By Nelson Banya and Helen Reid (Reuters) – A South African company is dumping the sludgy byproduct of mining into a historical diamond pit after the tailings dam that had stored the waste partially collapsed, killing one and leaving scores injured. The government agency overseeing cultural preservation said on Thursday it approved plans to fill the historic Jagersfontein diamond mining pit with waste from a second compartment of the tailings dam in order to prevent a secondary breach after one compartment of the dam failed. Public documents show Jagersfontein Developments, the company reproces…