[1][2] Mickells was born in Omaha, Nebraska and worked at the Cumberland Mine in Greene County, Pennsylvania before being laid off in 1987.
In that same year, Mickells attended the International Miners Organisation meeting also in the United Kingdom.
[2] In 1987, she was part of the SWP delegation which attended the 75th anniversary of the founding of the African National Congress, which was held in Arusha, Tanzania due to the apartheid policies in South Africa.
[1] In 1988, Mickells ran as the vice presidential candidate alongside James Warren on the SWP ticket.
[3] In 1991, Mickells ran as the SWP candidate for Mayor of Philadelphia, saying she would bring a working-class worldview to city politics.