FALL FROM DRAGLINE BOOM RESULTED IN BROKEN RIBS AND DISLOCATED SHOULDER. EE WAS PERFORMING ROUTINE MAINTENANCE GREASING THE SHEAVES ON THE GANTRY. THE BOOM WAS LOWERED TILL THE BOOM POINT WAS AT GROUND LEVEL AND THE GANTRY WAS LOWERED TO THE BOOM. HE WALKED DOWN THE BOOM AND GREASED THE LEFT SIDE, HE SLIPPED AND FELL 9' TO GROUND STRIKING THE BOOM STRUCTURE ON THE WAY DOWN.