Joseph Mathunjwa, the president of the Association of Mineworkers and Construction Union (Amcu), is disappointed that only seven police officers will be charged in connection with the murder of mineworkers during the Marikana strike.

The seven officers are expected to appear in the Rustenburg Magistrate's Court on a number of charges, including murder, attempted murder and defeating the ends of justice. The charges emanate from their alleged involvement in the killing of three workers near the Wonderkop koppie in 2012.

"Justice must be served because the culprits of these heinous acts have never been arrested or charged. I am disappointed that only seven officers will be appearing in court because there are more," Mathunjwa said.

This is the first time police officers will be dragged to court since the massacre and a commission of inquiry which was subsequently set up to probe the tragedy.

The officers will appear in court for the deaths of Thembelakhe Mati, Semi Jokanisi and Phumzile Sokhanyile.

"It's particularly disappointing that these officers' leaders will not be charged or even brought in for questioning because they did not act unilaterally. They received instructions to do what they did; we are hopeful that the truth will come out as the process unfolds."

He attributed the officers' charging to evidence tabled at the Farlam Commission in which the police said they met with striking miners who were on their way back to the koppie from one of the shafts where other miners were reported to be working during the protest.

The officers then met with North West deputy commissioner major-general William Mpembe who told striking mineworkers to give up their weapons but they refused, saying the weapons were for self-defence against members of the National Union of Mineworkers.

The miners requested the police to lead them to the koppie. But as they started moving a teargas canister was fired at them triggering a fight between miners and police which led to the killings of two police officers and three miners.

Mathunjwa announced Amcu's plans to embark on a nationwide protest on March 20 against mining job losses. The main protest is expected to take place in Pretoria where 20000 Amcu members will march to the Union Buildings. Other marches will take place in Durban, Polokwane and Welkom.