Zwartberg (Black mountain) is a parish, founded on 3 December 1926 in a district of Genk in the Belgian province Limburg.

A small group of members of the Rijkswacht (Gendarmerie) was waiting for them when they arrived at the entrance to the Waterschei mine, which was quickly surrounded by the miners.

They also stopped a truck, loaded with wood for the mines, and forced the driver to leave his cargo behind.

Armed with blocks of wood and other debris, the miners threw projectiles at the Rijkswacht, who at first responded by firing into the air as a warning.

[1] News of the tragedy spread rapidly and the government decided to retreat the Rijkswacht officers and replace them with the Para-commandos.