Riah Phiyega says she endorsed the police's plan to disarm protesters in Marikana a day before the shooting.
The national police commissioner will have to answer more questions at the inquiry.
The inquiry will determine whether the state must reinstitute charges against 279 miners.
Miners say Deputy President Cyril Ramaphosa must take responsibility for the Marikana massacre.
Julius Malema has compared the Marikana community to the struggle fighters in Soweto.
Hundreds are expected to gather at the Koppie today to pay tribute to those who lost their lives.