Gleision deaths: Map shows where miners worked
17 April 2014 Last updated at 20:57 BST
A map shown in court during a trial over the deaths of four mine workers in the Swansea Valley illustrates the size and complexity of the Gleision colliery.
It shows where the men would have entered the mine and where they worked.
Mine manager Malcolm Fyfield and the mine's owners MNS deny manslaughter charges. The trial continues.
Cemlyn Davies reports.