range of about 10 of each other alternatively the control system could be set to direct the movement of the bucket within a carry envelope 54 e with borders 56 e 58 e where the loads on hoist lines 16 22 are kept within 15 of each other as can be appreciated the control system can be set to dictate that the hoist lines stay within a certain prescribed load percentage of each other or as closely as possible to the desired variance to keep hoist line loads as close as possible such control alleviates as much as possible under the given circumstances unequal loading of the hoist lines and the premature wearing of the front hoist line there are times also when it may be desirable to operate the udd machine to balance the speed of the digging operation against the frequency of replacing the front hoist line for instance the digging cycle may be lengthened by having the control system direct the bucket to move in a range of motion where the loads in the front and rear hoist lines are predominantly within 5 of each other during the carry phase as an alternative the operator may set the control system to direct the movement of the bucket along a path where the loads in the front hoist line are within a predetermined difference of the loads in the rear hoist line by more than 5 in order to shorten.