Myong Nam Sin; Un Chol Han; Hyon Hyok Ri; Sung Il Jon
Abstract
Anthracite coal seam of Democratic People’s Republic of Korea was broken into particles to be soft due to geological tectonic actions through several stages in the Mesozoic era. Because the folds and faults have excessively developed and the shape of coal seam is very complicated, it is impossible ...
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Anthracite coal seam of Democratic People’s Republic of Korea was broken into particles to be soft due to geological tectonic actions through several stages in the Mesozoic era. Because the folds and faults have excessively developed and the shape of coal seam is very complicated, it is impossible to extract the anthracite coal by longwall mining system, and coal has been mainly mined by entry caving mining system. The aim of this work is to assess effectiveness of new combination of flying squirrel search algorithm (SSA) and artificial neural-network (ANN) for back-analysis of time-depending mechanical parameters of anthracite coal based on timber loads and displacements measured in the coal face entry. The case study deals with a coal face entry in Sinchang Coal Mine located in the Unsan County, South Pyongan Province, DPR Korea. To verify the good performance of new combination of the SSA and ANN, the comparison studies between proposed back-analysis method and other methods with the same purpose, are conducted using data measured in coal face entry. The mean absolute error (MAE) of weighted error norm of ANN-SSA is relatively smaller in comparison with other methods, which is 2.49. The new back-analysis is the good method to determine the suitable time-dependent mechanical parameters of anthracite coal surrounding the entry in very soft coal seam.
Mineral Processing
Chol Ung Ryom; Kwang Hyok Pak; Il Chol Sin; Kwang Chol So; Un Chol Han
Abstract
Scheelite ore with heavy and magnetic minerals can be generally concentrated using shaking table centered gravity-magnetic processing. When magnetic field is formed by fixing magnetic bars on which permanent magnets are arranged at a constant interval, above the table desk, heavy scheelite particles ...
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Scheelite ore with heavy and magnetic minerals can be generally concentrated using shaking table centered gravity-magnetic processing. When magnetic field is formed by fixing magnetic bars on which permanent magnets are arranged at a constant interval, above the table desk, heavy scheelite particles can be concentrated by gravity, whereas heavy magnetic mineral particles can be floated off like light mineral particles by upward magnetic force. In this paper, concentration of scheelite and removal of pyrrhotite floated by magnetic force was simulated using CFD for the sample containing 1% scheelite and 2% pyrrhotite, and compared with the experiment. As a result, WO3 grade and separation efficiency of concentrate were 65.3% and 80.1%, respectively, in the new table equipped with magnetic bars, whereas 28.4% and 76.5%, respectively, in conventional table. The magnetic field formed by fixing magnetic bars above table could be significant in simplifying the sequential tabling-magnetic separation process and reducing the loss of scheelite.
Kwang Hyok Kim; Tok Hyong Han; Un Chol Han; Ryo Myong Hong
Abstract
This paper focuses on a study concerned with estimation of the platform motion at the lower loading station in the Trucklift slope hoisting system with varying profile of track. The TruckLift slope hoisting system is an innovative transport technology for open-pit mines, and considerably accelerates ...
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This paper focuses on a study concerned with estimation of the platform motion at the lower loading station in the Trucklift slope hoisting system with varying profile of track. The TruckLift slope hoisting system is an innovative transport technology for open-pit mines, and considerably accelerates and cheapens transport from mine. When a truck drives onto or drives off the platform at the lower loading station in the Trucklift slope hoisting system with varying profile of track, the platform motion influences the operation of the Trucklift slope hoisting system, and the configuration of inclined rope hitched to the platform is varied. The simulation result by using the ADAMS (Automatic Dynamic Analysis of Mechanical Systems) software shows that the horizontal distance between lower loading station and platform varies when a truck drives onto or off the platform and the initial horizontal distance that is the distance between lower loading station and platform when the winder is applied the brake, can be an important factor in operation of the Trucklift slope hoisting system with varying profile track.
Myong Chun Pak; Un Chol Han; Dong Il Kim
Abstract
Mining Method Selection (MMS) is the first and the most critical problem in mine design, and depends on some parameters such as the geo-technical and geological features and economic factors. The factors affecting MMS are determined by some mining experts, and the most suitable mining method is selected ...
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Mining Method Selection (MMS) is the first and the most critical problem in mine design, and depends on some parameters such as the geo-technical and geological features and economic factors. The factors affecting MMS are determined by some mining experts, and the most suitable mining method is selected using the hesitant fuzzy group decision-making (HFGDM) and technique for order performance by similarity to the ideal solution (TOPSIS) method. These factors include the type of deposit, slope of deposit, thickness of orebody, depth below the surface, grade distribution, hanging wall Rock Mass Rating (RMR), footwall RMR, ore body RMR, recovery, capital cost, mining cost, annual productivity, and environmental impact. Firstly, we propose the group decision-making (GDM) method to determine the weights of multi-attributes based on the score function with the decision-makers’ weights, in which the n-dimensional hesitant fuzzy environment take the form of hesitant fuzzy sets (HFS). Then we calculate the weights of these factors using the HFGDM method. A simple case study is also presented in order to illustrate the competence of this method. Here, we compare the seven mining methods for an Apatite mine, and select the optimal mining method using the TOPSIS method. Finally, the sub-level stope mining method is selected as the most suitable method to this mine.
