While it was initially one of many new industrial unions to organise black workers, it was almost unique in surviving the Great Depression.
Thibedi was succeeded as general secretary by Murray Gow Purdy, who led the union into a strike for improved pay and conditions.
The union was unable to fund strike pay, but Purdy affiliated the union to the South African Trades and Labour Council (SAT&LC) on the day the strike started, and was thus able to draw on its funds, against the wishes of the SAT&LC leadership.
[1] Although the strike achieved some success, many union members were victimised, and Purdy stood down, being succeeded by Ralph Lee.
He left South Africa in 1935, and was replaced by Max Gordon, who attempted to use the union as a springboard to organising other groups of workers.