MARIKANA, South Africa – Thousands of mine workers gathered around a rocky hill on Tuesday to mark the anniversary of the deadliest protest in South Africa in decades.

Four years ago, police shot dead 34 miners at Marikana who were striking over low pay and poor living conditions.

Miners say those conditions have not improved since the shooting shocked South Africa and again exposed the tensions between mining companies and black workers who are often migrants.

“Comrades, this is hard labour that is poorly rewarded,” Joseph Mathunjwa, president of the Association of Mineworkers and Construction Union, told the crowd Tuesday.

The ceremony of remembrance was peaceful. Miners sang, danced and carried sticks.

Squalid living conditions without sewer systems or other basic services are a problem for mine workers across South Africa, whose economy was built on the mining industry.

Leaders of the country’s most prominent opposition parties used the commemoration to appeal for justice, and for political support.

“It is very painful when we remember that day, especially for us who were there when it happened,” said mine worker Thabang Khoete. “Because some people take it as if it was a game or a fairy tale. Even some use it as a tool to advertise their agendas. For us who were there, it is very painful.”