By Rhiannon Hoyle 
 

SYDNEY--Waste from a dam that failed at a mining operation jointly owned by BHP Billiton Ltd. (BHP) and Vale SA (VALE) is chemically stable, BHP said Thursday, after a pair of United Nations experts said the mud spilled contained "high levels of toxic heavy metals and other toxic chemicals."

The Nov. 5 failure of the dam operated by Samarco Minerao SA, a joint venture between BHP and Vale, swallowed entire communities and polluted hundreds of miles of waterways in southeast Brazil.

"The tailings that entered the Rio Doce were comprised of clay and silt material from the washing and processing of earth containing iron ore, which is naturally abundant in the region," BHP said in a statement. "Based on available data, the tailings are chemically stable. They will not change chemical composition in water and will behave in the environment like normal soils in the catchment."

On Wednesday, U.N. special rapporteurs John Knox and Baskut Tuncak cited new evidence showing the presence of toxic waste in the mud, contradicting repeated statements by the Brazilian government and the mining companies responsible for the dam that said the contents known as tailings that were released are harmless and consist mostly of mud and sand.

 

Write to Rhiannon Hoyle at rhiannon.hoyle@wsj.com

 

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(END) Dow Jones Newswires

November 25, 2015 21:13 ET (02:13 GMT)

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