The Study summarizes the consequences of comprehensive research on the mechanization of longwall faces which has been carried out at Taiheiyo Coal Mining Company's Kushiro Colliery since 1950 to this ...day. Due to the crucial economical circumstances surrounded Japanese coal mining industry being affected by import of abundant and cheap priced crude oil from OPEC, the coal mining companies inevitably challenged to restructure their constitution by way of, for instance, mechanization of longwall faces and / or rejuvenation of underground structure. At Kushiro Colliery, it was tried to introduce the powered supports to their thin seam(#2) and medium height seam(Lower Seam) on the experimental basis at the beginning, and as a final goal, it was also challenged to introduce multipass double wing mining method with 4 longwall faces where UU shaped Frame type with 12 legs powered supports were installed. As a Part-1 of the report, the author describes mainly the results of measurement and analysis for roof lowering phenomena under heavy earth pressure. The results of analysis are reflected for the design of the powered supports, in particular, stroke of the hydraulic legs.
•A novel IWSA based kinematic calibration method is developed.•Performances of proposed modification strategies and constraint-handling mechanism are evaluated.•The experiments show the superiority ...and effectiveness of proposed method.
Legged robots have become a hot topic in robotics owing to their superior mobility. In this study, a two-segment hydraulic robotic leg with the kinematic model is first presented. In this leg, the tracking accuracy of the joint angle depends on the kinematic model precision. However, this model is highly nonlinear and it is very difficult to obtain accurate parameters by means of traditional techniques. To overcome this problem, it is converted into a constrained multimodal function optimization problem; thereafter, a novel kinematic calibration method based on an improved whale swarm algorithm (IWSA) is proposed. Several modification strategies are implemented to improve the searching ability and robustness of the IWSA. Moreover, an effective constraint-handling mechanism is designed for the IWSA. To evaluate the IWSA performance, we compare the IWSA with the WSA and other algorithms on several benchmark functions and calibration experiments. The results indicate the superiority of the IWSA over its competitors. The further case study shows that the tracking accuracy is significantly improved after calibration, which confirms the application effectiveness of the proposed IWSA-based calibration method.
This paper presents the results of a study conducted to determine the dynamic power of a hydraulic leg. The hydraulic leg is the basic element that maintains the position of a powered roof support. ...It is located in the structure between the canopy and the floor base. The analysis assumes that its power must be greater than the energy of the impact of the rock mass. The energy of the rock mass is generated by tremors caused mainly by mining exploitation. The mining and geological structure of the rocks surrounding the longwall complex also have an influence on this energy generation. For this purpose, stationary tests of the powered roof support were carried out. The analysis refers to the space under the piston of the leg, which is filled with fluid at a given pressure. The bench test involved spreading the leg in the test station under a specified pressure. It was assumed that the acquisition of dynamic power would be at the point of pressure and increase in the space under the piston of the leg under forced loading. Based on the experimental studies carried out, an assessment was made with the assumptions of the methodology adopted. The results of the theoretical analysis showed consistency with the experimental results.
A mechanical support in a longwall complex requires proper supervision and control of operating parameters because it is responsible for the safety of machines and workers. Its main functions are to ...protect the excavation against the adverse effects of rock mass and to move it along with the operational progress of the shearer and the scraper conveyor. In the era of Industry 4.0 as well as green economy and sustainable development, the development of machines and devices included in the longwall complex is an important area of invention. When it comes to the mechanical support included in the longwall complex, the authors propose changes to the hydraulic control system. The main purpose of the work was to develop a system that can automatically expand the legs of the powered support. Tests were carried out under real conditions while equipping the support section with a prototypical hydraulic system and with a system monitoring the correct operation of the prototype. This article presents the development of a prototypical installation under real conditions for testing on a longwall. The innovative solution proposed by the authors consisted of introducing a prototypical double valve block into the hydraulic system of the housing, which enables the function of automatic section expansion. The authors proposed a solution aimed at shortening the work time of the powered-support-section operator. The research results made it possible to evaluate the usefulness of the proposed solution. This type of solution can be considered technical support in the process of coal mining in an underground mine. Analysis presented in this paper, along with results from research conducted and its conclusions, can be of practical help to enclosure users to improve reliability and achieve optimal performance.
The raw materials industry is widely considered to be too environmentally costly, and causing more losses than benefits. The responsible solving of the problems caused by this industry is not ...“exporting” its operations to less developed countries, but addressing all recognized hazards with dedicated technological developments. Such an approach is presented by the authors of this book. The contributions deal with the optimization of processes in the raw materials industry, obtaining energy from alternative fuels, researching the environmental aspects of industrial activities. This book determines some guidelines for the sustainable raw materials industry, describing methods of the optimized use of mined deposits and the recovery of materials, reductions in energy consumption and the recuperation of energy, minimizations in the emissions of pollutants, the perfection of quieter and safer processes, and the facilitation of modern materials-, water-, and energy-related techniques and technologies.
Considering the importance of the challenges for sustainable development, this Book is intended to disseminate the results of cutting-edge research and broadcast the opinions of scientists from ...around the world, providing technological breakthroughs in green energy and urbanism, recycling and modernization of basic industries, conducting fundamental research on the economic problems of the transition to sustainable development.
The designs of single- and double-telescopic hydraulic legs are analyzed, and the stand tests are carried out under dynamic loading in conformity with the requirements of European standards. The ...choice of facilities ensuring the reliable operation of powered support under different loading conditions is substantiated.
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