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In accordance with the latest trends, considerable emphasis is put on all mining companies in the Czech Republic not only on reducing the environmental impact of brown coal mining, but also on overall efficiency, the balance of which can be improved by increasing of the operational reliability of individual components of technological units and reducing operating costs. And it is the latter sphere, in that Vrsanska uhelna a.s. does considerable initiative. In cooperation with the firm RENOMAG s.r.o. and the Research Institute for Brown Coal a.s. carries out the development and laboratory and in situ operational tests of new types of buckets with corner edges and other material tests of disconnecting organs used in the extraction of brown coal by the surface method. The article briefly acquaints the reader with the progress of work on the development of new types of buckets with corner blades of a bucked-wheel excavator series KU 800 used for mining of the overburden at the site of the Czechoslovak Army mine (CSA) and its content follows a series of articles describing activities in the field for the monitored period within the solved project. Attention is paid mainly to the results of operational testing of new prototypes of blades on a real machine in the conditions of overburden mining at the Vrsany mine, based on other designs and modifications of replaceable corner blade were created, which were tested in real operation of CSA quarry. The new replaceable corner blade with an innovated shape and unique material composition was then used on the KU 800 excavator in order to verify the functionality of the edge geometry in specific operating conditions and to find out the appropriate edge geometry and abrasion protection for the given mining conditions. At the end of the article, the results and evaluation of the implemented long-term operational tests are described together with the final summary of specific benefits of deployed prototypes of buckets with corner edges. [ABSTRACT FROM AUTHOR]

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. The main target of this article is the brief description of realised research. It is design of the optimum methodology of bucket tooth cutting body heat and chemical treatment. These excavators are in operations during brown coal mining in all the Czech Republic and tooth wear hardness is necessary. This research is the part of solving of the project No. TH03020368 from the programme EPSILON titled „The optimisation of the shape and material of ground and mining machines research“. The main expected benefit is the optimization of the shapes and materials of excavators and ground machines in concrete mining conditions. It was applied modern data in the field of material engineering, cryogenic nanotechnologies and metallurgy for the increasing of the lifetime period and efficiency of key nodes of the mining and ground machines. We realised laboratory material tests of mostly used tooth named VP-7 during 2018 – 2019. This article gives the first information about heat and chemical treatment methodology, about testing of excavators key nodes life time increasing and about first analyses results. [ABSTRACT FROM AUTHOR]

The main aim of this paper is the description of experimental operation of new bucket in real conditions of the open pit mine and the evaluation of surface temperature increasing in the case of new bucket application. The experiment was realised in two excavators KU 300 operated in the same mining conditions. The target of this experiment is the bucket surface temperature increasing evaluation and the verification of new bucket tooth geometry with tooth ESCO U35T possibilities in comparison with original variety. The next target is selection of optimum tooth geometry for operation in ČSA mine conditions. The lignite mining in the main coalface is very difficult in the ČSA mine conditions, primarily in the law part of the cut near the contact with underlying hard clay. Cutting bodies of the excavator operate in hard stress. It is the reason of hard abrasion, breaking of parts of tooth and the bucket bandage destruction. The brown coal mining is realised by bucket wheel excavators KU 300. The wheel of the KU 300 excavator is without cell, 13 buckets are situated in the perimeter, volume of every bucket is 650 l. Original construction of these bucket was proposed by producer of the excavator, UNEX company. The buckets are welded from cast iron bandage and next parts from the construction steel. The tooth are fixed in the fixture, which is a part of cast iron bandage, The shape of the fixture are comply with tooth body, which is wedge shaped. These excavators are in operations during brown coal mining in all the Czech Republic and tooth wear hardness is necessary. This research is the part of solving of the project No. TH03020368 from the programme EPSILON titled „The optimisation of the shape and material of ground and mining machines research“. The main expected benefit is the optimization of the shapes and materials of excavators and ground machines in concrete mining conditions. [ABSTRACT FROM AUTHOR]