A broken spillway from a vanadium mine in northwest China has contaminated two nearby rivers with ore tailings, forcing authorities to rush to protect drinking water supplies, Xinhua news agency said on Wednesday.
Sludge spewed into the Shuanghe River and Donghe River in Shaanxi province's Shanyang county when the spillway collapsed early on Tuesday, Xinhua said.
Vanadium is a metallic element used to increase the shock resistance of steel alloys, such as in car parts.
Local officials had mobilized workers to block the leakage, build temporary dams along the rivers and open diverting channels to prevent the spill from tainting drinking water supplies downstream, Xinhua said.
"The black-colored waste water with a layer of white bubbles on the top is being stopped by multiple (makeshift dams) and stored and diverted to low-laying areas," Xinhua said, citing local officials.
The government had warned residents living downstream not to fetch water from the rivers, it said. No poisoning cases had been reported so far.
The spill came exactly a week after a similar leak of ore tailings from a gold mine in northeast China interrupted water supplies to a nearby city for a day.
In April, ore tailings from another vanadium mine in Shanyang county polluted and literally blackened three rivers, state media reported at the time.
China has been tightening controls over many minor metals including vanadium to curb development of energy-intensive or polluting industries and keep resources at home.