Abstract.A steady increase in coal extraction in Russian Federation and worldwide results from objective causes of natural resources availability and development of advanced coal processing technologies. In the context of the long-standing economic crisis, considerable investments in coal industry are not to be expected. Consequently, the reserve for extraction growth lies in increasing productivity of the key equipment applied in Kuzbass coal pits. The production data analysis revealed that the presented excavators working capacity does not depend on the bucket volume and the cycle time. It is hereby specified that working capacity is primarily dependent on the actual operation cycle time. As it is demonstrated, the key reserve for increasing the working capacity consists in elevating efficiency of actual performance time use.

Abstract. Coal extraction in Russian Federation increases by 3…4 %. This tendency will remain in the nearest 10…15 years. Opencast mining makes (70...72)% from the total extraction in the country. Though analysis shows that investments in coal mining within the last 25 years were insignificant. In these conditions the priority area for coal production cost reduction and increasing productivity of opencast coal mines is optimization of the main technological equipment (excavator park) maintenance system. The article shows that current system of scheduled preventive repair is not efficient and requires to be changed to the system of repair works due to actual state of the equipment.

-The purpose of the work is to increase efficiency in the use of dump trucks in open pit mining by improving operational reliability, reducing bounce rates, reducing the length of the vehicle repairing and, as a result, the cost of the final product.The article describes how to improve the reliability as well as the efficiency of the use of trucks operating in open-pit mining. The work's result is the methodology that allows defining of the loading reliability of all vehicles. The study is based on the data obtained experimentally in real conditions of operating trucks. During the processing of the experimental data, regression dependences were obtained of the oil temperature in the gears of the motorized wheels of quarry trucks on the factors that characterize the operating conditions. Also, the degree of influence of each of the said factors on the oil temperature was assessed. Subsequently, using the obtained dependences, the practical problem of determining the length of vehicle repair was solved.This work has a great scientific and practical importance because the results can determine the rational values of loading of dump trucks used in open pit mining, measuring the operating conditions.

The paper presents a pretreatment of the substrate material prior to the thermal spraying process. The ultrasonic finishing method allowed creation of a rolling topography comprising alternating projections and cavities, compressive stress, and increase of the number of defects on the surface. Optical profilometry and metallographic analysis allowed detecting of adhesion zones which form a strong physicochemical bond at the interface between the coating and the substrate material. This interfacial adhesion should provide a firm adhesion strength in end products.

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