**Abstract**

This paper considers the issue of predicting the reliability parameters of the dipper handle. Durability – or, mean life – was taken for the main indicator of reliability. The aim of this research was to substantiate the calculated dependences that help determine the numerical characteristics of the dipper handle life by means of physical reliability theory. The authors developed formulas to calculate the average handle life on the basis of measured or calculated loads and, consequently, the stresses arising in the handle. The latter are represented by a random value, which reflects the operating conditions of mining excavators and determines the random nature of the handle life. Accordingly, it was necessary to estimate possible deviation of the service life value from the average value. To estimate the spread of the service life values, the authors proposed a method for calculating the dispersion and the mean square deviation by linearization of the random arguments function. This resulted in a method for calculating the numerical values of the dipper handle life accounting for the random nature of this parameter, as well as the changing operating conditions. The authors provide an example of calculated service life of the EKG-5A excavator handle. The measured stresses experienced by the dipper handles at the mining site of Magnitogorsk Iron and Steel Works were taken as the initial data for the calculations. The authors used similar data to carry out a numerical computer experiment following the Monte Carlo method. The numerical characteristics of the dipper handle life determined through linearization of the random arguments function and by the Monte Carlo method prove to be consistent with the respective statistics referring to the mine excavators operated by the mining site of Magnitogorsk Iron and Steel Works.

**Keywords**

Reliability, durability, life, excavator, handle, failure, stresses.

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