A last-ditch bid to end the longest mining strike in South Africa's history faced a new threat Wednesday after unions made fresh wage demands that could scupper a deal struck last week.
The world's top platinum miners -- Anglo American Platinum, Impala Platinum and Lonmin -- rejected the new proposals, which come after both sides agreed in principle to end the five-month stoppage.
The "new and additional demands... if granted would mean huge additional costs of around 1 billion rand in aggregate," the miners said in a joint statement.
"The companies simply cannot afford the additional wage demands."
The strike has hit platinum production in the world's top exporting country, with companies reporting a combined loss of 23 billion rand ($22 million) in earnings.
The new demand emerged after bosses at the Association of Mineworkers and Construction Union (AMCU) this week gave the companies feedback from workers on the proposed pay deal.
The offer includes a wage hike from 5,500 rand per month to 10,500 rand ($980, 720 euros), by 2017. But it falls short of the 12,500 rand the miners were seeking.
The miners said they were "willing to discuss with the union leadership" the possibility of backdating some of the wage increases for workers.
Talks were ongoing and some workers who had left the mining town of Rustenburg were beginning to return, they added.
The strike, which began when more than 70,000 workers downed tools to demand higher wages and benefits in January, pushed mineral-rich South Africa into economic contraction for the first time in five years.
International credit ratings agency Standard & Poors last week lowered the country's sovereign credit rating to "BBB-" -- just a notch from junk bond status.
Fitch also revised the outlook on South Africa from stable to negative, but affirmed its credit rating at "BBB".