Re: "......the mine had closed."
1998 in fact
From the author's description, this sounds like Geevor, which closed in the 80s, opened again and then closed. For a year or two it was mothballed and had a small income from tours but shut for good in 1990.
Mrs R and I went on one of these tours - 400m+ down the main shaft in a cage that did not so much fall as plummet and then a few hundred metres walk down an incline to go down another 200m or so. That did not take us to the last working face, just a side tunnel of old workings. Any equipment there would be a long way from connecting to anything on the surface!
The site is now a museum and while they have underground tours, the areas we went in 1990 have long been flooded.
The mine closure made everyone in the nearby villages redundant and there was much bitterness. Not a great time to be a tourist there and I can totally understand why. There was us on holiday and there was them facing a dismal future. We went in the local pub one evening and it all went quiet, like a scene from a film. The landlord said he would serve us (we had quite a walk to get there) but it was best for us to leave straight after.