Two miners have been shot dead during clashes at a pit in South Africa, the latest in a series of deadly incidents.Security guards have been accused of chasing the miners and shooting them after they had tried to break into the mine's armoury, near Dannhauser in KwaZulu Natal province, police said.Officers say they are now investigating two counts of murder.A series of strikes across the mining industry has crippled output and had a major effect on the economy.Striking workers have been involved in several fatal clashes.In the worst incident, more than 40 people died in August in clashes between police and striking workers at a platinum mine near Rustenburg, 120km (70 miles) north-west of Johannesburg.In the latest incident, about 100 striking miners gathered at the Ladybank pit near Dannhauser.Police said in a statement it had been alleged that some of the workers had tried to break into the armoury.Security guards are then accused of chasing some of the men to a nearby informal settlement and opening fire, injuring two of them."Both men were taken for medical treatment but passed away from their injuries," the police said in a statement."Police are busy on the scene and have seized firearms from all the security guards that were on duty to establish who the shooters were."South Africa is one of the world's biggest producers of precious metals and has a huge coal-mining industry.