The miners work for up to 25 hours in one go.  They dont eat the whole time they mine and they start mining as young as 13 years old.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/38061770@N00">Jenny Mealing</a>
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/38061770@N00/71625784/">Potosi Mines</a>