(ShareCast News) - BHP Billiton said on Thursday that its Samarco joint venture iron ore operations in Brazil are unlikely to restart this year, adding that it has begun discussions with a view to cutting the workforce by around 40%.The company said Samarco was unlikely to have in place the necessary approvals to restart operations this year following the dam burst in November 2015."Samarco makes an important contribution to the national economy and the livelihoods of thousands of people but Samarco's operations will restart only when it is safe to do so, and when all regulatory approvals are granted and accepted by the relevant authorities and communities."In addition, BHP said Samarco was in talks with employees to adjust the workforce in line with expected production levels, which could see around 40% of the workforce choose to accept voluntary redundancies.BHP also said that it would be appealing the $6.2bn civil claim that was reinstated by the Superior Court of Justice on 30 June.Chief commercial officer Dean Dalla Valle said: "Samarco employees and members of affected communities have been working incredibly hard to deliver the remediation projects in the Framework Agreement and over 90% of the projects have been initiated."We believe the Framework Agreement sets out the best way forward to respond to this tragedy and BHP Billiton Brazil will continue to consult with affected communities and authorities and provide updates on the progress."At 0936 BST, BHP shares were down 1.2% to 20.34p.