Watch the full programme - as the man who led the Gleision investigation says nothing more could have been done to establish what happened.
Saturday marks the one year anniversary of the Gleision mining disaster
Tomorrow marks a year since the Gleision mining disaster, and the First Minister has led the tributes to the four men who lost their lives.
Tributes are being paid today to the four men who died in the Gleision mining disaster. It's exactly year since the tragedy in the Swansea Valley which shocked Wales and the world.
Some of the victims' families have been attending private remembrance events while the Welsh public and politicians have been paying their respects.
Nicola Hendy reports.
Our thoughts and prayers are with the loved ones of the 4 brave men who tragically lost their lives at the #Gleision mine a year ago today
Exactly 12months ago I started getting calls about an incident in Swansea Valley - never dreamt it would become the heartbreak of #Gleision
A year today, unbelievable. Rest in peace men of gleision. Mines rescue service 1912-2012. Let's have another 100! http://t.co/UsTlpcIM
Tomorrow marks a year since the Gleision Colliery disaster in which four men died.
First Minister Carwyn Jones says lessons must be learned to make sure an incident like it doesn't happen again.
An appeal fund for the families of the four miners killed in the Gleision colliery disaster closed today. David Powell, Garry Jenkins, Charles Breslin and Philip Hill died after becoming trapped underground in September. Trustees of the Fund have described the amount as 'absolutely phenomenal'.