 Dumping involves opening the dipper door to dump the load, while maintaining the correct dump height.Returning is when the dipper swings back to the bank, and involves lowering the dipper into the track position to close the dipper door.In the 1950s with the demand for coal at a peak high and more coal companies turning to the cheaper method of strip mining, excavator manufacturers started offering a new super class of power shovels, commonly called giant stripping shovels.