Complex sentence: Sigmund Kozma, who was 16 at the time he survived the explosion, was recently identified as the last living survivor of the Millfield Mine disaster; he was featured in a documentary of the explosion by Justin Zimmerman, entitled "Meeting Again".
Split into simpler sentences: Sigmund Kozma, who was 16 at the time he survived the explosion, was recently identified as the last living survivor of the Millfield Mine disaster. He was featured in a documentary of the explosion by Justin Zimmerman, entitled "Meeting Again".