Bert Pritchard
Bert Pritchard was a miner who worked at the Llanfairfach Colliery. He and Dave Griffiths were on duty when Dai Evans went down to try and find out what had killed Ted Hughes. When Evans called on the phone for help, Bert, accompanied by Jo Grant, went down to assist him, but Hinks had sabotaged the lift, trapping the three underground. Evans had fallen victim to the green death and soon died while they awaited rescue.
Bert left a note for the others with Evans' body, and then led Jo through to a disused part of the mine where he thought they could get out. The two became quite close during their journey, as Bert comforted Jo when she was scared. Coming upon some greenish slime trickling down a wall, Bert curiously touched it, and thus contracted the green death. As he began falling ill, he told Jo to go on without him, and, very reluctantly, she left him behind. He remained where he was and was found, still alive, by the Doctor and Dave Griffiths later after they'd repaired the lift and come down.
While the Doctor went to find Jo, he left Bert in the care of Dave, instructing him to get the sick miner topside and to a hospital quickly. The Doctor found Jo, and the two were rescued by Mark Elgin from Global Chemicals. After returning to the Nut Hatch, Jo was saddened to learn that Bert had succumbed to the illness and died while she and the Doctor were trapped underground.