Despite never having worked in the mining industry he was elected Secretary of the Nchanga branch of the African Mineworkers' Union (AMWU).
In 1954 Mwendapole led the Nchanga miners out on strike in sympathy with the African General Workers' Union, in defiance of direct instructions from Katilungu not to stop work.
[1] In 1956, following an extended period of strikes, the Northern Rhodesian government declared a State of Emergency on the Copperbelt and immediately arrested a large number of AMWU leaders, including Mwendapole.
The Labour MP John Stonehouse asked why Mwendapole had been refused a passport.
The Conservative MP Alan Lennox-Boyd, Secretary of State for the Colonies, replied that he had not applied for one.