JOHANNESBURG (AP) â¿¿ A South African gold mining company says two of its workers have been killed and another injured in violence at one of its mines as unrest continues in the industry. Harmony Gold Mining Co. Ltd. said Friday that the attack happened late Thursday at its Kusasalethu mine near Carletonville, about 80 kilometers (50 miles) southwest of Johannesburg. Harmony said production at the mine had not been affected by the attack. The company said police had begun an investigation. The killings come after weeks of labor unrest at mines across South Africa, one of the nation's biggest economic engines. Violence during strikes at Lonmin PLC's platinum mine near Marikana led to the deaths of 46 people, including 34 miners who were shot dead by police.