cylinder-to-cylinder variation was witnessed during dynamic braking for both test; 4% during the test cell work and 12.97 % during the field test. The least amount of variation was witnessed during rated operation at 0.59 % and 0.22 % for the test cell data and field test data respectively. The calibration changes made by Cummins resulted in virtually no distinguishable differences in combustion while the engine was operating at rated conditions. The largest differences in combustion were observed during dynamic braking and dumping operating modes. The peak in-cylinder pressures were found to be approximately 26 % lower, on average, for both modes of operation at high altitudes. The most significant impact found on the combustion process from altitude effects was increased ignition delays. A linear correlation was found during the dumping operation that showed increased ignition delays which resulted in higher maximum heat release rates. The maximum heat release rate was found to increase approximately 41.47 %, on average, between the test cell data and the field test data. Despite a 26 % decrease in the maximum in-cylinder pressure observed during the field tests, the final heat release exhibited by each engine remained within 10 %. Improved thermal efficiencies were observed at high altitude compared to sea level for the low load operating points at 2 % and 11 %, on average, for the dumping mode and dynamic braking mode respectively which was consistent with the reduce PMEP values at altitude

Rescaling Capital: The Potential of Small-Scale and Mass-Produced Physical Capital in the Energy and Materials Processing Industries

Observing the evolution of size of physical capital in fundamental infrastructure and processing industries such as energy, mining, and chemical processing, etc, over the last century suggests the prevalence of an unambiguous mantra -- "bigger-is-better." This dissertation questions some of the underlying arguments supporting this apparent orthodoxy. Moreover, arguments are put forth highlighting the potential in substantially diverting from this monolithic approach to productive capital and instead focus on a route marked by mass production of small-scale units. Such a shift would most likely herald transformational technology solutions to industries that have long been considered mature. One of the underlying drivers for scaling up in unit size rests on the empirical observation that fixed costs of productive capital generally increase only sub-linearly with size. Arguments suggesting that this trend, typically referred to as the "two-thirds-rule, " inherently favors a large unit scale on the basis of material consumption are rejected on physical grounds in this dissertation. With the number of units produced a different form of cost reduction can be attained -- through learning. Classifying technologies as either small or large based on the number of end consumers, a meta-study concludes that small-scale technologies learn substantially faster. In fact, comparing the two empirical formulations of cost reductions that typically accompany scaling up in size and scaling up in numbers reveals almost identical levels of cost scaling with aggregate capacity. To investigate the possible existence of operational returns to unit scale a case study in four different electricity generating technologies in the U.S. (coal, combined cycle, gas turbine and nuclear) is performed. With only one exception, these technologies exhibit a weak but significant trend of decreasing operational costs with unit (generator) size. However, this trend disappears, or is even reversed, once labor costs are subtracted from total cost. Thus, the relatively recent advent of low-cost automation technologies removes the main impetus to keep increasing unit scale from the perspective of operational cost. This conclusion from a statistical analysis of internally very different technologies suggests wider applicability. At least, it cannot be dismissed outright in other sectors. Abandoning large-scale and custom-made capital in favor of a small-scale and mass-produced variety will likely be accompanied by several heretofore new features. Two foreseen such features are shorter lifetime and lead time of investments. These two features will bring increased flexibilities of engagement and disengagement in a given market. The introduction herein of a real options model aims to quantify this flexibility. Among other applications, the introduced framework can be deployed to estimate the critical investment cost to render a small-scale solution competitive with a large-scale counterpart of known cost. A more detailed analysis of reverse osmosis desalination technology is performed from the perspective of unit scale. Studying transfer phenomena in a thin rectangular channel with semipermeable walls, simulating the conditions in commercial operation, reveals non-intuitive conclusions regarding optimal operating conditions in this technology. Not only would a shorter feed channel (small scale) result in reduced specific energy consumption in the separation stage, it would also suggest operating at lower recovery rates. The findings here suggest that operating at a smaller unit scale entails more than simply scaling down existing process units, rather, all steps need to be reevaluated

Multi-body dynamic and finite element modeling of ultra-large dump truck - haul road interactions for machine health and haul road structural integrity

Haul truck capacities have increased due to their economies of scale in large-scale surface mine production systems. Ultra-large trucks impose high dynamic loads on haul roads. The dynamic loads are exacerbated by road surface roughness and truck over-loading. The dynamic forces also subject trucks to high torsional stresses, which affect truck health. Current haul road response models are 2D and use static truckloads for low capacity trucks. Existing 3D models consider the road as a two-layer system. No models capture the truck dynamic effects on haul roads and predict strut pressures during haulage. Lagrangian mechanics was used to formulate the governing equations of the truck-haul road system. The equations were solved in MSC.ADAMS, based on multi-body dynamics, to generate the truck dynamic forces, which were verified and validated using data obtained from an open-pit mine. These forces were used in an FE model developed, verified and validated in ABAQUS to model the response of the haul road to the truck dynamic forces. The road was modeled using an elastoplastic Mohr-Coulomb model. The results showed that the maximum truck tire dynamic forces were 2.86 and 3.02 times the static force at rated payload and 20% over-loading, respectively. The trucks were exposed to torsional stresses that were up to 2.9 times the recommended threshold. Road deformation decreased with increasing layer modulus and increased with increasing payload. This study proposed novel multivariate models for predicting dynamic truck strut pressures. The novel 3D FE model and empirical relations for calculating truck dynamic forces incorporate truck dynamic forces into haul road design. This study forms a basis for designing structurally competent haul roads and improving truck health --Abstract, page iii