Episode Three
Series Episode Number: 352World Premiere: Sat 2 Jun 1973 - 5:51pm BST [BBC One] (United Kingdom)
First Broadcast: Sun 25 Sep 1983 - 11:00pm CDT [WTTW 11 Chicago]
Running Time: 25 minutes 12 seconds
7.80 Million (UK)
Chart Position: 29 () (UK)
Recorded on Mon 16 Apr 1973 in TC3
Archive State: PAL 2 VT
The Doctor and Jo discover the mine's terrible secret. Global Chemicals' managing director, Stevens, is determined that they won't live to reveal what they have learnt.
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