The vessel Jiaolong was expected to dive 20 times to research polymetallic sulfides, biological diversity, hydrothermal microbes and genetic resources in the southwestern Indian Ocean during the 120-day expedition.
China has already secured contracts to explore Indian Ocean for polymetallic sulphide ore and its research vessel has discovered two hydrothermal areas and four hydrothermal anomaly areas in February last year in southwest Indian Ocean.
Earlier China's State Oceanic Administration (SOA) said the discovery of poly metallic deposits in the southwest Indian Ocean as "beyond anticipation."
The SOA said that scientists onboard the "Dayang-1" research vessel also gained insight on the origins of carbonate hydrothermal areas and made successful attempts to explore for sulfide.
Hydrothermal sulfide is a kind of sea-bed deposit containing copper, zinc and precious metals such as gold and silver. Those metals formed sulfides after chemical reactions and came to rest in the seabed in "chimney vents," official media here reported earlier.
Firming up its foothold in India's backyard, China has gained approval in 2012 to explore a 10,000 sq km polymetallic sulphide ore deposit in an international seabed region of the southwest Indian Ocean.
The 15-year approval was secured by China from the International Seabed Authority (ISA).
China also has obtained exclusive rights to prospect in a 75,000-square-km polymetallic nodule ore deposit in the east Pacific Ocean in 2001.
Jiaolong for the first time also took the second batch of pilot trainees in the diving, which was intended to enable the trainees to learn some skills of submersible operation in active hydrothermal vent and collect samples of hydrothermal fluid, sulfide, rocks, sediment and water, said Yu Hongjun, chief commander of the mission.
Scientists are able to see active hydrothermal vent and polymetallic sulfide in seabed and know the exact site and environment of samples when diving with Jiaolong, Tao Chunhui, chief scientist of the mission, was quoted as saying by the state-run Xinhua News Agency.
The information is important for China's future research in the polymetallic sulfide exploration contract area, Tao said.
Named after a mythical dragon, Jiaolong reached its deepest depth of 7,062 meters in the Pacific's Mariana Trench in June 2012 and started its five-year trial period in 2013.