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  • Author: Jan Blata x
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Abstract

The article deals with the examination of the state of the ball track of the heavy mining machine ZP6600/Z79. It gives results of material exams which were taken on given samples and describes the progress and results of the numerical computation of the state of tenseness by finite element method of the bottom part of the ball track when it touches the ball.

Abstract

The article follows the research of the project number TA01020351 called “The research of possibilities when predicting steam origin and consequent spontaneous ignition of brown coal fuels” which was researched with the support of the Technological Agency in the Czech Republic in 2011-2014 in the connection with a realized technical research. Therefore, it gives a summary information about the evaluation of the risk degree for the origin of spontaneous ignitions of the brown coal. The presented way of evaluation is based on a numeric expression of a value for MHU criteria - the point load of particular indicators is added together with other results gained from this research project. Then, more information is taken from companies running the dumps of brown coal products - both for suppliers (mining companies) and big consumers (power engineering). The complex knowledge about prediction of the origin of the spontaneous ignition enables to make an early response to eliminate a threat of mining fire in open pit mines or on the dumps of coal products. Consequently, it reduces the risk of fire and breakdowns of transportation means DPD, heavy machines and preparation plants. The working injuries are reduced as well - burns by coal in fire or inhalation of gas products from imperfect combustion.

Abstract

The Brown Coal Research Institute started the solving of the research project based on the optimisation of the shape and material of ground and mining machines in 2018. This research is necessary for increasing of efficiency of mining process in conditions of the Most Basin. The very important part of the research was the geological characteristic of the Most Basin main mining localities. Evaluation of the geological situation of the Bílina, Vršany and Libouš mines (mining of the overburden rocks in the ČSA mine finished) is the first stage of the solving of the project described in this article. The occurrence of sandy strata and the parameters of hard rocks are the most important parameters. The most important used laboratory analyses were the content of crystalline quartz, content of siderite, content of calcite and compressive strength. The location of the overburden cuts with similar mining conditions in different mining localities, very important for need of future research, is described in the end of this article.

Abstract

This paper deals with the environmental aspects of combustor modification on Nuovo Pignone gas turbines. The mentioned company is engaged in the transport of natural gas to the Slovak Republic and further to other European markets. Legislation considering emissions is getting stricter every year. Original Nuovo Pignone gas turbines would not be able to meet the required emission limits for NOx and COr determined by legislation. Therefore, the company decided to modify seven gas turbines. Due to this reason, the combustion sections had to be replaced with a dry low emission system. These modifications were aimed at improvement of impacts of temperature on the emissions of NOx, since the NOx emissions are defined as thermal (there is an increase in emissions with the increase in temperature). Emissions were monitored continuously by an emission monitoring system (these data are continuously sent to the Office of Environment) and manually by a HORIBA PG-250 analyser. Gas delivery point is located in the flue pipeline, and data was processed by means of PC after reaching this point. The results lead us to conclusion that modification was an efficient and good solution in terms of economy, because this solution reduced emissions (from 300 mg·m−3 to 50 mg·m−3) and contributed to meeting of the stricter emission limits (from 370 mg·m−3 to 100 mg·m−3). Monitoring of the impacts of growing performance of equipment on emissions represents a possibility for further development of science in this field.

Abstract

The article is a summary of information about evaluation of a risk degree for a brown coal spontaneous ignition which is realized on the base of a database analysis of information about the development of stative quantities and desorbated gases in the stored bodies of the brown coal. The data were gained from the long term complex measurements which were realized at chosen companies during the coal mining in the previous parts of the project. In the last part of the project, we examined results of temperature models from thermographs with results of gasses and coal samples from the mines. Then, the influence of atmospheric conditions (insolation, water downfall, changes of barometric pressure etc.), the influence of coal mass degradation, the influence of physical and chemical factors, and the influence of other defective factors on the process of the coal spontaneous ignition. The gasmetry was assess with gas in-situ samples and laboratory gas models of indicative gasses for the spontaneous ignition, which were taken from the method of the thermic oxidation with the aim of the correlation finding for an epicentre of temperature within the spontaneous ignition.

Abstract

The expense of restoring of excavators cutting bodies is increasing these days in the Most Basin area, primarily the replacement of tooth because of abrasion expense. The main reason is the complicated geological situation of overburden rocks, first of all the occurrence of sands and hard structures in the overburden cuts rocks in the deep horizons of open pit mines. Description of the first part of the strength analysis and applicability of 3D models of the tooth serial number 2673 and the tooth ESCO Super V39VYH with application of finite element method (FEM) is the main topic of this article. This research is the stage of the project based on optimisation of the shape and primarily the material used during manufacturing of the mining and ground machines cutting bodies in concrete mining conditions. The research is going on with application of new knowledge in the field of material engineering, metallurgy, cryogenic and nanotechnology. The main target is the increasing of mining process efficiency and the mining machines key node lifetime. Research of the excavator tooth parameters described in this article is very important part of the research.