It is a decent little story. I find it especially fun that it's sort of a take on Orwell's 1984, with The Controller standing in for Big Brother and the obvious lie the oppressed people are made to believe, to show the regime's totalitarianism and fascism, is "There's no such thing as Macra" in place of "Oceania has always been at war with Eastasia"
It can drag a bit at points, however, and it is very convenient how The Doctor gets allowed full access to the mine operation room, with no supervision, which they try to address, but fail to do so convincingly, merely hinting at a loosening of The Macra's control over certain people, without ever making it explicit enough.

7/10