The accident occurred when the empty muck skip was lowering from surface into the shaft bottom placed on a flat car, after that the workers removed lock plates from both sides of muck skip, when the gantry crane lift up, During lift up from the muck skip, one of lock plates on the east side had moved back into muck skip hook, Thereby causing a jerk and getting the swing of lift beam and then hitting the cables. The crane operator quickly applied the brake and further movement of the crane was stopped. The tunnel supervisor/ engineer was informed about the incident and the necessary steps were taken to repair the cables. Normal activities resumed in about 4:00 AM