OSLO, March 27 (Reuters) – Norwegian aluminium producer Norsk Hydro said it would release on April 9 conclusions from its internal review and a review it ordered from green consultancy SGW Services on spills that took place at its Alunorte alumina refinery in Brazil. Last month Brazil ordered Hydro to halve its output from the plant after the spills during heavy rain, prompting the company to declare force majeure. Alunorte is the world’s largest alumina refinery. It transforms bauxite to alumina, which is turned into aluminium at huge smelters. The plant produced a record 6.4 million metric tonnes of alumina in 2017, Hydro said on Feb. 16. Hydro also said it had received on Monday a counterproposal from the public prosecutor’s office as part of its talks with Brazilian authorities to resume full operations. “This proposal will be evaluated by the company,” Hydro said in a statement posted on its website late on Monday, adding that there were no indications there had been “any significant or lasting impact” on the environment following the rainfall.