South Africa’s Association of Mineworkers and Construction Union (AMCU) has rejected a 9% wage increase offer from the world’s top platinum producers, prolonging a weeklong strike hitting 40% of global platinum supplies. Since late last week, union representatives sought to double monthly wages to $1,100 a month from Anglo American Platinum Ltd. (Amplats), Lonmin plc and Impala Platinum Holdings Ltd. Officials at the three platinum majors said the proposed wage increases are unsustainable amid a recovery from 2012’s strikes, based on conflicts between the AMCU and the National Union of Mineworkers (NUM), which crippled the industry.