Whilst looking at a couple of mines around Birmingham, Alabama, I came across something that I must admit didn’t know existed. The convict-lease system. Essentially in practice this entailed arresting black men on a trivial or trumped up charge, and sentencing them to hard labour. Once they were at the prisons they were then leased out to mining companies (and other industries) who then sent them to work in appalling conditions down the coal mines around Birmingham. This had been going on since 1866. Of the 128 miners killed in the Banner Mine disaster in 1911 125 were convicts of which I believe all but six were black. Economic interests were against any changes to the system. A brief overview here.
http://www.encyclopediaofalabama.org/face/Article.jsp?id=h-1135 An extract from the book "Slavery by Another Name" by Douglas A Blackmon.
http://www.npr.org/templates/story/story.php?storyId=89051115 Photos-anatomy of a Slave Mine.
http://slaverybyanothername.com/imagegallerymodule/view_gallery/id/2/src/@random47e2e6d383464/
The past is a foreign country: they do things differently there.