Johannesburg - Mining operations at Kumba Iron Ore [JSE:KIO] Sishen Mine in the Northern Cape have been suspended due to a wildcat strike, the company said on Thursday."Approximately 300 striking employees are blocking access to the pit," said company spokesperson Gert Schoeman.Although there were a number of entrances to the open pit, which was about 14km long and 2.5km wide, it was not safe to continue with mine operations, once the 300 workers had gathered there.Schoeman said most of the company's 12 700 workers were not on strike and were being given maintenance tasks and attending training shifts.The strike, which started on Wednesday, has been declared illegal by the court.Schoeman said the demands of the strikers remained unclear."Efforts to try and engage the strikers are continuing and the company is supplying them with food and water."He said Kumba was able to supply its customers for "some time" by using stockpiles of finished product and products from other mines where operations were ongoing.* Follow Fin24 on Twitter, Facebook, Google+ and Pinterest.