Big Coal worked in Merthyr Tydfil and Mountain Ash areas

Scope and Content

Two plans to be viewed together to show Big Coal workings. A key on one of the plans indicates that the following are depicted on the plans: Four Feet Seam, Top Six Feet Seam, Six Feet Seam, Across Measures, Faults and Rolls and Edge of Barren Gound in Six Feet Seam also shown.