Assessment of loads acting on the working attachment of a mine shovel (Part 1)

One of the major tasks in carrying out open-pit mining operations is timely and high quality maintenance and repair of mining equipment, in particular, mechanical shovels, which secures a required availability level. The most loaded are the lift and pressure drives of the shovel's working attachments, which significantly increases the risk of failure of their components. An adequate assessment of the loads acting on these drives through analyzing the changes in currents and voltages of their motors makes it possible to adjust the time between maintenance. In the course of the study, the representative points of the following three lumped working processes were obtained within the working cycle of 26.75 s: excavating; platform rotation with simultaneous movement of the shovel from the upper point of the path to the unloading point; reverse movement of the platform rotation mechanism with the returning and its positioning of the working attachment to the initial position. Changes in forces acting on the ropes of the lifting winch of the shovel were determined based on the evaluation of the obtained layout of the working attachment positions for the EKG-18R mechanical shovel and taking into account the driving and motion resistance forces within the working cycle. Analysis of the obtained force values acting on the ropes of the lifting winch at the three linear excavation paths with the inclination angles of 60, 70 and 80° has shown that the lowest forces in the lifting winch rope occur at the closest path with the angle of 60°. The received data will allow not only to select a rational path and the angle of bench mining, but also to adjust the time between maintenance according to the actual operating time of the lifting, pressure and movement drives.