Continuity mistake: In episode three, Eckersley turns on the security monitor. The very first image is of the entrance to the refinery, but it does not show the Doctor and Gebek trying to break in. Eckersley then flips through the images and finds one of the refinery with the Doctor and Gebek breaking in.
Plot hole: The temperature of the air being blown into the mines is controlled from the communications room when the Doctor needs to knock out the Ice Warriors. But conveniently, the ventilation system is controlled from the refinery when Eckersley needs to suffocate the miners.
Continuity mistake: In episode six, the Doctor is using the Aggedor statue to fight the Ice Warriors. The door to the refinery was partially destroyed by the Ice Warriors earlier. But in every shot of Aggedor appearing or re-appearing, the door can be seen intact at the edge of the shot.