BEIJING - China has gained the right to explore a polymetallic sulphide ore deposit located in the Indian Ocean over the next 15 years.

The contract making the action possible was signed Friday between the China Ocean Mineral Resources Research and Development Association and the International Seabed Authority.

The contract awarded the Chinese association exclusive rights to explore a 10,000-square-km of international seabed in the southwest Indian Ocean.

According to the contract, the Chinese association will have to give up 75 percent of the ore deposit region within 10 years before enjoying preemptive rights of commercially mining the remaining 2,500-square-km.

The Chinese association will also have to fulfill specified duties of conducting environmental monitoring, environmental baseline research and training scientific workers for other developing countries, according to the contract.

Friday's signing is the second time China has gained the right to explore an international seabed ore deposit. In 2001, the country obtained rights to prospect a 75,000-square-km area of international seabed for polymetallic nodule ore in the northeast Pacific Ocean.