scholarly journals Generating of Electric Energy by a Declined Overburden Conveyor in a Continuous Surface Mine

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4030
Author(s):  
Witold Kawalec ◽  
Robert Król
Keyword(s):  
Electric Energy ◽  
Surface Mining ◽  
Primary Energy ◽  
Gravitational Energy ◽  
Surface Mine ◽  
Electric Power Supply ◽  
Surface Mines ◽  
The Status ◽  
Continuous Surface

Exploitation of lignite in continuous surface mines requires removing masses of overburden, which are hauled to a dumpsite. There are some technological arrangements where the overburden is transported several dozen meters down to a spreader operating on a lower located dumping level. Depending on an angle of a declined transportation route, there is a possibility to convert the potential gravitational energy of conveyed down overburden masses into electric energy. To recover the maximum percentage of stored energy, an energy-effective and fully loaded belt conveyor should work in a generator mode. Due to the implementation of such a solution, a lignite continuous surface mine, which is a great electric energy consumer, can obtain the status of an electricity prosumer and reduce its environmental impact, in particular demonstrating significant savings in primary energy consumption. Though lignite surface mining is phasing out in Europe, the recuperative, overburden conveyors for downhill transport match up the targets of sustainable mining, understood as getting the maximum benefits from the exploited natural resources. According to the analyzed case study, an investment into the installation of regenerative inverters for the electric power supply of the declined overburden conveyor would pay off within 3–4 years.

Method for Location of An External Dump in Surface Mining Using the A-Star Algorithm

2014 ◽  
Vol 59 (3) ◽  
pp. 721-730 ◽  
Author(s):  
Maciej Zajączkowski ◽  
Zbigniew Kasztelewicz ◽  
Mateusz Sikora
Keyword(s):  
Target Function ◽  
Ground Surface ◽  
Optimal Solution ◽  
Surface Mining ◽  
High Concentration ◽  
Surface Mine ◽  
Factors Affecting ◽  
Surface Mines ◽  
The Individual ◽  
Elementary Field

Abstract The construction of a surface mine always involves the necessity of accessing deposits through the removal of the residual overburden above. In the beginning phase of exploitation, the masses of overburden are located outside the perimeters of the excavation site, on the external dump, until the moment of internal dumping. In the case of lignite surface mines, these dumps can cover a ground surface of several dozen to a few thousand hectares. This results from a high concentration of lignite extraction, counted in millions of Mg per year, and the relatively large depth of its residual deposits. Determining the best place for the location of an external dump requires a detailed analysis of existing options, followed by a choice of the most favorable one. This article, using the case study of an open-cast lignite mine, presents the selection method for an external dump location based on graph theory and the A-star algorithm. This algorithm, based on the spatial distribution of individual intersections on the graph, seeks specified graph states, continually expanding them with additional elementary fields until the required surface area for the external dump - defined by the lowest value of the occupied site - is achieved. To do this, it is necessary to accurately identify the factors affecting the choice of dump location. On such a basis, it is then possible to specify the target function, which reflects the individual costs of dump construction on a given site. This is discussed further in chapter 3. The area of potential dump location has been divided into elementary fields, each represented by a corresponding geometrical locus. Ascribed to this locus, in addition to its geodesic coordinates, are the appropriate attributes reflecting the degree of development of its elementary field. These tasks can be carried out automatically thanks to the integration of the method with the system of geospatial data management for the given area. The collection of loci, together with geodesic coordinates, constitutes the points on the graph used during exploration. This is done using the A-star algorithm, which uses a heuristic function, allowing it to identify the optimal solution; therefore, the collection of elementary fields, which occupy the potential construction area of a dump, characterized by the lowest value representing the cost of occupation and dumping of overburden in the area. The precision of the boundary, generated by the algorithm, is dependent on the established size of the elementary field, and should be refined each time by the designer of the surface mine. This article presents the application of the above method of dump location using the example of “Tomisławice,” a lignite surface mine owned by PAK KWB Konin S. A. The method made it possible to identify the most favorable dump location on the northeast side of the initial pit, within 2 kilometers of its surrounding area (discussed further in chapter 3). This method is universal in nature and, after certain modifications, can be implemented for other surface mines as well.

Varied Responses to Human-Induced Seismicity in the City of Azle, Texas

2019 ◽  
Vol 3 (1) ◽  
pp. 1-8
Author(s):  
Sarmistha R. Majumdar
Keyword(s):  
State Government ◽  
Induced Seismicity ◽  
Oil And Gas ◽  
The United States ◽  
The State ◽  
Prior History ◽  
Small Community ◽  
Regulatory Policies ◽  
The Status

Fracking has helped to usher in an era of energy abundance in the United States. This advanced drilling procedure has helped the nation to attain the status of the largest producer of crude oil and natural gas in the world, but some of its negative externalities, such as human-induced seismicity, can no longer be ignored. The occurrence of earthquakes in communities located at proximity to disposal wells with no prior history of seismicity has shocked residents and have caused damages to properties. It has evoked individuals’ resentment against the practice of injection of fracking’s wastewater under pressure into underground disposal wells. Though the oil and gas companies have denied the existence of a link between such a practice and earthquakes and the local and state governments have delayed their responses to the unforeseen seismic events, the issue has gained in prominence among researchers, affected community residents, and the media. This case study has offered a glimpse into the varied responses of stakeholders to human-induced seismicity in a small city in the state of Texas. It is evident from this case study that although individuals’ complaints and protests from a small community may not be successful in bringing about statewide changes in regulatory policies on disposal of fracking’s wastewater, they can add to the public pressure on the state government to do something to address the problem in a state that supports fracking.

Advanced Systems to Prevent Collisions of Mining Equipment and Personnel Accidents in Surface Mining

2020 ◽  
pp. 24-29
Author(s):  
A.F. Klebanov ◽  
M.V. Kadochnikov ◽  
V.V. Ulitin ◽  
D.N. Sizemov
Keyword(s):  
Human Life ◽  
Surface Mining ◽  
Production Cycle ◽  
Mining Equipment ◽  
Mining Operations ◽  
Emergency Situations ◽  
Surface Mines ◽  
Technical Requirements ◽  
Personal Devices ◽  
Blind Spots

The article addresses the issues of ensuring safe operation of mining equipment in surface mining. It describes the main factors and situations that pose a high risk to human life and health. The most dangerous incidents are shown to be related to limited visibility and blind spots for operators of mining equipment, which can result in collisions and personnel run over. The main technologies and specific solutions used to design collision avoidance systems are described and their general comparison is provided. A particular focus is placed on monitoring the health of employees at their workplace by means of portable personal devices that promptly inform the dispatcher of emergency situations. General technical requirements are formulated for designing of the system to prevent equipment collisions and personnel run over in surface mining operations. The paper emphasizes the importance of introducing a multifunctional safety system in surface mines in order to minimise the possibility of incidents and accidents throughout the entire production cycle.

scholarly journals Discursive Strategies and Sequenced Institutional Change: The Case of Marriage Equality in the United States

2021 ◽  
pp. 003232172110205
Author(s):  
Giulia Mariani ◽  
Tània Verge
Keyword(s):  
United States ◽  
Institutional Change ◽  
The United States ◽  
Marriage Equality ◽  
Agent Based ◽  
Discursive Strategies ◽  
Policy Debates ◽  
The Status ◽  
Private Actors

Building on historical and discursive institutionalism, this article examines the agent-based dynamics of gradual institutional change. Specifically, using marriage equality in the United States as a case study, we examine how actors’ ideational work enabled them to make use of the political and discursive opportunities afforded by multiple venues to legitimize the process of institutional change to take off sequentially through layering, displacement, and conversion. We also pay special attention to how the discursive strategies deployed by LGBT advocates, religious-conservative organizations and other private actors created new opportunities to influence policy debates and tip the scales to their preferred policy outcome. The sequential perspective adopted in this study allows problematizing traditional conceptualizations of which actors support or contest the status quo, as enduring oppositional dynamics lead them to perform both roles in subsequent phases of the institutional change process.

scholarly journals A Multiple Criteria Decision Making Method to Weight the Sustainability Criteria of System Selection for Surface Mining

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3066
Author(s):  
Michał Patyk ◽  
Przemysław Bodziony ◽  
Zbigniew Krysa
Keyword(s):  
Decision Making ◽  
Performance Assessment ◽  
Multiple Criteria Decision Making ◽  
Surface Mining ◽  
Open Pit ◽  
Mining Equipment ◽  
Surface Mines ◽  
Mining Conditions ◽  
And Performance ◽  
Selection Of

Selection and assessment of mining equipment used in open pit rock mines relies chiefly on estimates of overall exploitation cost. The rational arrangement of mining equipment and systems comprising loading machines, haul trucks and crushing plants should be preceded by a thorough analysis of technical and economic aspects, such as investment outlays and the costs of further exploitation, which largely determine the costs of mining operations and the deposit value. Additionally, the operational parameters of the mining equipment ought to be considered. In this study, a universal set of evaluation criteria has been developed, and an evaluation method has been applied for the selection of surface mining equipment and the processing system to be operated in specific mining conditions, defined by the user. The objective of this study is to develop and apply the new methodology of multi-criteria selection of open pit rock mining equipment based on multiple criteria decision-making (MCDM) procedures, to enable the optimization of loading, handling and crushing processes. The methodology, underpinned by the principles of MCDM, provides the dedicated ranking procedures, including the ELECTRE III. The applied methodology allows the alternative options (variants) to be ranked accordingly. Ultimately, a more universal methodology is developed, applicable in other surface mines where geological and mining conditions are similar. It may prove particularly useful in selection and performance assessment of mining equipment and process line configurations in mining of low-quality rock deposits. Therefore, we undertook to develop universal criteria and applications for the selection and performance assessment of process machines for surface mines, taking into account environmental aspects as well as deposit quality.

Implementation of medium voltage remote controlled switches to improve quality performance indexes – a case study

2020 ◽  
Vol 21 (4) ◽  
Author(s):  
Julio Cezar Santos ◽  
Wagner Santos ◽  
Guilherme Cestaro ◽  
Marcio Zamboti Fortes ◽  
Henrique Henriques
Keyword(s):  
Energy Distribution ◽  
Electric Energy ◽  
Regulatory Agencies ◽  
Quality Performance ◽  
Medium Voltage ◽  
Fast Detection ◽  
Performance Indexes ◽  
Short Time ◽  
Operation Center

AbstractThe growing demand for quality in the Energy Distribution Service, both by consumers and by regulatory agencies, obliges most distribution utilities to apply technologies that can be easily implemented and produce results in a short term horizon. The telecontrol technology is an essential tool every time it is necessary to fast restore the energy supply. This technology, which is completely supervised and controlled by the system operation center, allows the fast detection of a fault at a distance and switch an equipment without the aid of the operating crew, thus reducing the time that the power supply is unavailable. The present paper describes a Telecontrol Project, incorporated in an electric energy distribution utility in Brazil and compares the results in quality improvement with others usual investment actions, such as operating and maintenance procedures, laterals protection and network reinforcement. This paper shows, analyzing the results, that to improve the reliability indexes in a short time, when the company’s economic recovery is more important, the application of remotely controlled switch is more effective.

scholarly journals Experimental and Numerical Study of a Microcogeneration Stirling Unit under On–Off Cycling Operation

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 801
Author(s):  
Gianluca Valenti ◽  
Aldo Bischi ◽  
Stefano Campanari ◽  
Paolo Silva ◽  
Antonino Ravidà ◽  
...  
Keyword(s):  
Numerical Study ◽  
Thermal Storage ◽  
Primary Energy ◽  
Operational Cost ◽  
Cogeneration Plant ◽  
Economic Optimization ◽  
Viable Option ◽  
Heating Value ◽  
Energy Flows

Stirling units are a viable option for micro-cogeneration applications, but they operate often with multiple daily startups and shutdowns due to the variability of load profiles. This work focused on the experimental and numerical study of a small-size commercial Stirling unit when subjected to cycling operations. First, experimental data about energy flows and emissions were collected during on–off operations. Second, these data were utilized to tune an in-house code for the economic optimization of cogeneration plant scheduling. Lastly, the tuned code was applied to a case study of a residential flat in Northern Italy during a typical winter day to investigate the optimal scheduling of the Stirling unit equipped with a thermal storage tank of diverse sizes. Experimentally, the Stirling unit showed an integrated electric efficiency of 8.9% (8.0%) and thermal efficiency of 91.0% (82.2%), referred to as the fuel lower and, between parenthesis, higher heating value during the on–off cycling test, while emissions showed peaks in NOx and CO up to 100 ppm but shorter than a minute. Numerically, predictions indicated that considering the on–off effects, the optimized operating strategy led to a great reduction of daily startups, with a number lower than 10 per day due to an optimal thermal storage size of 4 kWh. Ultimately, the primary energy saving was 12% and the daily operational cost was 2.9 €/day.

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