Stockpiles of zinc concentrate produced at Australia's Century zinc mine have dropped by two-thirds to 10,000 tonnes in the last three weeks due to ongoing repair work to fix a broken transport pipeline, the mine's owner, China's Minmetals, said on Wednesday.

The 304-kilometre (190-mile) pipeline carrying wet concentrate from the world's second-largest zinc mine to a storage shed in the port of Karumba burst on Oct. 5, preventing the flow of the material.

The stockpile had stood at 30,000-35,000 tonnes on Oct. 22, down from 70,000 tonnes prior to the incident.