LONDON, April 13 (Reuters) - Global miner Rio Tinto RIO.L RIO.AX said on Friday it was in the process of declaring a force majeure on certain customer contracts after the U.S. imposed sanctions on Russian aluminium producer Rusal 0486.HK .
Rio said it was reviewing Rusal's 20 percent stake in the Queensland Alumina refinery, Rusal's supply and offtake arrangements, bauxite sales to Rusal's refinery in Ireland and offtake contracts for alumina that are used at Rio's smelters.
Force majeure is a clause in a contract that allows both parties not to fulfil the contract terms when they are affected by an extraordinary event or circumstance beyond their control.