The operation was installation of new drill line with mast in rigged up position. Traveling block was hanged by the crane and old drill line connected to the new drill line by Snake Grip tool. Driller on the brake started spooling up the line to the draw-work drum and at the last round of the spooling the new drill line slipped and disconnected from Snake grip tool and fall from 30m height onto the rig floor. The old drill line fell in between mast and draw works. Nobody inside Drop zone at the time of operation. Approximate weight of each portion of drill line is 90 kg.