Coal Chain Research Articles

Addressing deadlock in large‐scale, complex rail networks via multi‐agent deep reinforcement learning

AbstractRail freight planning problems pose specific challenges that have attracted the attention of academics and industry professionals for many decades. They involve multiple types of assets (trains, stations, terminals, etc.) and are subjected to structural, operational and safety constraints. Even though various approaches have been proposed, few can address the complexity and size of real‐world scenarios, and decentralized techniques, like multi‐agent systems (MAS), have become more prevalent. The current state of the art in disciplines such as agent technology, reinforcement learning and discrete‐event simulation allows the implementation of complex architectures, with multiple actors interacting and learning simultaneously. Therefore, this study takes advantage of these current advances and proposes an innovative approach to real‐time traffic management problems in freight railway networks through multi‐agent deep reinforcement learning (MADRL). This study was motivated by the decision‐making scheduling problems arising in the Hunter Valley Coal Chain (HVCC), located in New South Wales, Australia. The MADRL algorithm uses as the training environment the simulation model currently utilized for capacity planning of the HVCC, allowing experiments with actual data. Thus, we enhanced the simulation model to accommodate a MAS with intelligent agents representing system elements, such as trains, dump stations, and load points. Furthermore, these agents act in a decentralized fashion based on local observations, constituting a partially‐observed Markov decision process (dec‐POMDP). Three variations of the MADRL approach are presented: a baseline model, an extended model, and one that directly addresses deadlocks. Finally, we present a transfer learning method that improves deadlock resolution and leverages performance. In the experiments, we explore specific, complex scenarios arising in the HVCC, where trains frequently face deadlock conditions. The baseline model outperforms a first‐come‐first‐serve (FCFS) based heuristic used by HVCC's simulation model and a genetic algorithm in instances with up to 60 trains – but fails in more complex scenarios. On the other hand, the most advanced model, which addresses deadlocks via transfer learning, always finds feasible solutions and produces policies that outperform the FCFS‐based heuristic in 94% of the instances.

Research on Resilience Evaluation of Coal Industrial Chain and Supply Chain Based on Interval Type-2F-PT-TOPSIS

As unexpected events such as natural disasters, the COVID-19 pandemic, and overseas containment have caused inevitable shocks to the energy industrial chain and supply chain, the current global energy crisis is intensifying, and different countries and regions have adopted different strategies according to the characteristics of their own national resource endowments in order to cope with energy security. Maintaining the security of the coal industrial chain and supply chain is a prerequisite for energy security to be effectively ensured, considering the main position of coal in China’s energy. Therefore, in the face of multiple uncertain risk factors under today’s momentous changes, this paper constructs an industrial coal chain and supply chain resilience evaluation indicator system from the perspective of resilience, based on four representational capabilities of resilience, namely preparedness, absorptive capacity, recovery capacity, and adaptability, in order to profoundly understand and enhance the resilience of the coal industrial chain and supply chain. An integrated method combining Interval Type-2 Fuzzy Prospect Theory and Technique for Order Preference by Similarity to an Ideal Solution (Interval Type-2F-PT-TOPSIS) is proposed for evaluating the resilience level of the coal industrial chain and supply chain. In the case of Shaanxi Province in China, it was found that the worst level of resilience of the coal industrial chain and supply chain in Shaanxi Province was in 2018, and the best was in 2021. Finally, based on the evaluation results, recommendations are provided to the key nodes of the industrial chain and supply chain in Shaanxi Province with a view to improving their resilience levels to cope with uncertain risks.

Multi-Regional Energy Industrial Water Withdrawal Research under Different Energy Development Scenarios: A Case Study of China

Limited water resources are threatening the development of energy industry, especially for a country like China, with huge yet still fast increasing energy demand, geographically inverse distribution of energy resources and water resources. However, previous studies mainly focus on a nation-wide scale and merely in coal industry chain. Understanding the impact of regional differences on energy industrial water withdrawal remains a challenge. In this work, a multi-regional supply and demand analytical method is proposed, and China is divided into 17 regions for multi-regional analysis. Results indicate that water withdrawal pressure of energy industry differs greatly in different regions. An energy development path of carbon emission reduction can have a significant coordinating water-saving effect. long-distance power transmission may aggravate water shortage in water-scarce regions. Three representative coal-rich energy bases are analysed and the gap between demand of energy industrial water withdrawal and water supply is huge in a business-as-usual scenario. This gap can be reduced or eliminated only if both total amount control and intensity control strategies are jointly adopted.

Screening the Main Factors Affecting the Wear of the Scraper Conveyor Chute Using the Plackett–Burman Method

The wear of scraper conveyor chute causes both significant economic and environmental losses by shortening the service life. The life of the chute under coal abrasive wear situations is primarily decided by operating conditions and the materials properties. The comprehensive analysis of the influence factors had not been studied before. In this paper, the Plackett-Burman design (PBD) method was used to screen the main influence factors and a regression equation was developed to predict the wear loss. The steel was tested on a modified pin-on-disk apparatus in which coal abrasive was filled in the disk. The influence factors included water content, gangue content, coal particle size, Hardgrove Grindability-Index (HGI) of the coal, normal load, and scraper chain speed. The results of the investigation suggested that the significance of water content, normal load, and gangue content on wear loss was relatively higher than the HGI of coal, scraper chain speed, and coal particle size. The wear loss increased with the increase of water content, gangue content, normal load, and coal particle size while it decreased as increase in HGI of the coal and scraper chain speed. Based on the significance of the parameters, the regression equations were derived and verified further with a number of test cases. Optical microscope studies revealed the main wear mechanism of the chute was mainly micro-cutting and corrosive wear and accompanied by fatigue fracture.

Stack releases of radionuclides from an integrated steel plant in China

Crude steel production in China made up the majority of the global output, at 49.5% in 2014. High temperature smelting processes result in the release of natural radionuclides, including radon gas and other air pollutants into the atmosphere. This paper conducts an analysis of the raw materials, end products and flue gas sampled from an integrated steel plant from within China's Jiangxi Province, with annual production of 8.50 Mt of crude steel. Normalized stack emissions factors of radionuclides from steel production were first reported in China. The results showed that sintering was the main process that released natural radionuclides, and the main radionuclides released into the atmosphere were 222Rn (86.4 GBq/Mt), 210Pb (13.4 GBq/Mt), and 210Po (1.71 GBq/Mt). The results provided essential basic data for radiological impact assessment of steel production, as well as that of nuclear energy chain, coal chain and other electricity sources.

The Economical Operation of Coal Chain Grate Boiler

This paper analyzes the factors that influence the economic operation of the chain grate boiler, and introduces the relationship between the air distribution method and economic operation.

A modeling method for a disaster chain–Taking the coal mining subsidence chain as an example

ABSTRACTThe research of a disaster chain can help to determine the mechanism of disaster and the mechanism of mutual transformation between disasters; but at present, a unified and comprehensive modeling mechanism for the disaster chain evolution process has not been formed. Based on hierarchical modeling theory, a top-down refinement method for modeling the complex disaster chain evolution process was proposed in this article—the Spatio-temporal evolution process Multi-level description Framework for a Disaster Chain (STMFDC). The semantic description of the disaster chain is realized at the phenomenon level, changing element level, abstract semantics association level, and resource implementation level. In the spatio-temporal semantic constraint, combining the data integration methods, the evolution process model was also built to analyze the catastrophic process of the disaster chain. Finally, the mining subsidence disaster chain caused by human engineering activity was taken as an example to analyze the evolution process of a subsidence disaster chain based on the STMFDC to verify its generality. The study will thus form a new way of researching a disaster chain by building off the STMFDC approach.

Valuation Languages Along the Coal Chain From Colombia to the Netherlands and to Turkey

Environmental goods and bads are accumulated and unequally distributed along the coal supply chain, producing environmental injustices where actors deployed values and representations of coal to either resist or legitimize its extraction and consumption. This paper analyzes those valuation languages along the coal chain and their relationships with the territory where coal is extracted and burned. The paper examines and compares the coal chains between Colombia-Netherlands and Colombia-Turkey, assessing the various dimensions of the ecological distribution conflicts. The coal chain is analyzed through different layers and scales. To identify the valuation languages along both coal chains, semi-structured interviews and secondary data analysis were conducted. Discourse analysis methodologies were used to determine the frequency and relevance of the valuation languages. Results show that multiple valuation languages appear, which are peculiar to each country and to the economic and political contexts in which the different stages of coal chain are embedded. Environmental justice actions taken along the coal chain with the focus on acknowledging these multiple valuation languages are also discussed. In conclusion, the analysis reveals that these actions depend on the willingness of social actors to give up or negotiate their valuation languages or on the power to impose them.

Tracing the inter-regional coal flows and environmental impacts in Jing-Jin-Ji region

Coal, which plays a critical role in sustaining society development in Jing-Jin-Ji region (China), has become a controversial issue and has aroused extensive attention due to its impications with both climate change and human health. Based on the model of inter-regional transportation in Jing-Jin-Ji, we propose a Regional Coal Industry Chain Balance Table to define the full coal chain energy flows analysis framework. Besides, process chain analysis and input-output analysis are used for embodied energy accounting as well as for environmental impact assessment of 24 kinds of pollutants in the region.Results show that the direct use of raw coal represents a large proportion in Jing-Jin-Ji region’s coal industry chain. By comparing the results from embodied energy analysis with the energy analysis findings, we can ascertain that coal chemical industry still keeps quite a small share of the energy consumption of coal industry chain. Coke is the main source of energy uses in final consumption, being also the key contributor in terms of embodied energy. In terms of final consumption, the industry keeps the vast majority of the use share (about 90%) in both direct and indirect flows. Consequently, a more effective control of industrial use of coal resources would play a fundamental role for improving energy efficiency and for decreasing pollution. The energy utilization efficiency of coal cleaning, coal products processing and coking of coal conversion in Jing-Jin-Ji region during year 2012 were 87.77%, 92.46 and 90.97%, respectively, i.e. a little less than the energy utilization efficiency of coal refining in China for the same year (96.16%). The direct use of raw coal, coke and the coking process were the key contributors to the 7 main pollutants of coal industry chain in Jing-Jin-Ji region 2012. Responding appropriately would improve the direct use of raw coal, coke and the coking process, while reducing the emissions of coal industry chain in Jing-Jin-Ji region. This study provides theoretical support and policy suggestions to increase the energy utilization efficiency, to reduce the consumption of embodied energy and to reduce the emissions of coal industry chain in Jing-Jin-Ji region.

Stress Changes and Deformation Monitoring of Longwall Coal Pillars Located in Weak Ground

Coal pillar stability is strongly influenced by the site-specific geological and geotechnical conditions. Many geological structures such as faults, joints, or rock intrusions can be detrimental to mining operations. In order to evaluate the performance of coal pillars under weak roof degraded by igneous rock intrusion, stress and deformation monitoring was conducted in the affected tailgate areas of Nos. 8208 and 8210 longwalls in Tashan coal mine, Shanxi Province, China. The measurements in the 8208 longwall tailgate showed that the mining-induced stresses in 38-m-wide coal chain pillars under the overburden depth of 300–500 m started to increase at about 100 m ahead of the 8208 longwall working face and reached its peak level at approximately 50 m ahead of the longwall face. The peak stress of 9.16 MPa occurred at the depth of 8–9 m into the pillar from the tailgate side wall. In comparison, disturbance of the headgate block pillar area was negligible, indicating the difference of abutment pressure distribution between the tailgate and headgate sites where the adjacent unmined longwall block carried most of the overburden load. However, when the longwall face passed the headgate monitoring site by 360–379 m, the pillar stress increased to a peak value of 21.4 MPa at the pillar depth of 13 m from the gob side mainly due to stress redistribution in the chain pillar. In contrast to the headgate, at the tailgate side, the adjacent goaf was the dominant triggering factor for high stress concentrations in the chain pillar. Convergence measurements in the tailgate during longwall mining further indicated the evolution characteristics of coal pillar deformation, clearly showing that the gateroad deformation is mainly induced by the longwall extraction it serves. When predicting the future pillar loads from the monitored data, two stress peaks appeared across the 38-m-wide tailgate coal pillar, which are separated by the lower stress area within the pillar center. This 10-m-wide elastic pillar core area indicates that the coal pillar may be narrowed to 30 m to improve coal recovery. The measurements further indicate that, if the headgate of the next panel can be developed after the adjacent gob becomes stable, the coal pillar width may be further reduced to 20 m. This study is applicable for the chain pillar design, the gateroad secondary support design ahead of the longwall mining face, and the gateroad preparation of the next longwall panel under similar geological and geotechnical conditions.

A new rail access charging policy: Hunter Valley coal chain case study

We study a rail track access charging policy proposed by the Australian Rail Track Corporation (ARTC), in which a discount on access charges is offered if above-rail operators employ the “efficient train”. The efficient train is a train with a particular length, which results in the efficient use of a train path. The ARTC uses train paths to allocate access to the rail infrastructure. We discuss the motivation for and the goals of the proposed policy. As the new policy does not allow for differences in the equipment and track section, we argue that it may distort decisions about the net to gross tonne ratio, and it may not give the right incentives for future investment. Therefore, we conclude that defining the efficient train only in terms of length may not achieve its stated short term and long term goals and may have unintended consequences.

Cooperation strategies in port-oriented bulk supply chains: aligning concept and practice

It seems intuitively obvious that firms in supply chains may have more to gain than to lose from learning to cooperate; but it is now more than two decades since Poirier [1999. Advanced Supply Chain Management. San Francisco, CA: Barrett-Koehler] and others called for cooperation in order to capture mutual gains in supply networks and even now ‘cooperation is neither common nor easy’. The simple fact is that not only are supply chains exceptionally complex but so too is the ‘process of cooperating’ – often in the context of antitrust legislation and competition policy. This paper argues that there is a critical need to rethink the principles and processes of cooperation within the broader framework of the competitive behaviour of firms and business strategy. Particularly, it suggests that the relatively recent thinking of Greenwald and Kahn [2005. Competition Demystified A Radically Simplified Approach to Business Strategy. New York, NY: Portfolio, The Penguin Group] in their ‘radically simplified approach to business strategy’ offers sound conceptual insights into cooperation and cooperative strategies for firms not only in markets but also in chains. Furthermore, it notes that the analytical framework for cooperation and cooperative strategies which the authors develop is far removed from the notion of cooperation as ‘commitment and trust and shared thinking’ and from ‘buyer/seller reciprocity’ and ‘collaborative attitudes’ which tend to underwrite much contemporary thinking and research. The paper also argues that the Greenwald and Kahn framework – its single intelligence model of cooperation and cooperative strategies – resonates with real-world relevance, at least for particular supply chains. The paper focuses attention on research into globally significant export coal chains from major east coast Australian ports and in brief case studies finds substantial alignment between concept and practice.

Rail schedule optimisation in the hunter valley coal chain

This paper describes a method for scheduling trains on the Hunter Valley Coal Chain rail network. Coal for a particular ship is railed from different mines to stockpiles at one of the Port’s terminals. The coal producers decide which mines will supply each order in what proportion, so there is no flexibility in the allocation of mines to cargoes. We are presented with a list of tonnes of coal which need to be transported from specified load points at mines to specified stockpiles at the port. The operators of the rail network provide a number of paths, with specified arrival and departure times, that can be used for coal movement. The requirement to assign coal trains to these existing paths makes this rail scheduling problem different to most of those discussed in the literature. In this paper we describe the problem in detail, demonstrate that it is very large making it difficult to solve with commercial MILP solvers, and show that our Lagrangian heuristic is able to produce high quality solutions in a reasonable amount of time.

Towards Greening the South African Coal Supply Chain

South Africa is predominantly a carbon economy. The coal supply chain impacts on the environment commences with mining, processing, transportation and processing by the end users. The country possess the largest coal reserves in the African continent, it is among the leading producers in the world and one of the top twenty leading nations in carbon emissions globally. Coal is the primary source of energy in South Africa producing 88% of the total electricity generation and one-third of liquid fuels production. Hence, the needs for greening the coal supply chain.The South African government newly adopted national development plan for the next twenty years proposes future reduction for coal dependency by boosting development of renewables sources of energy despite their high implementation cost. There are new legislations in support of clean energy development and sustainability initiative as mandated by the United Nations Convention on Climate Change. Greening the coal supply chain require combined efforts from the government and the industry. The focus areas include use of clean technologies in mining, processing, burning coal at power stations and the industries. Improved transportation system in form of intermodal transport with emphasis on the rail use over the road and maintaining or increasing the use of conveyor belts where appropriate would be the future for the coal value chain. However, increased use of renewable energy, use of natural gas and shale gas for the generation of electricity as they produce less carbon emissions would be the ultimate goal for greening the South African coal supply chain. DOI: 10.5901/mjss.2014.v5n27p1632

A decision support tool for generating shipping data for the Hunter Valley coal chain

Strategic capacity planning is a core activity for the Hunter Valley Coal Chain Coordinator as demand for coal is expected to double in the next decade. Optimization and simulation models are used to suggest and evaluate infrastructure expansions and operating policy changes. These models require input data in the form of shipping stems, which are arrival streams of ships at the port, together with their cargo types and composition. Creating shipping stems that accurately represent future demand scenarios has been a time-consuming and daunting challenge. We describe an optimization-based decision support tool that facilitates and enhances this process, and which has become an integral part of the company׳s work flow. The tool embeds sampling to enable the generation of multiple shipping stems for a single demand scenario, employs targets, and desirable and permissable ranges to specify and control the characteristics of the shipping stems, and uses integer programming in a hierarchical fashion to generate shipping stems that best meet the set goals.

Analysis of Low Carbon Development Path for Coal Industry of Multiagent Network Structure under Carbon Tax Background

Based on coal industry chain features and decision-making behavior features, considering the marketing environment changes caused by the carbon tax, models are separately set up specific to the whole industry chain and different individuals’ optimized decision-making differences, and the individual decision-making target is taken as a connecting link between the preceding and the following for the variable to integrate the model into a double-layer programming model. The results show that the model can reflect the influence of the individual selection of the industry chain on the overall interests and direct the decision-making.

Low-Temperature Oxidation Gas Products and Spontaneous Combustion Tendency of Shengli Lignite

Oxygen adsorption and CO2 produced of samples at different adsorption temperatures was investigated, Combined with thermal analysis method, the combustion properties of coal samples was determined. The results show that the oxygen adsorption capacity and CO2 produced of the samples increase and later decrease with the enhanced of pyrolysis degree. In the process of low-temperature oxidation, coal molecular side chains break, then H2O, CO, CO2 and so on are detected in turn; with the enhanced of pyrolysis degree, it reveals that combustion reaction activity decreased and spontaneous combustion tendency weakened.

Land, life and labour in the sacrifice zone: The socio-economic dynamics of open-cut coal mining in the Upper Hunter Valley, New South Wales

This article provides a case study analysis of the social, economic and ecological impacts of open-cut coal mining in the Upper Hunter region of New South Wales (NSW) from the beginning of the resources boom in the early 1990s to the present. The article draws on secondary and grey literature relevant to open-cut coal mining in the Upper Hunter region to explore how the nature of the extractive process and its integrated logistics of ‘the coal chain’ directly affect mining workers, the community, primary producers and the physical environment, through an analysis of secondary and grey literature. It is argued that the operations of the mines has made the region a climate change ‘hot spot’ and a ‘sacrifice zone’ where the sacrifi ces are made by mining workforce, the people of the area and the land.

Value Innovation: New Entrants and Chain Restructuring in Australia’s Export Coal Chains

Recently, the entry of new players has prompted significant restructuring in the Australian coal market with value migrating away from the existing fragmented, traditional production/export model characterised by competing operators generally using 'common user' infrastructure facilities to new, fully integrated supply chains creating a multi-tiered production-consumer framework. This paper argues that not only are coal markets restructuring but they are doing so within the framework of a significant paradigm shift towards efficiency-seeking and efficiency-driven mechanisms. Value innovation and a deregulated market are enabling operators to enter the industry seeking and implementing end-to-end control of the supply chain - and, in so doing, capturing the significant gains of integration. This paper explores these changes within the framework of integrative efficiency - a product of end-to-end control by a single party, derived from a number of companies, or chain elements, working cooperatively rather than competitively, or a single operator vertically integrating the chain from point of production to point of consumption to capture and deliver significantly higher value. The paper focuses attention on this paradigmatic shift in a brief though detailed case study of a major new industry entrant into export coal chains from the rapidly developing Galilee Basin in northern Queensland. It examines the dynamics and implications of this shift in the context of chain efficiency and value innovation

VALUE INNOVATION: NEW ENTRANTS AND CHAIN RESTRUCTURING IN AUSTRALIA'S EXPORT COAL CHAINS

Recently, the entry of new players has prompted significant restructuring in the Australian coal market with value migrating away from the existing fragmented, traditional production/export model characterised by competing operators generally using ‘common user’ infrastructure facilities to new, fully integrated supply chains creating a multi-tiered production-consumer framework. This paper argues that not only are coal markets restructuring but they are doing so within the framework of a significant paradigm shift towards efficiency-seeking and efficiency-driven mechanisms. Value innovation and a deregulated market are enabling operators to enter the industry seeking and implementing end-to-end control of the supply chain - and, in so doing, capturing the significant gains of integration. This paper explores these changes within the framework of integrative efficiency - a product of end-to-end control by a single party, derived from a number of companies, or chain elements, working cooperatively rather than competitively, or a single operator vertically integrating the chain from point of production to point of consumption to capture and deliver significantly higher value. The paper focuses attention on this paradigmatic shift in a brief though detailed case study of a major new industry entrant into export coal chains from the rapidly developing Galilee Basin in northern Queensland. It examines the dynamics and implications of this shift in the context of chain efficiency and value innovation