RAPAPORT... Workers at De Beers' and Petra Diamonds' operations in South Africa are planning to go on strike after the parties failed to reach an agreement in their respective wage talks.Members of the National Union of Mineworkers (NUM) will begin a "protected strike" - meaning union workers cannot be disciplined by their employer for taking part - once they receive final approval, NUM said Friday. The Commission for Conciliation, Mediation and Arbitration awarded the companies a certificate of non-resolution of the disputes after talks it mediated between the employers and the union broke down. NUM requested an 8% across-the-board pay hike for workers at De Beers' Venetia mine, but said De Beers was offering only a 1.5% salary rise. Meanwhile, the union demanded Petra, which owns the Cullinan, Finsch and Koffiefontein sites in South Africa, increase workers' monthly wages by ZAR 1,000 ($60), noting the company was offering only 4%. NUM did not provide the percentage equivalent for the ZAR 1,000 increase."It is going to be a big, big fight," said William Mabapa, the NUM chief negotiator at De Beers and Petra. "Food prices, fuel prices and general inflation had skyrocketed. There is just no room for peanuts increases, and for that, we are prepared for war."Image: De Beers' Venetia mine. (De Beers)