Over the next fifty years the Rhondda would grow to become the largest producer of coal of the age .
The richest source for steam coal was the Rhondda Valleys , and by 1856 the Taff Vale Railway had reached the heads of both valleys .
Over the next fifty years the Rhondda Valleys would grow to become the largest producer of coal of the age .
The richest source for steam coal was the Rhondda Valleys , and by 1856 the Taff Vale Railway had reached the heads of both valleys .