Last May, three men strode into a suburban street and sprayed gunfire into a car, killing mining executive Nico Swart on his way to work.
Mr. Swart, 47 years old, had been a general manager at Richards Bay Minerals, or RBM, which is majority owned by global mining giant Rio Tinto PLC. His murder, which is still under investigation, marked another grim flashpoint in the decline of South Africa’s signature industry.