The article reviews and analyzes approaches to evaluation of working efficiency of open pit shovels by the mechanical availability factor. Maintenance and repair of process equipment is given considerable attention in the mining industry since reliability of mining machines directly governs a mine production output. The data for the working efficiency evaluation were collected during the long-term experimental observations over operation, maintenance and repair of shovels of high unit capacity in the conditions of an operating open pit iron ore mine. The current dispatching control in open pit mines allows distinguishing the production time, maintenance time and repair time in the life cycle of open pit shovels, as well as enables classification of time consumptions of each specific machine. Using the received statistics on operation of shovels, the actual and achieved maintenance and repair times as well as the planned performance of the repair unit at the study mining and processing plant are analyzed. It is revealed that the current maintenance and repair management possesses an essential potential for cutting down the repair time. The fleet renewal is insufficient for efficiency enhancement of shovels in open pit mines. Improvement of reliability and durability of mining machines is a burning problem as most of the calendar year time of mining shovels fall at downtime for repair, while the maintenance and repair charges make a substantial share of rock mass excavation cost. © 2020 Publishing house Mining book. All rights reserved.