Abstract: The WK-10C electric shovel buckets used in the stope of Zhulan Iron Mine fall down by themselves frequently，which causes several accidents that the buckets damage the high voltage power sup⁃ ply cables and the mine car baffles. In order to fundamentally avoid this problem，the shovel and its opera⁃ tion process in-depth investigation. It is determined that the root cause of bucket braking failure is that the exhaust of the compressor system of lifting mechanism is blocked. In view of this fault，the improvement scheme of adding gas pressure regulating valve is formulated. After the implementation of the scheme，the braking system responds quickly，and the bucket braking process can be completed in time and effective⁃ ly，and the failure rate of the shovel is significantly reduced.

Key words: WK-10C electric shovel, bucket out of control, compressor system