The gumboot dance (or Isicathulo) is an African dance that is performed by dancers wearing wellington boots. In South Africa these are more commonly called gumboots.

The boots may be embellished with bells, so that they ring as the dancers stamp on the ground. This sound would be a code or a different calling to say something to another person a short distance away. This was used to communicate in the mines as there was strictly no talking otherwise there would be severe, drastic punishments at the discretion of their superior.

Source: The history of the Gumboot Dance from South Africa. » GPAN